Universe Today

May 1, 2009December 24, 2015 by Fraser Cain

Spiral Galaxy

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When you think of a galaxy, you’re probably thinking of a spiral galaxy. You know, with the central bulge and grand sweeping arms that spiral outward from the center. In fact, our own Milky Way is a spiral galaxy, and there are many others out there in the Universe. But have you ever thought about how they form in such a beautiful shape?

A spiral galaxy is shaped like a flat disk with a thicker bulge in the center. Bright spiral arms start from the center and then coil outward like a pinwheel. All spiral galaxies rotate, but very slowly; our own Milky Way completes a single revolution once every 250 million years or so.

The spiral arms are actually density waves that move around the disk of the spiral galaxy. As the density wave passes over a region, masses are pulled together, and you get bright pockets of star formation. Then the density wave moves on, and encourages another region to begin star formation.

The central bulge at the center of a spiral galaxy contains older stars, similar to an elliptical galaxy. And at the very center, there’s always a supermassive black hole containing millions of times the mass of the Sun.

Spiral galaxies are also surrounded by a vast spheroidal halo of stars. These stars might not have formed in the galaxy, but were stolen through successive mergers with other galaxies. This galactic halo also contains many globular star clusters.

Astronomers think that spiral galaxies are slowly built over time through the merger of smaller galaxies. As these tiny galaxies came together, their total momentum set the merged galaxy spinning. This spin flattened out the galaxy and set the spiral arms in motion.

We have written many articles about the galaxies for Universe Today. Here’s an article with twin spiral galaxies interacting, and here’s spiral galaxy NGC 2403.

If you’d like more info on galaxies, check out Hubblesite’s News Releases on Galaxies, and here’s NASA’s Science Page on Galaxies.

We have also recorded an episode of Astronomy Cast about galaxies – Episode 97: Galaxies.

May 1, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – May 1-3, 2009

Greetings, fellow StarGazers! Let’s start the weekend off right by taking on a lunar club challenge and then kicking back to enjoy yet another spring meteor shower! (After all, if April showers bring May flowers, you do know what May flowers bring, don’t you? That’s right… Pilgrims!) Now that I’ve got you at least smiling, take out your binoculars, too… Because there’s two asteroids that are ripe for plucking – Hebe and Ceres. If you feel like being a little more serious about your lunar studies, why not do a little photographic map work? Just match the picture to what you see in the eyepiece and log your studies! Are you ready? Then I’ll see you in the back yard…

Friday, May 1, 2009 – This date is a rather special one in history. In 1543 on this date, Copernicus published and distributed the ‘‘ The Little Commentary ,’’ which described his heliocentric beliefs. In 1949, Gerard Kuiper discovered Nereid, a 150-kilometer-wide satellite of Neptune. It’s so distant from the planet that it requires almost one Earth year (360 days) to complete an orbit! At magnitude 18.7, Nereid is beyond the detection point of most average telescopes but can be ‘‘seen’’ using long exposure charge coupled AQ1 device (CCD) image stacking devices. Other sights that can’t be seen are the Van Allen Radiation Belts of our Earth, the discovery of which was announced in 1958 in this day’s copy of the Washington Evening Star. Thanks to James A. Van Allen’s use of the data from the Explorer I and Pioneer III space probes, we know that Earth’s magnetosphere contains concentrations of electrically charged particles. Say Happy Birthday to American astronaut M. Scott Carpenter, who was born on this date in 1925 and was one of the original seven Mercury astronauts to reach space in 1962.

Tonight’s outstanding lunar feature will be crater Maurolycus , just southwest of the three rings of Theophilus, Cyrillus, and Catharina. This Lunar Club Challenge spans 114 kilometers and goes below the lunar surface by 4,730 meters. Be sure to look for Gemma Frisius just to its north!

Now, relax and enjoy the peak of the Phi Bootid meteor shower, whose radiant is near the constellation Hercules. The best time to view most meteor showers is around 2:00 a.m. local time, but you may have good success watching for these meteors as soon as the Moon westers. The average fall rate is only about 6 per hour, but it’s a great way to spend a spring evening out under the stars!

Saturday, May 2, 2009 – Today, let’s start with the 1868 birth on this date of Robert Williams Wood. Although Wood’s primary research was on sound waves, he devised a ‘‘zone plate’’ that could replace the objective lens of a telescope! He also improved the diffraction grating, did research in spectroscopy, and made photographs showing both infrared and ultraviolet radiations. Also, take a moment to note the 1925 passing of the star cataloger, Johann Palisa. Palisa remains the most successful visual discoverer in the history of minor planet research, discovering 122 asteroids with a 600 telescope and no photographic plates!

