astrosocietyasppublications.org/37RYL62T/2020pdfs/Spr20.pdf · 2020. 6. 25. · Hidden Gems SARAH WELLS Because of its data collection and archival system, the Hubble Space Telescope

Spring 2020 Volume 49 • Number 2

astrosociety.org

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VOL. 49 NO. 2SPRING 2020 2

contents

Space NewsL I Z K R U E S I

A rundown of some of the most exciting developments in space and time.

Cosmic ViewsJ A S O N M A J O R

Take a dip into a vast cosmic lagoon and investigate a supermassive black hole’s enormous jet.

Hubble’s HandlersS T E V E M U R R AY

The 30th anniversary of the Hubble Space Telescope celebrates both the instrument and the creative people who have kept it going.

Searching Hubble’s Archives for Hidden GemsS A R A H W E L L S

Because of its data collection and archival system, the Hubble Space Telescope has changed how — and who — can do science.

departments3 Perspectives, Liz Kruesi Hello, Mercury Readers

4 First Word, Linda Shore Astronomy in the COVID Age

6 Annals of Astronomy, Clifford J. Cunningham Was There a Comet in 17 BCE?

8 Astronomer’s Notebook, Jennifer Birriel More than Pretty Pictures: Adventures with Hubble

11 Armchair Astrophysics, Christopher Wanjek Just Your Friendly Neighborhood Black Hole

13 A Little Learning, C. Renee James & Scott T. Miller Light Curves and Coronavirus Curves

18 Education Matters, Brian Kruse Virtual Teaching: An Adaptation, Not a Replacement

39 Reflections, Liz Kruesi Storms on Jupiter

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on the coverFront: NASA released this Hubble Space Telescope image to celebrate the scope’s 30th birthday. [NASA, ESA, and STScI]

Back: Earth from space shows no borders except those between land and water. [NOAA/NASA EPIC Team]


3VOL. 49 NO. 2SPRING 2020

Hello, Mercury Readersperspectives

I am thrilled to be the new Editor of both Mercury (the magazine you’re reading now) and Mercury Online (the blog companion). I come to the Astronomical Society of the Pacific with many years of writing about astronomy and astrophysics, following a bachelor’s degree in physics and graduate astronomy work.

Under my guidance, I plan to continue the quality of Mercury that my predecessor Ian O’Neill carefully grew — the wonderful con-tent from the columnists and talented feature writers. And I intend to cultivate further the content and iadding more diverse voices. I also hope the accompanying blog, Mercury Online, will continue to grow and be a valuable resource to members and non-members.

This issue, my first one as Editor, centers around the Hubble Space Telescope and its reliability. In times of sorrow and anxiety, I look to the sky and see familiar stars and their host constellations or trace the galaxy’s plane. I recall calm moments spent looking for meteors, or I think of the scale of the cosmos. Something here right now may bring pain, but it’s only a blip in cosmic time. I don’t say this to minimize

what humanity is currently experiencing, but instead to find peace where one can.

There is a lot to wrestle with right now, and of course the COVID-19 pandemic is only part of the story. In the United States, we may be at the brink of change in our country: true last-ing equality. Our country is hundreds of years old; our planet is 4.6 billion years old; and our universe is 13.8 billion years old. And here we are, existing in this time, experiencing these changes. It is what we do with this time that means something.

I truly believe astronomy and its splendor can bring peace, and that the wonder and awe of this science can be relatable and available to anyone: a glance at the Moon above or watch-ing for meteors from a dark site. I hope in our current time, astronomy and this Mercury issue can help bring you peace as well.

Liz KruesiEditor, Mercury

THE MAGAZINE OF THE ASTRONOMICAL SOCIETY OF THE PACIFICastrosociety.org

Spring 2020 • Volume 49, Issue 2

Editor: Liz KruesiArt Director: Leslie Proudfit

Editorial Board: Liz Kruesi, Linda Shore

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permission from the ASP.

ASP OFFICERS

CHIEF EXECUTIVE OFFICERLinda Shore

PRESIDENTKelsey Johnson, University of Virginia/NRAO

VICE PRESIDENTSunil Nagaraj, Ubiquity Ventures

PAST PRESIDENTChris Ford, HOVER Inc.

SECRETARYEdna DeVore, SETI Institute (retired)

CO-TREASURERSSunil Nagaraj, Ubiquity Ventures/Derrick Pitts, The Franklin Institute

BOARD OF DIRECTORS

Gibor Basri, University of California, Berkeley (retired)Jeffrey Bennett, Big Kid Science

Katy CaouetteChristine M. Darden, NASA (retired)Steven Dupree, Brandeis University

Cathy Langridge, RecologyAmy Mainzer, Lunar & Planetary Laboratory – University of Arizona

Renee Rashid, FacebookM. Katy Rodriguez Wimberly, University of California, IrvineAlexander Rudolph, California State Polytechnic University

James Negus, University of Colorado Boulder (Junior Board Fellow)

The Astronomical Society of the Pacific increases the understanding and appreciation of astronomy by engaging scientists, educators, enthusiasts and the public

to advance science and science literacy.

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As I write this, more than 8 million people on Earth have con-tracted COVID-19 and nearly 450,000 have died. The unem-ployment rate in the US has reached nearly 15%, numbers not seen since 1939. I am guessing that no one reading this column has been unaffected in some way by the pandemic.

In its 131 years, the ASP has been a witness to some of the most devastating events in modern history — the 1906 Earthquake and Fire, the Great Depression, and two world wars. I looked through the archives of our own professional journal — the Proceedings of the Astronomical Society of the Pacific (PASP) — to see what my predeces-sors might have written about the last great pandemic in the issues published between 1917 and 1919.

To my great surprise, I couldn’t find anything about the Spanish Flu, but plenty was written about the impact of the “Great War.” Astronomy came to nearly a halt during those years as virtually every (male) scientist was called into service. Observatories around the world were largely abandoned; universities sent most of their students and faculty to war. Each issue of PASP provided lists of the astronomers who had perished on the battle fields of Europe.

Yet while the world roiled in the upheaval of a world war and global plague, those years also marked the start of some of the greatest revolutions in science. In 1918, Harlow Shapley discovered that globular clusters were arranged in a spherical halo that wasn’t

Astronomy in the COVID AgeSometimes a massive shift in our way of life can lead to good things.

by Linda Shore

first word

During the last great pandemic, observations and measurements made during the total solar eclipse proved Albert Einstein’s general theory of relativity. [F. W. Dyson, A. S. Eddington, and C. Davidson]

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centered on Earth, but around a distant point later identified as the center of our Milky Way Galaxy — a revelation that transformed our understanding of the universe and our place within it. In 1919, Arthur Eddington detected the bending of light around the Sun during a total solar eclipse, confirming Albert Einstein’s general theory of relativity and leading to a revolution in our understand-ing of space and time.

What revolutions will be sparked by these difficult days? Is there an Isaac Newton out there, forced as a college student to return home from Cambridge University by the Black Death, that will emerge from the COVID pandemic with the equivalent of calculus, classical physics, and a treatise on the nature of light? Maybe.

But what days of isolation do is force us to take breaks from our normal routine. We see the world from a fresh perspective. We are given the opportunity to examine our beliefs, assumptions, and priorities. It’s little wonder that we are also examining equity, inclu-sion, and our relationship to one another. The mass demonstrations for racial justice across the globe aren’t happening because we have a lot of time on our hands. They have materialized because without the usual distractions, we are seeing the world as it is and reflecting on what a kinder and more compassionate planet might look like.

Stay safe. Keep looking up.

LINDA SHORE is the Chief Executive Officer of the Astronomical Society of the Pacific.

In 1918, Harlow Shapley realized globular clusters congregate around an area of the Milky Way far from Earth. That area is the galaxy’s center. [ESA/Hubble & NASA]

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The historical record in ancient Roman times attests several comets, including Halley’s Comet in 12 BCE. While it is not the earliest recorded sighting of Halley’s Comet, I men-tion this one as it occurred during the reign of the first Roman Emperor, Augustus. That reign lasted from 27 BCE to 14 CE.

Ten years after the Senate formally granted him imperial power and the title Augustus (his real name was Octavian), we come to the year 17 BCE. There are several special things about that year. Periods of a decade were highly regarded by the Romans, and in future centuries the ten-year anniversaries of Roman Emperors were marked by a major celebration, the Decennalia. Augustus decided to revive games known as the Ludi Saeculares to mark the first decade of his reign; the last time such games were held was about 120 years earlier.

Ideally such games were held every century, but the most recent period they would have been held was smack dab in the middle of a civil war that led to the rise of Octavian’s uncle, Julius Caesar. Caesar died in 44 BCE, the same year a notable comet appeared that was widely linked to his death. All this upheaval made celebratory games out of the question, but in 17 BCE the new Roman Empire was largely at peace. So Augustus decided to revive the games, but as the ultimate showman he needed to place his first ten years and the games against an even greater backdrop.

