Clouds on 'Failed Stars' Resemble Those on Neptune

Clouds on 'Failed Stars' Resemble Those on Neptune:

Researchers have found Neptune-like bands of clouds circling the surface of a brown dwarf, an object in between the size of a planet and a star.

Credit: NASA/JPL-Caltech

For the first time, scientists have seen bands of clouds drifting across the skies of failed stars known as brown dwarfs.

This work could help scientists analyze Earth-like planets someday, the new study's researchers said.

In the past 25 years or so, astronomers have confirmed the existence of more than 3,500 exoplanets, or planets outside Earth's solar system. Scientists have also detected numerous so-called brown dwarfs, objects that are about 13 to 90 times the mass of Jupiter — too big to be planets, but not quite big enough to be true stars. Researchers sometimes call brown dwarfs "failed stars," because nuclear fusion never ignited in their cores. [Brown Dwarf Photos: Failed Stars and Stellar Misfits Revealed]

Scientists have previously detected evidence of clouds on exoplanets and brown dwarfs. However, this is the first time that cloud bands have been spotted on one of those objects, study team members said.

Previous work suggested that brown dwarfs have much in common with giant exoplanets in terms of size, temperature and composition. As such, study lead author Daniel Apai, who is an astrophysicist and planetary scientist at the University of Arizona in Tucson, and his colleagues investigated brown dwarfs to learn more about giant exoplanets.

The fact that many brown dwarfs are located away from stars makes them easier for astronomers to examine than many giant exoplanets, Apai told Space.com. In contrast, giant exoplanets are typically obscured partly by the brightness of their stars, he added.

In the past five years, a number of studies have found that the infrared light from many brown dwarfs could vary in unusual ways over time. However, until now, there was no convincing explanation for this phenomenon.

To help solve this mystery, Apai and his colleagues analyzed data from NASA's Spitzer Space Telescope. They focused on the way the infrared brightness of three brown dwarfs changed over time as the objects completed a total of 192 rotations over the course of 1.5 years.

The observations of these brown dwarfs helped "derive crude maps for how their clouds are distributed and how they evolve," Apai said.

The scientists discovered rotating bands of clouds in the atmospheres of these brown dwarfs that are broadly similar to bands of clouds seen on Neptune. As the bands on the brown dwarfs rotated, slight differences in the speeds of the bands generated a pattern of beats in their infrared light, explaining the mystery regarding their shifting brightness, Apai said.

"This is the first time that the presence of bands is shown in brown dwarfs," Apai said. He added that scientists have not yet reported any evidence for bands of clouds in exoplanets.

Although the researchers looked at only three brown dwarfs, "the fact that all three brown dwarfs behaved the same way suggests that what we see should be a common, perhaps general behavior," Apai said. "What we learn from brown dwarfs should be applicable to the majority of the gas giant exoplanets, too."

In the future, the next major NASA space telescope, the James Webb Space Telescope, will help researchers analyze brown dwarfs and exoplanets in even greater detail, Apai said."The same technique we used for brown dwarfs now could be used to build crude maps of Earth-like planets, once we have the right telescopes, and NASA is exploring some designs that could do that in the future," he added.

The scientists detailed their findings in the Aug. 18 issue of the journal Science.

Follow Charles Q. Choi on Twitter @cqchoi. Follow us @Spacedotcom, Facebook and Google+. Original article on Space.com.

Best Astronomy and Astrophysics Books

Best Astronomy and Astrophysics Books:

The Veil Nebula, in the constellation Cygnus, is one of the most massive and brilliant features in the x-ray sky.

Credit: NASA, ESA, Hubble Heritage Team

The universe through the eyes of an astronomer or astrophysicist is a fascinating place — and a good book can give you a glimpse of that world without requiring years of study. Here are the Space.com writers' and editors' recommendations of astronomy and astrophysics books that will thrill, puzzle, intrigue and blow your mind.

(We are constantly reading new and classic space books to find our favorite takes on the universe. Our recently-read books in all categories can be found at Best Space Books. You can see our ongoing Space Books coverage here.)

'Sun Moon Earth' (Basic Books, 2016)

By Tyler Nordgren

"Sun Moon Earth: The History of Solar Eclipses from Omens of Doom to Einstein and Exoplanets" (Basic Books, 2016) by Tyler Nordgren.

Credit: Basic Books


Throughout history, solar eclipses have transformed from terrifying omens to the subject of scientific study. In "Sun Moon Earth: The History of Solar Eclipses from Omens of Doom to Einstein and Exoplanets," astronomer-artist Tyler Nordgren traces the natural history of eclipses and how they have inspired eclipse chasers to travel the world and witness the natural phenomenon.

Nordgren's narrative also details how observations of total solar eclipses have contributed to scientific discoveries about the sun, moon and Earth's place in the universe throughout history. ~ Samantha Mathewson

Read an interview with the book's author here.

'Exoplanets' (Smithsonian Books, 2017)

By Michael Summers and James Trefil

"Exoplanets: Diamond Worlds, Super Earths, Pulsar Planets and the New Search for Life Beyond Our Solar System" (Smithsonian Books, 2017) by Michael Summers and James Trefil

Credit: Ron Miller/Jody Billert


The search for planets beyond Earth's solar system has revealed countless surprises, including the existence of strange and unexpected worlds that astronomers would have never imagined existed only a few decades ago. A new book titled "Exoplanets: Diamond Worlds, Super Earths, Pulsar Planets and the New Search for Life Beyond Our Solar System" (Smithsonian Books, 2017) explores the history of exoplanet research, illustrates the many different types of planets that have been discovered to date and discusses how astronomers plan to further study these newfound alien worlds. ~Samantha Mathewson

You can read an interview with the authors here.

'Asteroid Hunters' (Simon & Schuster, 2017)

By Carrie Nugent

"Asteroid Hunters" (Simon & Schuster, 2017) by Carrie Nugent.

Credit: Simon & Schuster


The solar system is a wild place, and even Earth's immediate neighborhood is much more chaotic than maps would suggest — researchers discover more than 100 near-Earth asteroids every month. A new book by Carrie Nugent, an asteroid researcher from Caltech, goes through how we find asteroids and near-Earth objects and what we would do if one was heading toward us. "Asteriod Hunters" (Simon & Schuster, 2017) is a quick overview of the growing field, giving a feel for how science is done and where we'll have to pick up speed to protect Earth — plus, a visceral understanding of exactly how much risk is out there. ~Sarah Lewin

Read an interview with Nugent on the book and the latest in asteroid hunting here.