Why not salute his achievements by looking for the asteroid Hebe, which reaches opposition tonight? Hebe is the 13th largest asteroid by mass and the 5th brightest to observe. If you collect meteorites and have an H chondrite, chances are good you have a physical piece of Hebe, since it is thought to have contributed up to 40% of all recovered chrondites! Hebe is now coming in at 6th magnitude and given its prime location shouldn’t make it fairly easy for even those with just binoculars to find this cool asteroid.

Now, let’s have a look at the Moon! Tonight’s challenges are craters Cassini and Cassini A, which come into view just south of the black slash of the Alpine Valley. The major crater spans 57 kilometers and reaches a floor depth of 1,240 meters. Your assignment, should you decide to accept it, is to spot the central crater A. It only spans 17 kilometers, yet drops down another 2,830 meters below the primary crater’s floor!

Sunday, May 3, 2009 – How about starting the day with the bizarre and unusual? In 1375 BC, the oldest recorded total solar eclipse occurred—if we can believe eighth century Babylonian records! If you have a green laser pointer, or a telrad, you might want to wish Alfred Kastler a happy birthday. Born on this date in 1902, the physicist was very interested in what happened to atoms when excited by light or radio waves. Kastler developed a method called ‘‘optical pumping,’’ where atoms enter a higher energy state. Optical pumping is what makes your laser work!

Tonight notice just how close bright Regulus is to the Moon! If you’d like to try your hand at asteroid Ceres, you’ll find it approximately another 15 degrees north of the ‘‘Little King.’’

Tonight let’s take a long Moonwalk together and do some major crater exploration. Try using mid-range magnification in your telescope and see how many of the craters in this photograph you can identify!.

Ptolemaeus area: (1) Sinus Asperitatis, (2) Theophilus, (3) Cyrillus, (4) Catharina, (5) Rupes Altai, (6) Piccolomini, (7) Sacrobosco, (8) Abulfeda, (9) Almanon, (10) Taylor, (11) Abenezra, (12) Apianus (13) Playfair, (14) Aliacensis, (15) Werner, (16) Blanchinus, (17) Lacaille, (18) Walter, (19) Regiomontanus, (20) Purbach, (21) Thebit, (22) Arzachel, (23) Alphonsus, (24) Ptolemaeus, and (25) Albategnius.

Until next week? Ask for the Moon… But keep on reaching for the stars!

This week’s awesome images are (in order of appearance): M. Scott Carpenter (credit—NASA), Maurolycus (credit—Alan Chu), Johann Palisa (historical image), Hebe Chart (Your Sky), Cassini (credit—Wes Higgins), Alfred Kastler (historical image) and the Ptolemaeus area (credit—Greg Konkel). We thank you so much!

May 1, 2009December 24, 2015 by Anne Minard

Cosmic Rays too Wimpy to Influence Climate

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People looking for new ways to explain climate change on Earth have sometimes turned to cosmic rays, showers of atomic nuclei that emanate from the Sun and other sources in the cosmos.

But new research, in press in the journal Geophysical Research Letters, says cosmic rays are puny compared to other climatic influences, including greenhouse gases — and not likely to impact Earth’s climate much.

Jeffrey Pierce and Peter Adams of Carnegie Mellon University in Pittsburgh, Pennsylvania, point out that cycles in numerous climate phenomena, including tropospheric and stratospheric temperatures, sea-surface temperatures, sea-level pressure, and low level cloud cover have been observed to correlate with the 11-year solar cycle.

However, variation in the Sun’s brightness alone isn’t enough to explain the effects and scientists have speculated for years that cosmic rays could fill the gap.

For example, Henrick Svensmark, a solar researcher at the Danish Space Research Institute, has proposed numerous times, most recently in 2007, that solar cosmic rays can seed clouds on Earth – and he’s seen indications that periods of intense cosmic ray bombardment have yeilded stormy weather patterns in the past.

Others have disagreed.

“Dust and aerosols give us much quicker ways of producing clouds than cosmic rays,” said Mike Lockwood, a solar terrestrial physicist at Southampton University in the UK. “It could be real, but I think it will be very limited in scope.”

To address the debate, Pierce and Adams ran computer simulations using cosmic-ray fluctuations common over the 11-year solar cycle.

