Top News

More to Life Than the Habit-able Zone

Juno spacecraft spots Jupi-ter’s Great Red Spot

Vast new super cluster of galaxies named Saraswati

Yes, the sun is an ordinary, solar-type star after all

Better than Star Wars: Chem-istry discovery yields 3-D ta-ble-top objects crafted from light

Spiky ferrofluid thrusters can move satellites

Shedding light on galaxies’ rotation secrets

Planet 9 hypothesis alive and well

Smart atomic cloud solves Heisenberg’s observation problem

Micromotors are powered by bacteria, controlled by light

Smallest-ever star discov-ered by astronomers

Researchers develop tech-nique to control and mea-sure electron spin voltage

This Week’s Sky at a Glance, July 15-21, 2017

July 15, 2017 Shawwal 21, 1438 AH Volume 7, Issue 28

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Special Read:

In space, this is the age of re-usability

Spectacular Solar Sunspots and Eruptions - Mohamed Ta-lafha (Scass) July 09, 2017

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More to Life Than the Habit-able Zone

Two separate teams of scientists from the CfA have identified major challenges for the development of life in TRAPPIST-1. The TRAPPIST-1 system, depicted here in an artist’s concep-tion, contains seven roughly Earth-sized planets orbiting a red dwarf, which is a faint, low-mass star. This star spins rapidly and generates energetic flares of ultraviolet radiation and a strong wind of particles. The research teams say the behavior of this red dwarf makes it much less likely than generally thought that the three planets orbiting well within the habitable zone could support life. NASA/JPL-Caltech/R. Hurt

Two separate teams of scientists have identified major challenges for the development of life in what has recent-ly become one of the most famous exoplanet systems, TRAPPIST-1.

The teams, both led by researchers at the Harvard-Smith-sonian Center for Astrophysics (CfA) in Cambridge, Mass., say the behavior of the star in the TRAPPIST-1 system makes it much less likely than generally thought, that planets there could support life.

The TRAPPIST-1 star, a red dwarf, is much fainter and less massive than the Sun. It is rapidly spinning and generates energetic flares of ultraviolet (UV) radiation.

The first team, a pair of CfA theorists, considered many factors that could affect conditions on the surfaces of planets orbiting red dwarfs. For the TRAPPIST-1 system they looked at how temperature could have an impact on ecology and evolution, plus whether ultraviolet radiation from the central star might erode atmospheres around the seven planets surrounding it. These planets are all much closer to the star than the Earth is to the Sun, and three of them are located well within the habitable zone.

“The concept of a habitable zone is based on planets be-ing in orbits where liquid water could exist,” said Manasvi Lingam, a Harvard researcher who led the study. “This is only one factor, however, in determining whether a planet is hospitable for life.”

Lingam and his co-author, Harvard professor Avi Loeb, found that planets in the TRAPPIST-1 system would be barraged by UV radiation with an intensity far greater than experienced by Earth. ....Read More...

Juno spacecraft spots Jupi-ter’s Great Red Spot

This enhanced-color image of Jupiter’s Great Red Spot was creat-ed by citizen scientist Jason Major using data from the JunoCam imager on NASA’s Juno spacecraft. The image was taken on July 10, 2017 at 07:10 p.m. PDT (10:10 p.m. EDT), as the Juno space-craft performed its 7th close flyby of Jupiter. At the time the im-age was taken, the spacecraft was about 8,648 miles (13,917 kilometers) from the tops of the clouds of the planet. Credits: NASA/JPL-Caltech/SwRI/MSSS/Jason Major

mages of Jupiter’s Great Red Spot reveal a tangle of dark, veinous clouds weaving their way through a massive crimson oval. The JunoCam imager aboard NASA’s Juno mission snapped pics of the most iconic feature of the solar system’s largest planetary inhabitant during its Monday (July 10) flyby. The images of the Great Red Spot were downlinked from the spacecraft’s memory on Tuesday and placed on the mission’s JunoCam website Wednesday morning.

“For hundreds of years scientists have been observing, wondering and theorizing about Jupiter’s Great Red Spot,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. “Now we have the best pictures ever of this iconic storm. It will take us some time to analyze all the data from not only JunoCam, but Juno’s eight science instruments, to shed some new light on the past, present and future of the Great Red Spot.”

