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Space News Update — June 21, 2016 —
Contents
In the News
Story 1:
‘Electric Wind’ Can Strip Earth-like Planets of Oceans, Atmospheres
Story 2:
Detection of Methanol Shows Comets Are Forming in Distant Solar System
Story 3:
Cygnus Leaves Space Station and Conducts NASA Fire Experiment in Microgravity
Departments
The Night Sky
ISS Sighting Opportunities
NASA-TV Highlights
Space Calendar
Food for Thought
Space Image of the Week
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1. ‘Electric Wind’ Can Strip Earth-like Planets of Oceans, Atmospheres
This is an artist's concept of the electric wind at Venus. Rays represent the paths that oxygen and hydrogen ions take as
they are pulled out of the upper atmosphere. Credits: NASA/Goddard/Conceptual Image Lab, Krystofer Kim
Venus has an “electric wind” strong enough to remove the components of water from its upper atmosphere, which
may have played a significant role in stripping Earth’s twin planet of its oceans, according to new results from ESA’s
(European Space Agency) Venus Express mission by NASA-funded researchers.
“It’s amazing, shocking,” said Glyn Collinson, a scientist at NASA’s Goddard Space Flight Center in Greenbelt,
Maryland. “We never dreamt an electric wind could be so powerful that it can suck oxygen right out of an
atmosphere into space. This is something that has to be on the checklist when we go looking for habitable planets
around other stars.” Collinson is lead author of a paper about this research published June 20, 2016, in the journal
Geophysical Research Letters.
The space environment around a planet plays a key role in determining what molecules exist in the atmosphere —
and whether the planet is habitable for life. New NASA research shows that the electric fields around Venus helped
strip its atmosphere of the components needed to make water.
Venus is in many ways the most like Earth in terms of its size and gravity, and there’s evidence that it once had
oceans worth of water in its distant past. However, with surface temperatures around 860 F (460 C), any oceans
would have long since boiled away to steam and Venus is uninhabitable today. Yet Venus’ thick atmosphere, about
100 times the pressure of Earth’s, has 10,000 to 100,000 times less water than Earth’s atmosphere. Something had
to remove all that steam, and the current thinking is that much of the early steam dissociated to hydrogen and
oxygen: the light hydrogen escaped, while the oxygen oxidized rocks over billions of years. Also the solar wind — a
million-mile-per-hour stream of electrically conducting gas blowing from the sun — could have slowly but surely
eroded the remainder of an ocean’s worth of oxygen and water from Venus’ upper atmosphere.
“We found that the electric wind, which people thought was just one small cog in a big machine, is in fact this big
monster that’s capable of sucking the water from Venus by itself,” said Collinson.
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Just as every planet has a gravity field, it is believed that every planet with an atmosphere is also surrounded by a
weak electric field. While the force of gravity is trying to hold the atmosphere on the planet, the electric force (the
same force that sticks laundry together in a drier and pushes electricity through wires) can help to push the upper
layers of the atmosphere off into space. At Venus, the much faster hydrogen escapes easily, but this electric field is
so strong that it can accelerate even the heavier electrically charged component of water — oxygen ions — to
speeds fast enough to escape the planet’s gravity. When water molecules rise into the upper atmosphere, sunlight
breaks the water into hydrogen and oxygen ions, which are then carried away by the electric field.
“If you were unfortunate enough to be an oxygen ion in the upper atmosphere of Venus then you have won a
terrible, terrible lottery,” said Collinson, “You and all your ion friends will be dragged off kicking and screaming into
space by an invisible hand, and nothing can save you.”
The team discovered Venus’ electric field using the electron spectrometer, a component of the ASPERA-4
instrument, aboard the ESA Venus Express. They were monitoring electrons flowing out of the upper atmosphere
when it was noticed that these electrons were not escaping at their expected speeds. The team realized that these
electrons had been tugged on by Venus’ potent electric field. By measuring the change in speed, the team was able
to measure the strength of the field, finding it to be much stronger than anyone had expected, and at least five
times more powerful than at Earth.
“We don’t really know why it is so much stronger at Venus than Earth,” said Collinson, “but, we think it might have
something to do with Venus being closer to the sun, and the ultraviolet sunlight being twice as bright. It’s a
challenging thing to measure and even at Earth to date all we have are upper limits on how strong it might be.”