“In our simulations, changes in [cloud condensation nuclei concentrations] from changes in cosmic rays during a solar cycle are two orders of magnitude too small to account for the observed changes in cloud properties,” they write, “consequently, we conclude that the hypothesized effect is too small to play a significant role in current climate change.”

The results have met a mixed reception so far with other experts, according to an article in this week’s issue of the journal Science: Jan Kazil of the University of Colorado at Boulder has reported results from a different set of models, confirming that cosmic rays’ influence is similarly weak. But at least one researcher — Fangqun Yu of the University at Albany in New York — has questioned the soundness of Pierce and Adams’ simulations.

And so, the debate isn’t over yet …

Sources: The original paper (available for registered AGU users here) and a news article in the May 1 issue of the journal Science. See links to some of Svensmark’s papers here.

May 1, 2009April 26, 2016 by Nancy Atkinson

A Stunning Look at “The Big Picture”

My friend Carolyn Collins Petersen, a.k.a. The Spacewriter, has just started a new gig with Astrocast.tv. She now has a regular monthly show called “The Astronomer’s Universe.” Her first episode aired today, and it features “The Big Picture,” an image from the Palomar-Quest digital sky survey. It shows the Virgo Cluster of galaxies, and is something akin to the Hubble Deep Field image. Carolyn’s webcast is a stunning and beautiful look at this amazing part of our night sky, and with wonderful background music and Carolyn’s great voice, (can’t find enough superlatives!) this is must-see TV! Thanks to Carolyn and Astrocast.tv for sharing the video.
Continue reading “A Stunning Look at “The Big Picture””

April 30, 2009December 24, 2015 by Fraser Cain

Galaxies

Hello, is there anyone out there? With all of the galaxies in the Universe, is it possible that there is cognizant life somewhere else? Well, I can not answer that question for you, but I can offer you a great deal of information about galaxies so that you can make your own informed decision on the matter.

Our’s is a spiral galaxy. A spiral galaxy is shaped like a flat disk with a thicker bulge in the center. Bright spiral arms start from the center and then coil outward like a pinwheel. All spirals rotate very slowly. The Milky Way completes a single revolution once every 250 million years.

Most galaxies are billions of years old. The youngest known galaxy is 1 Zwicky 18. At an estimated age of a mere 500 million years, it is a babe in diapers compared to the Milky Way at 10-14 billion years, which is the average age of the known galaxies.

Scientists think that galaxy formation was led by dark matter. This invisible material clumped together and it attracted regular mass with its gravity, channeling material together into larger and larger collections. This process of matter accretion led to the first proto-galaxies.

The Canis Major Dwarf Galaxy is the closest galaxy to ours. It is actually contained within the Milky Way and only 42,000 light years form the galactic core.

In the links below you will find thousands of facts, figures, and images that will help you understand many things about galaxies in general and some specific types. Enjoy your reading.

April 30, 2009December 24, 2015 by Nancy Atkinson

It’s Official: Hubble Mission to Launch May 11

[/caption]After today’s Flight Readiness Review for space shuttle Atlantis’ STS-125 mission to the Hubble Space Telescope, mission managers unanimously agreed to set May 11 at 2:01 p.m. EDT as the launch date. This long awaited flight will repair and upgrade Hubble, likely the most significant satellite ever launched. And, for the space shuttle, it’s a final visit to a dear, old friend.

During the 11-day mission’s five spacewalks, astronauts will install two new instruments, repair two inactive ones and perform the component replacements that will keep the telescope functioning into at least 2014.

In addition to the originally scheduled work, Atlantis also will carry a replacement Science Instrument Command and Data Handling Unit for Hubble. Astronauts will install the unit on the telescope, removing the one that stopped working on Sept. 27, 2008, delaying this servicing mission until the replacement was ready.

Veteran astronaut Scott Altman will command the final space shuttle mission to service NASA’s Hubble Space Telescope, and retired Navy Capt. Gregory C. Johnson will serve as pilot. Mission specialists rounding out the crew are: veteran spacewalkers John Grunsfeld and Mike Massimino, and first-time space fliers Andrew Feustel, Michael Good and Megan McArthur.

Source: NASA

April 30, 2009December 24, 2015 by Nancy Atkinson

New Mysteries Unveiled on Mercury

The Rembrandt impact crater basin on Mercury. Credit: Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Smithsonian Institution/Carnegie Institution of Washington

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Even though Mercury looks like the Moon at first glance, scientists from the MESSENGER mission say it’s becoming apparent that Mercury is an amazingly dynamic planet, and is actually more like Mars. For example, before this mission, scientists weren’t sure if volcanism even existed on Mercury, but from the spacecraft’s two flybys, they now know it is a very important part of the planet’s history. Additional new findings from the second flyby of Mercury in October 2008 show that the planet’s atmosphere, magnetosphere, and geological past are all characterized by much greater levels of activity than scientists first suspected.

