Planetary traffic jam lookback / Speedy comet update

To capture the planet Uranus (at lower right) I had to overexpose the bright, sunlight lunar crescent. Naturally, this made the earth-lit portion stand out very clearly. Credit: Bob King

To capture the planet Uranus (at lower right) I had to overexpose the bright, sunlight lunar crescent. Naturally, this made the earth-lit portion stand out very clearly. Credit: Bob King

Wow, we had quite a weekend. The moon visited every evening sky planet while Venus and Mars squeezed together for their closest approach of the year. We’ve already looked at the “triple play” conjunction that occurred Friday. I thought it would be fun to look at the other alignments that have made the past few nights so memorable.

The moon (top) along with Venus and Mars Saturday evening Feb. 21, 2015. Credit: Guy Sander

The moon (top) along with Venus and Mars Saturday evening Feb. 21, 2015 from near Duluth, Minn. Credit: Guy Sander

Here, Guy has enlarged portions of the image to better see all three planets involved. Credit: Guy Sander

Here, Guy has enlarged portions of the image to better see all three planets involved. Credit: Guy Sander

Venus and Mars were still close Sunday night Feb. 22, but they will part in the coming days as Venus moves up and Mars slides closer to the Sun. Credit: Bob King

Venus and Mars were still close Sunday night Feb. 22, but they will part in the coming days as Venus moves up and away from the Sun while Mars slides closer. Credit: Bob King

As for that fast-moving comet discovered last week and en route to the evening sky, Karl Battams, an astrophysicist and computational scientist based at the Naval Research Laboratory (NRL) in Washington DC, is right now at his computer measuring positions of the comet from photos made with the orbiting Solar and Heliospheric Observatory (SOHO).

Comet SOHO-2875 survived its close passage of the Sun and may make an appearance in the evening sky soon. This photo montage was made using the coronagraph (Sun-blocking device) on SOHO. Click to watch a movie of the comet. Credit: NASA/ESA

Comet SOHO-2875 survived its close passage of the Sun and may make an appearance in the evening sky soon. This photo montage was made using the coronagraph (Sun-blocking device) on SOHO. Click to watch a movie of the comet. Credit: NASA/ESA

Once enough positions are known, he’ll send the data off to the Minor Planet Center where a preliminary orbit will be determined. With that information I can make a nice map showing us where to look for it. Stay tuned.

Mars mystery plumes might be auroras

Mystery plume in Mars' southern hemisphere photographed by amateur astronomer Wayne Jaeschke on March 20, 2012

Mystery plume in Mars’ southern hemisphere photographed by amateur astronomer Wayne Jaeschke on March 20, 2012. The feature extended between 310-620 miles and lasted for about 10 days.

Strange plumes in Mars’ atmosphere first recorded by amateur astronomers two years ago have planetary scientists still scratching their heads.

On two occasions in 2012 amateurs photographed cloud-like features rising to altitudes of over 155 miles (250 km) above the same region of Mars. By comparison, similar features seen in the past haven’t exceeded 62 miles (100 km). Back then, no one was certain of the cloud’s nature; it was thought ice crystals or even dust whirled high into the Martian atmosphere by seasonal winds could be the cause.

Mars High-altitude_plume_on_Mars

The top image shows the location of the mysterious plume on Mars (yellow circle)  along with different views of the plume’s changing shape taken by Wayne Jaeschke and Don Parker on March 21, 2012

But a recent paper by scientist Agustin Sanchez-Lavega of the Universidad del País Vasco in Spain explores other possibilities. One problem with dust or ice is altitude – 155 miles is way, way up there where Mars’ atmosphere grazes outer space. Just how clouds could form so high is unknown.

“One idea we’ve discussed is that the features are caused by a reflective cloud of water-ice, carbon dioxide-ice or dust particles, but this would require exceptional deviations from standard atmospheric circulation models to explain cloud formations at such high altitudes,” said Agustin.

Another idea is even more intriguing. The wisps could be Martian auroras linked to regions on the surface with stronger-than-usual magnetic fields.

 

The small protrusion extending into the night sky of Mars in this 1997 Hubble photo is probably a high cloud catching sunlight. Credit: NASA/ESA

The small protrusion extending into the night sky of Mars in this 1997 Hubble photo resembles the March 2012 plumes in appearance and altitude. Credit: NASA/ESA

Once upon a very long time ago, Mars may have had a global magnetic field generated by electrical currents in a liquid iron-nickel core much like the Earth’s does today. In the current era, the Red Planet has only residual fields centered over regions of magnetic rocks in its crust.

