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I love geeks. I love clever people. I love sciencey stuff.

So this fills my heart with squishiness: a skirt with rows of lights that illuminate when facing north:

Make those LEDs red and every astronomer could use it. Not to mention campers, hikers, and let’s face it, nerds like all of us. I would dance all night with someone wearing this.

Want one? She’s selling kits so you can make one yourself!

Of course, in 2012* when the poles flip the skirt will light up when facing south. Oh! I know! You could wear it backwards. Problem solved.

Tip o’ the compass needle to that bon vivant, Josh A. Cagan.

* This is a joke, OK? A joke. If you actually think I am being serious about 2012, then I suggest you check your tin foil beanie for breaches.

I have a Martian mystery for you today, and one that is writ quite large and dramatically. It seems weird at first, then simple next, but when you dig deeper — literally — things get very weird indeed.

It all starts with an out-of-control awesome picture that honestly made me reel back and say "Wow!"

I present to you out-of-control awesome:

Wow!

Click the pic to embiggen. This unnamed crater is about 700 meters (roughly half a mile) across, and sits in the northern mid-latitudes region of Mars. It’s interesting, isn’t it? The multiple concentric bowls of the crater are trying to tell us something, but what?

My first thought, also mentioned on the HiRISE blog, is that this is a coincidental double impact: the big terraced crater was the original impact, then a later, second object impacted almost exactly in the center of the older one, hitting the bulls-eye like William Tell splitting an arrow.

The topography seems to support that; the inner crater has a raised rim, as you might expect from a second impact, and that would be hard to explain in a single impact. The terracing — shelf-like structures sortof like an upside-down wedding cake layering — is seen sometimes when an impactor smacks into layered ground. Imagine a layer of dirt on top of ice on top of rocks: each layer reacts differently to the impact, leaving the circular, concentric shelves in the crater bowl.

Note too that the central crater doesn’t look exactly centered, supporting a second impact.

Case closed… but wait, Your Honor! We have a surprise witness!

This picture is actually part of a much larger region which provides some context:

You can see the extensive ejecta blanket (excavated material laid down from the impact ) around the crater now, which is nifty. But note the smaller crater to the lower right (indicated by the arrow): it looks a lot like the bigger crater! There’s a shallow bowl with a deeper crater almost but not quite in the center. There’s no terracing, but it’s a smaller impact and wouldn’t have dug so deeply into the surface.

So what gives? If all we had here was the big crater, I might believe the coincidence of a nearly perfect second impact bullseye inside it. But two of them? Right next to each other?

It seems unlikely, to say the least. And I thought I had an explanation for it… which I’ll give you. But note: I chatted for a few minutes with Alfred McEwen, the Principle Investigator of the HiRISE camera (which took the image), and he told me things still aren’t quite as they seem. Keep that in mind while I describe my thought…

My idea is/was this: both of those craters were single impact events. The terrain itself must explain the weird structures; there must be several layers of material with different solidity. In the lower right crater, the softer surface material deformed and splashed back, forming a shallow bowl. Underneath it is a stronger material, forming the raised rim central crater that’s slightly off-center. The fact that’s it’s not centered may be due to sloping in the surface, or that the surface layer isn’t constant in thickness across the surface. Perhaps there is stronger material to the left which resisted the impact pressure, leaving the inner crater off-center once the event was over.

This explains the big crater too. The outer bowl is shallow. Inside that is a raised rim, as you’d expect from a stronger material. The impactor was big enough to dig below even that layer to a third, deeper and even more resilient layer, leaving a beautiful raised rim. It’s not centered either, again perhaps due to the layers being irregular in thickness or to different material strengths in the layers themselves.

Finally, in the context image, you can see lots of shallow smaller craters. Again, I think this shows the top layer is something soft like ice, which leaves those barely visible bowls behind after smaller impacts.

Tadaa! Done.

But wait! Not so done. As Alfred pointed out to me, note that the second crater is actually sitting on the ejecta blanket from the first one (which is how we know that the smaller crater impact occurred after the bigger one). Since it’s on top of that material, the ground underneath the impact would’ve been different than the ground into which the original impactor hit. The other shallow craters are all sitting in that material as well. So we can’t simply state that the terrain was similar to the original event because the original impact changed the surface structure.

Also, the detail of the structure is difficult to interpret. Turns out that at this latitude glaciation is common, and that tends to screw up details, changing the way things look. Interestingly, the rim of the innermost crater in the big crater looks pretty fresh, too, like it happened after the original event, supporting the William Tell idea that a second asteroid impact hit right in the middle of the previously excavated crater.