Many Romans, especially the populace, were superstitious. The Roman historian Livy, who lived during the reign of Augustus, lamented that the occurrence of prodigies had declined in recent years. But remarkably, a trio of prodigies happened in 17 BCE. A later chronicler stated that Livy wrote that a tremendous earthquake was felt at the villa of Augustus’ wife and that a tower in the gardens of Augustus in Rome was struck by lightning. The third prodigy? According to a later chronicler, Livy wrote “A comet going from north to south lit up the night as if it were the middle of the day.”

Was There a Comet in 17 BCE?Historians are debating whether a trio of incredible natural events, including a brilliant comet, occurred that year.

Augustus reinstated the Ludi Saeculares in 17 BCE, and coins such as this one marked the occasion. [Classical Numismatic Group, Inc.]

by Clifford J. Cunningham

annals of astronomy

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In research published in 2016 by Susan Satterfield of Rhodes College in Memphis, all three of these prodigies were identified as fictions, promoted by Augustus to show that the gods themselves were giving their stamp of approval on his reign. Since the comet of 44 BCE was not employed as a fine excuse for the games, why not have a comet in 17 BCE when it was needed? While it may seem ludicrous now, Augustus was engaged in a massive overhaul of many ancient Roman ceremonies, which he revived and co-opted for his own political use.

This was not the first comet thought by some modern scholars to be an invention. The “Julius Caesar” comet of 44 BCE was argued to be “a construction of Augustan politics” by University of California, Los Angeles, historian Robert Gurval in his 1997 study, but it is now regarded as a certain comet as ancient Chinese annals also recorded its appearance. It was instead the 17 BCE comet that was just such a construction.

To make the point so that the common people would get the message, coins were issued with the herald of the Ludi Saeculares with a star on the herald’s shield on one side and Julius Caesar on the other. Above the image of Julius was a comet, signifying not only his apotheosis (from man to god) in 44 BCE, but the first decade of a new golden age in 17 BCE.

“Through the Ludi Saeculares,” wrote Satterfield, “Augustus trans-formed prodigies into something positive — a sign not of the gods’

anger but of their approval, focused upon Augustus himself.” It may not be a coincidence that when a comet really did appear over Rome, Augustus officially became Pontifex Maximus, the chief priest and most revered position of the former Roman Republic as it solidi-fied his position as head of both the religious and political aspects of existence: the ruler of everything. That was in 12 BCE, and the comet is now called Halley’s Comet.

CLIFFORD J. CUNNINGHAM is currently doing an archaeopoetic study of the comet of 1618.

Halley’s Comet swings by Earth every 76 years. [NASA/W. Liller]

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As we celebrate the 30th year of the Hubble Space Telescope (HST), it is likely that we will all make good use of NASA’s Hubble Site. It is a great source of stunning images and inspiring videos. However, let us not miss this opportunity to expand our horizons and delve deeper. What else can we do with students to improve their appreciation for the process of science and maybe even the history of science?

Diving into the scientific legacy of HST’s namesake, Edwin Hubble, is a good starting point in any course. Hubble’s first big discovery actually came in 1923: a Cepheid variable in Messier 31, the Andromeda Galaxy. Because a Cepheid pulsates with a period directly related to its intrinsic luminosity, he realized the star was very far away. This Cepheid enabled Hubble to determine the distance to M31 and establish it as a galaxy in its own right, finally resolving the Curtis-Shapely controversy. It’s also important to acknowledge that, like Sir Isaac Newton, Hubble “stood on the shoulders of giants” and his discoveries built upon previous scientific work.

After he used that Cepheid star to discover the Milky Way Galaxy wasn’t the only galaxy, Hubble went looking for more such stars. He found those variable stars in 24 other galaxies. When he graphed the galaxies’ distances compared to their motion, another discovery jumped out at him: Galaxies are moving away from us. We should remind ourselves of those who laid the foundation for Hubble’s

discovery of the expanding universe phenomenon. Such acknowledgements in the classroom are imperative as these more accu-rately represent the scientific process. Science history, with all its prog-ress and pitfalls, is a great way to engage students!

If you haven’t read Hubble’s 1929 paper, you definitely should! Hubble never claimed to have discovered the “expansion of the universe” but rather what he called a “redshift distance relationship”: more distant galaxies have higher observed

More than Pretty Pictures: Adventures with Hubble“Equipped with his five senses, man explores the universe around him and calls the adventure Science.” — Edwin P. Hubble

Edwin Hubble’s discovery of a variable star in M31 led to several of his later discoveries. [Courtesy Carnegie Institution for Science]

by Jennifer Birriel

astronomer’s notebook

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http://astrosociety.orghttps://hubblesite.org/https://obs.carnegiescience.edu/PAST/m31varhttp://www.nasonline.org/about-nas/history/archives/milestones-in-NAS-history/the-great-debate-of-1920.htmlhttp://aspbooks.org/custom/publications/paper/471-0097.htmlhttps://www.pnas.org/content/15/3/168?ijkey=2a945a21c3a9629ee2af3ffecaf2c4e9ba09ac91&keytype2=tf_ipsecshahttps://www.pnas.org/content/15/3/168?ijkey=2a945a21c3a9629ee2af3ffecaf2c4e9ba09ac91&keytype2=tf_ipsecsha


redshifts than those that are closer to us. Interestingly, while this velocity-distance relationship is presented today as v = Hod (where v is recession velocity, d is distance, and Ho is the expansion rate, now known as the Hubble constant), that’s not how he wrote it. However, Hubble did conclude that the relationship is definitely linear. It is also clear that Hubble was quite aware of the cosmological implica-tions of his observations.

Why was Hubble cautious in drawing conclusions? At the time, there were several unresolved scientific issues. For one, if the redshift did, in fact, represent the expansion of the universe then the implied expansion rate yielded an age of the universe of about two billion years — much younger than the estimated age of the stars and the geological age of Earth. Then, there was the very nature of the redshift observed in galaxies: did the redshift actually represent a recession velocity or did it result from some other physical process? In 1929,

seven months after Hubble’s paper, astronomer Fritz Zwicky published a paper examining the possible origins of these observed redshifts.

Zwicky argued that if the observed redshifts were a Doppler phe-nomenon, then galaxies receding from one another naturally imply an expansion of the universe. But he rejected this explanation, stating that the relationship would be linear only if a number of assumptions are made with regards to the distribution of galax-ies. Instead, Zwicky favored a static universe in which photons lose momentum to intervening matter while traversing the vast distances in the cosmos: lost momentum leads to an increase in wavelength. (Incidentally, this “tired light” theory, has recently been revived as a purported resolution to dark-energy.)

Physics majors can read each of these papers and participate in meaningful classroom discussions. They are relatively easy reads and not particularly long (only about 6 pages each). Hubble’s

The Hubble Space Telescope captured a portion of the Andromeda Galaxy, M31, in exquisite detail over 16 days. [NASA, ESA, J. Dalcanton, B.F. Williams, and L.C. Johnson (University of Washington), the PHAT team, and R. Gendler]

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http://astrosociety.orghttps://aapt.scitation.org/doi/10.1119/1.1427310https://www.pnas.org/content/15/10/773https://www.pnas.org/content/15/10/773https://www.intechopen.com/books/redefining-standard-model-cosmology/tired-light-denies-the-big-banghttps://www.intechopen.com/books/redefining-standard-model-cosmology/tired-light-denies-the-big-bang


paper presents observational results with a discussion of experi-mental uncertainties and the impact of changing your sample size. Zwicky’s paper explores theoretical explanations of the redshift phenomenon. It includes discussions of modern physics concepts including Compton scattering and relativity. Paired together, these would be appropriate for any third-year college course in modern physics or astrophysics.

If you have college seniors needing a capstone or thesis project, they can use actual Hubble data! In 2018, NASA placed over 100 TB of HST data on Amazon’s Web Services (AWS). Astronomer Ivelina Momcheva created a brief introduction to this exciting new database. This system requires a working knowledge of the Python program-ming language, and there will be some (small) fees charged by AWS for data usage.

For general education astronomy courses, nothing beats a well-guided lesson about Hubble plots. A more recent classroom activity, to appear in The Physics Teacher, presents data analysis targeted at intro-ductory classes. (However, I envision using this in my experimental physics course for college juniors and seniors as a short data anal-ysis project in which stu-dents collect their own data from the NASA Extragalactic Database [NED].)

Incidentally, don’t consider Hubble off limits to your first- and second-year physics students. Courses covering mechanics are also a good place to explore the physics of Hubble expansion and also invisible dark matter. You can even incorporate HST and its optics in your second semester physics: Why not devote a class to the mirror flaw after discussing mirrors?

