NASA’s LADEE spacecraft crashes into the moon – preliminary mission results

An artist’s concept of NASA’s Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft crashing into the moon’s farside Thursday April 17. Credit: NASA

What it may sound like a huge disaster, destroying the $263 million dollar spacecraft was NASA’s intention from the start. At 8:59 p.m. CDT April 17, the agency confirmed the probe had impacted the moon’s surface.

The Lunar Atmosphere and Dust Explorer or LADEE (pronounced ‘laddie’) began circling the moon last fall, its mission to study dust in its extremely rarefied lunar atmosphere. Much of the dust sputters off the surface during meteorite impacts, while some may be lofted into the sky by electrostatic forces active when the sun rises along the day-night borderline called the terminator.

LADEE only had so much fuel to conduct operations at the moon. When that was used up, the mission was complete. The vending-machine-sized probe broke apart as it heated up upon impact. Many pieces likely lie scattered across and inside craters. Credit: NASA Ames/Dana Berry

Prior to crashing, mission controllers gradually lowered the spacecraft’s orbit to study the moon’s near surface dust environment in ever more detail. While the moon lacks the atmosphere to slow a spacecraft and “drag” it down to the surface (like what happens at Earth), nature worked her wonders all the same. The moon’s gravity field is “lumpy”, with lighter, less dense regions alternating with denser concentrations of rock beneath the surface. Low-orbiting probes, perturbed by variations in pull of gravity are soon brought down.

An photo taken by the star trackers aboard LADEE of the moon’s surface illuminated by a nearly full Earth along with stars in the airless sky. Credit: NASA/Ames

“At the time of impact, LADEE was traveling at a speed of 3,600 miles per hour – about three times the speed of a high-powered rifle bullet,” said Rick Elphic, LADEE project scientist at Ames. “There’s nothing gentle about impact at these speeds — it’s just a question of whether LADEE made a localized craterlet on a hillside or scattered debris across a flat area. It will be interesting to see what kind of feature LADEE has created.”

LRO photographed LADEE about 5.6 miles beneath it on Jan. 14, 2014. Image width is about 898 yards (821 meters). LADEE appears stretched because it was moving and LRO builds an image a line at a time. Credit: NASA/Goddard/Arizona State University

NASA plans to work with the Lunar Reconnaissance Orbiter (LRO) team to overfly and capture an image of the impact site. LADEE struck the moon on the farside, a safe distance from any historic landing sites, all of which have been on the lunar nearside. Because radio communications can’t be received from the farside, NASA mission controllers had to wait for an hour during each ultra-low orbital pass. If LADEE began sending data again, they knew it was still “alive”. When LADEE didn’t show up at the planned time Thursday, the mission was declared over.

A thin crescent moon. Unseen except by space probes are the dribs and drabs of moon dust that comprise the moon’s rarefied atmosphere. Credit: Bob King

Scientists will be analyzing the data from the probe for a long, long time, but there are some preliminary results:

* LADEE survived the chill-inducing lunar eclipse earlier this week, demonstrating the spacecraft’s ability to endure low temperatures and a drain on batteries as it, and the moon, passed through Earth’s deep shadow.

* LADEE’s Lunar Dust EXperiment (LDEX) experiment detected an increase in the number of dust particles in the moon’s exosphere during the Geminid meteor shower in mid-December 2013.  The LDEX dust impacts are thought to be due to the ejecta, or spray, of particles that result when the Geminid meteoroids slam into the lunar surface. The exosphere or dilute lunar atmosphere contains dust particles as well as gases from the solar wind.

* The Ultraviolet and Visible light Spectrometer (UVS) carried out a series of before and after observations looking for effects of the Chinese Chang’e 3 landing in December and meteor showers. Analysis revealed an increase in sodium connected with the Geminids, as well as evidence of increased light scattering due to dust but no clear signal from the Chang’e 3 landing.

The UVS also has been monitoring specific wavelengths of light emitted by atomic oxygen, and has seen emissions that may indicate the presence of both iron and titanium in the lunar exosphere. All three are elements found in the lunar soil called regolith but have never been seen in the moon’s atmosphere before.