Finally, in the top image, look at the floor just outside that innermost crater. See the two crescent-shaped lobes at 1 and 2 o’clock? Those may be slumped material from the walls of the crater. If a second impact happened in the center of a pre-existing crater, you’d get some disturbance of the material, including debris flowing down from the walls.

So what do we conclude?

This place is a mess. That’s what I conclude. Alfred said my idea that layered terrain explains most everything has some merit, but so does the idea that a second impactor did the deed. We simply can’t tell.

If you think I’m having fun figuring this out, then dingdingding! I am. Because it is fun. This is good old-fashioned sleuthing, detective work on the scale of a city block. When we look at pictures like these we get evidence of a crime scene, perhaps millions of years old — talk about a cold case! — but still fresh enough that we can puzzle out what happened. The big crater is the main clue, drawing our attention, but the second, smaller crater may be a smoking gun, the surprise evidence that just might make everything else make sense.

It’s CSI Mars. But in this case it’s not some procedural drama on TV. It’s real, it’s huge, and it’s sitting there on another world for everyone to see. All you need to do is go there and look.

NASA's Robonaut 2 has no voice but is ready to tell you its story -- in 140 characters or less. The prototype robot will travel to space this fall to give NASA a deeper understanding of human-robotic interaction.

NASA astronaut TJ Creamer talks about his experience in space during a "Tweetup" at NASA Headquarters, Thursday, July 29, 2010, in Washington. Creamer, who spent 161 days living aboard the International Space Station as part of the Expedition 22/23 crew, set up the orbiting outpost's live Internet connection and posted updates about the mission to his Twitter account, sending the first live tweet from orbit. Image Credit: NASA/Paul E. Alers

Nasa Awards Neutral Buoyancy Laboratory, Space Vehicle Mockup Facility Support Contract

NASA has awarded a sole-source interim contract for electrical systems engineering services to MEI Technologies in Houston.

NASA mission controllers have not heard from the Mars Exploration Rover Spirit since March 22, and the rover is facing its toughest challenge yet – trying to survive the harsh Martian winter.

One possible explanation for the irregular pattern is the remains of an exploded supernova, such as the nearby supernova remnant Vela, whose location corresponds to one of the cosmic-ray hotspots.

I know I haven’t been posting much astronomy the past few days — Comic Con, w00tstock, and "Bad Universe" have kept me hopping — so to make up for it a little bit, here’s a lovely image sent back a billion kilometers from Cassini:

This is Tethys, an ice moon of Saturn. The angle of Cassini, Tethys, and the Sun light the moon as a crescent. The most obvious feature is Ithaca Chasma, a (more than) thousand-kilometer-long gash in the side of the object. Note that Tethys is only about 1000 km in diameter, so the chasm runs along a third of the moon’s surface (circumference = diameter x π, remember).

How big is that? Stand up and take a long stride. That’s about one meter. Now do it 999,999 more times. That’s a megameter: a million meters, or 1000 kilometers. Better pack a lunch.

The chasm is billions of years old, and may have formed when water inside the moon froze, expanded, and cracked the surface open. It’s a hundred kilometers across and 3-5 km deep, too. It’s far larger than the Grand Canyon, the largest canyon on Earth.

Space is big, and weird, where even small objects have huge features. It’s surprising, but surprising things are the best things to know.

Tip o’ the dew shield to Carolyn Porco.

Related posts:

- An otherwordly eclipse
- A billion km distant ice mountain against the black

Orbital Debris The dots on this NASA-generated chart represent known pieces of large orbital debris. NASAThe Fengyun satellite that China blew up in 2007 is space enemy number one

NASA has been tracking a piece of space junk on course for a near collision with the International Space Station this week, but while the agency continues to monitor the debris -- a leftover from China's brilliant shooting down of the Fengyun 1C weather satellite during a missile test in 2007 -- Russian Flight Control authorities have issued an all-clear, saying an avoidance maneuver will not be necessary.

This month, NASA's Orbital Debris Program Office released data naming the top ten incidents contributing to the space junk problem. The Fengyun fiasco is hands down the largest single contributor to the growing space junk crisis. NASA has identified some 19,000 objects larger than four inches that are running loose in orbit at extremely high rates of speed just waiting for a functioning satellite, a spacecraft, or the ISS to get in their paths. Of those, 2,841 are thought to have come from the destruction of Fengyun 1C.

Most of the garbage hurtling through space belongs to China and the Soviet Union, the report says, though Western commercial interests and space agencies also shoulder their shares of the blame. Some of the blame can even be divvied up; last year an operational Iridium communications satellite collided with a spent Russian Cosmos spacecraft, spawning nearly 2,000 pieces of smaller debris.