The concept of universal expansion is difficult for students and teaching it is fraught with perils. But there are plenty of ways to teach these successfully. And, do be prepared to answer the hard questions: What exactly is this expansion and how are redshift, velocity, and expansion related?

JENNIFER BIRRIEL is Professor of Physics in the Department of Physics, Earth Science, and Space Systems Engineering at Morehead State University in Kentucky. She was a junior in college when the Hubble mirror flaw was revealed and remembers her optics professor using it as a “teachable moment.”

In 1929, Edwin Hubble published his foundational paper that showed that galaxies are moving away from one another. [PNAS]

Edwin Hubble sits at the 100-inch telescope he used for much of his life’s work. [Courtesy of the Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, California]

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http://astrosociety.orghttp://www.aspbooks.org/publications/523/671.pdfhttps://aapt.scitation.org/doi/abs/10.1119/1.4868929?journalCode=ptehttps://ui.adsabs.harvard.edu/abs/2020arXiv200202439H/abstracthttps://aapt.scitation.org/doi/full/10.1119/1.3684469https://aapt.scitation.org/doi/full/10.1119/1.3684469https://aapt.scitation.org/doi/10.1119/1.4965269https://aapt.scitation.org/doi/10.1119/1.4965269https://iopscience.iop.org/article/10.1088/0031-9120/51/6/065011https://iopscience.iop.org/article/10.1088/0031-9120/51/6/065011


Astronomers tell us the universe is filled with black holes, an awesome fact usually followed by the reassurance that these dangerous beasts are far, far away. The closest confirmed black hole is A0620–00, a binary system in the constellation of Monoceros some 3,400 light years from Earth. One object is a K-type main-sequence star; the other is a 6.6 solar mass black hole.

Three-thousand-plus light years is a nice buffer between warm, wet Earth and falling into oblivion. The otherwise nondescript A0620–00 made the news in June 2018. That’s when the European Space Agency, via a radio antenna at its Cebreros station, sent the black hole a memorial message that physicist Stephen Hawking had died.

Just Your Friendly Neighborhood Black HoleBlack holes are common, yes, but also quite possibly closer than you think.

A team of astronomers announced they’ve found a new invisible black hole in the star system HR 6819 (illustrated here). If confirmed, this black hole, would be the closest such object to Earth at just 1,000 light years away. [ESO/L. Calçada]

by Christopher Wanjek

armchair astrophysics

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A0620–00 should receive that message in year 5475. Then it will eat it. (If Hawking was right, the black hole eventually might burp out the message in some garbled form.)

But A0620–00 might no longer be the closest known black hole. In May, astronomers reported a black hole system only about 1,000 light years away.

This newest black hole candidate is in HR 6819, a triple star system in the southern constellation of Telescopium. That’s two regular stars plus one black hole. Indeed, until now, HR 6819 was thought to be a binary star system with just two fairly normal hydrogen-burning stars. The black hole discovery came as a surprise.

A team led by Thomas Rivinius at the European Southern Observatory (ESO) was studying HR 6819 as part of a large collec-tion of binaries — a project started more than a decade ago. The team noticed something unusual about the orbital velocity of the stars: one was hardly moving, and the other was moving quickly but around nothing. They speculated that there likely was a third star in the region causing this irregular motion. Sadly, one of their colleagues key to this work, Stanislav Štefl, died in a car accident in 2014, and they put their deeper analysis on hold.

When returning to the data last year, inspired in part by recent observations of a different strange binary system, LB–1, system thought to contain a black hole, Rivinius’ team determined that one of the stars was orbiting an unseen object once every 40 days. The astronomers calculated that the object is 4.2 solar masses. And put-ting two and two together — high mass and invisible — they con-cluded this must be a stellar-size black hole.

Black holes usually reveal themselves when they accrete mat-ter from nearby stars; the rush of gas spiraling into the black hole causes the region to flare. Yet the black hole in HR 6819 is not accret-ing. It’s truly black. This makes HR 6819 one of the firmest detections

of a black hole based on orbital dynamics, not radio or X-ray flaring, Rivinius says. (It’s a matter of ironic trivia that this triple system is vis-ible to the naked eye at 5.3 magnitude.)

More observations will be needed to confirm this discovery and clear up some confusion. The black hole progenitor should have “kicked” its companions farther away when its outer layers exploded as a supernova. But those stars are still there; why, and how?

A Galaxy of Unseen Black Holes?And here’s an issue of some gravity that there’s no escaping: There are likely other similar systems in the Milky Way, invisible to us because they never flare. “There must be hundreds of millions of black holes out there, but we know about only very few,” Rivinius says. “Knowing what to look for should put us in a better position to find them.”

One of Rivinius’ colleagues, Dietrich Baade also at ESO, says that finding a black hole in a triple system so close to Earth indicates that we are seeing just “the tip of an exciting iceberg.”

So, how close can a black hole be to us? Our galaxy has an esti-mated 20,000 O-type stars, the kind that burn quickly and ultimately produce black holes. And there might be one black hole for every 1,000 stars, Rivinius said. The chances of one being near to us, pro-duced eons ago, is high.

“The closest ‘soon-to-happen’ supernova progenitors within 1,000 light years that may leave black holes behind are Antares and Betelgeuse,” Rivinius says. Antares is 550 light years away; Betelgeuse is 700 light years away.

Fun to think about, as long as they are close enough to study but not close enough to fall into.

CHRISTOPHER WANJEK is a Baltimore-based science writer and author of a new book, Spacefarers, published by Harvard University Press in the heart of a coronavirus black hole.

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Renée, 16 January 2020, First day of classBetelgeuse was acting up. The variable supergiant had been unques-tionably dimming over just a few months, dropping a full magnitude and appearing noticeably dim. It was the perfect lead-in for discus-sions of light curves and magnitudes in an introductory stars and galaxies class, and also the perfect glimmer of hope.

The hope was that it would explode, a cosmic event that I and all my students were eager to witness. I want to see a supernova for the obvious reason that I want to see a supernova. My students, still unaware of what a star was, much less what a supernova was, wanted Orion’s armpit gone for different reasons. For more than two decades, I have told my classes that if there is a naked-eye super-nova visible from the latitude of Houston before grades are due, everyone in all my classes gets an automatic A.

Cosmically speaking, exploding stars are fairly common, I explained, but our galaxy is centuries overdue for one. Even though the astronomical community agreed that the bottoming out of Betelgeuse’s brightness almost assuredly didn’t signal its impending death, it still gave me hope.

SCOTT & RENÉE: 4 FEBRUARY 2020

A one-act play

INT. OFFICE - DAY

RENÉE

Wow, I’m way ahead of schedule

this semester.

SCOTT

I know! We haven’t had any snow

days or floods!

RENÉE

No sick kids, either. I might

even get to gravitational waves

at the end!

MORGAN FREEMAN

She would, in fact, not get to

gravitational waves at the end.

Light Curves and Coronavirus CurvesLet’s compare the changes in the sky with the changes to teaching here on Earth.

by C. Renée James and Scott T. Miller

a little learning

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Renée: 6 February 2020, First exam, T-minus 32 days until the announcement of remote learningIt had been an average semester so far. Nearly 20% of my class had missed an online quiz deadline, and on any given day, I could expect about 20% of the class to be absent, even with the promise of daily activities that would factor into their grades. Exam days were always different, though. Only a handful of students would skip a morning exam, even if they seemed content to skip the material leading up to it.

Like everything else so far, their performance on the exam had been typical. Still, despite a fair showing, students were holding out hope that an exploding Betelgeuse would make the rest of the semester pointless. I wondered as I looked at the obviously dimmer star if I really might get to see a supernova in my lifetime. Little did I know that Betelgeuse had reached the end of its weird phase and was heading back to normal.

Lucky Betelgeuse.

Renée, 5 March 2020, T-minus 7 days until the an-nouncement of remote learningThe second in-class exam went predictably well, but students were definitely hitting the mid-semester slump. Attendance had dropped to about 75% and a whopping 30% had simply missed the second online quiz.

On the rise, though, was Betelgeuse’s light curve, along with complaints about its apparent resurrection. Images taken by the European Space Observatory’s (ESO’s) Very Large Telescope showed a Betelgeuse that had apparently donned a dark face mask between January 2019 and January 2020, but now it seemed to feel safe enough to take it off.

Sigh. No supernova after all. Just an ordinary semester. With half the term under their belts, my students left the classroom for what

would be the last time, although we didn’t know that then. I stayed at the office a bit later than usual that day, ambitiously prepping the material for the week after spring break. Copies of the upcom-ing group activity on hydrogen fusion sat at my desk waiting to be completed by well-rested students.