Instead of a single, planet-wide field that funnels particles from the Sun into the atmosphere to generate auroras, Mars is peppered with pockets of magnetism, each potentially capable of connecting with the wind of particles from the Sun to spark auroras.

Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their tops, auroras can sometimes form. Credit: NASA

Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their tops, auroras can form. Credit: NASA

Auroras were first discovered on Mars in 2004 by the European Space Agency’s Mars Express orbiter. NASA’s MAVEN spacecraft, which has been orbiting Mars since last September, is well-equipped to study the planet’s upper atmosphere and auroras, so perhaps we’ll have a more definitive answer soon on the makeup of the mysterious plumes.

Spectacular fireball over Pittsburgh / Juvenile moon alert


Pittsburgh fireball February 17

A fireball meteor at least as bright as the full moon flared over the Pittsburgh region around 4:50 a.m. Eastern time Tuesday morning. The object, detected by three NASA meteor cameras, was moving at a speed of 45,000 miles per hour. Based on its brightness, NASA’s Meteoroid Environment Office estimated the object at 2 feet across with a weight of 500 pounds. Something like a very heavy TV falling out of the sky.

“I’ve seen many meteor showers and this wasn’t anything like that. Instead of crossing the upper atmosphere, this feel almost directly down and brighter than any thing I’ve ever seen of this nature,” reported John D. of Elyria, Ohio. “It looked so big that my son and I expected to hear or see an impact.”

Based on data from pictures taken by multiple cameras, an orbit for the Pittsburgh fireball could be made. Originating in the asteroid belt between Mars and Jupiter, it came a long way to get to PA.Copyright David L. Clark, prepared by NASA MEO

Based on pictures taken by multiple cameras, NASA scientists determined an orbit for the Pittsburgh fireball. Originating in the asteroid belt between Mars and Jupiter, it came a long way to get to PA. Copyright David L. Clark, prepared by NASA MEO

“The entire landscape was lit up like daytime. Startling experience. I was very fortunate to be looking out window at the time.” So wrote Robert M. of Clarion, Penn. in his report to the American Meteor Society’s fireball reporting website.

Map showing reported sightings of the fireball. To date, 125 reports have been received. Credit: AMS

Map showing reported sightings of the fireball. To date, 125 reports have been received. Credit: AMS

NASA’s cameras first spotted the meteor at an altitude of 60 miles northwest of Pittsburgh and last saw it 13 miles above Kittanning, northeast of Pittsburgh. Around 13 miles altitude, the meteoroid entered its “dark flight” phase, when the air slowed it down enough to drop in free fall.

When we see a meteor, we don’t actually see the object itself but rather a brilliant “tube” of ionized air caused by the rock’s incredibly speedy passage through the atmosphere. Once a meteoroid loses sufficient speed, it no longer has the energy to ionize or make the air glow around it and falls in dark flight.

Earth seen from the perspective of the meteoroid moments before it entered our atmosphere to become a fireball. Click to see the movie. Credit:

Earth seen from the perspective of the meteoroid moments before it entered our atmosphere to become a fireball. Click to see the movie. Credit: Copyright David L. Clark, prepared by NASA MEO

Some people heard sonic booms during the fall, a good sign that the meteoroid (what you call a meteorite before it hits the ground) fragmented and dropped pieces on the ground east of Kittanning. According to Bill Cooke of the Meteoroid Office, seismographs in the region recorded the pressure wave created by the meteoroid’s flight.

Like most meteors and meteorites, this one’s a visitor from the main asteroid belt located between Mars and Jupiter. If pieces did survive the atmosphere’s ferocity, may I be the first to welcome them to their new home.

Watch for a 1-day-old super-thin crescent moon below the duo of Venus and Mars tonight. This map shows the sky about 35 minutes after sundown. Source: Stellarium

Watch for a 1-day-old super-thin crescent moon below the duo of Venus and Mars tonight. This map shows the sky about 35 minutes after sundown. Source: Stellarium

On another note, I wanted to remind moon lovers that a very young, very thin 1-day-old moon will be visible during early twilight in the western sky this evening starting about 25 minutes after sundown.