Such information also helps us understand other worlds around the solar system. “We’ve been studying the electrons flowing away from Titan [a moon of Saturn] and Mars as well as from Venus, and the ions they drag away to space,” said Andrew Coates, who leads the electron spectrometer team at University College London in the U.K. “The new result here shows that the electric field powering this escape is surprisingly strong at Venus compared to the other objects. This will help us understand how this universal process works.” Another planet where the electric wind may play an important role is Mars. NASA’s MAVEN mission is currently orbiting Mars to determine what caused the Red Planet to lose much of its atmosphere and water. “We are actively hunting for Mars’ electric wind with MAVEN’s full arsenal of scientific instruments,” said Collinson. “MAVEN is a robotic detective on this four-billion-year-old mystery of where the atmosphere and oceans went, and the electric wind has long been a prime suspect.” Taking the electric wind into account will also help astronomers improve estimates of the size and location of habitable zones around other stars. These are areas where the temperature could allow liquid water to exist on the surface of alien worlds, making them places where life might be found. Some stars emit more ultraviolet light than the sun, so if this creates stronger electric winds in any planets orbiting them, the habitable zone around such stars may be farther away and narrower than thought. “Even a weak electric wind could still play a role in water and atmospheric loss at any planet,” said Alex Glocer of NASA Goddard, a co-author on the paper. “It could act like a conveyor belt, moving ions higher in the ionosphere where other effects from the solar wind could carry them away.” ESA’s Venus Express was launched on Nov. 9, 2005, to study the complex atmosphere of Venus. The electron spectrometer was built by the Southwest Research Institute in San Antonio, Texas, and is led by University College London. The spacecraft orbited Venus between 2006 and December 2014. After a successful mission that far exceeded its planned life, the spacecraft exhausted its fuel supply and burned up upon entry into Venus’ dense atmosphere. The research was funded by NASA’s MAVEN (Mars Atmosphere and Volatile Evolution) mission and NASA’s Solar System Workings program.
Source: NASA Return to Contents
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2. Detection of Methanol Shows Comets Are Forming in Distant Solar System
This artist’s impression shows the closest known protoplanetary disc, around the star TW Hydrae in the huge constellation
of Hydra (The Water Snake). The organic molecule methyl alcohol (methanol) has been found by the Atacama Large
Millimeter/Submillimeter Array (ALMA) in this disc. This is the first such detection of the compound in a young planet-
forming disc, and points to a region where comets are forming. Illustration credit: ESO/M. Kornmesser.
Astronomers have just announced that they have found the organic molecule methyl alcohol, or methanol, in
the TW Hydrae protoplanetary disc. This is the first such detection of this chemical compound in a young
planet-forming disc. Because methanol forms on the icy coatings of small dust grains, this discovery provides a
window into the region where comets are likely forming.
“When looking at methanol vapor in the TW Hydrae disc, we’re probing the precursors of exo-comets,” says
study co-author Karin Oberg of the Harvard-Smithsonian Center for Astrophysics (CfA).
The protoplanetary disc around the young star TW Hydrae is the closest known example to Earth, at a
distance of only about 175 light-years. As such, it is an ideal target for astronomers to study discs in detail.
This system is about 10 million years old, and resembles how our solar system looked more than four billion
years ago.
The team made the detection using the Atacama Large Millimeter/Submillimeter Array (ALMA) — the most
powerful observatory in existence for mapping the chemical composition and the distribution of cold gas in
nearby discs.
The ALMA observations have revealed the fingerprint of gaseous methyl alcohol, or methanol (CH3OH), in a
protoplanetary disc for the first time. Methanol, a derivative of methane, is one of the largest complex organic
(carbon-containing) molecules detected in discs to date. Identifying its presence represents a milestone for
understanding how organic molecules are incorporated into nascent planets.
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Furthermore, methanol is itself a building block for more complex chemicals like amino acids and sugars. As a
result, methanol plays a vital role in the creation of the rich organic chemistry needed for life.
Catherine Walsh (Leiden Observatory, the Netherlands), lead author of the study that appear in the
Astronomical Journal, explains: “Finding methanol in a protoplanetary disc shows the unique capability of
ALMA to probe the complex organic ice reservoir in discs and so, for the first time, allows us to look back in
time to the origin of chemical complexity in a planet nursery around a young Sun-like star.”
Gaseous methanol in a protoplanetary disc has a unique importance in astrochemistry. While other molecules
detected in space are formed by gas-phase chemistry alone, or by a combination of both gas and solid-phase
generation, methanol is a complex organic compound that is formed solely in the ice phase via surface
reactions on dust grains.