I suspect they’re still on my office chair. I haven’t been back since then.

Scott, 12 March 2020, The Day Teaching Stood Still “Well, I guess we’re really doing this,” I thought as I saw the email from our university’s administration. Students who had signed up for a face-to-face class were expected to learn fully online. Now, instead of getting a uniform in-class experience, my 140 Solar System Astronomy students were going to be in their own individual classrooms.

Before I could fully begin to adjust to this new reality, the emails from students began.

“I was wondering how this online classes is going to work now, as school is now closed and is going to online. Please give me an update.”

“I just got the email from the university, how does this affect the class schedule? Is the exam still next week?”

“I just heard about classes going online, how does …”

Other students were pan-icking that they would not be allowed back to their dorms, the only place they had to live

The Center for Disease Control and Prevention released this poster as a reminder. We also sent along a similar message to our students. [CDC]

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for the semester, while another subset worried about meal plans and health services.

How was I — their astronomy professor — supposed to know the answers to these questions? Clearly the students needed to hear something, anything, from me, so I sent them the following:

1. Keep calm 2. Wash your hands 3. Wait for further instructions

But how could they keep calm?

Scott, Sometime During Spring Break, v. 2.0 We had been granted an extra week to prepare for finishing the term online, and the questions from students ramped up:

“I traveled overseas and now have to self-quarantine, so what hap-pens now?”

“I’m at home with family. I need to work to help provide. There’s no quiet here. I have younger siblings at home as well and they also need the computer.”

“I’m considered an essential worker and my hours increased to 50-70 hours/week”

“I am very busy, worried about getting laid off and not being able to provide for myself, but overall trying to stay positive.”

Stay positive. Keep calm. Wash your hands.“Are you getting my emails?” I asked in a one-question online sur-

vey. Only 75% responded. How can I communicate with my students if they aren’t even reading their emails?

Renée and Scott, 18 March 2020Our department held a meeting to discuss strategies for dealing with the new normal. While other faculty members were making optimistic plans to hold synchronous class meetings, maintain

student collaboration, or electronically proctor exams, we took a more minimalist approach.

SCOTT

I don’t think we can assume any-

thing about their circumstanc-

es or their access to technol-

ogy, and I don’t think we should

force them to convert to an on-

line class.

RENÉE

Agreed. I’m trying to make all

my content accessible by phone.

I won’t require webcams, and I

won’t expect anything in real

time. I’ve got a GroupMe chat go-

ing, and it looks like most of

them are on it.

We had both taught our respective classes online during summer sessions, but this was different. Instead of requiring the students to adapt, we adapted, while trying to provide a learning experience as similar to their face-to-face one as possible. We fully expected all participation to take a nosedive for the rest of the semester, and we were prepared to adjust their final grades accordingly.

Scott, 23-27 March 2020, The First Week of Remote LearningThe second exam was scheduled. They had taken their first exam in class, where it was easy to make sure that the students weren’t using

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any resource other than their brains. But for the second exam, I had no chance of ensuring they weren’t sitting there with every resource within arm’s reach.

Naturally, I let them use whatever notes and resources they had. Allowing this freedom meant I needed to create a different style

of test, one that focused mainly on higher-level thinking questions about concepts that could not easily be Googled. Gone were the rote memorization questions. A typical in-class exam would have at least a few of these, largely to boost the class average and give even the low-performing students something to hang their hats on.

The result? Unsurprisingly, they got a lower average. Whether this was due to the more conceptually difficult questions or to life during a pandemic, I don’t know. It didn’t matter. The only fair thing to do, as far as I could tell, was to adjust the distribution of scores to better match the grade distributions of past exams.

Yes, I applied a coronavirus curve, and no, it wasn’t flattened.

Renée, Sometime in April, during the Great Merging of DaysTrying to adhere to the spirit of my original syllabus, I had replaced “One Minute Papers” with online “Lecture Checkpoints” so that stu-dents could 1) get their attendance credit; 2) wrestle with questions that would have been posed as personal response questions; and 3) have the main points of each class reinforced. Homework quiz-zes, which they had already been taking online, continued in the same format as before, along with homework submissions. Thank goodness they’d already become accustomed to submitting work through the university’s learning management system.

Group interactions, though — a mandatory staple in my pre-spring break active-learning classroom — became optional. I feared that students would drop off, so I continually asked everyone in the

now buzzing GroupMe chat to check in on their group members.

“Can we get an auto-matic A for a pandemic?” one hopeful student asked in the chat. “That’s gotta be as rare as a supernova.”

There was no denying at this point that Betelgeuse was coming out of its slump. Unfortunately, it was just starting for many students. Some students’ phone plans had been cut off for non-payment, and I had several requests for extensions on checkpoints because students were working while accessing Wi-Fi by sitting outside a closed Starbucks.

I had gone from encouraging student interactions during “normal” class times to engaging in chats and email exchanges at midnight. Whenever students informed me of extenuating circumstances, I accepted them without question. I was less concerned about stu-dents “gaming the system” than I was about letting my more vulner-able students down.

And, as I was about to find out, every student was vulnerable. This supernova of understanding became fully apparent at 10:30

p.m. on a Sunday. I received a message from my daughter’s 8th grade history teacher that she had turned in nothing — nothing — since remote learning had begun. It made no sense. We had reli-able Wi-Fi, food security, housing, a parent who could actually work through algebra proofs and Spanish lessons, and a nice yard to

When you compare the light curve of Betelgeuse over the past decade, it’s clear the star dimmed considerably as 2019 turned into 2020. [AAVSO]

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escape to. She had her own study room and a school-issued device. She was, in short, nothing like over half my students. Meanwhile, next door her sixth-grade brother was crying because I

had suggested a small clarification in a sentence in an English essay. Whatever stress I thought they felt during their usual school days

paled in comparison to the emotional devastation that the pan-demic brought with it. My own children were flailing and, in some cases, failing. Tensions frequently ran high. If this was what was going on in my household, where everyone had a room and a reli-able device, what was it like for my 200 students?

Scott and Renée, 8 May 2020We faced down the rest of the semester together with our students. They didn’t simply survive the term. They smashed it.

Unexpectedly, for all of our classes, participation went up. By both our metrics, “attendance” was nearly 10% higher than it had been in person. The number of students missing online quizzes and assign-ments actually dropped during the remote learning phase. The only

aspect of class that saw a slight decrease was the completion of labs, which are a source of frustration and anxiety even during the best of times. Now, without a lab partner or a circulating TA to address dif-ficulties the instant they popped up, students felt adrift.

We agreed to compute grades two ways — cumulative and pre-spring break – and awarded them the higher of the two. Some students had been doing great before remote learning kicked in, but fell precipitously after spring break. Some students seemed to thrive on having our classes as a constant in their uncertain lives, engaging like never before.

“I felt that I learned more on my own. It was easier than being in a large class,” said one student. Another remarked, “This class was my steadiest. I knew for certain when things were due, and [the pro-fessor] kept up amazing communication with the whole class and made the transition more bearable.”

It was a learning curve for everyone involved, forcing us to think more deeply about our class structure than any of our previous stud-ies of incremental changes or single teaching strategies ever did.

MORGAN FREEMAN

Then again, all of this could have

been avoided if Betelgeuse had

simply exploded back in February.

THE END

C. RENÉE JAMES is a science writer and professor of physics at Sam Houston State University, where she has taught introductory astronomy since 1999. She is the author of two books, “Seven Wonders of the Universe That You Probably Took for Granted” (2010) and “Science Unshackled” (2014).SCOTT T. MILLER is a Professor of physics and astronomy at Sam Houston State University, where he has taught introductory astronomy for non-science majors and engaged in astronomy education research for 12 years.

Betelgeuse was much brighter at the start of 2019. It appears as though the star donned a face mask at the end of last year. [ESO/M. Montargès et al.]

January 2019 December 2019

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http://astrosociety.orghttps://www.amazon.com/Seven-Wonders-Universe-Probably-Granted/dp/080189798Xhttps://www.amazon.com/Seven-Wonders-Universe-Probably-Granted/dp/080189798Xhttps://www.amazon.com/dp/B00MABNA1S/ref=dp-kindle-redirect?_encoding=UTF8&btkr=1


It’s challenging enough to engage a group of teenagers in an inquiry-based investigation when they are in the same room with you. This involves creating optimal cooperative groups, managing necessary materials, engaging in formative assessment and moni-toring of student progress, and holding them accountable for their behavior. In the normal course of a day in the classroom, teachers circulate, engaging students. They encourage their students through questioning and assist with the manipulation of equipment, all the while keeping an eye and ear trained on what the rest of the class is doing. The metaphorical teacher has “eyes in the back of their head.”