'Earth in Human Hands' (Grand Central Publishing, 2016)

By David Grinspoon

"Earth in Human Hands" (Grand Central Publishing, 2016) by David Grinspoon

Credit: Grand Central Publishing


Over the past century, humankind's influence over our environment has increased dramatically. Astrobiologist and planetary scientist David Grinspoon argues that our species is arriving at a point that lifeforms across the galaxy may face — become self-sustaining or perish. In "Earth in Human Hands," Grinspoon explores the ways that, for good or bad, humans have seized control of the planet. The choice is whether we do so mindlessly, or whether we act in a responsible, considerate manner. Such a dilemma may be common to all life, and the most successful, long-lasting civilizations in the galaxy may live on planets they have engineered to be stable over extensive periods of time, making them more difficult to identify than rapidly-expanding societies. ~Nola Redd

You can read an interview with Grinspoon (and watch video clips of him discussing the book with Space.com) here.

NightWatch: A Practical Guide to Viewing the Universe (Firefly Books, 2016)

by Terence Dickinson

"NightWatch: A Practical Guide to Viewing the Universe," Revised Fourth Edition, by Terence Dickinson

Credit: Firefly Books


"NightWatch" is the perfect introduction to astronomy and stargazing. It has been the top-selling stargazing guide for over 20 years. Now in its revised fourth edition, the book contains everything you need to know about what's up in the sky through the year 2025. The bookre chapter is dedicated to stargazing technology, like binoculars and telescopes. "NightWatch" assumes that the reader has no prior experience with astronomy. It is clear and concise enough for any beginner to understand, but is pac is filled with star charts, tables with information about stargazing events and incredible photos of space. An entiked with information that even the most experienced stargazers will find comes in handy. ~Hanneke Weitering

Watch our gift guide video about the book here.

Buy NightWatch on Amazon.com.

'The Glass Universe' (Viking, 2016)

By Dava Sobel

"The Glass Universe" follows the women of the Harvard College Observatory and their groundbreaking measurements of the stars.

Credit: Viking


"The Glass Universe" highlights the remarkable story of how a group of women, called "computers," shaped the field of astronomy during the mid-19th century — when women were not typically employed outside the home. At that time, astronomers relied on grounded telescopes to record nightly observations of the stars. Women computers at the Harvard College Ovesrvatory were then tasked with interpreting those observations, captured on photographic glass plates. Author Dava Sobel follows the stories of several women, which she collected from old diaries, letters and published observatory log books. Based on their calculations, these women — including Williamina Fleming, Antonia Maury, Henrietta Leavitt, Annie Jump Cannon and Cecilia Payne — made some of the most fundamental discoveries of our universe. ~Samantha Mathewson

Read a Q&A with Sobel about the book here.

'Facts From Space!' (Adams Media, 2016)

By Dean Regas

"Facts From Space!" by Dean Regas

Credit: Adams Media, 2016


For any space fan looking to learn crazy, fun facts about the universe, "Facts From Space!" is a great place to start. Dean Regas, an astronomer and public outreach educator for the Cincinnati Observatory, has gathered together all the cool, quirky and mind-blowing facts you probably never knew you'd want to know about the universe. Regas chronicles everything from the sometimes silly adventures of space travelers in Earth's orbit and on the moon to black holes, galaxies and nebulas far away in deep space, listing all the best facts about the universe in a way that is fun and easy to read. Readers of all ages can understand and appreciate the contents of this book. No attention span is necessary to enjoy it — flip to any page and you'll find a handful of short facts and cartoons that make learning about space a simple and entertaining experience. ~Hanneke Weitering

Space.com spoke with Dean Regas about making "Facts From Space!" exciting and accessible here.

'Spooky Action at a Distance' (Farrar, Straus and Giroux, 2015)

By George Musser

"Spooky Action at a Distance" by George Musser

Credit: Farrar, Straus and Giroux


Space and time are weird. Human understanding of the universe relies on space and time separating things — one object cannot affect another unless they're touching, or unless object A sends an intermediary out to touch object B, like a photon bouncing off of something and into your eye. All very straightforward, and good for scientific investigation.

But the problem is, there are hints that nature doesn't actually work that way. This new book by science writer George Musser delves into the different ways that scientists are grappling with this concept of "nonlocality" — what Albert Einstein famously called "spooky action at a distance" in the quantum mechanics world. Particles that are entangled affect each other instantaneously even when separated; paradoxical black holes can be explained if the stuff sucked in exists inside their gravitational pull and on the surface at the same time. Musser explores the history of humans grappling with nonlocality and what these strange effects are teaching quantum mechanics researchers, astronomers, cosmologists and more about how the universe works — and while doing so, showing the messy, nonlinear and fascinating way researchers push forward to understand the physical world. ~Sarah Lewin

Read a Q&A with George Musser about his new book and the nature of reality here.

'Black Holes and Time Warps: Einstein's Outrageous Legacy' (W. W. Norton, 1994)

By Kip Thorne

"Black Holes and Time Warps: Einstein's Outrageous Legacy" by Kip Thorne.

Credit: W.W. Norton & Company


Theoretical astrophysicist Kip Thorne has spent his career exploring topics that once seemed relegated to science fiction, such as whether time travel is possible, and how humans could potentially travel from galaxy to galaxy via wormholes. In "Black Holes and Time Warps," Thorne provides an introduction to these and other mind-bending topics, at a level appropriate for nonscientists. The book is not a light read — it goes deeper into the science than many pop physics books — but Thorne is the perfect person to take readers on this journey: He's a patient and entertaining teacher, and he never loses the thread of the story. On top of the science lessons, Thorne introduces a cast of characters who pushed these fields forward, and chronicles the fight by American and Russian physicists to continue scientific collaboration during the Cold War. (Twenty years after its publication, Thorne talked with Space.com about the new science he would add to the book.) ~Calla Cofield

'Cosmos' (Random House, 1980)

By Carl Sagan

"Cosmos" by Carl Sagan.