The moon’s about about one fist held at arm’s length below the pair of Mars and Venus. Tonight’s act is a warm-up for tomorrow night’s very close gathering of the moon with the two planets. For more information on that event, click HERE.

Tracking down February’s mystery supermoon – where is it?

This week’s new moon will be unusually close to Earth. Think of it as a ghostly supermoon. As is true for any new moon, it will be too close to the Sun in the daytime sky to see. This illustration shows the moon’s appearance and location if our eyes could somehow make it out through all the daylight. Source: Stellarium

Here comes the supermoon! But wait, doesn’t that only happen around full moon? Well, not always. Every month the moon swings around Earth in its elliptical (oval) orbit. On one side of the ellipse, it’s closest to Earth and on the opposite side, farthest. When it’s at its closest point, called perigee, at the time of full moon, we call it a supermoon.

During the closest supermoons, our satellite can appear up to 30% brighter and 14% larger. Whether anyone can actually see the difference is open to debate simply because there’s no normal-distance moon nearby with which to make a comparison.

No one pays attention to first quarter or crescent supermoons even though the moon can be closest to us at those phases, too. Thanks to incessant media coverage, only full supermoons get coverage. We like full moons for all sorts of reasons. When an extra close one’s in the offing, as happens on Sept. 27 this year, that’s just one more reason to like them.

The moon’s orbit around Earth is an ellipse with the Earth off-center at one the ellipse’s foci. During its 27-day-long orbit, the moon passes through perigee (closest) and apogee (farthest) points. This week’s new moon will be the second closest perigee of the year after the Sept. 27 full moon. Illustration not to scale. Credit: Bob King

Lest crescents and quarters get short shrift I’m here to hawk this month’s supermoon. Full disclosure. Since it occurs during new moon phase on Feb. 18 you won’t see it. No one sees a new moon except when it happens to be eclipsing the Sun. But northern hemisphere skywatchers can spot the moon two days before new and just one day after new this month, and it’ll be nearly as super as on the18th.

Tomorrow morning Feb. 16 the planet Mercury will lie about 9.5° (about one fist held at arm’s length) to the lower left of the thin crescent two days before new moon phase. This map shows the sky facing southeast about 40 minutes before sunrise. Source: Stellarium

What’s more, if you have a good view of the southeast horizon, tomorrow morning’s skinny crescent will lie near the planet Mercury low in the southeastern sky 40 minutes before sunrise. Be sure to carry along a pair of binoculars as Mercury is near “last quarter” phase and not nearly as bright as it can be.

The moon’s average distance is 240,000 miles, but tomorrow morning at 6 a.m. (CST) it will lie just 226,549 miles from Earth. At 1 a.m. Feb. 18 – the time of the invisible supermoon –  it will be 4,723 miles closer. The following day the moon slides out a bit to 222,092 miles en route to a striking double conjunction with Mars and Venus on Friday the 20th.

Even though we won’t see February’s supermoon, our planet will sense the difference. The additional gravitational force exerted by the close moon will make for unusually high tides. High tides occur when the Sun, moon and Earth are all in a line as they during both new moon phase and at full moon.

The moon, still very close to perigee, pops up in the western sky at dusk on Thurs. Feb. 19 well below Venus and Mars, now in close embrace. This map shows the sky about 35-45 minutes after sunset facing west. Source: Stellarium

So tomorrow morning you can catch the moon near Mercury at dawn, and on Thursday the 19th you’ll have the chance to enjoy the delicate grin of a one-day-old crescent in the west at dusk. Finally, on Friday, don’t miss the close conjunction of the moon with Mars and Venus.

Our satellite has a busy schedule this week!

 

A triple-scoop conjunction with a cherry on top!

Venus and Mars (at right) are drawing closer every night. This photo was taken at dusk Thursday Feb. 12 an hour and 15 minutes after sunset. On Feb. 20-21 they’ll be just half a degree apart or 8 times closer. The moon joins the pair on the 20th. Details: 35mm lens, f/3.5, ISO 800, 12 second exposure. Credit: Bob King

Get ready. One week from tonight fate has arranged a celestial spectacle. That night (Feb. 20) a two-day-old crescent moon will “triple up” with the planets Venus and Mars after sundown.

The entire bunch will fit within a circle 1.5° wide or just three times the diameter of the full moon. Like a glittering pendant around your sweetheart’s neck the trio will dangle above the western horizon in the afterglow of sunset. This is a not-to-miss event and one that should be fairly easy to photograph.