The spring 2020 COVID-19 pandemic created a situation where classrooms even as small as 20 students had the potential to act as centers of distribution for the virus. As schools closed around the nation, teachers prepared to finish out the school year virtually, via a variety of platforms. These powerful tools — such as Zoom and WebEx — connect people geographically separated. Many organi-zations, the ASP included, have utilized them for years to conduct meetings and deliver professional development to educators in both formal and informal settings. The ASP has shown there is little differ-ence in learning outcomes via virtual settings compared to in-person opportunities. The caveat: All of these opportunities were with moti-vated and experienced educators who already had a rich background in the content covered in the virtual professional development.

In the spring, teachers had to learn rapidly how to virtually engage a classroom of 20 first graders or 40 juniors. Virtual charter schools have claimed to accomplish this for years. The data however tell a different tale, with such charters achieving at much lower levels than in-person public schools. They are not the model to look to for guid-ance on how to shift daily in-person instruction to a virtual platform.

Virtual Teaching: An Adaptation, Not a ReplacementThe COVID-19 pandemic has forced educators to change their teaching style.

Early this spring, educators across the country had to pivot quickly to teach online. Unfortunately, vir-tual education often lacks the human connection that teachers nurture. [© ake1150 - stock.adobe.com]

by Brian Kruse

education matters

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http://astrosociety.orghttps://doi.org/10.3102/0013189X20909814https://www.brookings.edu/blog/brown-center-chalkboard/2020/06/02/virtual-charter-schools-and-online-learning-during-covid-19/?fbclid=IwAR12Vh7L1EwzuqoWJ9Wg8N826GJ4Y14qO9D4vJzzohwQ0CWO5-KQiKydHtY


Science teaching is perhaps the most problematic area to shift to the virtual realm. The need to have students actively engaged while investigating natural phenomena, sometimes with specialized equipment, makes the online learning environment less rich than the physical classroom. It is difficult to imagine a teacher having students learn about chemical reactions experimentally in a home environ-ment. In astronomy, some of the in-person modeling experiences are challenging for even the educators, making it problematic to expect young learners to figure out the spatial relations without direct guid-ance. One teacher notes that he, at the start of the pandemic, had students take home some of their lab equipment, then had them follow along while he conducted the lab live via the virtual platform. Another teacher used simulations more extensively to replace hands-on lab experiences. In the classroom, students actively gather evi-dence to support their learning. There, the teacher is able to see at a glance how every student is performing, in terms of material manipu-lation and skill development as well as the building of mental models of how the universe operates. The small camera-generated window into the learner’s home provides scant evidence for their progress.

While the sudden shift to virtual learning due to the pandemic is not likely indicative of long-term changes, there were some trends teachers have noted. The frequency of contact with students in the secondary grades was on average twice per week, with about 80% of those registered attending. Some virtual-conferencing programs let a host create “breakout rooms,” where students can work in small groups, but few teachers took advantage of this feature. Teachers eliminated group projects due to logistical constraints. They also noted preparing for virtual instruction was more time intensive than for in-class activities.

The major area teachers identify as setting the virtual environ-ment apart from the in-person experience is building relationships,

which takes places on a moment by moment basis in the classroom. Teachers note the prior relationships they had with their students were helpful as they finished out the school year online. A com-pletely virtual classroom from the first day of the school year would not create, nor foster, the sort of relationships teachers have with their students. The non-verbal language and the short interactions showing care and empathy, these and more are the building blocks of human relationships. From relationship stems the ability to more fully reveal student thinking about the phenomena we are asking them to investigate and explain.

It has taken a number of years for teachers to implement the shifts called for in A Framework for K-12 Science Education and the Next Generation Science Standards. While those shifts are perhaps incom-patible with a complete move to online instruction, there are ways to integrate, and mitigate, including some form of three-dimen-sional learning into the virtual environment. It is not the sort of thing that will happen instantaneously, if that is the route education takes in response to the ongoing pandemic. Teachers are resilient and adaptable, and immensely talented at creating innovative learning experiences for their students.

Too often, teaching is seen as delivery of information, and the par-ticulars of the method used are not important. As any teacher will tell you, there is a lot more to it than pure delivery. The cognitive realm is only a small part of encouraging and engaging those teenagers — or any grade level — to do their part in the educational process. The affective realm, the social nature of the interaction, is perhaps more important in motivating both teacher and students in the learning process. Both areas are best nourished within the classroom. In a virtual classroom, it is far too easy to hide behind a digital wall.

BRIAN KRUSE manages the formal education programs at the ASP.

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Astronauts Launch from U.S. Soil

On May 30 at 3:22pm Eastern time, a SpaceX Falcon 9 rocket lifted off from NASA’s Kennedy Space Center with a SpaceX Crew Dragon at the top. Within the confines of that capsule were two veteran NASA astronauts. This launch transpired seamlessly. Next, the first stage separated and flew back to land on a drone ship, to be used again. The rocket’s second stage then pushed Crew Dragon to orbit. That all took less than 3 minutes. Another 9 minutes later, and stage 2 separated from the capsule. “Thank you for the first human ride for Falcon 9,” said astronaut Doug Hurley. “It was incredible.” At that moment Crew Dragon was making its own way to the International Space Station (ISS), and Bob Behnken and Hurley settled in for a nearly 19-hour ride.

The following day, at 10:29am Eastern time, Dragon Crew docked with the ISS. Two hours later, the astronauts climbed onboard the station and joined three crewmates who flew up in April, on a Russian Soyuz spacecraft.

It marked the first time since July 8, 2011, — the final NASA Space Shuttle launch — that the United States launched their own astro-nauts into space. It’s the first time ever that a private company did so. And it was an incredible moment of pride for space exploration and for the United States.

Engineer and retired NASA astronaut Melvin Leland was at NASA offering commentary on the mission. He summarized the hope that such a launch can provide, that it “shows what we can do when we

come together as a team.” The “team” he spoke about is most likely referring to NASA, commercial partners, scientists, engineers, and the other experts who worked together to make the launch happen. Or maybe the quote reflected what was happening on Earth’s sur-face. That last weekend in May saw massive demonstrations bring-ing attention to racial inequalities across America, making such a statement that no one could ignore the long-standing disparities.

What will the U.S. be like when Dragon Crew returns to Earth later this summer? Perhaps it would be a more hopeful and equal land, where we can come together, as a team. After all, space and our planet do not exist in isolation. — Liz Kruesi

Atop a SpaceX Falcon 9 sat two NASA astronauts in a SpaceX Dragon crew capsule. The rocket launched from the Florida coast May 30. [NASA]

space news

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http://astrosociety.orghttps://www.nasa.gov/press-release/nasa-astronauts-launch-from-america-in-historic-test-flight-of-spacex-crew-dragonhttps://www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts135/launch/sts-135_mission-overview.html


MESSENGER Data Keeps Giving

Venus is Earth’s often-neglected neighbor. Occasionally, though, missions to Mercury and the Sun swing by Venus on their way to their targets, and in the process collect much-needed data of Venus. An April Nature Astronomy paper uses some of that precious data to piece together what’s happening in Venus’ atmosphere.

In June 2007, on its way to Mercury, NASA’s MESSENGER spacecraft passed 210 miles (338 km) over Venus. This flyby used Venus’ gravity to alter the probe’s orbit, and it also tested MESSENGER’s instruments.

As high-energy cosmic particles slam into Venus’ atmosphere, they can interact with gas particles and release neutrons. Molecular nitro-gen — the second-most abundant molecule in the atmosphere of Venus — is especially prone to this interaction. Those neutrons collide with more material in the atmosphere and lose energy. An instru-ment onboard MESSENGER looked for neutrons coming from Venus. Years later, a team of physicists from Johns Hopkins Applied Physics Laboratory (JHUAPL) in Laurel, Maryland, looked at the data.

By studying the energies of the escaping neutrons, Patrick Peplowski and David Lawrence could learn about the amounts and at what depth that nitrogen comes from. They built a computer model that broke apart Venus’ 62-miles- (100-km-) thick atmosphere into 1.2-miles- (2-km-) thick sections. They then varied the nitro-gen content in those layers and measured the energy the neutrons carried. The model that fit the MESSENGER data closest showed that nitrogen is 40 percent more prevalent in the upper half of the

atmosphere than at altitudes below 31 miles (50 km). A chance to confirm the discovery might come in the next few years, though. If picked, one of the four proposed small-scale NASA planetary science missions would study the atmosphere of Venus.