And by the way, isn’t this a stunning picture of an impact basin? It’s one of the new discoveries from MESSENGER.

One of the most exciting results from the second flyby of Mercury is the discovery of a previously unknown large impact basin. The Rembrandt basin is more than 700 kilometers (430 miles) in diameter, and actually, to see the entire basin, it took combined images from both the first and second flyby to create the stunning picture above. Rembrandt is a relatively young impact basin, and forming about 3.9 billion years ago, is younger than any other known impact region on the planet. It shows pristine terrain on the outer portion of the crater, as well as unusual tectonic fault features, not found in any other big crater.

“This is the first time we’ve seen terrain exposed on the floor of an impact basin on Mercury that is preserved from when it formed” says MESSENGER scientist Thomas Watters. “Landforms such as those revealed on the floor of Rembrandt are usually completely buried by volcanic flows. We know that after Rembrandt formed, the planet was still contracting, so it is an exciting and unique new member of planetary craters we can study.”

MESSENGER’s Mercury Atmospheric and Surface Composition Spectrometer, or MASCS, detected significant amounts of magnesium clumped in the planet’s tenuous atmosphere, called the exosphere. Scientists had suspected magnesium would be present, but were surprised at its distribution and abundance.

“Detecting magnesium was not too surprising, but what is surprising is the distribution and amounts of magnesium that was recorded,” said Bill McClintock, a MESSENGER co- investigator.
The instrument also measured other exospheric constituents during the October 6 flyby, including calcium and sodium, and he suspects that additional metallic elements from the surface including aluminum, iron, and silicon also contribute to the exosphere.

The differences in Mercury's magnetosphere in the two flybys by MESSENGER. Credit: Image produced by NASA/Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory//Carnegie Institution of Washington. Image reproduced courtesy of Science/AAAS.

MESSENGER observed a radically different magnetosphere at Mercury during its second flyby, compared with its earlier January 14, 2008 encounter. In the first flyby, no dynamic features were found. But the second flyby was a totally different situation, said James Slavin, MESSENGER Co-Investigator.

“MESSENGER measured large magnetic flux leakage through the dayside magnetopause, about a factor of 10 greater than even what is observed at the Earth during its most active intervals. The high rate of solar wind energy input was evident in the great amplitude of the plasma waves and the large magnetic structures measured by the Magnetometer throughout the encounter.”

Slavin said Mercury’s magnetic field bears a marked resemblance to what we have at earth, but it is about 100 times weaker, which implies interior of Mercury is in part molten. “There is a dynamo action that is ongoing which regenerates and maintains the planetary magnetic field,” he said.

A subsurface interpretation of an impact basin on Mercury. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington.

Scientists are also learning more abour Mercury’s crustal evolution, and have now mapped about 90% of the planet’s surface. About 40% is covered by smooth plains which are now known to be of volcanic origna. “These plains are globally distributed (in contrast with the Moon, which has a nearside/farside asymmetry in the abundance of volcanic plains),” said Brett Denevi, MESSENGER team member.

Data shows an enhanced iron- and titanium content in an ancient basin studied by MESSENGER, which are exposed on the surface only through impact events, and may formed when dense minerals settled out as they crystallized from a cooling magma. “There are a complex series of events going on here, but we see it everywhere, so this is a microcosm of the entire planet” said Denevi.

These discoveries are more clues to the mystery of the creation of the rocky, bizarre planet that resides closest to the sun.

Source: NASA Press conference, MESSNEGER press release

April 30, 2009December 24, 2015 by Nancy Atkinson

The NASA Buzz: Shuttle Extension, Abandoning the Moon, and What About an Administrator?

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The blogosphere and Twitterverse has been buzzing the past couple of days with NASA what-ifs and possibilities. But that usually happens whenever there are Congressional hearings about our favorite space agency. Here’s the run-down of what is really happening: No extra money has been given to extend the shuttle program as of yet but it is a possibility. NASA is not going to abandon going to the Moon. And no, President Obama hasn’t named a new NASA administrator yet. Want the details?

