Mars Gets Bombarded by 200 Small Asteroids and Comets Every Year

A relatively new cluster of impact craters on Mars as seen by the HiRISE camera on the Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/MSSS/Univ. of Arizona

One of the benefits of having a spacecraft in orbit around another planet for several years is the ability to make long-term observations and interpretations. The Mars Reconnaissance Orbiter has been orbiting Mars for over seven years now, and by studying before-and-after images from the High Resolution Imaging Science Experiment (HiRISE) camera, scientists have been able to estimate that the Red Planet gets womped by more than 200 small asteroids or bits of comets per year, forming craters at least 3.9 meters (12.8 feet) across.

“It’s exciting to find these new craters right after they form,” said Ingrid Daubar of the University of Arizona, Tucson, lead author of the paper published online this month by the journal Icarus. “It reminds you Mars is an active planet, and we can study processes that are happening today.”

New impact site on Mars formed between November 2005 and October 2010. Credit: NASA/JPL-Caltech/MSSS/Univ. of Arizona
New impact site on Mars formed between November 2005 and October 2010. Credit: NASA/JPL-Caltech/MSSS/Univ. of Arizona

Over the last decade, researchers have identified 248 new impact sites on parts of the Martian surface in the past decade from spacecraft images, determining when the craters appeared. The 200-per-year planetwide estimate is a calculation based on the number found in a systematic survey of a portion of the planet.

The orbiters took pictures of the fresh craters at sites where before-and-after images by other cameras helped figure out when the impacts occurred. This combination provided a new way to make direct measurements of the impact rate on Mars. This will lead to better age estimates of recent features on Mars.

Daubar and co-authors calculated a rate for how frequently new craters at least 3.9 meters in diameter are excavated. The rate is equivalent to an average of one each year on each area of the Martian surface roughly the size of the U.S. state of Texas. Earlier estimates pegged the cratering rate at three to 10 times more craters per year. They were based on studies of craters on the moon and the ages of lunar rocks collected during NASA’s Apollo missions in the late 1960s and early 1970s.

“Mars now has the best-known current rate of cratering in the solar system,” said HiRISE Principal Investigator Alfred McEwen of the University of Arizona, a co-author on the paper.

Examples of craters listed in the paper 'The Current Martian Cratering Rate.' Credit: NASA/JPL/Univ. of Arizona.
Examples of craters listed in the paper ‘The Current Martian Cratering Rate.’ Credit: NASA/JPL/Univ. of Arizona.

These asteroids, or comet fragments, typically are no more than 3 to 6 feet (1 to 2 meters) in diameter. Space rocks too small to reach the ground on Earth cause craters on Mars because the Red Planet has a much thinner atmosphere.

For comparison, the meteor over Chelyabinsk, Russia, in February was about 10 times bigger than the objects that dug the fresh Martian craters.

HiRISE targeted places where dark spots had appeared during the time between images taken by the spacecraft’s Context Camera (CTX) or cameras on other orbiters. The new estimate of cratering rate is based on a portion of the 248 new craters detected. It comes from a systematic check of a dusty fraction of the planet with CTX since late 2006. The impacts disturb the dust, creating noticeable blast zones. In this part of the research, 44 fresh impact sites were identified.

Estimates of the rate at which new craters appear serve as scientists’ best yardstick for estimating the ages of exposed landscape surfaces on Mars and other worlds.

One of many fresh impact craters spotted by the UA-led HiRISE camera, orbiting the Red Planet on board NASA's Mars Reconnaissance Orbiter since 2006. (Photo: NASA/JPL-Caltech/MSSS/UA).
One of many fresh impact craters spotted by the UA-led HiRISE camera, orbiting the Red Planet on board NASA’s Mars Reconnaissance Orbiter since 2006. (Photo: NASA/JPL-Caltech/MSSS/UA).