Credit: Random House


"Cosmos," by famed astronomer and science communicator Carl Sagan, is a deep dive into the history of science, philosophy and the universe. The book acts as a partner with Sagan's beloved 1980s TV show, "Cosmos: A Personal Voyage." This book is a beautiful glimpse inside one of the greatest scientific minds in history. While some of it may seem dated, the book still stands up as one of the best popular science books ever written, and the language is just beautiful. ~Miriam Kramer

'The Demon-Haunted World: Science as a Candle in the Dark' (Ballantine Books/Random House, 1995)

By Carl Sagan and Ann Druyan

"The Demon-Haunted World: Science as a Candle in the Dark" by Carl Sagan and Ann Druyan.

Credit: Ballantine Books


Sagan was one of the 20th century's greatest ambassadors and popularizers of science, and he doesn't disappoint in "The Demon-Haunted World." The book explains to laypeople just what science is, and how researchers use the process of scientific inquiry to understand the universe around us. There's a lot of debunking in "The Demon-Haunted World" — of alien encounters, channeling and other paranormal experiences — and Sagan even provides readers a "baloney detection kit" to help them navigate a confusing and chaotic world. Like other Sagan works, this one is a fun and engaging read, but a great deal of ambition lurks beneath the fluid prose, as this quote from the book reveals: "If we can't think for ourselves, if we're unwilling to question authority, then we're just putty in the hands of those in power. But if the citizens are educated and form their own opinions, then those in power work for us. In every country, we should be teaching our children the scientific method and the reasons for a Bill of Rights. With it comes a certain decency, humility and community spirit. In the demon-haunted world that we inhabit by virtue of being human, this may be all that stands between us and the enveloping darkness." ~Mike Wall

'Hyperspace: A Scientific Odyssey Through Parallel Universes, Time Warps, and the Tenth Dimension' (Oxford University Press, 1994)

By Michio Kaku

"Hyperspace: A Scientific Odyssey Through Parallel Universes, Time Warps, and the Tenth Dimension" by Michio Kaku.

Credit: Anchor


Our brains evolved to comprehend the world around us on a local and accessible scale. We're really not equipped to understand the universe as a 10-dimensional entity — and yet "Hyperspace" explains this revolutionary idea in such a lucid and engaging way that it makes a good deal of sense. By the time you're done reading this book, you'll have a pretty solid grasp of why Kaku and other scientists think the basic forces in our universe — electromagnetism, gravity and the strong and weak nuclear forces — may actually just be vibrations in higher-dimensional space. And it's an extremely fun read, too, with excursions into such sexy topics as parallel universes, time travel and wormholes. For example, did you know that you might be able to create a wormhole in your own kitchen using just an ice cube and a pressure cooker? All you have to do is figure out a way to heat the ice cube up to a temperature of 10³² degrees Kelvin. ~Mike Wall

We're adding to these lists all the time; let us know your favorites in the comments below!

Follow us @Spacedotcom, Facebook and Google+. 

The Most Distant Massive Galaxy Observed to Date Provides Insight into the Early Universe

The Most Distant Massive Galaxy Observed to Date Provides Insight into the Early Universe:

In their pursuit of learning how our Universe came to be, scientists have probed very deep into space (and hence, very far back in time). Ultimately, their goal is to determine when the first galaxies in our Universe formed and what effect they had on cosmic evolution. Recent efforts to locate these earliest formations have probed to distances of up to 13 billion light-years from Earth – i.e. about 1 billion years after the Big Bang.

From this, scientist are now able to study how early galaxies affected matter around them – in particular, the reionization of neutral atoms. Unfortunately, most early galaxies are very faint, which makes studying their interiors difficult. But thanks to a recent survey conducted by an international team of astronomers, a more luminous, massive galaxy was spotted that could provide a clear look at how early galaxies led to reionization.

The study which details their findings, titled “ISM Properties of a Massive Dusty Star-forming Galaxy Discovered at z ~ 7“, was recently published in The Astrophysical Journal Letters. Led by researchers from the Max Planck Institute for Radio Astronomy  in Bonn, Germany, the team relied on data from the South Pole Telescope (SPT)-SZ survey and ALMA to spot a galaxy that existed 13 billion years ago (just 800 million years after the Big Bang).

Illustration of the depth by which Hubble imaged galaxies in prior Deep Field initiatives, in units of the Age of the Universe. Credit: NASA and A. Feild (STScI)

In accordance with Big Bang model of cosmology, reionization refers to the process that took place after the period known as the “Dark Ages”. This occurred between 380,000 and 150 million years after the Big Bang, where most of the photons in the Universe were interacting with electrons and protons. As a result, the radiation of this period is undetectable by our current instruments – hence the name.

Just prior to this period, the “Recombination” occurred, where hydrogen and helium atoms began to form. Initially ionized (with no electrons bound to their nuclei) these molecules gradually captured ions as the Universe cooled, becoming neutral. During the period that followed – i.e. between 150 million to 1 billion years after the Big Bang – the large-scale structure of the Universe began to form.

Intrinsic to this was the process of reionization, where the first stars and quasars formed and their radiation reionized the surrounding Universe. It is therefore clear why astronomers want to probe this era of the Universe. By observing the first stars and galaxies, and what effect they had on the cosmos, astronomers will get a clearer picture of how this early period led to the Universe as we know it today.

Luckily for the research team, the massive, star-forming galaxies of this period are known to contain a great deal of dust. While very faint in the optical band, these galaxies emit strong radiation at submillimeter wavelengths, which makes them detectable using today’s advanced telescopes – including the South Pole Telescope (SPT), the Atacama Pathfinder Experiment (APEX), and Atacama Large Millimeter Array (ALMA).

NASA’s Spitzer Space Telescope captured this stunning infrared image of the center of the Milky Way Galaxy, where the black hole Sagitarrius A resides. Image: NASA/JPL-Caltech

For the sake of their study, Strandet and Weiss relied on data from the SPT to detect a series of dusty galaxies from the early Universe. As Maria Strandet and Axel Weiss of the Max Planck Institute for Radio Astronomy (and the lead author and co-authors on the study, respectively) told Universe Today via email:

“We have used light of about 1 mm wavelength, which can be observed by mm telescopes like SPT, APEX or ALMA. At this wavelength the photons are produced by the thermal radiation of dust. The beauty of using this long wavelength is, that for a large redshift range (look back time), the dimming of galaxies [caused] by increasing distance is compensated by the redshift – so the observed intensity is independent of the redshift. This is because, for higher redshift galaxies, one is looking at intrinsically shorter wavelengths (by (1+z)) where the radiation is stronger for a thermal spectrum like the dust spectrum.”