The observation of methanol in the gas phase implies that methanol formed on the disc’s icy grains and was
subsequently vaporized. This first observation helps to clarify the puzzle of the methanol ice/gas transition,
and more generally the chemical processes in astrophysical environments.
CfA co-author Ryan A. Loomis adds: “Methanol in gaseous form in the disc is an unambiguous indicator of rich
organic chemical processes at an early stage of star and planet formation. This result has an impact on our
understanding of how organic matter accumulates in very young planetary systems.”
This successful first detection of cold gas-phase methanol in a protoplanetary disc means that the production
of ice chemistry can now be explored in discs, paving the way to future studies of complex organic chemistry
in planetary birthplaces. In the hunt for life-sustaining exoplanets, astronomers now have access to a powerful
new tool.
The team's research appeared in The Astrophysical Journal and is available online.
This release is being issued jointly with the European Southern Observatory.
Atacama Large Millimeter/Submillimeter Array (ALMA)
Source: Harvard-Smithsonian Center for Astrophysics Return to Contents
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3. Cygnus Leaves Space Station and Conducts NASA Fire Experiment in
Microgravity
The SAFFIRE experiment. Credit: NASA
Bidding farewell to the International Space Station on June 14th, the commercial Cygnus cargo ship separated
to a safe distance before igniting an intentional fire in microgravity like never before, all in the name of
science.
The NASA-sponsored Spacecraft Fire Experiment, or SAFFIRE, was conducted to better understand how flames
will behave in weightlessness and improve fire safety techniques for future spacecraft.
Scientists have lacked the ability to study large-scale fires in space because of the inherent danger to
astronauts and the spacecraft. But Cygnus offers an ideal research platform for the first time, serving as a
man-rated craft for the experiment at the end of its mission before deorbiting to burn up in the atmosphere.
The Orbital ATK-owned freighter, the ‘S.S. Rick Husband’, reached orbit March 22 atop a United Launch
Alliance Atlas 5 rocket from Cape Canaveral and successfully delivered over 7,000 pounds of supplies,
provisions and equipment to the station.
It was filled with 4,087 pounds of trash and disposables — broken hardware, dirty laundry, empty food
containers — before the astronauts closed the hatch for the unberthing.
The station’s Canadian robotic arm, operated remotely by Mission Control, detached the Cygnus from the Unity
module at 7:43 a.m. EDT (1143 GMT) and deftly maneuvered it under the outpost to the prescribed departure
box.
At 9:30 a.m. EDT (1330 GMT), Expedition 47 commander Tim Kopra of NASA released the vessel 254 miles
above Paraguay to fly away on its own, completing 80 days berthed at the International Space Station.
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Several hours after departure and with a large distance between Cygnus and the station, controllers at Orbital
ATK facilities in Dulles, Virginia, sent commands to start the SAFFIRE experiment.
A hot wire along the upstream edge of the fiberglass-cotton fabric material sample triggered the fire. The
sample measured 15.7 inches wide by 37 inches tall.
“The SAFFIRE experiment, designed to understand fire in microgravity, is now burning successfully,” NASA’s
Glenn Research Center tweeted at 4:54 p.m. EDT (2054 GMT).
“Our SAFFIRE experiment traveled 1,000 miles in space while burning on Cygnus,” was tweeted at 5:28 p.m.
EDT (2128 GMT).
“The purpose for SAFFIRE is to address fire safety on exploration vehicles and habitats,” said Gary Ruff,
project manager and co-investigator for SAFFIRE at NASA-Glenn in Cleveland.
“The specific goals of the SAFFIRE experiments are to investigate the spread of a large-scale fire in
microgravity, essentially trying to answer the questions of how large does a fire get and how rapidly does it
spread, or how long does it take to get to the point of being really hazardous to the crew?”
The flames were contained within an instrumented research box — measuring 35 by 52 inches (3 by 4.4 feet)
— that was strapped into the commercial vehicle before launch and never touched during its stay at the space
station.
“On Earth all inhabited structures — be it a building, airplane, ship or a car — we’ve done full-scale testing of
fires and how it grows. So we have an understanding of how to build vehicles and structures and how to
defend against fires,” said David Urban, SAFFIRE’s principal investigator.
“In spacecraft, we’ve never had the opportunity to burn anything larger than approximately an index card…We
really don’t know what the fate of a fire is. So our building of future spacecraft is based on one-G
understanding and extrapolation of very small, short-duration experiments.”