Wow, that’s a lot of sunspots! Aurora in the forecast April 19-20

A very busy sun photographed early this morning with NASA’s Solar Dynamics Observatory. Sunspot region 2035 shot off a moderately strong M-class flare on April 16. NOAA forecasters predict a 60% chance for more flares today from one or more of the sunspot groups. Credit: NASA

I can’t recall seeing the sun this peppered with sunspots in a long time. Through the scope this morning I counted nine separate groups. No single spot or group stood out as unusually large, but the combined effect of seeing so many blemishes in one glance made an impression. I encourage you to point your telescope – suitably equipped with a safe solar filter of course – at the sun today to appreciate how fraught with magnetic activity our sun has become.

Each group marks a region on the sun’s shiny outer skin called the photosphere where magnetic energy is concentrated. Strong magnetic fields within a sunspot group quell the turbulent churning of the photosphere, chilling the region by several thousand degrees. Sunspots appear dark against the sun’s blazing disk because they’re cooler.

A powerful solar flare in sunspot region 2036 captured this morning around 8:30 a.m. CDT April 14 in extreme ultraviolet light by the Solar Dynamics Observatory. Credit: NASA

Energy stored in sunspots’ twisted magnetic fields can suddenly be released in violent, explosions called solar flares. Billions of tons of solar plasma – the sizzling mix of protons and electrons that composes the sun – are heated to millions of degrees during the explosion and rapidly accelerated into space. Radiation from radio waves to X-rays and gamma rays fan out at the speed of light. Fortunate for us, our atmosphere and planetary magnetic field protect us from most of what flares can dish out.

The powerful X4.9 solar flare of Feb. 25, 2014 recorded in six different wavelengths of ultraviolet light. Credit: NASA/SDO

Not everything though. Strong X-class flares can cause radio blackouts, damage satellite electronics and disrupt poorly protected power grids. They also can spark displays of northern lights. An M-class flare from sunspot region 2035 on April 16 may kick off auroras overnight Saturday April 19-20. NOAA forecasters predict a 25% chance of a minor auroral storm.


Video of February’s X4.9 flare shown in multiple wavelengths of light

Conditions are ideal if it comes to pass. Moonlight won’t be a problem and night temperatures are decidedly more pleasant than in February.

Kepler-186f: First Earth-sized planet found in the habitable zone of another star

The artist’s concept depicts Kepler-186f , the first validated Earth-size planet to orbit a distant star in the habitable zone—a range of distance from a star where liquid water might pool on the planet’s surface. Four additional planets orbit the star but they’re too close and too hot to support life. Credit: NASA

We’ve come a long way. First it was only giant planets seared by hot proximity to their host stars. Not anymore. Astronomers announced the discovery today of the first Earth-sized planet in the “habitable zone” of its host star. Habitable, when it comes to extra-solar planets, means the right distance for liquid water to pool on the planet’s surface. Water is intimately tied to life on Earth and may also be on other worlds.

Other planets have been discovered in their stars’ habitable zones, but they’ve all been at least 40% larger than Earth. This one, named Kepler-186f, nearly matches Earth in size and orbits Kepler-186, a star with four previously known planets 500 light years away in the constellation Cygnus (Northern Cross).

The diagram compares the planets of our inner solar system to Kepler-186, a five-planet star system about 500 light-years from Earth in the constellation Cygnus. The five planets of Kepler-186 orbit an M dwarf, a star that is is half the size and mass of the sun. M-dwarfs are numerous, making them likely places to find Earth-like planets. Credit: NASA

“Being in the habitable zone does not mean we know this planet is habitable,” cautions Thomas Barclay, a research scientist at the Bay Area Environmental Research Institute at Ames, and co-author of the paper. “The temperature on the planet is strongly dependent on what kind of atmosphere the planet has. Kepler-186f can be thought of as an Earth-cousin rather than an Earth-twin. It has many properties that resemble Earth.”

Kepler-186f is 10% larger than Earth and orbits an M class red dwarf star every 130 days, soaking in just one-third the amount of heat Earth receives from the sun. That places it near the edge of the habitable zone. Its mass and composition are still unknown, but previous studies imply planets this size are made of rock like Earth.