See the abstract and other information here.
Source: JPL

Timelapse Shows the Blazing Beauty of a ‘Ring of Fire’ Eclipse

Images and videos are still coming in from last week’s spectacular annular eclipse of the Sun, seen across Australia and the southern Pacific region on May 10, 2013. This gorgeous timelapse by Colin Legg captures the eclipse from 3 locations in the Pilbara, Western Australia where the Sun was rising at the time of the event. “If you ever get to see an annular eclipse, I recommend going to the path limits (sunset or sunrise),” Legg said on Vimeo. “All sorts of weird things happen to the Sun, right on the horizon.”

Wow.

See more at our previous gallery of images and video from the eclipse.

Continue reading “Timelapse Shows the Blazing Beauty of a ‘Ring of Fire’ Eclipse”

Astrophoto: Stonehenge, the Milky Way and an Eta Aquarids Meteor

A meteor from the Eta Aquarids flashes over the iconic Stonehenge. Credit and copyright: Peter Greig.

Astrophotographer Peter Greig (St1nkyPete on Flickr) had always wanted to go to Stonehenge in Wiltshire, England, and chose to go there this year for his birthday. It turns out the Universe gave him a little birthday present, with a fabulous clear evening to see the Milky Way shining overhead, along with a few Eta Aquarid meteors flashing in the sky. He captured this amazing shot on May 12. Happy birthday, Peter!

Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Orion’s Secret Fire Dance

In this image, the submillimetre-wavelength glow of dust clouds in the Orion A nebula is overlaid on a view of the region in the more familiar visible light, from the Digitized Sky Survey 2. The large bright cloud in the upper right of the image is the well-known Orion Nebula, also called Messier 42. Credit: ESO/Digitized Sky Survey 2

The Great Orion Nebula has captivated observers for at least four hundred years, but the ancient Mayans may have known about its secrets long before then. According to legend, the nebula might have been the smoke situated between the “Three Hearthstones” and the light of the emerging stars seen as the very embers of creation itself. Now the ESO-operated Atacama Pathfinder Experiment (APEX) in Chile has revealed what we cannot see. At wavelengths too long for human vision, this new image shows us an ancient fire dance painted in colors of cold interstellar dust.

As we know, deposits of gas and interstellar dust are virtual star factories. However, the very material which creates stars also masks them. So how do we peer behind the veil? The answer is to observe at alternative wavelengths of light. In this case, the submillimetre wavelength reveals what our eyes cannot see… dust grains igniting the view, even though they are just a few tens of degrees above absolute zero. This makes the APEX telescope with its submillimetre-wavelength camera LABOCA, located at an altitude of 5000 metres above sea level on the Chajnantor Plateau in the Chilean Andes, the perfect instrument to play the tune for this cold fire dance.

Take a look around the picture. It’s just a small portion of a vast complex known as the Orion Molecular Cloud. Wafting across hundreds of light years space some 1350 light years away, this rich arena of hot young stars, cold dust clouds and bright nebula is the epitome of stellar creation. The image reveals the submillimetre-wavelength glow in shades of orange and it is combined with visible light for a total visual experience. Note deep ribbons, sheets and bubbles… These are the product of gravitational collapse and the effects of stellar winds. Powerful stellar processes are at work here. The atmospheres of the stars are crafting the clouds much the same way a gentle breeze swirls the smoke from a fire.

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Credit: ESO/Nick Risinger (skysurvey.org), Digitized Sky Survey 2. Music: movetwo

As beautiful as it is, there is still science behind the imagery. Astronomers have employed the data taken with ESA’s Herschel Space Observatory, along with the APEX information, to aid them in their search for early star formation. At this point in time, the researchers have been able to verify more than a dozen candidate protostars – objects which appear far brighter at longer wavelengths rather than short. It’s a triumph for the researchers. These new observations could well be the youngest protostars so far observed and it brings astronomers just one step closer to witnessing the moment when a star ignites.

Original Story Source: ESO News Release.