NASA intends to launch SAFFIRE experiments twice more this year. The SAFFIRE 1 and 3 tests use single
samples 15.7 inches wide by 37 inches tall to watch the development and spread of a large-scale low-gravity
fire. Scientists want to know if there is a limiting flame size and to quantify the size and growth rate of flames
over large surfaces.
On SAFFIRE 2 later this summer, nine smaller samples, each measuring 2 inches wide by 10 inches long, will
be burned sequentially to investigate the in-space “maximum oxygen concentration” flammability limits to
determine if the flame propagates or self-extinguishes.
“SAFFIRE is a box with a wind tunnel in it, a flow duct, that contains the sample that will be burned,” said
Ruff. Prior space combustion experiments have been limited to samples no larger than 4 inches in length and
width. Two cameras were positioned to capture the fire. Other instruments measured oxygen, carbon dioxide,
heat, pressure and flame growth.
Cygnus is remaining in orbit for 8 days to downlink all the SAFFIRE data to the ground. The craft will execute
its deorbit engine firing June 22 at 8:45 a.m. EDT (1245 GMT) for a harmless disposal over the South Pacific.
It will hit the atmosphere at 9:05 a.m. and any surviving debris will impact the water by 9:35 a.m. EDT.
During the plunge into the atmosphere, one final experiment will be conducted, called the Re-entry Breakup
Recorder.
Sensors will monitor pressures, temperatures and accelerations as the spacecraft disintegrates. That data will
be transmitted to scientists via a commercial Iridium satellite telephone link.
Source: SpaceflightNow.com Return to Contents
8 of 13
The Night Sky
Source: Sky and Telescope Return to Contents
Tuesday, June 21
Vega is the brightest star very high in the east.
Barely to its lower left after dark is one of the
best-known multiple stars in the sky: 4th-
magnitude Epsilon (ε) Lyrae, the Double-Double.
It forms one corner of a roughly equilateral
triangle with Vega and Zeta (ζ) Lyrae. The
triangle is less than 2° on a side, hardly the width
of your thumb at arm's length.
Binoculars easily resolve Epsilon, and a 4-inch
telescope at 100× or more should resolve each of
Epsilon's wide components into a tight pair.
Zeta Lyrae is also a double star for binoculars;
much tougher, but easily split with any telescope.
Delta (δ) Lyrae, below Zeta, is much wider and
easier.
Wednesday, June 22
As evening grows late, even the lowest star of
the Summer Triangle climbs fairly high in the
east. That would be Altair, a good three or four
fists at arm's length below or lower right of bright
Vega.
Look left of Altair, by hardly more than one fist,
for the compact little constellation Delphinus, the
Dolphin.
Thursday, June 23
Now that there's a long dark spell between the end of twilight and moonrise, tear your telescope away
from Mars and Saturn and take a tour of the faint globular clusters swarming nearby, east of Antares. Your
guide is Sue French's Deep-Sky Wonders column in the July Sky & Telescope, page 56.
Friday, June 24
This is the time of year when the two brightest stars of summer, Arcturus and Vega, are about equally
high overhead shortly after dark: Arcturus is toward the southwest, Vega is toward the east.
Arcturus and Vega are 37 and 25 light-years away, respectively. They're examples of the two commonest
types of naked-eye stars: a yellow-orange K giant and a white A main-sequence star. They're 150 and 50
times brighter than the Sun — which, combined with their nearness, is why they dominate the evening
sky.