This was followed by data from ALMA, which the team used to determine the distance of the galaxies by looking at the redshifted wavelength of carbon monoxide molecules in their interstellar mediums (ISM). From all the data they collected, they were able to constrain the properties of one of these galaxies – SPT0311-58 – by observing its spectral lines. In so doing, they determined that this galaxy existed just 760 million years after the Big Bang.

“Since the signal strength at 1mm is independent of the redshift (look back time), we do not have an a priori clue if an object is relatively near (in the cosmological sense) or at the epoch of reionization,” they said. “That is why we undertook a large survey to determine the redshifts via the emission of molecular lines using ALMA. SPT0311-58 turns out to be the highest redshift object discovered in this survey and in fact the most distant massive dusty star-forming galaxy so far discovered.”

The Hubble Ultra Deep Field seen in ultraviolet, visible, and infrared light. Image Credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)

From their observations, they also determined that SPT0311-58 has a mass of about 330 billion Solar-masses, which is about 66 times as much as the Milky Way Galaxy (which has about 5 billion Solar-masses). They also estimated that it is forming new stars at a rate of several thousand per year, which could as be the case for neighboring galaxies that are dated to this period.

This rare and distant object is one of the best candidates yet for studying what the early Universe looked like and how it has evolved since. This in turn will allow astronomers and cosmologists to test the theoretical basis for the Big Bang Theory. As Strandet and Weiss told Universe Today about their discovery:

“These objects are important to understanding the evolution of galaxies as a whole since the large amounts of dust already present in this source, only 760 million years after the Big Bang, means that it is an extremely massive object. The mere fact that such massive galaxies already existed when the Universe was still so young puts strong constraints on our understanding of galaxy mass buildup. Furthermore the dust needs to form in a very short time, which gives additional insights on the dust production from the first stellar population.”

The ability to look deeper into space, and farther back in time, has led to many surprising discoveries of late. And these have in turn challenged some of our assumptions about what happened in the Universe, and when. And in the end, they are helping scientists to create a more detailed and complete account of cosmic evolution. Someday soon, we might even be able to probe the earliest moments in the Universe, and watch creation in action!

Further Reading: CfA, The Astrophysical Journal Letters



The post The Most Distant Massive Galaxy Observed to Date Provides Insight into the Early Universe appeared first on Universe Today.

Prelude to Totality: A Final Look at the Total Solar Eclipse

Prelude to Totality: A Final Look at the Total Solar Eclipse:

Totality! The view during the November 2012 total solar eclipse. Image credit and copyright: Sharin Ahmad (@Shahgazer)

It’s hard to believe: we’re now just one short weekend away from the big ticket astronomical event for 2017, as a total solar eclipse is set to cross over the contiguous United States on Monday, August 21^st.

Celestial mechanics is a sure thing in this Universe, a certainty along with death and taxes that you can bet on. But there are still a few key question marks leading up to eclipse day, things that we can now finally make intelligent assumptions about a few days out.

Although totality slices through the U.S., partial phases of the eclipse touch on every continent except Antarctica and Australia. Credit: Michael Zeiler/The Great American Eclipse.

First up is solar activity. If you’re like us, you’ll be showing off the Sun in both visible and hydrogen alpha as the Moon begins making its slow hour long creep across the disk of Sol. First, the good news: sunspot active region AR 2671 made its Earthward debut on Tuesday August 15^th, and will most likely stick around until eclipse day. The bad news is, it most likely won’t have lots of friends, as solar cycle #24 begins its long slow ebb towards the solar minimum in 2019-2020. Likewise, I wouldn’t expect to see any magnificent sprouting red prominences in the solar chromosphere in the seconds bracketing totality, though we could always be pleasantly surprised.

The Earthward face of Sol as of August 17, four days before totality. Sunspot AR 2671 is robust and growing in complexity. Credit: NASA/SDO/HMI

How will the white hot corona appear during totality? This is the signature climax of any total solar eclipse: veteran umbraphiles can actually glance at a photo of totality and tell you which eclipse it was from, just on the shape of the corona. The National Solar Observatory released a model of what that Sun’s magnetosphere was doing one Carrington rotation (27 days) prior to the eclipse on July 25th, a pretty good predictor of the corona might look like during those fleeting moments of totality:

The shape of the field lines of the solar corona, one rotation prior to the August 21st total solar eclipse. Credit: The National Solar Observatory.

NASA will be chasing the umbra of the Moon with two converted W-57 aircraft during the eclipse, hoping to unlock the “coronal heating paradox,” image Mercury in the infrared, and hunt for elusive Vulcanoid asteroids near the eclipsed Sun.

The view of the corona during totality? This computational model was derived from NASA SDO data during the last solar rotation. Credit: Predictive Science Inc.

The corona is about twice as bright as a Full Moon, and its interface with the solar wind extends out past the Earth. The very onset of totality is like the footstep of a giant passing over the landscape, as the door of reality is suddenly ripped open, revealing the span of the glittering solar system at midday. Keep your eyes peeled for Mercury, Venus, Mars, Jupiter and twinkling Regulus tangled up in the corona, just a degree from the Sun-Moon pair:

The line up of the planets, bright stars and the eclipsed Sun during totality at 2:37 PM EDT as seen from Franklin, North Carolina. Credit: Stellarium.

Also, be sure to scan the local horizon for a strange 360 degree sunset as you stand in the umbra of the Moon. An “eclipse wind” may kick up, as temperatures plummet and nature is fooled by the false dawn, causing chickens to come home to roost and nocturnal animals to awaken. I dare you to blink. Totality can affect the human heart as well, causing tears to cries of surprise.