Chris Hadfield’s 5-month Space Mission in 90 Seconds

Expedition 35 Commander Chris Hadfield of the Canadian Space Agency (CSA), left, Russian Flight Engineer Roman Romanenko of the Russian Federal Space Agency (Roscosmos), center, and NASA Flight Engineer Tom Marshburn sit in chairs outside the Soyuz Capsule just minutes after they landed in a remote area outside the town of Dzhezkazgan, Kazakhstan, on Tuesday, May 14, 2013. Hadfield, Romanenko and Marshburn are returning from five months onboard the International Space Station where they served as members of the Expedition 34 and 35 crews. Photo Credit: (NASA/Carla Cioffi)

Already missing him being in space? I’ve seen several tweets about people going through Hadfield withdrawal. But to tide you over until he starts tweeting again (just give him a little time to get his Earth-legs again) here’s a mashup/supercut of Chris Hadfield’s video and image highlights from his five-month stay on the International Space Station.

How to Plant a Garden on Mars — With a Robot

Sketch of the ‘AstroGardening’ robot within its Mars garden Credit: Vanessa Harden.

Editor’s note: This guest post is written by Louisa Preston, an Astrobiologist and Planetary Geologist. She is a TED Fellow, and Postdoctoral Research Associate at The Open University, UK.

In the last century humanity has taken gigantic leaps forward in the robotic exploration of the cosmos — not least in the search for habitable worlds and environments that could house life outside of the Earth. The next logical step is for humanity itself to leave the confines of our planet, and take on long-term human exploration of the Solar System. Mars in particular is a key target for future human planetary adventures even though on the face of it, it seems so hostile to human life. In fact Mars actually has the most clement environment of any planet in the Solar System outside of Earth and is known to have all of the resources necessary in some accessible form, to sustain life on the surface. So how might we survive on Mars? The crucial things for humans on Mars are the availability of oxygen, shelter, food and water, and not just endless consumables delivered to the planet from Earth. For humans to live long-term on Mars, they will need a self-sustaining habitat to be able to thrive in for generations.

In short, they’ll need a garden. And maybe a robot, too.

Any garden on Mars would need protection in the form of a greenhouse or geodesic dome that could keep the vegetables, fruits, grains and flowers sheltered from the extreme UV radiation that floods the Martian surface, whilst still allowing enough sunlight through to allow them to grow. This dome would also have to be strong enough to provide support and protection against potentially devastating Martian dust storms.

The crops would need to be kept warm, as outside the dome it will be on average a freezing -63 °C. Solar panels arranged outside the habitat and heating filaments underneath it could provide the desired warmth.

garden on mars

Liquid water is needed for irrigation of the plants and for future human consumption, but with water on Mars mainly frozen beneath the surface, we would need to mine the ice and melt it. The atmosphere on Mars is chiefly composed of CO2, which humans cannot use for any of our vital functions. However plants can! They can utilise this atmospheric CO2 to photosynthesise, which would actually create the oxygen we would need.

These are all important aspects of long-term human habitation of Mars that need to be tested and perfected before we arrive, but thankfully most of these can be investigated whilst safely here on the Earth in Mars analogue environments and specially designed spaces.

Our premise is that of a pioneer AstroGardening robot, designed and built by ourselves, to be sent to Mars to set up garden habitats in advance of the first human inhabitants. It will scatter ‘seed pills’ containing various seeds, clay and nutrients across the habitat and nurture the growing plants.

But before we actually go to Mars, we are working on an interactive ‘Mars Garden’ exhibit and AstroGardening Rover designed to educate and inspire.

Installation designer Vanessa Harden and I are building such a space; an interactive experience designed for museums and science centers to entertain and educate on the perils and benefits of gardening on Mars, the ways in which we need to design tools to do this, the plants that would best grow in Mars soil and the methods we might use to obtain liquid water.