Moon, Mars and Venus around 6:45 p.m. (CST) on Feb. 20 in the western sky. Be sure to look for the darkly-lit part of the moon illuminated by sunlight reflecting off Earth called earthshine. It’s a beautiful sight in binoculars. Source: Stellarium

Look toward the west in the direction of the setting Sun; the best viewing time will be 45 to 90 minutes after sunset. With plenty of light to work with, taking a picture of the scene shouldn’t be too difficult. Attach your camera to a tripod and use the information in the photo caption as a place to start. Try to keep your exposure times to 20 seconds or less. Any longer and the planets will stretch into short trails instead of compact dots due to Earth’s rotation.

When you look at the LCD screen on the back of your camera, don’t be surprised if the crescent moon is completely filled out. Time exposures in semi-darkness necessarily overexpose the bright sunlit crescent. The rest of the moon is illuminated by dimmer earthshine, sunlight reflected from the Earth to the moon and back.

From the East Coast, the moon will lie a little farther to the right of Venus and Mars than depicted in the map; from the West Coast, it sits above the pair. Conjunction with Venus occurs around 5 p.m. (CST) and with Mars an hour later.

Venus and Mars will be close conjunction the following night (Feb. 21) only 0.5° or one moon diameter apart. If the weather doesn’t cooperate on the 21st, don’t sweat it – the two planets will be close from the 19th through the 22nd. You’ll easily tell the two apart. Venus is SO much brighter than Mars (about a hundred times) and the lunar crescent brighter yet. This promises to be one of the best moon-planet gatherings of the year.

Uranus in early twilight (left) just before its dramatic disappearance behind the earth-lit edge of the moon on Feb. 21 as seen from Portland, Maine. 36 minutes later Uranus emerges at the bright crescent’s edge. Both disappearance and reappearance occur in a dark enough sky to see in a small telescope. Source: Stellarium

Here’s a wider view of Uranus and the moon on Feb. 21 as seen from the Midwest about an hour and a quarter after sunset. Source: Stellarium

Ah, but the moon won’t be quite finished with its magic. There’s still the cherry on top. The very same night – Feb. 21 – the crescent covers up or occults the planet Uranus for skywatchers in northeastern U.S. and southeastern Canada during twilight. For the Central Time Zone Uranus will lie 0.5° west of the moon, 1° from the Mountain States and 1.5° for the West Coast. Amazing stuff – yet another opportunity to easily spot planet #7 in binoculars.

Map showing where the occultation of Uranus by the moon will be visible. Between the white lines, it’ll be visible in a dark sky. Blue is twilight and the red dotted line is daytime. Uranus is too faint to see in the daytime sky. Click the map to get a list of disappearance and reappearance times for a variety of cities. Credit: IOTA/Occult

Most of the time the moon occults stars along its path since there are a lot more of those than planets. Because they’re so remote, stars are little more than points of light; as the moon moves over them they disappear with surprisingly suddenness. Since Uranus displays a real, measurable disk it takes a second or two to disappear behind the moon’s edge. This should be a very fun occultation for those lucky skywatchers living out East. Maybe it will help take their minds off the unrelenting snow.

Mars Opportunity rover falters, may be on the chopping block

Surprise landing! On January 25, 2004 the airbag-cushioned lander carrying the Opportunity rover came to rest smack in the middle of Eagle Crater. Mars Reconnaissance Orbiter photo colorized by the author. Credit: NASA/JPL-Caltech

If you have a digital camera you’re familiar with reformatting your memory card after you’ve filled it up and downloaded your images. Reformatting clears the card and allows you to write to it again. But after maybe a hundred of these digital lobotomies a card will often begin to malfunction. Now unreliable, it can’t be trusted, so you toss it and pop in a fresh one.

After climbing out of Eagle Crater, Opportunity looked back to photograph the lander. Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

NASA’s now in the same situation with the flash memory drive in the Mars rover Opportunity. The drive, which stores data when the rover “sleeps” at night, is wearing out after more than 11 years on the Red Planet. As with any camera memory card there are limits to how many times you can write to and erase data.

Over the past six months NASA has had difficulties getting the rover to store commands sent from Earth. Commands, data and photos are normally stored in Opportunity flash memory or hard drive. But the rover’s has lately taken to moving some of that information into its “volatile” or RAM (random access memory) like that found in your computer.