As planned by the Juno team, citizen scientists took the raw images of the flyby from the JunoCam site and processed them, providing a higher level of detail than available in their raw form. The citizen-scientist images, as well as the raw images they used for image process-ing, can be found at: www.missionjuno.swri.edu/junocam/processing

“I have been following the Juno mission since it launched,” said Jason Major, a JunoCam citizen scientist and a graphic designer from Warwick, Rhode Island. “It is always excit-ing to see these new raw images of Jupiter as they arrive. But it is even more thrilling to take the raw images and turn them into something that people can appreciate. That is what I live for.”

Measuring in at 10,159 miles (16,350 kilometers) in width (as of April 3, 2017) Jupiter’s Great Red Spot is 1.3 times as wide as Earth. The storm has been..Read More...

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Vast new super cluster of galaxies named Saraswati

The distribution of galaxies, from Sloan Digital Sky Survey (SDSS), in Saraswati supercluster. It is clearly visible that the density of galaxies is very high in the Saraswati supercluster region. The typical size of a galaxy here is around 250,000 light years. The galaxy sizes are increased for representation.

A team of astronomers from the Inter University Centre for Astronomy and Astrophysics (IUCAA) and Indian Institute of Science Education and Research (IISER), both in Pune, India, and members of two other Indian universities, have identified a previously unknown, extremely large super-cluster of galaxies located in the direction of constellation Pisces. This is one of the largest known structures in the nearby universe and is at a distance of 4,000 million (400 crore) light-years away from us.

This novel discovery is being published in the latest issue of the Astrophysical Journal, the premier research journal of the American Astronomical Society.

Large-scale structures in the universe are found to be hi-erarchically assembled, with galaxies, together with as-sociated gas and dark matter, being clumped in clusters, which are organized with other clusters, smaller groups, filaments, sheets, and large empty regions (“voids”) in a pattern called the “cosmic web,” which spans the observ-able universe.

Superclusters are the largest coherent structures in the cosmic web. A supercluster is a chain of galaxies and gal-axy clusters, bound by gravity, often stretching to several hundred times the size of clusters of galaxies, consisting of tens of thousands of galaxies. This newly discovered ‘Saraswati’ supercluster, for instance, extends over a scale of 600 million light-years and may contain the mass equiv-alent of over 20 million billion Suns.

When astronomers look far away, they see the universe from long ago, since light takes a while to reach us. The Saraswati supercluster is observed as it was when the uni-verse was 10 billion years old.

The long-popular “cold dark matter” model of the evolution of the universe predicts that small structures like galaxies form first, which congregate into larger structures. Most forms of this model do not predict the ..Read More...

Yes, the sun is an ordinary, solar-type star after all

In this video you are placed inside a simulation of the interior of a solar-type star. The red and blue shapes represent the turbulent convective motions that animate the external shell of the Sun, which covers 30% of its radius.

he Sun is a solar-type star, a new study claims - resolving an ongoing controversy about whether the star at the cen-ter of our Solar System exhibits the same cyclic behavior as other nearby, solar-type stars.

The results also advance scientists’ understanding of how stars generate their magnetic fields.

The Sun’s activity - including changes in the number of sunspots, levels of radiation and ejection of material - var-ies on an eleven-year cycle, driven by changes in its mag-netic field.

Understanding this cycle is one of the biggest outstand-ing problems in solar physics, in part because it does not appear to match magnetic cycles observed on other so-lar-type stars - leading some to suggest the Sun is funda-mentally different.

Here, by carrying out a series of simulations of stellar magnetic fields, Antoine Strugarek and colleagues show that the Sun’s magnetic cycle depends on its rotation rate and luminosity.

This relationship can be expressed in terms of the so-called Rossby number; they show that the magnetic cycle of the Sun is inversely proportional to this number.

Comparing the results of their simulations with available observations of cyclic activity in a sample of nearby so-lar-type stars, the authors further find that the cycle pe-riods of the Sun and other solar-type stars all follow the same relationship with the Rossby number. The results demonstrate that the Sun is indeed a solar-type star. ...Read More...