The 2007 MESSENGER data has even more informa-tion to give scien-tists. Jack Wilson — also at JHUAPL and a third-author on the Nature Astronomy paper — lead a study that used the Venus neutron data and an observation collected during a 2008 flyby from Mercury to measure how long a neutron lives. A neutron that’s not restricted to a nucleus doesn’t last long. It converts into three lower-mass particles in under 15 minutes, although the exact time is highly debated. This new study, published in Physical Review Letters, shows that it is pos-sible to measure these neutron lifetimes in space, and with future observations perhaps measure the precise lifetime. — Liz Kruesi

In 2007, MESSENGER flew by Venus and captured this view. [NASA/JHUAPL/Carnegie Institution of Washington]

space news

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http://astrosociety.orghttps://nssdc.gsfc.nasa.gov/planetary/planets/venuspage.htmlhttps://www.nature.com/articles/s41550-020-1079-2https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.2.023316https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.2.023316


Is it a Planet or a Star?

A few years ago, astronomers released research and a striking image of the gas and dust near the young star AB Aurigae. Those observa-tions — using the ALMA Observatory — showed hints of a young planet forming. So another team of astronomers decided to follow up and observe the same object with a different instrument that has slightly different sensitivity.

In December and January, Anthony Boccaletti from the Observatoire de Paris and colleagues used the European Southern Observatory’s Very Large Telescope to take another look at AB Aurigae. The telescope’s SPHERE instrument captured the near-infrared light that small dust grains near the star scatter. By looking at the scattered light, they can trace the dust and coupled gas. And they captured a glorious image, of spiral arms twisting outward from a clump near the star.

Boccaletti’s team said that clump is a planet in the early stages of formation. As it orbits its star, it sweeps up more gas and dust to build into a full-fledged planet. The idea is that as the protoplanet sweeps up the gas and dust in the disk, turbulence from orbiting through the material could create spirals. “The twist is expected from some theoretical models of planet formation,” says coauthor Anne Dutrey, of Le Laboratoire d’Astrophysique de Bordeaux, France. The astronomers’ observations and conclusion appeared online May 20 in Astronomy & Astrophysics. If Boccaletti and colleagues are correct, this would be the first time that planet formation has been seen,

and not just theorized or computationally modeled. A different team, however, said the twist and its resulting spirals

are likely the consequence not of a planet forming, but of a star forming. Binary stars are common in the universe, and because AB Aurigae is only a few million years old, another forming star wouldn’t be surprising.

Further research will likely be needed to nail down specifically what type of object is at that bright twisting clump near AB Aurigae. Whatever it is, it’s incredible to see the detail in these newly released observations, of either a protoplanet or protostar forming around a young, hot star lying 520 light years away. — Liz Kruesi

That bright yellow twist near center is either a planet or star forming. [ESO/Boccaletti et al.]

space news

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http://astrosociety.orghttps://iopscience.iop.org/article/10.3847/1538-4357/aa6af7/metahttps://www.aanda.org/articles/aa/pdf/2020/05/aa38008-20.pdfhttps://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/staa1655/5856580?redirectedFrom=fulltexthttps://academic.oup.com/mnras/advance-article-abstract/doi/10.1093/mnras/staa1655/5856580?redirectedFrom=fulltext


Cosmic Structure and Slime Mold?

The universe’s large-scale structure looks like a “cosmic web” or foam. It should have nothing to do with a single-cell organism Physarum polycephalum that grows on decaying vegetation (think dead tree trunks and old leaf piles), and yet a new paper shows that it does.

The cosmic web is a consequence of gravity; galaxies and gas and dark matter seem to move efficiently in space-time toward other areas with more mass (and thus a stronger gravitational pull). Galaxies sit at the locations where the scaffolding intersect, and diffuse streams of regular gas trace the scaffolding as they feed into galaxies. Telescopes see the galaxies, the bright points of light situ-ated within larger reservoirs of dark matter. But seeing those fila-ments and the large-scale structure isn’t easy.

“Slime mold creates an optimized transport network, finding the most efficient pathways to connect food sources,” says the study lead author Joe Burchett, of the University of California, Santa Cruz, in a press statement. Scientists have used this Physarum polycephalum species to map other forms of distribution networks (like transporta-tion networks in Japan). Maybe it could work with the universe’s mat-ter distribution?

So Burchett and computer scientist Oskar Elek, also of UCSC, applied to a cosmic structure simulation a computational algorithm based off Physarum polycephalum’s movement. They inputted the 3D positions of 37,662 galaxies, which served as “food” sources for the slime mold “agents,” serving as the underlying dark matter. Next, they

compared the model to observations of gas between some of those galaxies. “We knew where the filaments of the cosmic web should be thanks to the slime mold, so we could go to the archived Hubble spec-tra for the quasars that probe that space and look for the signatures of the gas,” says Burchett. They used distant active galaxies (called quasars) that shine brightly through diffuse material, like a lighthouse through fog. And those observations matched with their slime mold model. Astronomers can now add another term to describe the uni-verse’s large-scale structure: slime-mold like. — Liz Kruesi

A model based off the growth of slime mold mimics the cosmic web surprisingly well. (Observational galaxy data in yellow, while the superimposed model is in purple.) [Burchett et al., ApJL, 2020]

space news

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http://astrosociety.orghttps://iopscience.iop.org/article/10.3847/2041-8213/ab700c#apjlab700cs3


A Brilliant Flash 3.5 Million Years Ago

A supermassive black hole sits at the center of our galaxy. This extremely dense object holds the mass equal to 4 million times our Sun, but it’s invisible. Astronomers can see glimmers of light occa-sionally, as material near the black hole glows from friction. While this supermassive black hole, called Sagittarius A, is remarkably dim today, new research finds that 3.5 million years ago, it glowed brightly. And astronomers used quite a detective trail to see back in time.

At our galaxy’s outskirts lies a stream of gas and stars, gravita-tionally torn from the Large and Small Magellanic Clouds long ago. Andrew Fox of the Space Telescope Science Institute (STScI) and his colleagues used the Hubble Space Telescope to capture the ultravio-let light passing through that Magellanic Stream. That light shows dips where different elements absorb the light, and those dips are at specific wavelengths characteristic of each wavelength. At all the elements they looked, they saw intense absorption dips that were aligned. The astronomers did not see the same dips when looking at a different stream, which lies in a different area of the sky.

The reason for those absorption dips, they say, is an energetic flash occurred at the galaxy’s center. “The flash was so powerful that it lit up the stream like a Christmas tree — it was a cataclysmic event!,” said Fox in a press statement. The flash funneled away from Sagittarius A perpendicularly to the galaxy’s plane, and the Magellanic Stream was passing through that cone. The blast was so powerful that it changed elements to ions in the Magellanic Stream, and those changes are

visible today. The other stream was not in the right place at the right time to feel the effects of that ionizing radiation.

This research adds on to dozens of studies that show something energetic happened at the center of our galaxy millions of years ago. For example, astronomers a decade ago discovered huge 25,000-light-years-tall bubbles emanating from the center and glowing in gamma ray light. The same area also has similar-shape structures that radi-ate radio waves. Researchers think both these gamma-ray and radio bubbles formed in the past few million years. — Liz Kruesi

The Magellanic Stream, shown here in a pink hue, stretches across an enormous portion of our sky. An explosive event at our galaxy’s center some 3.5 million years ago bathed the stream in high-energy radiation. [David L. Nidever, et al., NRAO/AUI/NSF and Mellinger, LAB Survey, Parkes Observatory, Westerbork Observatory, and Arecibo Observatory.]

space news

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http://astrosociety.orghttps://arxiv.org/abs/2005.05720


cosmic viewsby Jason Major

Take a Dip into a Vast Cosmic Lagoon

Here is the central region of the Lagoon Nebula, aka Messier 8, an enormous interstellar cloud located within our own Milky Way Galaxy. It’s about 4,200 light-years away from Earth in the constellation Sagittarius. This view is a color-composite mosaic created with image data captured by the Hubble Space Telescope in visible and infrared wavelengths on February 12–15, 2018, and made publicly available online through the Space Telescope Science Institute’s Mikulski Archive for Space Telescopes (MAST).

The bright young stars embedded within the nebula give off enormous amounts of ultraviolet radiation, ionizing interstellar gas in the nebula and causing it to glow. Isolated darker regions are dense clouds of cold dust and gas, opaque to visible light. Eventually they will condense and collapse far enough to form new stars of their own.

This view above spans an area about 10 light-years across. For a sense of comparative scale, our solar system from the Sun all the way out to the orbit of Pluto is only about 11 light-hours across. [NASA/ESA, STScI, Max Mutchler (PI). Processing by Jason Major]

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cosmic viewsby Jason Major

A Supermassive Black Hole’s Enormous Jet

This is a view of a clumpy, twisted, 5,000 light-year-long relativistic jet blasting into space from the supermassive black hole (SMBH) inside the elliptical galaxy Messier 87, located 53 million light-years away in the constellation Virgo. The black hole in M87 is also the one whose light-lensed shadow was famously revealed to the world in April 2019 by the Event Horizon Telescope team. It’s a cosmic behemoth estimated to contain the equivalent mass of 6.5 billion Suns.