Transiting Exoplanet Survey Satellite (TESS) – the next generation in exoplanet discovery

The Kepler space telescope infers the existence of a planet by the amount of starlight blocked when it passes in front of its host star. From these data, a planet’s size, orbital period and the amount of energy received from the host star can be determined. Before an equipment failure, Kepler observed nearly 150,000 stars simultaneously looking for dips in the stars’ light made by orbiting planets.

To date, about a thousand planets have been confirmed with the Kepler data with another nearly 3,000 unconfirmed candidates.

“Future NASA missions, like the Transiting Exoplanet Survey Satellite and the James Webb Space Telescope, will discover the nearest rocky exoplanets and determine their composition and atmospheric conditions, continuing humankind’s quest to find truly Earth-like worlds,” said Paul Hertz, NASA’s Astrophysics Division director.

Like we often do in our personal lives, we’re looking for someone like us. Earth’s twin is out there. We’re getting closer.

Venus hides a star for 7 minutes


Venus occults or covers the star Lambda Aquarii April 17, 2014 

A planet covering a naked eye star is rarer by far than a total eclipse of the moon, and yet Venus did just that yesterday afternoon (U.S. time) from Australia, New Zealand and Micronesia. No one in the northern hemisphere witnessed the event; Venus passed south of the star from our perspective.

Jonathan Bradshaw of Australia captured this exceptional alignment well in his video despite the shaky atmosphere. Lambda Aquarii, a 4th magnitude star in Aquarius, was wiped from the sky for all of seven minutes.

It’s believed that the last bright star Venus or any major planet covered up was 2nd magnitude Nunki in Sagittarius for observers in eastern Africa in November 1981. Venus next occults Pi Sagittarii in 2035 and bright Regulus on Oct. 1, 2044. Mercury will cover up Theta Ophiuchi on Dec. 4, 2015.

Mars will pass in front of Jupiter in an extremely rare planet-over-planet occultation on Dec. 2, 2223. Stellarium

Very rarely, planets pass in front of each other. Over the 300 year span from 1800 to 2100 only 7 “mutual occultations” of this sort have or will occur. Venus crossed in front of Jupiter in 1818 – that was the last observable one. The next will happen when Mars passes in front of Jupiter on Dec. 2, 2223. Clearly, you and I and even our kids won’t be around for that event, but maybe some of our kids’ kids will.

Nature shows that once again even the most unlikely things can happen as long as one key ingredient is available – oodles of time.

Moon closes in on Saturn tonight, beckons us back to the sky

The moon, one day past full, rises over the ice on Lake Superior last night. Its squished shape is caused by atmospheric refraction. Near the horizon, light rays from the bottom half of the moon are bent more strongly upward than those from the top, causing the bottom half to “push up into” the top and creating an oval shape. Credit: Bob King

No way is the moon done serving up delights. Tireless as ever even after a long slog through Earth’s shadow Monday night, it lifts our gaze to the planet Saturn tonight.

Lovely shot of the moon reflecting off both ice and water in Lake Superior last night. Credit: Jan Karon

Look moon-ward after 11 o’clock tonight and bang – Saturn will be right in front of your nose. The two worlds are in conjunction this evening and paired up very close to one another in the southern sky.

Moonrise happens around 10 p.m. but I’d suggest you wait until after 11 to see them best. From most locations, the two will be only about a degree apart.

Glare made seeing Spica before last night’s eclipse challenging unless you covered the moon with your thumb. Saturn and the moon will be just as close tonight, but the moon’s slimmed and dimmed since full and Saturn’s brighter than Spica, so you should have no problem seeing them side by side.

Looking southeast around 11:30 p.m. this evening you’ll see the moon rise right alongside the planet Saturn. Stellarium

Use the opportunity to point your telescope at the planet famous for its hula hoop act. Saturn will be brightest and closest for the year on May 10 when it reaches opposition. Just as with Mars and the other outer planets, opposition is the time when a planet lines up with Earth on the same side of the sun. This cozy familiarity brings the planet into bright view. 10x binoculars will reveal the planet’s oval shape (thanks to the extra added width of the rings), and a small telescope magnifying 40x will bring at least one ring into clear view.