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Better than Star Wars: Chem-istry discovery yields 3-D ta-ble-top objects crafted from light

The set-up for the SMU 3-D light pad includes this ultraviolet pro-jector as well as a visible projector. The two project patterns of light into a chamber of photoactivatable dye. Wherever the UV light intersects with the green light it generates a 3-dimensional image inside the chamber. Credit: SMU

A scientist’s dream of 3-D projections like those he saw years ago in a Star Wars movie has led to new technology for making animated 3-D table-top objects by structuring light.

The new technology uses photoswitch molecules to bring to life 3-D light structures that are viewable from 360 de-grees, says chemist Alexander Lippert, Southern Method-ist University, Dallas, who led the research.

The economical method for shaping light into an infinite number of volumetric objects would be useful in a variety of fields, from biomedical imaging, education and engi-neering, to TV, movies, video games and more.

“Our idea was to use chemistry and special photoswitch molecules to make a 3-D display that delivers a 360-de-gree view,” Lippert said. “It’s not a hologram, it’s really three-dimensionally structured light.”

Key to the technology is a molecule that switches be-tween non-fluorescent and fluorescent in reaction to the presence or absence of ultraviolet light.

The new technology is not a hologram, and differs from 3-D movies or 3-D computer design. Those are flat dis-plays that use binocular disparity or linear perspective to make objects appear three-dimensional when in fact they only have height and width and lack a true volume profile.

“When you see a 3-D movie, for example, it’s tricking your brain to see 3-D by presenting two different images to each eye,” Lippert said. “Our display is not tricking your brain—we’ve used chemistry to structure light in three ac-tual dimensions, so no tricks, just a real three-dimensional light structure. We call it a 3-D digital light photoactivat-able dye display, or 3-D Light Pad for short, and it’s much more like what we see in real life.” ...Read More...

Spiky ferrofluid thrusters can move satellites

A ferrofluid is a magnetic liquid that turns spiky in a magnetic field. Add an electric field and each needle-like spike emits a jet of ions, which could solve micropropulsion for nanosatellites in space. Credit: Sarah Bird/Michigan Tech

Brandon Jackson, a doctoral candidate in mechanical engi-neering at Michigan Technological University, has created a new computational model of an electrospray thruster us-ing ionic liquid ferrofluid—a promising technology for pro-pelling small satellites through space. Specifically, Jackson looks at simulating the electrospray startup dynamics; in other words, what gives the ferrofluid its characteristic spikes.

He is the lead author of a recent article in Physics of Flu-ids, “Ionic Liquid Ferrofluid Interface Deformation and Spray Onset Under Electric and Magnetic Stresses”.

Up in Space

More than 1,300 active satellites orbit the Earth. Some are the size of a school bus, and others are far smaller, the size of a shoebox or a smart phone.

Small satellites can now perform the missions of much larger and more expensive spacecraft, due to advances in satellite computational and communications systems. However, the tiny vehicles still need a more efficient way to maneuver in space.

Scaled-down plasma thrusters, like those deployed on larger-class satellites, do not work well. A more promising method of micropropulsion is electrospray.

Electrospray involves microscopic, hollow needles that use electricity to spray thin jets of fluid, pushing the space-craft in the opposite direction. But the needles have draw-backs. They are intricate, expensive and easily destroyed.

Flying with Ferrofluids

To solve this problem, L. Brad King, Ron & Elaine Starr Professor in Space Systems at Michigan Tech, is creating a new kind of microthruster that assembles itself out of its own propellant when excited by a magnetic field. The tiny thruster requires no fragile needles and is essentially indestructible. ..Read More...

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Shedding light on galaxies’ rotation secrets

Spiral galaxies are found to be strongly rotating, with an angular momentum higher by a factor of about 5 than ellipticals.

The dichotomy concerns the so-called angular momentum (per unit mass), that in physics is a measure of size and rotation velocity. Spiral galaxies are found to be strongly rotating, with an angular momentum higher by a factor of about 5 than ellipticals. What is the origin of such a dif-ference? An international research team investigated the issue in a study just published in the Astrophysical Journal.

The team was led by SISSA Ph.D. student JingJing Shi un-der the supervision of Prof. Andrea Lapi and Luigi Danese, and in collaboration with Prof. Huiyuan Wang from USTC (Hefei) and Dr. Claudia Mancuso from IRA-INAF (Bologna).