House and Senate leaders have agreed to authorize $2.5 billion to keep the U.S. space shuttle fleet flying through 2011. While no money has actually been appropriated for that yet, the extension would happen only if necessary to complete currently planned missions to the international space station. If another flight were added to the shuttle manifest, it’s possible the controversial Alpha Magnetic Spectrometer instrument would be brought to the station. AMS was mothballed after the Columbia accident in 2003 as a cost cutting move, but the because of the international scientific community’s outcry about cutting the one really exciting science experiment to fly on the space station (that was mostly paid for by other countries) last year Congress told NASA to reconsider. They are supposed to make a decision today.

But the shuttle retirement is controversial from a political point of view because it affects thousands of aerospace industry jobs, not only in Florida, but nationwide. Retiring the shuttle in 2010 would also give a five year gap (at least) until the Orion crew vehicle is ready to fly, making the US dependant on Russia for bringing humans and supplies to the ISS. This week House and Senate budget conferees agreed on “the strategic importance of uninterrupted human access to space” and said the extra $2.5 billion is provided “in anticipation that the funding is needed” to safely “complete the construction and equipping” of the space station.

But some NASA officials and contractors worry that giving more funding to the shuttle program would hamper the efforts for the Constellation program, funneling money away from the new rocket that will help return humans to the moon, hopefully by 2020. The Constellation program has already begun shifting gears and figuring out how to make flying by 2015 actually work. Ian reported last week that the Orion crew size would likely be decreased from six to four, which also makes the spacecraft lighter. One issue engineers have been facing has been excess weight. Other reports look like this is likely a done deal.

Speaking of returning to the Moon, Wednesday’s appropriation hearings created some buzz when Chris Scolese, the agency’s acting administrator, said he anticipates changes. Some reports said Scolese gave vague answers. Others had NASA abandoning the a base on the Moon, but that is likely an exaggeration.

“I just can’t tell you what those changes would be,” Scolese told members of the House Appropriations Subcommittee on Commerce, Justice, Science and Related Agencies. “We’re still looking at options for what do we mean by the moon. Do we mean a colony on the moon? That’s clearly very expensive. Are we looking at something along the lines of what we did with Apollo?” he said.

But that correlates completely with legislation passed in October, 2008 that says:

“As NASA works toward the establishment of a lunar outpost, NASA shall make no plans that would require a lunar outpost to be occupied to maintain its viability. Any such outpost shall be operable as a human-tended facility capable of remote or autonomous operation for extended periods.”

Scolese also pointed out that the budget overview released earlier this year by President Obama clearly backs the previous administration’s goal of sending astronauts to the moon by 2020, a decade after the scheduled retirement of the shuttle fleet.

“It will probably be less than an outpost on the moon, but where it fits between sorties — single trips to the moon to various parts — and an outpost is really going to be dependent on the studies that we’re going to be doing,” he said.

What will really end up happening on the Moon is likely to change over time, just as the Constellation program already appears to be changing.

And finally, the current administration has yet to name a new NASA administrator. One person whose name had been floating around recently, General Lester Lyles, withdrew himself from consideration Wednesday. Another name that has surfaced is Lori Garver, former NASA associate administrator who headed Obama’s space transition team.

Sources: Florida Today, Lunar Network Blog, MSNBC, Wall Street Journal

April 30, 2009December 24, 2015 by Nancy Atkinson

Starbursts from Dwarf Galaxies Like Fireworks

These images, taken by NASA's Hubble Space Telescope, show myriad stars residing in the central regions of the three dwarf galaxies NGC 4163, NGC 4068, and IC 4662. Credit: NASA, ESA, K. McQuinn (University of Minnesota, Minneapolis), and I. Karachentsev (Special Astrophysical Observatory of the Russian Academy of Sciences, Russia)

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Fireworks in space? Astronomers are comparing “starbursts” from a galaxy that is in the throes of star formation to a Fourth of July fireworks display. And three particular galaxies are like my children’s favorite part of a fireworks display: the grand finale. These bursts occur at a fast and furious pace, lighting up a region for a short time before winking out. But that’s only part of the story. Archived data from the Hubble Space Telescope are showing that starbursts — intense regions of star formation — sweep across the whole galaxy and last 100 times longer than astronomers thought. The longer duration may affect how dwarf galaxies change over time, and therefore may shed light on galaxy evolution.

A group of astronomers studied three dwarf galaxies, NGC 4163, NGC 4068, and IC 4662. Their distances range from 8 million to 14 million light-years away. The trio is part of a survey of starbursts in 18 nearby dwarf galaxies.