Saturn with its rings wide open to view on April 6, 2014. The three most prominent are visible: the innermost, translucent C Ring, the wide bright B Ring and the outer A ring. Cassini’s Division, a 3,000-mile-wide gap, separates the A and B rings. The rings shine brightly because they’re made of chunks of water ice. Credit: Anthony Wesley

Most skywatchers would agree that Saturn is most attractive when the rings are tilted near their maximum. During planet’s 29.5 year orbit around the sun, their inclination to Earth varies from 0 degrees (edge-on) to 27 degrees. This month we see the north face of the rings tilted near maximum at 21.7 degrees.

Open rings means you can spot Saturn’s biggest ring gap called Cassini’s Division more easily now than anytime in the past few years. Named after Giovanni Cassini, a Italian/French astronomer who discovered the division and four of Saturn’s moons back in 1675, this “clear zone” spans some 3,000 miles (4,800 km) and separates the bright, wide B Ring from the narrower A Ring.

Although it looks like a black, empty gap, spacecraft have discovered that Cassini’s Division is filled with material similar to that in the less massive and translucent C Ring. It shows up well in this photo taken by the Cassini spacecraft under the planet’s ring plane with the rings and division backlit by the sun. The moon Mimas is at top. Credit: NASA

Spacecraft like NASA’s Cassini probe, which has been orbiting and studying the planet since 2004, have revealed that the gap isn’t as vacant as it appears. As far back as 1980, the Voyager 1 probe showed that that Cassini’s Division contains material similar to that found in the less massive C Ring. It’s even organized into multiple concentric rings divided by yet finer gaps.

Wishing you a happy night.

Totally awesome eclipse awes us all

An “around the clock” sequence starting with the uneclipsed moon (left), followed by the penumbral and then partial phases, flanks a photo at mid-totality when the moon was fully immersed in Earth’s shadow. The three frames at bottom are overexposed to better show how the moon looks in deep partial eclipse with a sunlit crescent cupping the red moon. Details: 4″ f/7 refractor, ISO 400, exposures from 1/250″ to 6 seconds. Credit: Bob King

What a fine eclipse! I hope you were as fortunate as we were to have clear skies. Here are a few photos taken during a very long night with my friend Will. After looking at and photographing the moon through the telescope in the countryside, we set off for the city to see how a big red ball paired with familiar scenes.

The moon just out of total eclipse, Spica (lower right of moon) and Mars (upper right) decorate the sky around the old Central High School clocktower in downtown Duluth, Minn. U.S. Tuesday morning. Credit: Bob King

I first noticed the penumbral or outer shadow of the Earth about a half hour before partial eclipse as a brownish shading along the moon’s left side. The edge of the inner, dark shadow – called the umbra – was fuzzy and smoky orange-brown in the telescope. What fun to watch it creep over the moon’s face covering one crater after another.

Pretty scene at the telescope taken during totality early this morning by Jim Schaff of Duluth

During total eclipse, the top of the moon, which was closest to the center of the umbra was very dark orange with the naked eye, while the bottom rind – the portion of the moon farthest from umbral center – glowed a dull yellow. Colors varied some depending on whether you viewed with the naked eye, binoculars or telescope.

The fully eclipsed moon is tucked inside the outline of a bird in the Wild Ricing Moon sculpture on the University of Minnesota-Duluth campus Tuesday morning. Credit: Bob King

One of our favorite sights was seeing the totally eclipsed moon alongside its starry companion Spica in binoculars. In the 8×40 glass, the moon looked pumpkin-colored. My older daughter said the eclipsed moon looked like a toasted marshmallow!

This wide field view showing the moon and Spica from Duluth is a composite of two photos – 0.6 seconds for eclipse, 5 seconds for stars, 200mm f/4 ISO400, Canon 50D.  Credit: Tom Nelson

As the moon progressed through the umbra, a yellow “smile” of a crescent slowly slid from one side to the other along the moon’s bottom edge. A minute after emerging from totality, the brilliant “cap” of light on the moon’s left side resembled a polar cap on the red planet Mars. What a fine coincidence the real Mars was just a fist away.