The Opportunity Mars rover took this mosaic self-portrait in March 2014. Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

When you shut down your computer, the important stuff remains on the hard drive while all the temporary settings or RAM memory’s erased. But when Opportunity powers down at night, commands and data that shouldn’t have been moved to RAM are deleted along with all the temporary stuff.

Before Christmas, mission control sent three days’ worth of commands to the rover, but memory troubles meant that only the one day’s activities were kept and completed.

Since the trouble began, the mission’s operations team has been avoiding using the flash system and is currently working on a software fix. In the meantime, they’ve been downloading everything into RAM memory every day before the rover’s nightly shuteye.

Opportunity explored the interior of Victoria Crater back in 2007-2008. Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

That might not be the end of Opportunity’s woes. There’s no money in the proposed federal budget to fund the rover beyond the current budget year. Unless additional funding is found by NASA, Opportunity will bite the Martian dust sometime this fall.

The agency has the difficult task of deciding how to divide a limited amount of money between new missions and continuing to fund old ones.

Opportunity landed on Mars on January 25, 2004 and was only designed to operate for 90 days. The rover is presently sniffing around on the west rim of Endeavour Crater heading towards “Marathon Valley,” where abundant clay minerals may lie just about 984 feet (300-m) away from its present position. Then it’s off to the “Spirit of St. Louis” crater.

The aptly-named Cape Tribulation along a segment of the rim of Endeavour Crater which the rover reached in early January. Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

Opportunity has truly run a marathon in its 11-plus years with 26 miles of roving to its credit, the farthest any machine has driven on the surface of another world besides Earth. It snatched the record last July from the former Soviet Union’s remote controlled Lunokhod 2 rover, which ambled across 24.2 miles (39 km) of the moon back in 1973.

Gosh, it’s bleak on Mars. Photo taken by Opportunity yesterday February 3, 2015. Credit: NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.

So yes, Opportunity has outlived its original design lifetime more than 44 times over. And yes, it’s starting to lose its nimble mind, but I believe the relatively small amount of money (its 2014 budget was $14 million) it would take to keep it going another year or two is well worth it if only because of the potential for additional discoveries and opportunities. Remember, only Opportunity got a decent photo of Comet Siding Spring when it passed close to Mars last fall. Once it’s shutdown, the only feet on Martian ground will be the Curiosity rover’s.

Mars has close brush with Neptune tonight

Binocular view (~5 field) of Mars, Neptune and nearby stars this evening. The planets will be very close together – only one-fifth of a full moon diameter apart. Mars is bright, but Neptune will look like a faint star to the planet’s upper right. Stars shown to magnitude +8.5. Source: Stellarium

Mars has been hiding away in Aquarius low in the southwestern sky at dusk minding its own business. But tonight however the Red Planet will pass VERY close to another more distant planet, Neptune.

To find Mars you’ll need an open view to the southwest. This map shows the sky facing southwest at the end of evening twilight. Mars is about 12-15° above the horizon at that time. Diphda is a fairly bright star in the constellation Cetus the Sea Monster. Source: Stellarium

You can see the “double planet” faintly in 10×50 or larger binoculars but a small telescope will make it a snap. The chart shows a binocular view just the way you’d see the scene facing southwest at nightfall with north toward the upper right. The best time to view the conjunction will be at the end of twilight when they’re highest.

Track of Mars in the next few days as it glides by the planet Neptune. This is also a 5° field of view similar to what you’d see in a pair of binoculars. Created with Chris Marriott’s SkyMap software

Also in your binocular view you’ll see the stars Sigma and 58 Aquarii. Neptune will look exactly like a star and surprisingly close to Mars.

NASA to ESA: We found your dog!

NASA’s HiRise camera on the Mars Reconnaissance Orbiter detected the glint (top) of the Beagle 2 in photos taken last year and released this week. The lander appears to have at least partially deployed. Credit: NASA

Ruff-ruff! The long-lost Beagle 2 lander has been found. Wish I could say it’s still wagging its tail, but at least we finally know where it is after 11 years of wondering.

Built by the Brits and sent to the Red Planet aboard the European Space Agency’s Mars Express spacecraft in June 2003, it was set to land on Christmas Day that year. Everything worked flawlessly, with the first radio contact expected shortly after the scheduled landing time, but no signal was received. Then or ever.