But Europe could soon take the top spot on the space junk tally. When the European Space Agency's Envisat Earth observation satellite goes defunct in three years, the ESA will be the proud owner of the largest and most dangerous piece of junk out there: a nearly 9-ton, $2.9 billion piece of orbiting detritus that won't be pulled into Earth's atmosphere for 150 years. The danger isn't that the massive satellite might slam into the ISS -- the chances of that are quite slim. But if it collides with another large piece of junk at high speed -- say, a rocket stage or another retired satellite -- the impact could release 10 times as much junk as the Iridium-Cosmos smash up.

With so much junk up there, the DoD has even warned of a scenario in which such a massive collision could trigger a cataclysmic chain reaction in which one impact begets another and then another until entire orbits are unusable. Unlikely, sure, but some insist it's possible. The good news is we're working on the problem. Northrop Grumman is working with DARPA to develop a ground-based radar system to help track space debris from the ground, and the U.S. Air Force is planning to launch a Space-Based Space Surveillance satellite in the near future that will help direct traffic in space. Assuming, of course, a piece of orbiting junk doesn't knock it clean out of the sky.

[Space, Network World, Voice of Russia]

Pareidolia is the psychology term for seeing faces in random patterns. This usually gets air time due to some vaguely Christlike shape in a stain or something, but not every instance has to be religiously motivated. I don’t want to ignore those secular ones, because, after all, I hate to let anything go to waste.

Behold!

This picture, taken by Mitchell Whitney, was snapped right after an, um, incident that required some vigorous plunging. The only conclusion is that the toilet itself was relieved when it was all over as well.

I have a series of puns all trying to push their way out of my brain, but I’ll let them go because it’s been an exhausting week. I’m pooped.

Tip o’ the plumber’s helper to Dan Durda.

I never get tired of the stunning pictures being sent to Earth from the Lunar Reconnaissance Orbiter. This one is particularly cool:

It’s a little weird, isn’t it? What you’re seeing is sunset over some mountains on the Moon, with only the peaks popping up into the sunlight. It might help to pull back a bit:

[Click to embiggen.]

That’s a little better. You can see the long shadows of the two mountains on the hills farther back, giving the image a bit of context and relief.

But you’re still missing the coolest part. Ready? Here’s the entire shot:

Whoa! Getting the picture now? Those three mountains are actually the central peaks of the crater Bhabha, a 64 kilometer (40 mile) wide impact scar on the far side of the Moon. With really big impacts, the shock waves bounce around inside the crater bowl, making the rock flow like a fluid. The rock flows outward, then sloshes back inward, splashing up to form peaks. Usually there’s only one, but Bhaba has three.

This shot is from the west, facing east. It was taken just minutes before the Sun set over the peaks, throwing them into two weeks of darkness — remember, the far side of the Moon gets light just like the near side; when we see a thin crescent Moon that means the Sun is shining down on the other side, just like day on one side of the Earth means night on the other.

This picture is a vivid reminder that the Moon is a world in its own right. Eventually, I hope, people will once again get to see views like this by simply looking out the window. Until that time, LRO will provide us with these amazing pictures.

Image credit: NASA/GSFC/Arizona State University

Scientists have uncovered two pairs of planets so close to each other that they interact gravitationally.

Perfectly circular, powerful Hurricane Celia spaned hundreds of miles over the Pacific Ocean in this image from June 24, 2010. Rough-textured clouds surround the storm’s distinct eye. Farther from the center of the storm, spiral arms appear thinner and smoother. The Moderate Resolution Imaging Spectroradiometer, or MODIS, on NASA’s Aqua satellite captured this true-color image of Hurricane Celia at 1:55 p.m. Pacific Daylight Time on June 24, 2010. Just five minutes later, the U.S. National Hurricane Center classified Celia as a Category 4 hurricane with sustained winds of 135 miles per hour. Image Credit: NASA

NASA is inviting the public to choose an area in northern Arizona where explorers will conduct part of the annual Desert Research and Technology Studies, known as Desert RATS.

NASA personnel are among a group of international researchers who are in the Canadian Arctic assessing concepts for future planetary exploration as part of the Haughton-Mars Project, or HMP-2010.

The Australian Vaccination Network, an antivax organization fronted by Meryl Dorey, has long been an antiscience group devoted to spreading any kind of nonsensical rhetoric they can. The good news? Now they’re being called out on it.

As The Sceptic’s Book of Poo-Poo extensively documents, the media used to be pretty easy on the AVN, but now are routinely pointing out that they are antivax, and one has even highlighted some of Dorey’s outrageous and fallacious claims. This all comes on the heels of the New South Wales Health Care Complaints Commission concluding that the AVN is in fact and in deed antivax, and needs to have disclaimers on their site — a finding Dorey has ignored.