Visitors to this Mars concept habitat will get to meet the AstroGardening robot himself and walk around a lush and tranquil Martian garden. They will also get to see the range of food stuffs that we can actually grow in the Martian soil such as asparagus, potatoes, sweet potatoes, radish, alfalfa, and mung bean.

Our aim for this exhibit is to communicate the science behind future human habitation of Mars, the effect we as humans can have on an environment, and the ethics and logistics of colonising other planets.

The exhibit has already been invited to tour around some of London’s most celebrated and beautiful venues such as observatories and planetariums, museums and art galleries, schools and universities, before heading across the ocean to the US and Canada.

But we need the public’s help to make this tour and exhibit a reality.

We have a Kickstarter page for this concept to raise the funds to begin building our vision. See our page and watch our video (below) to find out how you can help.

AstroGardening – Designing for Life on Mars from vanessa harden on Vimeo.

Stunning Astrophotos Reveal the Importance of Dark Skies

The Milky Way and Aurora over Godafoss, waterfall of the gods, Iceland, by Stephane Vetter from France, the first place winner in Beauty of the Night Sky category, TWAN 2013 Earth & Sky Photo Contest.

The World at Night’s (TWAN) annual Earth & Sky photography contest showcases the stunning beauty of the night sky while highlighting the challenges of keeping our skies free from light pollution. TWAN has now announced the winners of this year’s contest, and the winning photos are simply breathtaking. This year’s theme of “Dark Skies Importance,” were judged in two categories: “Beauty Of The Night Sky” and “Against The Lights,” said Babak Tafreshi, the founder and director of TWAN,” and the winners were selected from submissions by photographers in about 45 countries.”

The selected images were judged to be those most effective in impressing the public on both how important and delicate the starry sky is as an affecting part of our nature, and also how bad the problem of light pollution has become.

Tafreshi added that “the amazing number of eye-catching entries from across the world tells how public attention to night sky is growing as well as interest to sky photography and we are very pleased if TWAN has a role on this increasing awareness.”

The overall contest winner and first prize in the Beauty Of The Night Sky category is our lead image, taken by Stephane Vetter of France, for his March 2013 panoramic photo “Sky Above Godafoss” of aurora and the Milky Way over the “Waterfall of the Gods” in Iceland.

See more winners and more information about the contest below:

The first prize in Against The Lights category goes to Andreas Max Böckle of Austria for his photo “Under the Hood” taken from overlooking the city of Salzburg in a moonlit night:

Stars over Salzburg, Austria by Andreas Max Böckle, the first winner in Against the Lights category in TWAN 2013 Earth & Sky Photo Contest.
Stars over Salzburg, Austria by Andreas Max Böckle, the first winner in Against the Lights category in TWAN 2013 Earth & Sky Photo Contest.

David Malin, one of the judges and a world-known pioneer in scientific astrophotography said, “The 685 entries the judges examined (more than twice than the 2012 judged images) represent some of the best TWAN-style photographs ever gathered together in one place… I feel privileged to have seen so many beautiful images in such a short time!”

Click on the images here to see larger versions. You can see all the winners (and the great prizes they won) at the TWAN website, and this video highlights the winning photos:

‘Crossed Destinies,’ the Milky Way of Reunion Island, Indian Ocean by Luc Perro from France is the 2nd place winner in the Beauty of the Night Sky category in the TWAN 2013 Earth & Sky Photo contest.
‘Crossed Destinies,’ the Milky Way of Reunion Island, Indian Ocean by Luc Perro from France is the 2nd place winner in the Beauty of the Night Sky category in the TWAN 2013 Earth & Sky Photo contest.

Mercury Shows Off Its Reds, Whites, and Blues

An 11-color MESSENGER targeted image of Mercury's Tyagaraja crater

At first glance, the planet Mercury may bear a striking resemblance to our own Moon. True, both are heavily-cratered, airless worlds that hide pockets of ice inside polar shadows… but there the similarities end. In addition to being compositionally different than the Moon, Mercury also has surface features that you won’t find on the lunar surface — or anywhere else in the Solar System.