The Beagle 2 lander, named after HMS Beagle, the ship that carried Charles Darwin on expeditions around the world, looks something like a pocket watch before deployment. Upon landing, the watch top (right) snapped open and the individual panels unfolded from the bottom of the lander. Credit: ESA

Beagle was the first British and European attempt to soft land on Mars. All attempts to contact the probe failed, leading some to believe that the Beagle 2 had crash landed. Later, it was determined that an error had prevented two of the spacecraft’s four solar panels from deploying, blocking the spacecraft’s ability to communicate.

Michael Croon of Trier, Germany, a former member of the European Space Agency’s Mars Express operations team pored over images taken by NASA’s Mars Reconnaissance Orbiter (MRO), which operates a high-resolution camera capable of seeing objects the size of a kitchen table on Mars, and found evidence for the Beagle 2.


This photo shows where features seen in a 2014 observation by NASA’s Mars Reconnaissance Orbiter have been interpreted as hardware from the Dec. 25, 2003, arrival at Mars of the United Kingdom’s Beagle 2 Lander. The scale bar at right shows 0.1 km or a distance of 328 feet. Click to enlarge.

NASA then directed MRO to re-photograph the expected landing location in Isidis Planitia, a large, ancient impact basin near the Martian equator. Analysis of those images revealed a bright object that appeared in multiple pictures taken at different times, ruling out the possibility it was a cosmic ray hit on the camera’s sensor. Cosmic rays, high-speed particles (mostly single protons) careen through space all the time. When they hit a camera sensor they can leave bright streaks or spots.

Two images taken months apart, with the sun at different angles, are merged in this view. A glint comes from a different part of the lander in one than in the other, interpreted as evidence of more than one deployed panel on the lander. Credit: HiRISE/NASA/JPL/Parker/Leicester

Due to the small size of Beagle 2 (less than 7 feet, or 2 meters across for the deployed lander) it’s right at the limit of detection of HiRISE, but enhanced photos clearly show what appear to be the solar panels. That means the lander made it safely to surface after all and even partially deployed.

It’s a shame we weren’t able to establish communications. Beagle 2 was equipped with a pair of stereo cameras, a microscope and a drill to collect rock samples that could be analyzed on site.

Simulation of Beagle 2 on Mars showing the instrument-studded robotic arm and the “mole” (at left). Credit: NASA

It even carried a small “mole” or Planetary Undersurface Tool (PLUTO) that could move across the surface at just under an inch per second. When a suitable spot was found, the mole would have burrowed into the ground to collect a sample. Finished with its task, the mole and its sample would have been reeled back to the lander on its power cable. Gods, what a cool idea!

“I can imagine the sense of closure that the Beagle 2 team must feel,” said Richard Zurek of JPL, project scientist now for Mars Reconnaissance Orbiter (MRO).

Even if our best plans go awry, there’s nothing like closure to help us move on to the next opportunity.

Mars gets a new crater, smiles for the camera

This new crater excavated by an impacting meteorite on Mars shows a striking pattern of ejecta – rocks and other debris blasted off the surface during the impact. The shape of the ejecta indicate that the incoming space rock likely struck from the west (left). Credit: NASA/JPL/Univ. of Arizona

Close your eyes. OK, now open them again. In a cosmic blink of the eye, this brand new crater appeared on the Martian plain called Elysium. It formed sometime between February 2012 and June 2014 as revealed by NASA’s Mars Reconnaissance Orbiter (MRO). A previous image showed only ancient cratered terrain.

Before (left) and after photos show relatively smooth plain with numerous older crater and the fresh impact (right). Credit: NASA/JPL/Univ. of Arizona

The impact exposed removed the ubiquitous orange-hued dust to reveal darker materials beneath the surface. The crater’s rim has a sharp outline showing virtually zero erosion. Some of the smaller, irregular divots near the strike were formed when huge chunks of rock from the impact fell back to the surface creating secondary craters.

A closer-in view shows how sharp and fresh the crater’s rim is. One way astronomers estimate relative ages of craters by examining how sharp or soft their rims appear. Click for hi-res image. Credit: NASA/JPL/Univ. of Arizona

This is far from the first fresh crater recorded at Mars by orbiting spacecraft. More than 400 have been found over the years as researchers pour over the hundreds of thousands of images returned by probes like MRO. Although I have no indication how large our featured crater is, the largest new crater ever discovered on the planet measures 161 feet (49-meters) or half the length of a U.S. football field.