Here’s an interesting, though remote, possibility. Could a sungrazing “eclipse comet” photo bomb the show? Karl Battams (@SungrazerComets) raises this question on a recent Planetary Society blog post. Battams works with the Solar Heliospheric Observatory (SOHO), which has discovered an amazing 3,358 comets crossing the field of view of its LASCO imagers since 1995. Comets have been discovered during eclipses before, most notably in 1882 and 1948. To be sure, it’s a remote possibility this late in the game, but Battams promises to give us one last quick look via SOHO the morning of the eclipse on his Twitter feed to see if any cometary interlopers are afoot.

The possible search area for Kreutz group sungrazers during the August 21st eclipse. Credit: Karl Battams.

Now, on to the biggest question mark going into this eclipse weekend: what’s the weather going to be like during the eclipse? This is the ever-dominating factor on everyone’s mind leading up to eclipse day. Keep in mind, the partial phases are long; even a partly cloudy sky will afford occasional glimpses of the Sun during the partial phases of an eclipse. Totality, however, is fleeting – 2 minutes and 40 seconds near Hopkinsville, Kentucky and less for most – meaning even a solitary cumulus cloud drifting across the Sun at the wrong moment can spoil the view. No weather model can predict the view of the sky to that refined a level. And while best bets are still out west, lingering forest fires in Oregon are a concern, along early morning fog on the western side of the Cascade Mountains. Michael Zeiler over at The Great American Eclipse has been providing ESRI models of the cloud cover over the eclipse path for Monday… here’s the outlook as of Thursday, August 17^th:

A look at cloud cover prospects over the eclipse path as of August 17. Credit: Michael Zeiler/Great American Eclipse/ESRI.

Computer models should begin to come into agreement this weekend, a good sign that we know what the weather is going to do Monday. Needless to say, a deviation from the standard climate models could send lots of folks scrambling down the path at the last minute… I’ve heard of folks with up to 5 (!) separate reservations along the path of totality, no lie…

The NOAA also has a fine site dedicated to weather and cloud coverage across the path come eclipse day, and Skippy Sky is another great resource aimed at sky viewing and cloud cover.

Clouded out? The good folks at the Virtual Telescope have got you covered, with a webcast for the total solar eclipse starting at 17:00 UT/1:00 PM EDT:

Credit: The Virtual Telescope Project.

Of course, you’ll need to use proper solar viewing methods during all partial phases of the eclipse. This means either using a telescope with a filter specifically designed to look at the Sun, a pin hole projector, or certified ISO 12312-2 eclipse glasses. If you’ve got an extra pair, why not convert them into a safe filter for those binoculars or a small telescope as well:

Also be wary of heatstroke, standing out showing folks the partially eclipsed Sun for an hour or more. It is August, and heat exhaustion can come on in a hurry. Be sure you have access to shade and stay cool and hydrated in the summer Sun.

Finally, eyes from space will be watching the eclipse from the International Space Station as well. Looking out at Monday, the ISS will pass through the penumbra of the Moon and see partial phases of the eclipse three times centered on 16:32, 18:20, and 20:00 Universal Time. The center time is particularly intriguing, as astros have a chance to see the dark umbral shadow of the Moon crossing the central U.S. This also means that eclipse viewers on planet Earth around southern Illinois might want to glance northward briefly, to spy the ISS during totality. Also, viewers along a line along southern central Canada will have a chance to catch an ISS transit across the face of the partially eclipsed Sun around the same time. Check CALSky for details.

Three passes of the International Space Station versus the path of of totality. The inset shows the view of the partially eclipsed Sun as seen from the ISS. Credit: NASA/JSC.

We’ll be at the Pisgah Astronomical Research Institute in southwestern North Carolina, for a glorious 104 seconds of totality. We expect to be out of wifi range come eclipse day, but we’ll tweet out key eclipse milestones as @Astroguyz. We also plan on writing up the eclipse experience with state-by-state testimonials post eclipse.

Perhaps, the August 21st total solar eclipse will bring us all together for one brief moment, to witness the grandest of astronomical spectacles. We’re lucky to share a small patch of time and space where total solar eclipses are possible.  Good luck, clear skies, and see you on the other side early next week!

• Read more about the August 21^st total solar eclipse and the true tale of Edison’s chickens and the 1878 eclipse in our free e-book: 101 Astronomical Events for 2017.
• The oldest video featuring totality? Read the mystery of the August 21^st, 1914 over war torn Europe and this amazing video over Sweden.
• Eclipse… sci-fi? Read our original eclipse-fueled tales Exeligmos, Shadowfall, Peak Season and more.
• Read our CNN Op-Ed, Why We Chase Eclipses.

The post Prelude to Totality: A Final Look at the Total Solar Eclipse appeared first on Universe Today.

Gravitational Lensing Provides Rare Glimpse Into Interiors of Black Holes

Gravitational Lensing Provides Rare Glimpse Into Interiors of Black Holes:



The observable Universe is an extremely big place, measuring an estimated 91 billion light-years in diameter. As a result, astronomers are forced to rely on powerful instruments to see faraway objects. But even these are sometimes limited, and must be paired with a technique known as gravitational lensing. This involves relying on a large distribution of matter (a galaxy or star) to magnify the light coming from a distant object.

Using this technique, an international team led by researchers from the California Institute of Technology’s (Caltech) Owens Valley Radio Observatory (OVRO) were able to observe jets of hot gas spewing from a supermassive black hole in a distant galaxy (known as PKS 1413 + 135). The discovery provided the best view to date of the types of hot gas that are often detected coming from the centers of supermassive black holes (SMBH).

The research findings were described in two studies that were published in the August 15th issue of The Astrophysical Journal. Both were led by Harish Vedantham, a Caltech Millikan Postdoctoral Scholar, and were part of an international project led by Anthony Readhead – the Robinson Professor of Astronomy, Emeritus, and director of the OVRO.

The Owens Valley Radio Observatory (OVRO) – located near Bishop, California – is one of the largest university-operated radio observatories in the world. Credit: ovro.caltech.edu

This OVRO project has been active since 2008, conducting twice-weekly observations of some 1,800 active SMBHs and their respective galaxies using its 40-meter telescope. These observations have been conducted in support of NASA’s Fermi Gamma-ray Space Telescope, which has be conducting similar studies of these galaxies and their SMBHs during the same period.