Pulled-in material swirls around the black hole forming its accretion disc. That material gets caught up in the powerful magnetic fields there and then forcefully ejected far out into space as focused jets from its rotational poles. The material in M87’s jet is ejected so energetically, in fact, that it’s traveling very close to the speed of light itself. And because of the jet’s angle near our direct line of sight it actually creates an illusion that it’s moving several times faster than light speed — although not in reality the case.

The data comprising this color-composite image were acquired by the Hubble Space Telescope in January 2016 with the Wide Field Camera 3. [NASA/ESA, STScI, John A. Biretta (PI). Processing by Jason Major]

JASON MAJOR is a graphic designer and space enthusiast living in Rhode Island. He has written online articles for Discovery, National Geographic, Universe Today, and has had processed images featured by The Atlantic, Astronomy,

Science Channel, and NASA. You can find more of his work at LightsInTheDark.com.

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http://astrosociety.orghttps://lightsinthedark.com/


Hubble’s Handlers The 30th anniversary of the Hubble Space Telescope celebrates both the instrument and the creative people who have kept it going.

By Steve Murray

The Hubble Space Telescope berthed in Space Shuttle Columbia’s bay during the observatory’s fourth servicing mission, in 2002. [NASA]

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As of April 24, the astonishing Hubble Space Telescope completed 30 years in space (about 164,500 orbits, to be precise). Many astronomers who use Hubble today weren’t even born when it was launched. The project’s success is owed to three decades of hard work by scientists and engineers who continually push its capabilities and fix its problems. As some of these people look back on Hubble’s accomplishments at this anniversary, they’re equally excited about what it will achieve in the future.

The Bix FixRobert Williams is a Distinguished Osterbrock Professor at the University of California, Santa Cruz, and Astronomer Emeritus at the Space Telescope Science Institute (STScI) in Baltimore, Maryland. STScI manages the telescope science program while a partnership between NASA Goddard Spaceflight Center in Greenbelt, Maryland, and the European Space Agency (ESA) manages Hubble operations. Williams served as the Institute Director during some critical early years, 1993 to 1998.

His first big decision was whether to even take the job. After all, the telescope had been in space for three years by that time, and its faulty optics were known worldwide. “It was uncertain whether or not it would be successful,” says Williams. “Still, it was the pre-mier facility in the world at the time. How could you not want to be involved with it?”

The first Space Shuttle mission to repair Hubble’s optics took place just four months into his tenure. With so much riding on its success, it wasn’t easy to watch the astronauts from the ground where he had little control on the outcome. “We were all on edge,” says Williams. “Some people were so nervous that they left town for the week.”

And while the optical system recieved the most attention, other issues were also found soon after launch. As the telescope tran-sitioned between daylight and darkness during each orbit, for example, the solar arrays would buckle or “snap” slightly from the temperature change. That movement would often cause the fine guidance sensors — essential for orienting Hubble in space — to

In December 1999, astronauts onboard Space Shuttle Discovery replaced the Hubble Space Telescope’s main computer and the observatory’s gyroscopes. Hubble wouldn’t be the amazing machine it still is if it weren’t for the humans involved in the decades-long project. [NASA/JSC]

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lose lock on their guide stars. The electronics that drove the guid-ance sensors weren’t sufficiently protected from the radiation of space, either. As Hubble traveled over the South Atlantic Anomaly, where the Van Allen radiation belt comes closest to the Earth’s surface, says Larry Dunham, Chief Systems Engineer for Hubble. “You’d get radiation hits that turned ones to zeros and zeros to ones.” Fortunately, Hubble ground engineers addressed both prob-lems with software changes until later Shuttle missions installed upgraded equipment.

What if that first servicing mission had failed? “I had taken the risk,” says Williams, “so I was prepared to be the guy who turned off the lights at the institute if it came to that. Hubble would still have com-pared well to the best ground-based telescopes, but you don’t want to spend $2 billion on an instrument that ends up only ‘as good’ as ground-based instruments.”

Flexing Hubble’s MusclesThe telescope did important science during its first three years, but things (literally) brightened immediately after the first Shuttle repairs, and the telescope soon showed its true potential. Williams used his Director’s Discretionary Time (10% of the observing budget, awarded to high-risk projects) to ramp up two Hubble projects that would yield pioneering discoveries in astronomy: a search for the oldest galaxies and a new measure of cosmic expansion.

“Hubble was the premier research telescope in existence,” he says. “Someone had to see what it could reveal of the distant uni-verse.” But to push what the telescope could do would take days and days of observing time. With astronomers clamoring for that precious resource, it was a controversial decision. Williams took a chance and allowed the telescope to stare for 10 days at a tiny spot in the constellation Ursa Major and built up an image only

2.6 arcminutes on a side. (That’s less than one-tenth of the diam-eter of the Moon.) That image is now famous as the Hubble Deep Field. This tiny, seemingly uncluttered spot actually contains almost 3,000 objects. Most are galaxies; the light from some of the most distant of them has traveled more than 10 billion years to get to Hubble.

The Hubble Space Telescope launched with Space Shuttle Discovery. The next day, astronauts onboard Discovery captured this image of the telescope. [NASA]

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“Until Hubble came along,” Williams explains, “the farthest dis-tance that we’d been able to see galaxies was four billion light years away — only about 25% of the time back to the Big Bang. The faintest objects in that image are more than 90% of the time to the Big Bang, and those galaxies really looked different. They weren’t

symmetrical; they looked like train wrecks.” In the Hubble deep field image, astronomers were seeing how galaxies had evolved, from clumpy young galaxies to the grand spiral and elliptical galaxies of our nearby universe.

That wasn’t the only high-risk project Williams led with his discre-tionary time. He later supported two teams of astronomers trying to better determine the rate of cosmic expansion, known as the Hubble constant (HO). “That was a difficult series of observations that pushed the telescope to its limit,” Williams recalls.

Both teams planned to observe exploding stars called supernovas at far distances. Their final results, however, were revolutionary. They expected to measure how cosmic expansion was slowing down but found, instead, that it was speeding up. That meant that a new energy source was involved – today known as dark energy and mak-ing up some two-thirds of the universe. “Most people would agree it was the most important result that’s come out of the telescope,” says Williams. In fact, the discovery also won the three lead researchers the 2011 Nobel Prize in Physics.

The Last MissionIn 2009, the last Shuttle servicing mission repaired the Space Telescope Imaging Spectrometer (STIS) and installed Wide Field Camera Three (WFC3), a panchromatic instrument that could see wavelengths from ultraviolet into the near infrared. And as with pre-vious missions, Goddard engineers were online, furnishing real-time assistance to the Shuttle crew. “Probably the most exciting times of my career,” says Dunham, “were when the astronauts were up there, and I was down here trying to support them. Our control room would be packed with 100 people on two different shifts.”

Even after five servicing missions, though, anxiety was still a big part of the process. Sometimes it helped to be far away from the

Hubble stared at a seemingly empty speck of space for 10 days in December 1995. The resulting image, the Hubble Deep Field, revealed thousands of galaxies across cosmic time. [R. Williams (STScI), the Hubble Deep Field Team and NASA/ESA]

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action in the control rooms. “I agreed to give a talk at my daughter’s school back in 2009,” said Tom Brown, Head of the Hubble Space Telescope Mission Office at the STScI. Brown had worked on STIS after installation and WFC3 during development and test. “As luck would have it, the time they asked me to come was the very morn-ing they installed Wide Field Camera Three.” The instrument repre-sented years of work to Brown.

The astronauts had to uninstall the old camera (WFC2) to put the new one in the same slot, but WFC2 was stuck. After repeated failed tries, NASA gave the astronauts permission to crank a release bolt as hard as needed. Everyone held their breath. If it cracked or stripped, that would be it for WFC3 but, happily, the gamble worked. “I got back after talking to the kids, and everyone at work was still kind of hyper-ventilating,” recalls Brown. “I’m really glad I wasn’t there to see that!”

In the telescope’s 30-year history, the Hubble team has captured more deep-field images. This one is a composite of several of them. [NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)]

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Fixes From A DistanceAfter the Shuttle servicing missions ended more than 10 years ago, technical changes to the telescope could be implemented only from the ground, with software coding as their only tool. NASA Goddard engineers, however, had been doing this kind of remote work for a long time. “There always seems to be something going on with the telescope,” says Dunham, “especially with the fine guidance sen-sors and the [gyroscopes]. We’ve updated the logic for them several times in the past few years.” Deep institutional knowledge also helps to sustain the effort. “We’ve got a team of 83 people here,” he adds, “with an average experience of 22 years.” Dunham himself joined the

program back in 1982 — a year before the telescope even got the name Hubble — and he’s been with the telescope full-time longer than anyone else.

Some engineering, of course, tries to anticipate potential future problems, too. “Hubble had six newly installed gyroscopes after the last servicing mission,” explains Jennifer Wiseman, Senior Project Scientist for Hubble at NASA Goddard, “but over the years gyro-scopes naturally wear out. Since that mission, we’ve lost three.” The telescope can point accurately at targets using three gyroscopes, but, she adds, “our ground team has already developed procedures that use other sensors to complement the working gyros, and keep pointing capability, should we lose any more.”

Hubble science processes, as well as Hubble systems, can also be beefed up from the ground. “We’re using the gravity of galaxy clus-ters as lenses to view light from the more distant galaxies behind them,” says Wiseman. And one of the innovative things astronomers can do with that lensed light is disentangle the patterns of the dis-torted light to learn how the invisible dark matter in the intervening galaxy cluster is distributed.

Spatial scanning is another tool developed by STScI astronomers. “That’s where we intentionally drag the field of view and smear out all the stars” says Brown. The technique measures an object’s motion against background stars, using parallax to determine its distance. ”It’s terrible for pictures,” he adds, “but you get amazingly accurate astrometry perpendicular to the direction you’re dragging.”

And now Hubble is emerging as a critical player in so-called multi-messenger astronomy, owing to its unique wavelength cover-age. “All of the new observatories coming online are going to want to get data with Hubble,” Brown says, “particularly in the ultraviolet and optical where Hubble has unique capabilities.” While the next large space observatory James Webb Space Telescope (JWST) will do

During the final serving mission, in 2009, the Hubble control room was a busy place. During the mis-sion, team members took a break to pose for a photo. [NASA]

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amazing science, it detects only infrared radiation. Pairing JWST with Hubble can do incredible things.

“Even now, 10 years after the last servicing mission,” says Brown, “Hubble is on the bleeding edge of what you can do in astronomy.”

Ultimately, Everything EndsSo far, Hubble has traveled about 4.5 billion miles (7.2 billion km) in its orbit around Earth, and Wiseman is optimistic about its future longevity. “Just from the trending of the health of the components of Hubble,” she says, “the probability curves show that it has a great chance of being productive, at least to 2025, and probably many

years beyond that.” Hubble will almost surely be around in 3.5 years, then, to pass the 5-billion-mile (8-billion-km) mark.

Nevertheless, something important will eventually fail on the telescope. What happens then? A research gap would last until a replacement comes along. LUVOIR, for example, is an infrared-optical-ultraviolet space telescope being evaluated in the National Academy of Sciences Decadal Survey right now. Although recom-mendations from the survey are expected in six to nine months, however, the telescope still wouldn’t be ready to launch before the 2030s or 2040s. These workhorse projects take time. In fact, the National Academy of Sciences recommended the Large Space Telescope, what became Hubble, in 1969.

Williams is philosophical about the situation. “We have to face the fact that there are these gaps, particularly since pioneering facilities are so expensive,” he says. “You can only undertake a few of them at any one time.” The next couple large space telescopes that NASA is developing will be infrared instruments. “And so when Hubble eventually shuts down,” he adds, “there’s likely to be a time in which ultraviolet astronomy, at least in the United States, will not be viable.” That’s because ultraviolet astronomy is not possible from the ground, due to Earth’s protective atmsphere.

In the meantime, there’s still a lot of work for Hubble to do. “There’s no shortage of science that needs to be done with the tele-scope,” says Wiseman. “In fact, the pressure from proposers around the world is as high as ever.” As of May, almost 1,100 science propos-als had been received for Hubble’s next observation cycle.

“There’s plenty of discovery space left,” she adds. And as long as it’s healthy, the Hubble Space Telescope will be in orbit to fill it.

STEVE MURRAY is a freelance science writer & NASA Solar System Ambassador. A former research engineer, he follows developments in astronomy, space science, and aviation.

To replace the previous generation camera with the Wide Field Camera 3 during the final servicing mission, astronauts had to crank hard on a release bolt. [NASA]

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Searching Hubble’s Archive for Hidden GemsBecause of its data collection and archival system, the Hubble Space Telescope has changed how — and who — can do science.

By Sarah Wells

Spiral galaxy NGC 1309 hosted a supernova in 2012. By searching through archival Hubble data from 2005-2006, astronomers found out the type of star that exploded: a remnant white dwarf. [NASA, ESA, The Hubble Heritage Team (STScI/AURA), and A. Riess (JHU/STScI)]

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For three decades, a treasure trove of data and discoveries about the cosmos has sat safely in a Maryland facility stored inside hundreds of tapes, laser-written optical disks, magnetic disks, and computer “jukeboxes.” Spurred by requests from around the world, workers in the ’90s and early ’00s would rummage through dense aisles of these data-filled vessels day-in-and-day-out to col-lect, copy, and share the information collected by one of NASA’s most ambitious projects: the Hubble Space Telescope.

In its first 30 years of life, Hubble has faced peril as well as delights. The telescope’s breathtaking images have taught us to think deeply about our universe and have inspired generations of scientists to learn how to explore it. These data have led to the discovery of dark energy and supermassive black holes at the centers of galaxies, and also characterized alien worlds. But, while direct observations made using the telescope have been incredibly important for the science Hubble has been able to do, securing time on the telescope has con-tinued to be competitive and challenging.

That is where NASA’s jukeboxes of data become essential. The Hubble Legacy Archive is a first of its kind data archive of not only directly observed Hubble data but also of high-level science prod-ucts created using new analysis processes on decades old data-sets. While originally stored on only physical disks and tapes in the Maryland facility, this massive database of every Hubble observation has been moved to the cloud in recent years. Organizers have joined that data with the archives of NASA’s K2, the forthcoming James Webb Space Telescope, and other missions in a massive international archive called the Mikulski Archive for Space Telescopes (MAST).

While archives may conjure images of dusty museum basements with miles of drawers filled with ancient beaver pelts, the Hubble archive is one of the project’s most active and creative resources. In 2019 alone, published papers using Hubble observations were

based on at least 50 percent archival data. Discoveries made using the Hubble Legacy Archive have not only shaped our understanding of science in the past decades, but the archive has shaped how we do science as well.

From a Place to the Cloud Long before the archive was the international superstar it is today, Rick White, the Space Telescope Science Institute Archive branch chief, says it was simply a back room in Maryland filled to the brim with data on optical discs.

“The only way people could get data from the telescope is that it would flow from the telescope, get processed, get sorted and archived, and then they’d retrieve it from the archive — all data went through the archive,” says White. That’s because the raw data had to first be processed before it could be read by scientists.

The Hubble Legacy Archive has been collecting data since the telescope launched in 1990, and for many years it was the first stop before any data ever reached its intended scientists. But the influx of data was too large for typical storage systems, said White.

“The way it physically worked was that the volume of data com-ing in from Hubble in 1990 was too large to store on [normal]

Hubble Space Telescope data initially were etched onto laser-written optical discs (left), which were placed in “jukeboxes” by archival staff (right). [STScI]

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disks… so there was this big, complex set-up that involved writing the data on to optical disks, which were these big, 12-inch-sized platters,” said White. “There were optical disk ‘jukeboxes’ that had slots to hold something like hundreds of disks.”

These disks used to hold hundreds of gigabytes of data, but today the cloud-based database can hold hundreds of terabytes.

Long before the archive had moved to the cloud and could be easily accessed around the world with just a simple click, archive staff would physically fulfil data requests by locating stored optical disks in their respective jukeboxes and copying the data on to tapes, which they then physically mailed off to researchers. Each data request would be answered in a 24-hour period. While staffers often had to work hard to complete those requests on time, White recalls a particular event that sent requests through the roof — not from the scientific community, but from the general public.

In 2013, a UFO conspiracy website discovered an image in the archive that had strange lines and stripes. That website told its fan-base how to access the Hubble archive to download the image themselves for proof. “There were several million people who were doing exactly the same thing — they were following the link

from this post and they were downloading the image, and it completely saturated our web server,” says White. “Our web server is not setup to handle the interest of millions of people.”

That image (shown below) was actually a composite of three exposures of Comet C/2012 S1 ISON, and those strange lines and stripes were just a parallax effect. The comet was close enough to the telescope compared to back-ground stars that it moved and its image smeared between those individual exposures. White says they were able to quell the onslaught of requests by posting a small letter on the archive’s main webpage

Documents

astrosocietyasppublications.org/37RYL62T/2020pdfs/Spr20.pdf · 2020. 6. 25. · Hidden Gems SARAH WELLS Because of its data collection and archival system, the Hubble Space Telescope