Credit: EarthSky.org
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ISS Sighting Opportunities (from Denver)
No Sighting Opportunities at Denver through Sunday Jul 3, 2016
NASA-TV Highlights (all times Eastern Time Zone)
Thursday, June 23
1 p.m. - ISS Expedition 48 In-Flight Event with Motherboard and the CBS Radio Network with ISS
Commander Jeff Williams of NASA (Starts at 12:55 p.m.) (all channels)
Friday, June 24
10 a.m. - Video File of the ISS Expedition 48-49 Crew’s Departure from the Gagarin Cosmonaut
Training Center in Star City, Russia for the Baikonur Cosmodrome in Kazakhstan (Ivanishin, Rubins,
Onishi) (all channels)
Watch NASA TV online by going to the NASA website. Return to Contents
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Space Calendar
Jun 21 - Cartosat 2C PSLV Launch
Jun 21 - Comet P/2004 T1 (LINEAR-NEAT) Closest Approach To Earth (2.843 AU)
Jun 21 - Comet 198P/ODAS At Opposition (3.894 AU)
Jun 21 - Comet 52P/Harrington-Abell At Opposition (4.250 AU)
Jun 21 - Aten Asteroid 2013 ND15 (Venus Trojan) Near-Earth Flyby (0.076 AU)
Jun 21 - Amor Asteroid 2016 LR1 Near-Earth Flyby (0.095 AU)
Jun 21 - Asteroid 3953 Perth Closest Approach To Earth (1.272 AU)
Jun 21 - Asteroid 293909 Matterhorn Closest Approach To Earth (1.699 AU)
Jun 21 - Asteroid 171381 Taipei Closest Approach To Earth (1.870 AU)
Jun 21 - Asteroid 3259 Brownlee Closest Approach To Earth (2.043 AU)
Jun 21 - Herbert Friedman's 100th Birthday (1916)
Jun 22 - Comet C/2013 X1 (PANSTARRS) Closest Approach To Earth (0.640 AU)
Jun 22 - Comet C/2015 WZ (PANSTARRS) Closest Approach To Earth (1.110 AU)
Jun 22 - Asteroid 87 Sylvia (2 Moons) Occults TYC 6815-03609-1 (11.7 Magnitude Star)
Jun 22 - Apollo Asteroid 2016 LH10 Near-Earth Flyby (0.057 AU)
Jun 22 - Amor Asteroid 2016 LR9 Near-Earth Flyby (0.068 AU)
Jun 22 - Amor Asteroid 2016 LV9 Near-Earth Flyby (0.089 AU)
Jun 22 - Apollo Asteroid 10563 Izhdubar Closest Approach To Earth (0.642 AU)
Jun 22 - Asteroid 215423 Winnecke Closest Approach To Earth (1.034 AU)
Jun 22 - Asteroid 263251 Pandabear Closest Approach To Earth (1.186 AU)
Jun 22 - Asteroid 16522 Tell Closest Approach To Earth (2.035 AU)
Jun 22 - Asteroid 6030 Zolensky Closest Approach To Earth (2.189 AU)
Jun 22 - 40th Anniversary (1976), Salyut 5 Launch (USSR Space Station)
Jun 23 - Amor Asteroid 3199 Nefertiti Closest Approach To Earth (1.851 AU)
Jun 23 - Asteroid 4701 Milani Closest Approach To Earth (1.867 AU)
Jun 23 - Lecture: Juno Mission to Jupiter, Washington DC
Jun 24 - MUOS 5 Atlas 5 Launch
Jun 24 - Aten Asteroid 441987 (2010 NY65) Near-Earth Flyby (0.028 AU)
Jun 24 - Aten Asteroid 2014 OL339 Closest Approach To Earth (0.277 AU)
Jun 24 - Apollo Asteroid 5731 Zeus Closest Approach To Earth (1.273 AU)
Jun 24 - Asteroid 4037 Ikeya Closest Approach To Earth (2.213 AU)
Jun 24 - Centaur Object 10370 Hylonome At Opposition (22.364 AU)
Jun 24 - Ellison Onizuka's 70th Birthday (1946)
Jun 24 - Robert Sharp's 105th Birthday (1911)
Jun 24 - 135th Anniversary (1881), William Huggins Makes 1st Photographic Spectrum of a Comet (1881 III)
Source: JPL Space Calendar Return to Contents
11 of 13
Food for Thought
Measuring the Impacts of Light Pollution: Light pollution is pervasive, and its
impact on people is larger than you might think. By: Ana V. Aceves
A map of North America's night sky brightness. The brighter the color, the more artificial sky brightness. Note that about
half of the U. S. has high levels of night sky brightness. Credit: Falchi et al.
I clearly remember the night I decided I wanted to be an astronomer. It was a cool summer evening when 12-year-
old me sat on my front porch and contemplated the universe. I traveled to the edge of the galaxy and explored the
known universe. The euphoria I felt at that moment is incomparable.
Growing up in the 1990s in rural California allowed me to experience this life-dictating event—unfortunately, many
12-year-olds may not get the same experience. One third of the human population cannot see the Milky Way at
night due to the glow of artificial lights, according to an updated and just-released “New World Atlas of Artificial
Night Sky Brightness” that quantifies the global impact of light pollution.
Moreover, more than 80% of the world’s citizens and more than 99% of those in the U.S. and Europe live under an
artificial skyglow, or reflected light scatter in the atmosphere from the electric lighting below. This isn’t just a
problem in megacities and urban areas. For instance, Death Valley is awash with skyglow from Las Vegas and Los
Angeles, which are 80 and 150 km away, respectively.