As the team indicated in their two studies, these observations have provided new insight into the clumps of matter that are periodically ejected from supermassive black holes, as well as opening up new possibilities for gravitational lensing research. As Dr. Vedantham indicated in a recent Caltech press statement:

“We have known about the existence of these clumps of material streaming along black hole jets, and that they move close to the speed of light, but not much is known about their internal structure or how they are launched. With lensing systems like this one, we can see the clumps closer to the central engine of the black hole and in much more detail than before.”

While all large galaxies are believed to have an SMBH at the center of their galaxy, not all have jets of hot gas accompanying them. The presence of such jets are associated with what is known as an Active Galactic Nucleus (AGN), a compact region at the center of a galaxy that is especially bright in many wavelengths – including radio, microwave, infrared, optical, ultra-violet, X-ray and gamma ray radiation.

Illustration showing the likely configuration of a gravitational lensing system discovered by OVRO. Credit: Anthony Readhead/Caltech/MOJAVE

These jets are the result of material that is being pulled towards an SMBH, some of which ends up being ejected in the form of hot gas. Material in these streams travels at close to the speed of light, and the streams are active for periods ranging from 1 to 10 million years. Whereas most of the time, the jets are relatively consistent, every few years, they spit out additional clumps of hot matter.

Back in 2010, the OVRO researchers noticed that PKS 1413 + 135’s radio emissions had brightened, faded and then brightened again over the course of a year. In 2015, they noticed the same behavior and conducted a detailed analysis. After ruling out other possible explanations, they concluded that the overall brightening was likely caused by two high-speed clumps of material being ejected from the black hole.

These clumps traveled along the jet and became magnified when they passed behind the gravitational lens they were using for their observations. This discovery was quite fortuitous, and was the result of many years of astronomical study. As Timothy Pearson, a senior research scientist at Caltech and a co-author on the paper, explained:

“It has taken observations of a huge number of galaxies to find this one object with the symmetrical dips in brightness that point to the presence of a gravitational lens. We are now looking hard at all our other data to try to find similar objects that can give a magnified view of galactic nuclei.”

Artist’s representation of an active galactic nucleus (AGN) at the center of a galaxy. Credit: NASA/CXC/M.Weiss

What was also exciting about the international team’s observations was the nature of the “lens” they used. In the past, scientists have relied on massive lenses (i.e. entire galaxies) or micro lenses that consisted of single stars. However, the team led by Dr. Vedantham and Dr. Readhead relied on an what they describe as a “milli-lens” of about 10,000 solar masses.

This could be the first study in history that relied on an intermediate-sized lens, which they believe is most likely a star cluster. One of the advantages of a milli-sized lens is that it is not large enough to block out the entire source of light, making it easier to spot smaller objects. With this new gravitational lensing system, it is estimated that astronomers will be able to observe clumps at scales about 100 times smaller than before. As Readhead explained:

“The clumps we’re seeing are very close to the central black hole and are tiny – only a few light-days across. We think these tiny components moving at close to the speed of light are being magnified by a gravitational lens in the foreground spiral galaxy. This provides exquisite resolution of a millionth of a second of arc, which is equivalent to viewing a grain of salt on the moon from Earth.”

What’s more, the researchers indicate that the lens itself is of scientific interest, for the simple reason that not much is known about objects in this mass range. This potential star cluster could therefore act as a sort of laboratory, giving researchers a chance to study gravitational milli-lensing while also providing a clear view of the nuclear jets streaming from active galactic nuclei.

Image of the 40-meter telescope of the Owens Valley Radio Observatory (OVRO), located near Bishop, California. Credit: Anthony Readhead/Caltech

Looking ahead, the team hopes to confirm the results of their studies using another technique known as Very-Long Baseline Interferometry (VLBI). This will involve radio telescopes from around the world taking detailed images of PKS 1413 + 135 and the SMBH at its center. Given what they have observed so far, it is likely that this SMBH will spit out another clump of matter in a few years time (by 2020).

Vedantham, Readhead and their colleagues plan to be ready for this event. Spotting this next clump would not only validate their recent studies, it would also validate the milli-lens technique they used to conduct their observations. As Readhead indicated, “We couldn’t do studies like these without a university observatory like the Owens Valley Radio Observatory, where we have the time to dedicate a large telescope exclusively to a single program.”

The studies were made possible thanks to funding provided by NASA, the National Science Foundation (NSF), the Smithsonian Institution, the Academia Sinica, the Academy of Finland, and the Chilean Centro de Excelencia en Astrofísica y Tecnologías Afines (CATA).

Further Reading: Caltech, The Astrophysical Journal, The Astrophysical Journal (2)



The post Gravitational Lensing Provides Rare Glimpse Into Interiors of Black Holes appeared first on Universe Today.

NASA Plans to Send CubeSat To Venus to Unlock Atmospheric Mystery

NASA Plans to Send CubeSat To Venus to Unlock Atmospheric Mystery:

From space, Venus looks like a big, opaque ball. Thanks to its extremely dense atmosphere, which is primarily composed of carbon dioxide and nitrogen, it is impossible to view the surface using conventional methods. As a result, little was learned about its surface until the 20th century, thanks to development of radar, spectroscopic and ultraviolet survey techniques.

Interestingly enough, when viewed in the ultraviolet band, Venus looks like a striped ball, with dark and light areas mingling next to one another. For decades, scientists have theorized that this is due to the presence of some kind of material in Venus’ cloud tops that absorbs light in the ultraviolet wavelength. In the coming years, NASA plans to send a CubeSat mission to Venus in the hopes of solving this enduring mystery.

The mission, known as the CubeSat UV Experiment (CUVE), recently received funding from the Planetary Science Deep Space SmallSat Studies (PSDS3) program, which is headquartered as NASA’s Goddard Space Flight Center. Once deployed, CUVE will determine the composition, chemistry, dynamics, and radiative transfer of Venus’ atmosphere using ultraviolet-sensitive instruments and a new carbon-nanotube light-gathering mirror.

Ultraviolet image of Venus taken by NASA’s Pioneer-Venus Orbiter in 1979, lending Venus a striped, light and dark appearance. Credit: NASA

The mission is being led by Valeria Cottini, a researcher from the University of Maryland who is also CUVE’s Principle Investigator (PI). In March of this year, NASA’s PSDS3 program selected it as one of 10 other studies designed to develop mission concepts using small satellites to investigate Venus, Earth’s moon, asteroids, Mars and the outer planets.