Most of us who saw the eclipse couldn’t help but also notice the bright star Spica in Virgo accompanying the moon. To the upper right Mars shone brilliantly. Credit:  Bob King

A favorite pastime during total lunar eclipses is watching the darkness return as the moon gets clipped by Earth’s shadow. The change is slow at first but soon you’re staring up marveling at how all those stars got there. During totality the sky’s was as dark as a moonless night and stayed that way for over an hour.

Soma Acharya sent several photos she and her husband Kaushik took of the eclipse. This one features the trio of the moon, Spica (right) and Mars. Credit: Soma Acharya

When moonlight returned, the stars fled and the Milky Way faded away in the lunar glare … until the next eclipse in October! Thank you everyone for sharing your images. I also encourage you to continue to share your impressions in the Comments section below.

The moon in partial eclipse along with Spica appear to remain still as a flag flaps in chilly winds in downtown Duluth, Minn. Credit: Bob King

I couldn’t resist. During total eclipse the sky became so dark the Milky Way sparkled across the eastern sky. After totality, it faded away. Credit: Bob King

Closeup of the moon near mid-eclipse. The top or northern half of the moon is darker than the bottom because it’s closer to the center of Earth’s umbral shadow. Also, the bottom of the moon is covered by more of the lighter-toned lunar highlands versus the “sea-heavy” northern half. Credit: Bob King

Saturn makes a new moon named ‘Peggy’

The disturbance visible at the outer edge of Saturn’s A ring in this image from NASA’s Cassini spacecraft could be caused by an object replaying the birth process of icy moons. Credit: NASA/JPL

That bright swelling in Saturn’s A ring may very well be ice balls stirred up by a newborn moon nicknamed ‘Peggy’. Estimated at just a half-mile (1 km) across, the newcomer could be the first moon ever seen to form right before our eyes.

Images taken by the Cassini probe April 15, 2013, revealed several disturbances at the very edge of Saturn’s A ring, the outermost of the planet’s large, bright rings. One of them is the arc shown above that’s about 20 percent brighter than its surroundings and spans some 750 miles (1,200 km) long by 6 miles (10 km) wide. It even sports a little bump that interrupts the smooth profile of the ring’s edge.

“We have not seen anything like this before,” said Carl Murray of Queen Mary University of London, the report’s lead author. “We may be looking at the act of birth, where this object is just leaving the rings and heading off to be a moon in its own right.”

The object probably won’t grow any larger and in fact, may even be falling apart according to astronomers. Like the rings, many of Saturn’s moons are composed of ice. It’s believed that long ago, the rings were larger and more massive and gave rise to larger moons like Enceladus and Titan in a similar birthing process. Today these moons are relatively far from the planet but may have migrated there after self-assembling via gravity within the ring plane.

Similar to how planets formed and migrated in the early solar system, scientists think that ice in Saturn’s rings stuck glommed together to form some of its many moons. Credit: NASA/JPL/Caltech

As exciting as the birth of a new moon is, I find it equally fascinating that Saturn’s ring system may serve as a model of the early solar system when it was little more than rings of rocky and icy debris surrounding the infant sun. From these dribs and drabs, all the planets, comets and asteroids took form.

We’re almost certain that most if not all the planets migrated through this debris-strewn traffic jam similar to what appears to have happened  at Saturn. Earth and the inner planets were likely farther from the sun billions of years ago and migrated inward, while Jupiter and Saturn took off in the opposite direction.

“Witnessing the possible birth of a tiny moon is an exciting, unexpected event,” said Cassini Project Scientist Linda Spilker, of NASA’s Jet Propulsion Laboratory. According to Spilker, Cassini’s orbit will move closer to the outer edge of the A ring in late 2016 and provide an opportunity to study Peggy in more detail. Maybe even take a picture.

If theory is proven true then Saturn’s rings are much depleted after a life of making moons, leaving only enough material left to fashion a mini-moon or two.

I’m rooting for Peggy to step out of the shadows and lead a life of her own. How wonderful it would be to witness the birth of a new Saturnian moon in our lifetime.