The AVN has been the loudest of the antivaxxers in Australia, a country that has seen a rise in many preventable diseases, including pertussis, which has claimed the lives of several infants.

This is not a free speech issue, and this is not an issue where two sides need equal and balanced discussion. In this case, the AVN and Meryl Dorey are wrong, wrong, wrong, and what they are preaching is dangerous and, in fact, can be deadly. As I have said many times, vaccines are one of the greatest medical triumphs in history, saving literally hundreds of millions of lives.

The antivaxxers, on the other hand, only have spin, distortion, and scare tactics… which, sadly, can be effective with people. I am very glad the media have finally figured out Dorey, and are vocal about it.

Now if we can just get them to do the same with Jenny McCarthy, Jim Carrey, Kevin Trudeau, Andrew Wakefield, purveyors of homeopathy…

And remember: it’s not just Australia, and this isn’t happening to poorly educated people in rural areas. Whooping cough is making a comeback in Marin County, California, home of some of the wealthiest and best-educated people in the country. These diseases are coming back because vaccine rates are low. Go to your doctor and get the real info, and if they recommend getting vaccinated, do it.

Tip o’ the syringe to my brother Sid for the link to the MSNBC video.

Related posts:

- Australian skeptics jeer Meryl Dorey
- Major step against antivaxxers in Australia
- The AVN is reaping what they sowed
- Australian skeptics strike back against antivaxxers

As I wrote about recently, I have teamed up with Skepchick Surly Amy to raise money for the American Cancer Society: she has created 200 lovely hand-made ceramic Bad Astronomy pendant necklaces, and for each one she sells for $20 she’s donating $10 to the ACS. Each one is different, so check them all out!

Over half the necklaces have been sold, but there are still quite a few left. Hurry and buy one (or more) soon; the total raised will be announced at the star party at Dragon*Con this year, September 2!

Find out more at Amy’s Skepchick post, which has more pictures, including one cute one of how one necklace is keeping a couple together, despite their reading material.

Mars' Valles Marineris NASA/JPL-Caltech/Arizona State University

Youth and vigor have their advantages, but there is something to be said for longevity. NASA's Mars Odyssey orbiter has been circling the red planet since 2001 and has just released the best map ever made of the Martian surface.

The new Martian map is a composite of 21,000 images captured by Odyssey over the last decade that can be zoomed to scales as small as 100 meters across. While the newer Mars Reconnaissance Orbiter will eventually trump that with higher resolution maps that can zoom in down to about one meter wide, it still has a lot of landscape to cover.

The above image is a detail of Mars' Valles Marineris, capturing a swath of terrain about 90 miles across, so that should give you some idea of how detailed the map really is. But rather than take our word for it, you can check out the real thing here. Taken on the whole it looks fairly unimpressive, but zoom in and you can see individual features on the Martian surface quite clearly.

Though Odyssey's "most detailed map" record will eventually be eclipsed, it still has the chance to capture one more record if it can hang on for a few more months. NASA's Mars Global Surveyor is currently the longest-operating Martian spacecraft, having operated for just more than nine years. Odyssey began orbiting in October of 2001, so if it can reach the new year, it will collect a longevity record as well.

[NASA JPL via New Scientist]

I just found out that video of my talk at w00tstock has been posted on YouTube. The quality is a little shaky, since it was a handheld video taken from a distance back, so some of the pictures may be hard to discern, but I think it suffices to get the point across.

This may surprise you, but the content is pretty much Not Safe For Work. Yeah, I know: I’m not generally known for that. But hey– it’s an astronomy talk! What better place to go a little blue?

The video is in two parts; the first has the last couple of minutes of the warmup before my talk (I came on after the intermission), and the second part includes the premier of the trailer for my new TV show. The reaction of the audience was… well. It made me happy indeed.

Here are both parts. Part 1…

… and Part 2:

That last slide with the Hubble image says, "W00tstock: Where no astronomer has gone before."

I want to make sure I give plenty of credit Amanda Bauer, aka AstroPixie, once again for her inspiration for this talk. It’s something I’d been thinking of doing for a long time, but her blog post really got things started. Way-hey. Giggity.

There are pictures going up about w00tstock all over the place, so check with Flickr to see ‘em. And also, please read Wil Wheaton’s thoughtful and wonderful words about that night.

Thanks also to Kevin Savino Riker for posting that video. One of the beautiful things about w00tstock is that everything is licensed under the Creative Commons theme, which means it can posted publicly. Why? Because like Wil, Adam, Paul & and Storm, I agree that things like this get better the more they are shared, and become more valuable when they cost less. Or nothing at all.

[Brief update: Julia Sherred has many more w00tstock videos on her blog.]