Venus is of particular interest to scientists, given the difficulties of exploring its thick and hazardous atmosphere. Despite the of NASA and other space agencies, what is causing the absorption of ultra-violet radiation in the planet’s cloud tops remains a mystery. In the past, observations have shown that half the solar energy the planet receives is absorbed in the ultraviolet band by the upper layer of its atmosphere – the level where sulfuric-acid clouds exist.

Other wavelengths are scattered or reflected into space, which is what gives the planet its yellowish, featureless appearance. Many theories have been advanced to explain the absorption of UV light, which include the possibility that an absorber is being transported from deeper in Venus’ atmosphere by convective processes. Once it reaches the cloud tops, this material would be dispersed by local winds, creating the streaky pattern of absorption.

The bright areas are therefore thought to correspond to regions that do not contain the absorber, while the dark areas do. As Cottini indicated in a recent NASA press release, a CubeSat mission would be ideal for investigating these possibilities:

“Since the maximum absorption of solar energy by Venus occurs in the ultraviolet, determining the nature, concentration, and distribution of the unknown absorber is fundamental. This is a highly-focused mission – perfect for a CubeSat application.”

CubeSats being deployed from the International Space Station during Expedition 47. Image: NASA

Such a mission would leverage recent improvements in miniaturization, which have allowed for the creation of smaller, box-sized satellites that can do the same jobs as larger ones. For its mission, CUVE would rely on a miniaturized ultraviolet camera and a miniature spectrometer (allowing for analysis of the atmosphere in multiple wavelengths) as well as miniaturized navigation, electronics, and flight software.

Another key component of the CUVE mission is the carbon nanotube mirror, which is part of a miniature telescope the team is hoping to include. This mirror, which was developed by Peter Chen (a contractor at NASA Goddard), is made by pouring a mixture of epoxy and carbon nanotubes into a mold. This mold is then heated to cure and harden the epoxy, and the mirror is coated with a reflective material of aluminum and silicon dioxide.

In addition to being lightweight and highly stable, this type of mirror is relatively easy to produce. Unlike conventional lenses, it does not require polishing (an expensive and time-consuming process) to remain effective. As Cottini indicated, these and other developments in CubeSat technology could facilitate low-cost missions capable of piggy-backing on existing missions throughout the Solar System.

“CUVE is a targeted mission, with a dedicated science payload and a compact bus to maximize flight opportunities such as a ride-share with another mission to Venus or to a different target,” she said. “CUVE would complement past, current, and future Venus missions and provide great science return at lower cost.”

A cubesat structure, 1U in size. Credit: Wikipedia Commons/Svobodat

The team anticipates that in the coming years, the probe will be sent to Venus as part of a larger mission’s secondary payload. Once it reaches Venus, it will be launched and assume a polar orbit around the planet. They estimate that it would take CUVE one-and-a-half years to reach its destination, and the probe would gather data for a period of about six months.

If successful, this mission could pave the way for other low-cost, lightweight satellites that are deployed to other Solar bodies as part of a larger exploration mission. Cottini and her colleagues will also be presenting their proposal for the CUVE satellite and mission at the 2017 European Planetary Science Congress, which is being held from September 17th – 22nd in Riga, Latvia.

Further Reading: NASA

The post NASA Plans to Send CubeSat To Venus to Unlock Atmospheric Mystery appeared first on Universe Today.

Perseid by the Sea

Perseid by the Sea:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 16

Explanation: Just after moonrise on August 12 this grain of cosmic sand fell by the sea, its momentary flash part of the annual Perseid Meteor Shower. To create the Perseid meteors, dust along the orbit of periodic comet Swift-Tuttle is swept up by planet Earth. The cometary debris plows through the atmosphere at nearly 60 kilometers per second and is quickly vaporized at altitudes of 100 kilometers or so. Perseid meteors are often bright and colorful, like the one captured in this sea and night skyscape. Against starry sky and faint Milky Way the serene view looks south and west across the Adriatic Sea, from the moonlit Dalmatian coast toward the island of Brac.

TRAPPIST-1 could be twice the age of the Solar System

TRAPPIST-1 could be twice the age of the Solar System:

This illustration shows what the TRAPPIST-1 system might look like from a vantage point near planet TRAPPIST-1f (at right). Image & Caption Credit: NASA/JPL-Caltech

The red dwarf star TRAPPIST-1 and its seven known planets have been around far longer than the Solar System, according to a new study by scientists who have estimated the system’s age.

Small and dim, low-mass red dwarf stars have life spans longer than the age of the universe, which is approximately 13.7 billion years old. In contrast, Sun-like stars have lifespans of about 10 billion years.

The TRAPPIST-1 system, approximately 40 light-years from Earth, was discovered earlier this year through data returned by the Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile, along with observations conducted by NASA’s Spitzer Space Telescope and several ground-based telescopes.

Of the six Earth-sized planets found orbiting TRAPPIST-1, three are located in its habitable zone, where temperatures would allow liquid water to exist on their surfaces.

Young red dwarf stars are very active and frequently undergo flares that release high-energy radiation. That radiation can strip the atmospheres of orbiting planets, destabilize their orbits, and make them inhospitable to life.

Based on the size of TRAPPIST-1, scientists knew the system had to be at minimum 500 million years old. This is because low-mass stars take that long to contract enough to reach their ultimate sizes, slightly larger than Jupiter.

However, without an upper limit on the system’s age, there was no way to know whether the planets had survived early radiation exposure with intact atmospheres and stable orbits or had enough time for life to develop and evolve.

Illustration of the Sun compared with the TRAPPIST-1 star. The red dwarf is slightly larger than the planet Jupiter. Image Credit: ESA

In an effort to answer these questions, scientists Adam Burgasser, of the University of California in San Diego, and Eric Mamajek, a deputy program scientist in NASA’s Exoplanet Exploration Program at the agency’s Jet Propulsion Laboratory (JPL) in Pasadena, California, attempted to determine TRAPPIST-1’s age.

The researchers looked at various factors commonly used to discover the age of a star, including measurement of its speed in orbiting the galaxy, the chemical composition of its atmosphere, and the rate of its stellar flares.