The researchers inferred from observations the amount of gas fallen into the central region of a developing galaxy, where most of the star formation takes places.

The outcome is that in elliptical galaxies only about 40% of the available gas fell into that central region. More rel-evantly, this gas fueling star formation was characterized by a rather low angular momentum since the very begin-ning. This is in stark contrast with the conditions found in spirals, where most of the gas ending up in stars had an angular momentum appreciably higher.

In this vein, the researchers have traced back the dichoto-my in the angular momentum of spiral and elliptical galax-ies to their different formation history. Elliptical galaxies formed most of their stars in a fast collapse where angular momentum is dissipated.

This process is likely stopped early on by powerful gas outflows from supernova explosions, stellar winds and possibly even from the central supermassive black hole. For spirals, on the other hand, the gas infelt slowly con-serving its angular momentum and stars formed steadily along a timescale comparable to the age of the Universe.

“Till recent years, in the paradigm of galaxy formation and evolution, elliptical galaxies were thought to have formed by the merging of stellar disks in the distant Universe. Along this line, their angular momentum was thought to be the result of dissipative processes during such merging events” say the researchers. ...Read More...

Planet 9 hypothesis alive and well

Artist’s concept of a distant, massive, undiscovered planet in our own solar system, via NASA/ SINC.

Caltech astronomers said over a year ago they had sol-id theoretical evidence for a 9th major planet in our so-lar system, located some 700 times farther from the sun than Earth. They nicknamed it Planet 9 and said they hoped other astronomers would search for it. At least two searches involving citizen scientists (one in the Northern Hemisphere and one in the Southern Hemisphere) are cur-rently ongoing. Meanwhile, some astronomers have said there were “biases” in the observational data used by the Caltech astronomers, which calls their Planet 9 hypoth-esis into question. This week, two Spanish astronomers announced word of their analysis of the orbits of a spe-cial class of extreme trans-Neptunian objects, that is, the small, known objects beyond Neptune’s orbit. The work of the Spanish astronomers confirms that something is per-turbing the orbits of small bodies in the outer solar sys-tem. They say it might be an unknown planet located 300-400 times farther from the sun than Earth.

These astronomers – who are from the Complutense Uni-versity of Madrid – published their work late last month in the Letters section of the peer-reviewed journal Monthly Notices of the Royal Astronomical Society.

The two astronomers say their analysis technique is “nov-el” and “less exposed to observational bias.”

They looked at a special type of trans-Neptunian objects: the so-called extreme trans-Neptunian objects, or ETNOs. These are objects located at average distances greater than 150 Earth-sun distances, which never cross Nep-tune’s orbit.

The Spanish astronomers looked at a special point in the orbits of these objects, specifically their nodes, the points where the orbits cross the ecliptic, or Earth-sun plane. This useful plane more or less defines the plane of most plan-ets and moons in our solar system. An article about this work via Information and Scientific News Service (SINC) explained: “ [The nodes] are the precise points where the probability of interacting with other objects is the largest, and therefore, at these points, the ETNOs may experience a drastic change in their orbits or even ...Read More...

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Micromotors are powered by bacteria, controlled by light

A micromotor, with microchambers shown in the inner cylindrical structure. Credit: Vizsnyiczai et al. Published in Nature Communi-cations.

When researchers deposit a drop of fluid containing thou-sands of free-swimming, genetically engineered E. coli onto an array of micromotors, within minutes the micromo-tors begin rotating. Some of the individual bacteria have swum head-first into one of the 15 microchambers etched on the outer edge of each micromotor, and with their fla-gella protruding outside the microchambers, together the swimming bacteria cause the micromotors to rotate, some-what similar to how a flowing river rotates a watermill.

The researchers, led by Roberto Di Leonardo, a physics professor at Sapienza Università di Roma and at NAN-OTEC-CNR, both in Rome, have published a paper on the bacteria-powered micromotors in a recent issue of Nature Communications.

“Our design combines a high rotational speed with an enor-mous reduction in fluctuation when compared to previous attempts based on wild-type bacteria and flat structures,” said Di Leonardo. “We can produce large arrays of inde-pendently controlled rotors that use light as the ultimate energy source. These devices could serve one day as cheap and disposable actuators in microrobots for collecting and sorting individual cells inside miniaturized biomedical lab-oratories.”