Total lunar eclipse tonight! Updates – weather – live streaming

Beautiful sequence of the July 16, 2000 total lunar eclipse from Maui, Hawaii showing partial eclipse (upper left), totality (middle) and the return to partial eclipse at right. Credit: Fred Espenak

I’m excited. Beginning late tonight and continuing into the small hours tomorrow morning, skywatchers across the Americas will have ringside seats for one of nature’s most unique and colorful celestial events – a total eclipse of the moon.

The satellite view at 3:15 p.m. CDT this afternoon shows lots of clouds across the eastern half of the country. Clouds across the central and southwestern parts of the U.S. are expected to depart by eclipse time. Expect clear skies in those regions, partly cloudy conditions in the north central U.S. and overcast in the eastern third of the country. Credit: NOAA

Anyone hoping to see the eclipse will be paying attention to the local forecast. Weather really can mess with your head. While you can perform chemistry experiments clear or overcast, astronomy requires the fickle cooperation of Mother Nature. Remember last month’s widely-publicized occultation of Regulus by the asteroid Erigone? One of the rarest events to occur in years, clouds, snow and rain made sure that no one – not a single person to date – got to see it.

Tonight’s cloud cover forecast map. Dark green is clear, white is cloudy. Click to see the latest version. Credit: The Weather Channel

Today’s satellite weather map shows widespread clouds across the eastern third of the country but clear or clearing skies will be the rule across the western and central U.S. To get a local forecast, click HERE and enter your zip code or city name.

You can also consult Attila Danko’s Clear Sky Chart. Type in your city to get a detailed cloud/transparency forecast I’ve found to be surprisingly accurate.

During a total lunar eclipse, the moon moves into Earth’s shadow, becomes darkened and then exits out the other side and gradually returns to full brightness. Sunlight filtered and bent by Earth’s atmosphere spills into the shadow cone and colors the moon a coppery red. From the outer shadow – the penumbra – Earth only partially blocks the sun. That’s why the penumbral shadow isn’t nearly as dark as the umbral.  Credit: Starry Night

Just to refresh, a lunar eclipse occurs when the sun, Earth and moon are precisely lined up in a row at the time of full moon. Watching the moon slowly disappear will make even those who don’t pay much attention to the sky turn to look. The event begins with a brilliant full moon that disappears by degrees into the shadow until it hangs suspended among the stars like a dark cherry. Beautiful!

If you get skunked by bad weather, several organizations will be streaming the eclipse live. Here’a s few to check out:

* NASA TV live  – Commentary and coverage begin at midnight CDT Tuesday morning

* NASA Flickr for tagging, sharing images

* SLOOH – Coverage begins 1 a.m. CDT

* Virtual Telescope Project begins 1:30 a.m. CDT

Simulated binocular view of the moon only about a degree from the bright star Spica ten minutes before the start of total eclipse. Stellarium

Use a tripod-mounted camera to photograph the moon during the partial phases with exposures ranging from 1/250 (bright moon) to 1/8 second (closer to totality) with the lens opened to f/5.6 – f/8.

Increase your exposure to 4-5 seconds (or longer – depends on how dark this eclipse will be) and set your lens aperture to f/4 – f/5.6. These are general guidelines using ISO 400. As always, experiment.

I know there are lots of places to share images these days, but if you get one you like, I’d be happy to post it here on Tuesday. Just send an e-mail to rking@duluthnews.com with ‘Eclipse photo’ in the subject box. Thanks!

Below is a table with the times for all key eclipse events across the four major U.S. time zones beginning with the first hint of shading from Earth’s outer shadow, the penumbra. And here’s a link to more eclipse information.
Eclipse Events                     EDT             CDT                 MDT                PDT

Penumbra visible 1:20 a.m. 12:20 a.m. 11:20 p.m. 10:20 p.m.
Partial eclipse begins 1:58 a.m. 12:58 a.m. 11:58 p.m. 10:58 p.m.
Total eclipse begins 3:07 a.m. 2:07 a.m. 1:07 a.m. 12:07 a.m.
Mid-eclipse 3:46 a.m. 2:46 a.m. 1:46 a.m. 12:46 a.m.
Total eclipse ends 4:25 a.m. 3:25 a.m. 2:25 a.m. 1:25 a.m.
Partial eclipse ends 5:33 a.m. 4:33 a.m. 3:33 a.m. 2:33 a.m.
Penumbra visible  ——– 5:10 a.m. 4:10 a.m. 3:10 a.m.