The picture above, part of an 11-color targeted image acquired by MESSENGER on April 25, 2013, shows the varied terrain found within the 97-kilometer-wide Tyagaraja crater located near Mercury’s equator. The reds, blues, greens, and oranges, much more saturated than anything we’d see with our own eyes, correspond to surface materials of different compositions… and the brightest spots within the crater are features called “hollows” that are truly unique to Mercury, possibly resulting from the planet’s close interaction with the solar wind.

First noted in September of 2011, hollows have been identified across many areas of Mercury. One hypothesis is that they’re formed by the sublimation of subsurface material exposed inside larger craters. Being so close to the Sun and lacking a protective atmosphere, Mercury is constantly being scoured by the solar wind — a relentless stream of charged particles that’s actively “sandblasting” exposed volatiles from the planet’s surface!

Read more about hollows here.

A previous MESSENGER image of hollows inside Tyagaraja crater
A previous MESSENGER image of hollows inside Tyagaraja crater

The reddish spot at the center of the crater in the top image is likely material surrounding a pyroclastic vent, which appear red and orange in MDIS images. The dark material that appears bluish is something called “low reflectance material” (LRM).

The image was acquired as a targeted high-resolution 11-color image set. Acquiring 11-color targets is a new MESSENGER campaign that began in March and utilizes all of the Wide-Angle Camera’s 11 narrow-band color filters. Because of the large data volume involved, only features of special scientific interest are targeted for imaging in all 11 colors.

Full of geologically interesting features the crater was named for Kakarla Tyagabrahmam, an 18th century composer of classical South Indian music.

The first spacecraft to establish orbit around Mercury in summer 2011, MESSENGER is capable of continuing orbital operations until early 2015.

Read more on the Johns Hopkins University APL MESSENGER site here.

Credits:  NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Yet Another X-Class Flare From AR 1748

An X3.2-class flare observed by SDO's AIA instrument at 0114 UT on May 14 (NASA/SDO/AIA)

Last night, as Commander Hadfield and the Expedition 35 crew were returning to Earth in their Soyuz spacecraft, the Sun unleashed yet another X-class flare from active region 1748, the third and most powerful eruption yet from the sunspot region in the past 24 hours — in fact, at a level of X3.2, it was the most intense flare observed all year.

And with this dynamic sunspot region just now coming around the Sun’s limb and into view, we can likely expect much more of this sort of activity… along with a steadily increasing chance of an Earth-directed CME.

According to SpaceWeather.com AR1748 has produced “the strongest flares of the year so far, and they signal a significant increase in solar activity. NOAA forecasters estimate a 40% chance of more X-flares during the next 24 hours.”

(Find out more about the classification of solar flares here.)

The sunspot region just became fully visible to Earth during the early hours of May 13 (UT).

Most recent SDO image of AR1748 (NASA/SDO/AIA)
Most recent SDO image of AR1748 (NASA/SDO/AIA)

Sunspots are regions where the Sun’s internal magnetic fields rise up through its surface layers, preventing convection from taking place and creating cooler, optically darker areas. They often occur in pairs or clusters, with individual spots corresponding to the opposite polar ends of magnetic lines.

Sunspots may appear dark because they are relatively cooler than the surrounding area on the Sun’s photosphere, but in ultraviolet and x-ray wavelengths they are brilliantly white-hot. And although sunspots look small compared to the Sun, they are often many times larger than Earth.

Read more: How Big Are Sunspots?

According to SDO project scientists Dean Pesnell on the SDO is Go! blog, AR1748 is not only rapidly unleashing flares but also changing shape.

“The movies show that the sunspot is changing, the two small groups on the right merging and the elongated spot on the lower left expanding out to join them,” Pesnell wrote earlier today.