A fluid such as the one used here, which contains large amounts of swimming bacteria, is called an “active fluid” due to the mechanical energy it contains. In order for active fluids to be used as a fuel for propelling micromachines, the disordered motion of the bacteria must be controlled so that all (or most) of the bacteria move in the same di-rection.

This is essentially what the micromotors do. The micro-chambers along the edges of each micromotor are tilted at an angle of 45°, which maximizes the total torque with which the bacteria can cause the motors to rotate. In their design, the researchers also built a radial ramp with stra-tegically placed barriers that direct the swimming bacteria into the microchambers. In experiments, the researchers found that a micromotor’s rotational speed ..Read More...

Smart atomic cloud solves Heisenberg’s observation problem

The atomic part of the hybrid experiment is shown. The atoms are contained in a micro-cell inside the magnetic shield seen in the middle. Credit: Ola J. Joensen

Scientists at the University of Copenhagen have devel-oped a hands-on answer to a challenge linked to Heisen-berg’s Uncertainty Principle. The researchers used laser light to link caesium atoms and a vibrating membrane. The research, the first of its kind, points to sensors capable of measuring movement with unseen precision.

When measuring atom structures or light emissions at the quantum level by means of advanced microscopes or other forms of special equipment, things are complicated due to a problem which, during the 1920s, had the full attention of Niels Bohr and Werner Heisenberg. And this problem, dealing with inaccuracies that taint certain measurements conducted at quantum level, is described in Heisenberg’s Uncertainty Principle, which states that complementary variables of a particle, such as velocity and position, can never be simultaneously known.

In a scientific report published in this week’s issue of Na-ture, NBI researchers demonstrate that Heisenberg’s Un-certainty Principle can be neutralized to some degree. This has never been shown before, and the results may spark development of new measuring equipment, and new and better sensors.

Professor Eugene Polzik, head of the Quantum Optics (QUANTOP) at the Niels Bohr Institute, led the research, which involved the construction of a vibrating membrane and an advanced atomic cloud locked up in a minute glass cage.

Light ‘kicks’ object

The Uncertainty Principle emerges in observations con-ducted via a microscope operating with laser light, which inevitably will lead to the object being kicked by photons. As a result of those kicks, the object begins to move in a random way. This phenomenon is known as quantum back action (QBA), and these random movements put a limit to the accuracy with which measurements can be carried out at quantum level. To conduct the experiments at NBI, pro-fessor Polzik and his collaborators used ..Read More...

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Smallest-ever star discovered by astronomers

Credit: Amanda Smith

The smallest star yet measured has been discovered by a team of astronomers led by the University of Cambridge. With a size just a sliver larger than that of Saturn, the grav-itational pull at its stellar surface is about 300 times stron-ger than what humans feel on Earth.

The star is likely as small as stars can possibly become, as it has just enough mass to enable the fusion of hydro-gen nuclei into helium. If it were any smaller, the pressure at the centre of the star would no longer be sufficient to enable this process to take place. Hydrogen fusion is also what powers the Sun, and scientists are attempting to rep-licate it as a powerful energy source here on Earth.

These very small and dim stars are also the best possible candidates for detecting Earth-sized planets which can have liquid water on their surfaces, such as TRAPPIST-1, an ultracool dwarf surrounded by seven temperate Earth-sized worlds.

The newly-measured star, called EBLM J0555-57Ab, is lo-cated about six hundred light years away. It is part of a binary system, and was identified as it passed in front of its much larger companion, a method which is usually used to detect planets, not stars. Details will be published in the journal Astronomy & Astrophysics.

“Our discovery reveals how small stars can be,” said Alex-ander Boetticher, the lead author of the study, and a Mas-ter’s student at Cambridge’s Cavendish Laboratory and Institute of Astronomy. “Had this star formed with only a slightly lower mass, the fusion reaction of hydrogen in its core could not be sustained, and the star would instead have transformed into a brown dwarf.”

EBLM J0555-57Ab was identified by WASP, a planet-find-ing experiment run by the Universities of Keele, Warwick, Leicester and St Andrews. EBLM J0555-57Ab was detect-ed when it passed in front of, or transited, its larger parent star, forming what is called an eclipsing stellar binary sys-tem. The parent star became dimmer in a periodic fashion, the signature of an orbiting object. Thanks to this special configuration, researchers can accurately measure the mass and size of any orbiting companions, in this case a small star. The mass of EBLM J0555-57Ab was established via the Doppler, wobble method, ...Read More...

Researchers develop tech-nique to control and mea-sure electron spin voltage

Researchers used atomic-size defects in diamonds to detect and measure magnetic fields generated by spin waves. Credit: Peter and Ryan Allen/Harvard University

Information technologies of the future will likely use electron spin—rather than electron charge—to carry in-formation. But first, scientists need to better understand how to control spin and learn to build the spin equivalent of electronic components, from spin transistors, to spin gates and circuits.

Now, Harvard University researchers have developed a technique to control and measure spin voltage, known as spin chemical potential. The technique, which uses atomic-sized defects in diamonds to measure chemical potential, is essentially a nanoscale spin multimeter that allows measurements in chip-scale devices.

The research is published in Science.

“There is growing interest in insulating materials that can conduct spin,” said Amir Yacoby, Professor of Physics in the Department of Physics and of Applied Physics at Harvard John A. Paulson School of Engineering and Ap-plied Sciences and senior author of the paper. “Our work develops a new way to look at these spins in materials such as magnets.”

In conducting materials, electrons can carry information by moving from point A to point B. This is an electric cur-rent. Spin, on the other hand, can propagate through in-sulating materials in waves—each electron standing still and communicating spin to its coupled neighbor, like a quantum game of telephone.

To drive these waves from point A to point B, the re-searchers needed to develop a technique to increase the spin chemical potential—spin voltage—at a local level.

“If you have a high chemical potential at location A and a low chemical potential at location B, spin waves start diffusing from A to B,” said Chunhui Du, a postdoctoral fellow at the Department of Physics and co-first author of the paper. “This is a very important ...Read More...

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Special Read:

In space, this is the age of reusability

Credits: NASA/JHUAPL Falcon 9 launch in March 2017. Credit: SpaceX/flickr

Big plans are being made in space.

nvestment banks want to mine asteroids for rare, valuable metals. Japan wants to build a solar power station. Billionaire tycoons want to build hotels in orbit for space tourists.

We could be seeing the start of an economic boom in space. But so far, none of these ideas have made it far from the drawing board. What’s holding them back?

Reusing rockets

First and foremost, it’s hard to make profit in space. Moving “stuff” (cargo, equipment and people) from Earth into space is an expensive process. This is because we haven’t learnt how to recycle rockets yet.

Since the launch of Sputnik started the space age 60 years ago, most of the spacecraft that have been launched are Expendable Launch Vehicles (ELVs), which only fly once. After delivering their payload, they either come crashing back down to Earth, burn up in the atmosphere, or simply remain in orbit as “space junk”.

Every time a new payload needs to be sent into space, a new ELV has to be built, costing millions of dollars. Imagine how much an Uber would cost if the driver had to buy a new car for every trip!

It might seem that the obvious solution is to reuse rockets. The idea of Reusable Launch Vehicles (RLVs) isn’t new, but reusing rockets has proven tricky in the past.

The first real attempt at making an RLV was NASA’s Space Shuttle program.

The Space Shuttle fleet was meant to lower the cost of space transportation by being partially reusable. But rather than lowering costs, the program increased them. The complexity and risk of the Space Shuttle fleet made maintaining and operating them expensive. And when the 30-year program ended in 2011, it may have seemed like the argument for RLVs ended with it.

Recovering and recycling

But proponents of RLVs were undeterred. A few months after the final Space Shuttle flight, SpaceX, a start-up company founded by tech billionaire Elon Musk announced a plan to make its Falcon 9 rocket reusable. SpaceX began working on ways to recover and reuse the Falcon 9’s booster stage, the largest, most expensive part of the rocket. ...Read More...

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Spectacular Solar Sunspots and Eruptions

Credit: Mohamed Talafha (SCASS Observatory - July 09, 2017)

This Week’s Sky at a Glance:July 15-21, 2017

Jul 16 Third-quarter Moon (23:25) Jul 20 Aldebaran 0.4º S of Moon (03:37) Jul 21 Moon at perigee 21:09 (361238 km)