“Our analysis shows that starburst activity in a dwarf galaxy happens on a global scale,” explains Kristen McQuinn of the University of Minnesota in Minneapolis and leader of the study. “There are pockets of intense star formation that propagate throughout the galaxy, like a string of firecrackers going off.” According to McQuinn, the duration of all the starburst events in a single dwarf galaxy would total 200 million to 400 million years.

These longer timescales are vastly more than the 5 million to 10 million years proposed by astronomers who have studied star formation in dwarf galaxies. “They were only looking at individual clusters and not the whole galaxy, so they assumed starbursts in galaxies lasted for a short time,” McQuinn says.

Hubble ACS image of NGC 4163. Click for larger version.

Dwarf galaxies are considered by many astronomers to be the building blocks of the large galaxies seen today, so the length of starbursts is important for understanding how galaxies evolve.

“Astronomers are really interested to find out the steps of galaxy evolution,” McQuinn says. “Exploring these smaller galaxies is important because, according to popular theory, large galaxies are created from the merger of smaller, dwarf galaxies. So understanding these smaller pieces is an important part of filling in that scenario.”

With the high resolution Hubble data, McQuinn and her team were able to pick out individual stars in the galaxies and measure their brightness and color, two important characteristics astronomers use to determine stellar ages. By determining the ages of the stars, the astronomers could reconstruct the starburst history in each galaxy.

Two of the galaxies, NGC 4068 and IC 4662, show active, brilliant starburst regions in the Hubble images. The most recent starburst in the third galaxy, NGC 4163, occurred 200 million years ago and has faded from view.

The team looked at regions of high and low densities of stars, piecing together a picture of the starbursts. The galaxies were making a few stars, when something, perhaps an encounter with another galaxy, pushed them into high star-making mode. Instead of forming eight stars every thousand years, the galaxies started making 40 stars every thousand years, which is a lot for a small galaxy, McQuinn says. The typical dwarf is 10,000 to 30,000 light-years wide. By comparison, a normal-sized galaxy such as our Milky Way is about 100,000 light-years wide.

About 300 million to 400 million years ago star formation occurred in the outer areas of the galaxies. Then it began migrating inward as explosions of massive stars triggered new star formation in adjoining regions. Starbursts are still occurring in the inner parts of NGC 4068 and IC 4662.

The total duration of starburst activity depends on many factors, including the amount of gas in a galaxy, the distribution and density of the gas, and the event that triggered the starburst. A merger or an interaction with a large galaxy, for example, could create a longer starburst event than an interaction with a smaller system.

McQuinn plans to expand her study to another larger sample of more than 20 galaxies. “Studying nearby dwarf galaxies, where we can see the stars in great detail, will help us interpret observations of galaxies in the distant universe, where starbursts were much more common because galaxies had more gas with which to make stars,” McQuinn explains.

McQuinn’s results appeared in the April 10 issue of The Astrophysical Journal.

Source: HubbleSite

April 29, 2009December 24, 2015 by Nancy Atkinson

Where In The Universe #52

Its time once again for another Where In The Universe Challenge. The goal of this challenge is to test your skills and knowledge of the cosmos. Guess where in the Universe this image is from, and give yourself extra points if you can guess which spacecraft is responsible for the image. Post your guess in the comment section (no links to hints please!) and check back tomorrow for the answer. Good luck!

UPDATE: The answer has now been posted below.

As many of you said, this is an image from the Mars Pathfinder rover, Sojouner. The rock was named “Yogi” and is a meter-size rock located about 5 meters northwest of the Mars Pathfinder lander and was the second rock visited by the Sojourner Rover’s alpha proton X-ray spectrometer (APXS) instrument. To get one picture of the entire rock, it took several pictures stitched together in a mosaic, combining four “Super Pan” frames taken with the Sojouner’s camera. This composite color mosaic consists of 7 frames from the right eye, taken with different color filters that were enlarged by 500% and then co-added using Adobe Photoshop to produce, in effect, a super-resolution panchromatic frame that is sharper than an individual frame would be.

Doing this, scientists were able to address questions about the texture of this rock and what it might tell us about its mode of origin.

This is the approximate the true color of Mars. The shadow around Yogi looks a little funny, because shadows were processed separately from the rest of the rock and combined with the rest of the scene to bring out details in the shadow of Yogi that would be too dark to view at the same time as the sunlit surfaces. This resulted in the unusual color fringing at the edges of the shadow.

So, there you have it, a little blast from the past from Pathfinder. I hope you enjoyed this image, and check back next week for another WITU challenge.