Curiosity rover revels in ravishing rocks at ‘the Kimberley’

A view of Curiosity’s new digs called ‘the Kimberley’, named for a wilderness region in Western Australia. Taken on April 11 it shows tilted sandstones separated by windblown sands. The hilly rim of Gale Crater is seen in the distance. Click to enlarge. Credit: NASA/JPL-Caltech

NASA’s one-ton Curiosity rover has beamed back thousands of photos of amazing landscapes within Gale Crater since landing in August 2012. And that’s after driving only 3.8 miles, probably the distance to the nearest grocery store for many of us.

The Kimberley seen from orbit with the rover’s path highlighted. Curiosity rolled into the new location around the 589th Martian day or “sol”. Scientists selected the area based on pictures and studies made from orbit showing it to be rich in different rock types all exposed in the same location. Credit: NASA/JPL-Caltech

Earlier this month, the rover entered the Kimberley, a rise within the crater dotted with three buttes – Mounts Remarkable, Joseph and Christine – that exposes several varieties of rock scientists are eager to study. The area will be the focus of exploration for weeks to come before Curiosity resumes its journey to the slopes of Mount Sharp, a broad peak that rises 3 miles (5 km) from the crater’s floor.

Sandstones on Mars near the Kimberley photographed on March 29, 2014. Click to enlarge. Credit: NASA/JPL-Caltech

The Kimberley is strewn with some of the most beautiful sandstones yet seen on Mars. Sandstones form when water or wind carries along grains of sand until depositing them in a layer at the bottom of a stream or on the ground as in a desert. Minerals within the pore spaces between the sand grains cement the grains together to create sandstone. Sometimes layers of deposited sand can build up one atop another helping to further compact the material into stone.

Differing degrees of resistance to erosion result in a stair-stepped pattern visible in this photo taken 1/4 mile northwest of the Kimberley on Feb. 25, 2014. Steeper steps result from more resistant rock, so the flat, tan surface (foreground) is a weakly resistant sandstone. The small steps to the right center are a bit more resistant, and the steeper steps near the top of the scene are even more resistant. Click to enlarge. Credit: NASA/JPL-Caltech/MSSS

Cement materials vary greatly. Clay minerals build sandstones that crumble with a rap of a hammer and more quickly erode in the Martian winds. Quartz cement creates a tougher rock more resistant to erosion. If you’ve ever marveled at the sight of a western, canyon-filled landscape, you’re seeing the varying resistance of sandstone to erosion at work. The same thing happens on Mars:

Another spectacular view of tipped and tilted sandstones with Mt. Remarkable in the distance photographed on April 11, 2014. Click to enlarge. Credit: NASA/JPL-Caltech

“A major issue for us now is to understand why some rocks resist erosion more than other rocks, especially when they are so close to each other and are both likely to be sandstones,” said Michael Malin of Malin Space Science Systems, San Diego. Malin added that variations in cement material of sandstones could provide clues to different types of wet environmental conditions in the area’s history.

Curious furrows are seen in the foreground in this photo taken at the Kimberley on April 3, 2014. Click to enlarge. Credit: NASA/JPL-Caltech/MSSS

At Yellowknife Bay, Curiosity’s last major waypoint, erosion had exposed both sandstones and a lower layer of mudstone that was once part of an ancient lake bottom. The rover will be tooling around the Kimberley for a while – why not join the exploration by periodically checking out the Mars raw image archive?

A conglomerate rock formation at the Kimberley formed of boulders and rocks that were transported from elsewhere – by river or glacier for instance – and cemented together. Click to enlarge. Credit: NASA/JPL-Caltech/ MSSS

Forbidding Planet: Scientists find remains of monster asteroid impacts on early Earth

Artist’s view of Earth several billion years ago during the Late Heavy Bombardment, when the planet is thought to have been battered by impacts of comets and asteroids. Credit: Chris Butler/SPL

Earth 3.5 billion years ago was a terrifying place. Picture a rocky landscape pounded by meteorites and asteroids with a surface resembling that of the moon. Volcanoes spewed water vapor but also a toxic mix of carbon dioxide, sulfur dioxide and methane. If you could whisk yourself back to this world by time machine, you’d need to be fully protected by a spacesuit and lucky enough to not get picked off by a falling space rock. Oh, and bring a boat too. Hot-water oceans likely covered a fair portion of the planet back then.