A star’s orbital speed is important because older stars are known to travel at faster speeds.

These indicators revealed TRAPPIST-1 to be a surprisingly old system. Burgasser and Mamajek estimate its age to range from 5.4 to 9.8 billion years. In contrast, the Solar System is about 4.5 billion years old.

“Our results really help constrain the evolution of the TRAPPIST-1 system because the system has to have persisted for billions of years. This means the planets had to evolve together; otherwise, the system would have fallen apart long ago,” Burgasser said.

TRAPPIST-1 is currently quiet in comparison with other red dwarfs, a trait consistent with its older age.

Knowing the system’s age still does not tell scientists whether the planets are habitable. Because of their close orbits, all are likely tidally locked to the star, meaning one side always faces TRAPPIST-1 while the other always faces away from it.

Although the planets survived the frequent flares that occurred during the star’s early years, the impact of those flares on them remains unknown.

Radiation from those flares could have left the seven worlds with conditions similar to those of either Venus or Mars in the Solar System.

If the TRAPPIST-1 worlds – all of which have lower densities than Earth – have successfully held on to thick atmospheres containing volatile molecules such as water, then those atmospheres would have protected them from the ultraviolet radiation produced by stellar flares, as well as distributed heat to the sides facing away from the star, increasing their potential habitability.

However, thick atmospheres could also have resulted in a runaway greenhouse effect, as happened on Venus, making the planet too hot for life.

On the other hand, over billions of years, high levels of radiation could have boiled off the atmospheres and any water on all but the furthest worlds, TRAPPIST-1g and TRAPPIST-1h, in a process similar to that believed to have occurred on Mars.

“If there is life on these planets, I would speculate that it has to be hardy life because it has to be able to survive some potentially dire scenarios for billions of years,” Burgasser said.

Additional observations of the system will be conducted using NASA’s Hubble Space Telescope, Spitzer Space Telescope, and James Webb Space Telescope (JWST). The latter is scheduled for launch in 2018.

Scientists hope these observations will reveal whether the planets have atmospheres, the composition of those atmospheres, and the planets’ densities.

The findings of Burgasser and Mamajek’s study will be published in The Astrophysical Journal.

TRAPPIST-1 is an ultra-cool dwarf star in the constellation Aquarius, and its seven planets orbit very close to it. Image & Caption Credit: NASA/JPL-Caltech

The post TRAPPIST-1 could be twice the age of the Solar System appeared first on SpaceFlight Insider.

Gravity's Grin

Gravity's Grin:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 5

Explanation: Albert Einstein's general theory of relativity, published over 100 years ago, predicted the phenomenon of gravitational lensing. And that's what gives these distant galaxies such a whimsical appearance, seen through the looking glass of X-ray and optical image data from the Chandra and Hubble space telescopes. Nicknamed the Cheshire Cat galaxy group, the group's two large elliptical galaxies are suggestively framed by arcs. The arcs are optical images of distant background galaxies lensed by the foreground group's total distribution of gravitational mass. Of course, that gravitational mass is dominated by dark matter. The two large elliptical "eye" galaxies represent the brightest members of their own galaxy groups which are merging. Their relative collisional speed of nearly 1,350 kilometers/second heats gas to millions of degrees producing the X-ray glow shown in purple hues. Curiouser about galaxy group mergers? The Cheshire Cat group grins in the constellation Ursa Major, some 4.6 billion light-years away.

Spiral Galaxy NGC 1512: The Inner Ring

Spiral Galaxy NGC 1512: The Inner Ring:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 7

Spiral Galaxy NGC 1512: The Inner Ring

Image Credit: NASA, ESA, Hubble Space Telescope


Explanation: Most galaxies don't have any rings -- why does this galaxy have two? To begin, the bright band near NGC 1512's center is a nuclear ring, a ring that surrounds the galaxy center and glows brightly with recently formed stars. Most stars and accompanying gas and dust, however, orbit the galactic center in a ring much further out -- here seen near the image edge. This ring is called, counter-intuitively, the inner ring. If you look closely, you will see this the inner ring connects ends of a diffuse central bar that runs horizontally across the galaxy. These ring structures are thought to be caused by NGC 1512's own asymmetries in a drawn-out process called secular evolution. The gravity of these galaxy asymmetries, including the bar of stars, cause gas and dust to fall from the inner ring to the nuclear ring, enhancing this ring's rate of star formation. Some spiral galaxies also have a third ring -- an outer ring that circles the galaxy even further out.

Two Weeks from Today: An American total eclipse of the Sun

Tomorrow's picture: waves of Saturn

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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August's Lunar Eclipse

August's Lunar Eclipse:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 9

Explanation: August's Full Moon is framed in this sharp, high dynamic range composition. Captured before sunrise on August 8 from Sydney, Australia, south is up and the curve of the Earth's dark, umbral shadow is at the left, near the maximum phase of a partial lunar eclipse. Kicking off the eclipse season, this time the Full Moon's grazing slide through Earth's shadow was visible from the eastern hemisphere. Up next is the much anticipated total solar eclipse of August 21. Then, the New Moon's shadow track will include North America, the narrow path of totality running coast to coast through the United States.

Night of the Perseids

Night of the Perseids:

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2017 August 10

Night of the Perseids

Image Credit & Copyright: Petr Horálek


Explanation: This weekend, meteors will rain down near the peak of the annual Perseid Meteor Shower. Normally bright and colorful, the Perseid shower meteors are produced by dust swept up by planet Earth from the orbit of Comet Swift-Tuttle. They streak from a radiant in Perseus, above the horizon in clear predawn skies. Despite interfering light from August's waning gibbous moon, this year's Perseids will still be enjoyable, especially if you can find yourself in an open space, away from city lights, and in good company. Frames used in this composite view capture bright Perseid meteors from the 2016 meteor shower set against a starry background along the Milky Way, with even the faint Andromeda Galaxy just above center. In the foreground, astronomers of all ages have gathered on a hill above the Slovakian village of Vrchtepla.

Tomorrow's picture: eclipse of Saros 145

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< | Archive | Submissions | Index | Search | Calendar | RSS | Education | About APOD | Discuss | >

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
NASA Web Privacy Policy and Important Notices
A service of: ASD at NASA / GSFC
& Michigan Tech. U.