How Mars’ largest new crater was discovered

We wrap up today with a big smile from the Red Planet’s south polar cap. MRO takes images throughout the Martian year (687 Earth days) of the polar regions to document changes in carbon dioxide ice coverage. Mars’ polar regions contain both water and CO2 ices which vaporize in the spring and summer heat, causing the caps to shrink back toward their respective poles.

The residual polar cap at Mars south pole in the summer season is rich in carbon dioxide or dry ice. Ice vaporizing in sunlight created as series of low mounds that resemble a smiling face. Click to enlarge. Credit: NASA/JPL/Univ. of Arizona

This fun photo was taken last November 30th and depicts an area about 1/3-mile across (500 meters) that resembles a smiley face. Just as sunlight and wind sculpts wild patterns in snow and ice on Earth, so too on Mars.

Stargazing on Christmas night

Merry Christmas and a happy holiday! I hope you’re enjoying time with family and friends and a clear night is in the forecast. Should you poke your head out tonight, here’s what’s up.

Look for the crescent moon and Mars in the southwestern sky at the end of twilight tonight December 25th. Comet Finlay and Mars will still be tight the next few nights.  The alignment is line-of-sight only — the two are actually about 45 million miles apart. Stellarium

At nightfall, a pretty crescent moon ornaments the dim constellation of Capricornus not far from Mars. Barely half a degree to the planet’s east a 6-inch or larger telescope will net you Comet 15P/Finlay, now fading from its recent outburst. It’s currently magnitude 9.6 with a little tail pointing to the east.

Comet 15P/Finlay passed only 1/6th of a degree from Mars on December 23-24. This photo was taken on the 24th and shows the glaring planet and comet almost touching. Click for a map to help you find Finlay in your telescope. Credit: Damian Peach

In a remarkable coincidence, comets have passed very close to the planet Mars twice this year. Comet Siding Spring drew physically close on and around October 19th, while Comet Finlay only appears next to the planet thanks to a lucky line-of-sight alignment.

A grand entry of stars dances across the southeastern sky around 10 o’clock local time. Comet C/2014 Q2 Lovejoy will be 10° high at that hour in the constellation Columba the Dove as seen from the northern U.S. and even higher from the central and southern states. Stellarium

Later tonight, around 10 o’clock, look to the south. Orion has now climbed boldly into view along with sparkling Sirius and the “Winter Triangle” figure. Tucked below Lepus the Hare you’ll find our Christmas comet, Lovejoy, now glowing at magnitude 5.5 and faintly visible to the naked eye from a dark sky location. Binoculars show it as a big ball of fuzz. For more information and a map showing its travels in the coming nights, click HERE.

Comet Lovejoy on December 23 looks like a Roman candle with a blue coma and long, faint tail. Credit: Michael Jaeger

Photos of Lovejoy show a huge coma or comet atmosphere more than half the size of the full moon tinted green from fluorescing carbon and cyanogen molecules; its super-skinny tail glows blue from light given off by carbon monoxide excited by ultraviolet light from the Sun.

Jupiter is easy to see now in the eastern sky in Leo around 10 o’clock local time. Stellarium

If you now direct your gaze to the east around 10 p.m., Jupiter jumps right out. After Sirius and the moon, it’s the brightest nighttime object the sky this winter. Use the planet to help you find the Sickle or head of Leo the Lion and its brightest star, Regulus.

Jupiter in binoculars tonight around 10 p.m. (CST). All four of its bright moons will be strung out in a nearly straight line very close to the planet (big glow at center). Stellarium

Sharply-focused and steadily held 10x binoculars will show all four of its bright moons, assuming one or more aren’t passing either behind or front of the planet or in eclipse. Lucky for us, Io, Europa and Ganymede will line up in a neat row east of Jupiter with Callisto well off to its west tonight. How many will you see?

Wow! What a blast. This fireball lit up Japanese skies early this morning. The Belt of Orion is at upper right. Credit: SonotaCo

Finally, reports are coming in about a powerfully bright fireball that streaked across Japan’s skies around 2 a.m. local time this Christmas morning. I’ve not been able to track down a brightness estimate, but the pictures show an object at least as brilliant as the full moon.