This time-lapse illustration of the Nice (pronounced ‘neece’) model of solar system evolution shows how outer planet migrations kick asteroids into the inner solar system

Scientists call the period from about 3.8 billion to 1.8 billion years ago the Late Heavy Bombardment (LHB), a time when the number of asteroids and their fragments pelting the inner planets and their moons spiked. Why then? No one’s absolutely certain, but the leading theory posits that the migration of the giant outer planets to their present positions “stirred the gravitational pot”, slinging boatloads of asteroids into the inner solar system, where they rained down on Earth and its neighbors in hellish monotony for millions of years.

Anyone with a small telescope can see resulting devastation to this day. Just take a long look at the moon’s battered and cratered surface and thank your lucky stars you’re around during a more peaceful time. Finding Earth’s craters is trickier because water and wind erosion, along with the continual recycling of much of our planet’s crust through plate tectonics, has erased much of our violent past.

The Vredefort Dome – these concentric hills, which rebounded after the impact that created Vredefort Crater – are what remains after an asteroid about 3-6 miles wide struck Earth 2 billion years ago. Credit: NASA

About 180 craters are known on Earth today, but we’re aware of only three resulting from the Late Heavy Bombardment. The oldest, estimated at 3 billion years old and 62 miles (100 km) wide, is also the most recently discovered. Found in western Greenland in 2012, all that remains of the impact are rocks rattled by the massive shock wave that penetrated 15 miles (25 km) deep within Earth’s crust.

You can still see the remains of the impacts that formed the 112-mile-wide (180 km) Vredefort Crater in South Africa, which is 2 billion years old, and the youngest LHB member, the 155-mile (250-km) Sudbury crater in Canada dated at 1.85 billion years.

Map of South Africa with the Barberton greenstone belt shown in red. Shock waves from the impact of an asteroid 3.26 billion years ago created telltale formations within the belt. No one knows yet where the impact happened.

Now, a group of scientists have announced they’ve found evidence for an even older impact, one that occurred 3.26 billion years ago and left its signature in a South African region known as the Barberton greenstone belt.

A recent press release describes the huge impactor as between 23 and 36 miles wide (37- 58 km). Colliding with the planet at 12 miles per second, the jolt delivered was bigger than a 10.8 magnitude earthquake and propelled seismic waves hundreds of miles through the Earth, breaking rocks and setting off other large earthquakes. Tsunamis thousands of feet deep swept across the oceans that covered most of the planet at that time.

A graphical representation of the size of the asteroid thought to have killed the dinosaurs (left), and the crater it created, compared to an asteroid thought to have hit the Earth 3.26 billion years ago and the size of the crater it may have generated. A new study reveals the power and scale of the event some 3.26 billion years ago which scientists think created geological features found in a South African region known as the Barberton greenstone belt. Credit: American Geophysical Union

“We knew it was big, but we didn’t know how big,” Donald Lowe, a geologist at Stanford University and a co-author of the study, said of the asteroid.

The collision would have blasted out a crater some 300 miles (500 km) wide, filled the atmosphere with fiery rock vapor and set the surface of the ocean a-boil. We’re talking serious cataclysm. Somehow life found a way through the heat and crater-punching to gift us with the rolling green hills, coral reefs and forests that characterize Earth today.

Table from the book “Near Earth Objects – Finding Them Before They Find Us” by Donald Yeomans showing average asteroid impact results and probabilities by size. Credit: Donald Yeomans

I try to imagine the dark days of the LHB to help me appreciate these calmer times. Yet we know in our gut – and in fact, thanks to probability – that we’ll never truly be out of the woods. Asteroids lurk in the deep that could one day cause a similar scenario. Don’t let it worry you too much – the chance of a 10-mile-wide space rock striking Earth is once every 89 million years. You’ve still got time to take a nap, catch a show and enjoy a few nights out on the town. Probably.