“There’s almost no place in some of these countries that looks dark anymore, at least by this atlas’s estimates,” said
Christopher Luginbuhl (Flagstaff Dark Skies Coalition).
Singapore is the most light-polluted country, where the entire population lives under skies so bright that their eyes
can never fully adapt to night vision. Virtually everyone living in Kuwait, Qatar, United Arab Emirates, and Saudi
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Arabia also experiences this level of light pollution. The countries with populations least affected by light pollution
are Chad, Central African Republic, and Madagascar, with more than three-quarters of their population living under
pristine sky conditions.
Gathering data
Fabio Falchi (Light Pollution Science and Technology Institute, Thiene, Italy) and an international team of
colleagues took advantage of the newly available, low-light imaging data from the Visible Infrared Imaging
Radiometer Suite Day/Night Band sensor on the Suomi National Polar-orbiting Partnership satellite. This satellite
orbits at 800 km above the Earth and takes high-resolution photos from the ground at night.
The team also used new precision measurements made at ground level using CCD detectors and handheld Sky
Quality Meters (SQMs) made with the help of the U.S. National Park Service and thousands of citizen scientists
around the world. These data don’t depend on models, so they are very important for the atlas’s calibration.
Cultural Impact
The researchers make a point that light pollution is a concern for everyone, not just astronomers. Biological systems
and human health are also affected by an increase in light pollution. Our internal circadian rhythm — a cycle for
sleep and wake patterns, hunger, activity, hormone production, body temperature, and other physiological
processes — has been developing over billions of years. Yet we’ve only been living with electricity since the late
1800s.
The skyglow reported in the atlas is probably below the threshold for directly affecting our circadian rhythms, but
the skyglow measurement is from the atmospheric reflection of electric lights in our local environment. Those lights
are in many, if not most, cases enough to cause circadian disruption. These include the lights from inside homes
and commercial buildings, and even some forms of street lighting.
Biological sciences have begun to show what forms of light and what times of day are most, or least, harmful to our
circadian health. This knowledge is being used to produce light sources that are more appropriate for the time of
day being used—bright light with high-blue content (fluorescents) in the morning and dim light with low-blue
content (low-wattage incandescent) beginning at dusk.
Bright lights like fluorescents and LED lights may be significantly contributing to the amount of light pollution. While
high-pressure sodium (HPS) lights are yellow and with a low correlated color temperature, LED lights are white,
have a higher correlated color temperature, and emit energy in blue and green wavelengths. The American Medical
Association has just-released a policy document blasting the use of blue-rich LED streetlights.
“White LED light threatens to dramatically increase the amount of outdoor lighting. We need to slow down this LED
juggernaut and think about it more carefully.” said Luginbuhl. Unless the blue-light emission is restricted, switching
to LEDs can more than double the night sky brightness as perceived by our dark-adapted eyes.
Moving Forward
Luginbuhl thinks that beyond being a biological problem, light pollution is a societal problem. It’s wasted energy
that’s flooding into space. But culturally, we won’t do anything about light pollution unless it matters to more than a
few thousand astronomers. He says that when the person down the street thinks, “that matters to me,” only then
do we have a chance of putting sufficient effort and resources into fixing the problem.
“You don’t have to be an astronomer to be influenced by a view of a starry night,” said Luginbuhl. “And you don’t
have to know how far a star is to get the basic message that the universe over your head has meaning and
perspective to give to human life.”
Perhaps if we continue to work to reduce light pollution, we can create a night sky visible enough to inspire more
12-year-olds sitting on their front porches.
Source: Sky and Telescope Return to Contents
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Space Image of the Week
Sputnik Planum vs. Krun Macula Image Credit: NASA, Johns Hopkins Univ. /APL, Southwest Research Institute
Explanation: Pluto's pitted plains meet rugged highlands in this stunning view. On the left lies a southeastern
extent of the bright region still informally known as Sputnik Planum. At right the edge of a dark region,
informally Krun Macula, rises some 2.5 kilometers above the icy plains. Along the boundary, connected clusters
of large pits form deep valleys, some over 40 kilometers long with shadowy floors. Nitrogen ice is likely
responsible for the more reflective plains. The dark red color of the highlands is thought to be from complex
compounds called tholins, a product of ultraviolet light induced chemical reactions with methane in Pluto's
atmosphere. The enhanced color image includes portions of the highest and second highest resolution image
data from the New Horizons July 2015 flyby of the distant world.
Source: NASA APOD Return to Contents