Of course, as a solar scientist Pesnell is likely much more excited about the chance to observe further high-intensity activity than he is concerned about any dramatically negative impacts of a solar storm here on Earth, which, although possible, are still statistically unlikely.

“Great times ahead for this active region!” he added enthusiastically.

For updated information on AR1748’s activity visit SpaceWeather.com and NASA’s SDO site, and also check out TheSunToday.org run by solar physicist C. Alex Young, Ph.D.

Images courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.

 

Hadfield, Marshburn and Romenko Return Safely to Earth

Canadian astronaut Chris Hadfield gives a thumbs up after landing safely in Kazahkstan. Via NASA TV.

Coming home to clear blue skies, green grass and warm weather, the Expedition 35 crew of Canadian astronaut Chris Hadfield, NASA’s Tom Marshburn and Russia’s Roman Romanenko has returned after spending just over five months on the International Space Station. “It’s beautiful!” one of the crew radioed in Russian just before landing. “It’s morning here.”

The Soyuz TMA-07M spacecraft landed right on target on the steppe of Kazakhstan, southeast of Dzhezkazgan at 10:31 pm EDT on May 13 (02:31 UTC and 8:31 am local time, May 14, 2013.) The crew undocked from the ISS on Monday.

Keeping with his Expedition-long constant updates via Twitter (updated by his son Evan during the return flight and landing) Hadfield’s location changed appropriately to “In a Soyuz” to “In a field in Kazahkstan.”

A few hours later, Hadfield tweeted, “Safely home – back on Earth, happily readapting to the heavy pull of gravity. Wonderful to smell and feel Spring.”

Expedition 35 Commander Chris Hadfield of the Canadian Space Agency (CSA), left, Russian Flight Engineer Roman Romanenko of the Russian Federal Space Agency (Roscosmos), center, and NASA Flight Engineer Tom Marshburn sit in chairs outside the Soyuz Capsule just minutes after they landed in a remote area outside the town of Dzhezkazgan, Kazakhstan, on Tuesday, May 14, 2013. Hadfield, Romanenko and Marshburn are returning from five months onboard the International Space Station where they served as members of the Expedition 34 and 35 crews. Photo Credit: (NASA/Carla Cioffi)
Expedition 35 Commander Chris Hadfield of the Canadian Space Agency (CSA), left, Russian Flight Engineer Roman Romanenko of the Russian Federal Space Agency (Roscosmos), center, and NASA Flight Engineer Tom Marshburn sit in chairs outside the Soyuz Capsule just minutes after they landed in a remote area outside the town of Dzhezkazgan, Kazakhstan, on Tuesday, May 14, 2013. Hadfield, Romanenko and Marshburn are returning from five months onboard the International Space Station where they served as members of the Expedition 34 and 35 crews. Photo Credit: (NASA/Carla Cioffi)

The crew smiled and gave thumbs up after being extracted from the Soyuz craft, which appeared to land upright and then tipped on its side. Hadfield and Marshburn will soon head back to Johnson Space Center in Houston, with Romanenko going to Star City, Russia.

The Expedition 35 crew has now wrapped up 146 days in space, 144 days on the ISS. While on board they completed 2,336 orbits around the planet and clocked almost 100 million kilometers (62 million miles) In total, Marshburn has spent 162 days in space, 166 days for Hadfield, and 334 days for Romanenko.

The Soyuz TMA-07M spacecraft is seen as it lands with the Expedition 35 crew.  Photo Credit: (NASA/Carla Cioffi)
The Soyuz TMA-07M spacecraft is seen as it lands with the Expedition 35 crew. Photo Credit: (NASA/Carla Cioffi)
The Soyuz TMA-07M spacecraft is seen as it lands. Photo Credit: (NASA/Carla Cioffi)
The Soyuz TMA-07M spacecraft is seen as it lands. Photo Credit: (NASA/Carla Cioffi)

This video shows the crews saying goodbye; then later the undocking, followed by the landing and crew extraction: