Blogs / Bad Astronomy

Mars is weird. It’s small, and cold, and has a thin atmosphere that’s almost entirely carbon dioxide, and what isn’t CO₂ is nitrogen and, bizarrely, argon.

So you expect to see weird landscapes. But even so, Mars has the potential to be really, really weird. Check this out:

That slightly disturbing image (click to embiggen) is not a microscopic picture of a scientist’s colon (at least, not as far as you know). It’s actually a region near the Martian south pole. It was taken with the HiRISE camera on the Mars Reconnaissance Orbiter, and the area shown is roughly 700 meters across (about 0.4 miles).

What you’re seeing are layers of the polar ice cap. The ice is mostly CO₂. Mars is so cold that a lot of the cap persists throughout the year, and is called the residual cap. Some of it does sublimate, though, which means it goes right from a solid to a gas. Underneath that layer is something more solid, perhaps water ice, that does not sublimate. As the upper layer partially goes away, it leaves these weird Swiss-cheese-like patterns, revealing the smooth layer below.

This image only shows a small portion of a much larger area where this occurs. Here’s the "context image", a zoom out if you will:

I marked the rough outline of the zoomed image in this one (it’s rotated about 90 degrees counterclockwise in the zoom). You can see that this odd terrain (aresain?) goes on for kilometers. It really does look like some sort of bacterial colony. But it’s actually the result of millennia, maybe millions of years, of constant annual atmospheric deposition and sublimation.

And just as a reminder — because I love to point this out — Mars was 250 million kilometers (150 million miles) away from Earth on August 20, 2009, when this image was obtained. Yet MRO was only 250 km above its target, yielding this fine imagery at a resolution of 25 centimeters (10 inches) per pixel. Got a ruler handy? Pick it up, hold it in your hand, and think on the fact that we have spacecraft orbiting Mars, an alien world, that can take pictures of objects on its surface about the size of that ruler.

Man. I love this stuff.

[P.S. If you like this image, the HiRISE page has wallpaper versions of it; the links are at the lower right at that link.]

Well, not literally, though that would be really amusing.

Jamie Hyneman and My Close Personal Friend Adam Savage™ were on the always-hilarious Late Night with Craig Ferguson show a little while back, and the video is on YouTube (note: somewhat NSFW dialogue):

Did you hear what Adam mentioned roughly six minutes in? The JREF! Woohoo! Adam is great about donating stuff from Mythbusters to the JREF so we can auction it off to raise money, and that particular gift was pretty special. Rarefied, you might say.

And, thanks to Greg Fish, I can add this:

Yer darn tootin’.

[Get it? Tootin'! Hahahaha!]

Image from ROFLRazzi.

In Russia, thousands of Muslims are flocking to see a baby who has verses from the Koran mysteriously appearing on his body:

I’d like to be very clear here: this is not pareidolia, our ability to see patterns in random objects. The verses are clearly there, and not just random. As one pilgrim said, "It’s proof that Allah exists, that he is all-mighty…"

However — and perhaps this is just me here — it seems far more likely that instead of an actual miracle, someone is maybe, y’know, writing the verses on the baby. The mother says the baby is cranky when the words appear, which (if she’s being truthful) you might expect if someone is scraping or otherwise irritating the baby’s skin to make the words appear. I’ll note that the words fade with time, too, just as expected if this is a fraud.

If this whole thing is a fake (and the JREF has a million dollars on the line to say something about that) then I don’t know what’s worse: the parents or whoever is behind this doing this to the baby, or the crowd who simply believes it.

Oh, wait! I know what’s worse: the reporter who did this story and the editor who approved it not injecting one single shred of skepticism into the report. There was no journalism here, no investigation. This was simple stenography, the credulous retelling of what is almost 100% guaranteed to be a hoax at best and a scam at worst. Not to mention child abuse.

People sometimes ask me what it’s like to be a skeptic all the time. Maybe I should simply answer, “nauseated.”

Today (as I write this), the Cassini spacecraft passed just a hair under 100 km (62 miles) from the surface of Enceladus, an icy moon of Saturn. This little moon is scientifically incredibly interesting; there are geysers at the south pole that are spewing out water! The images are just now coming in, and have not been calibrated or processed yet, but they are still breathtaking. I particularly like this one:

[Click to embiggen, as usual.]

That, me droogs, is high art. Enceladus was about 190,000 km (118,000 miles) away from Cassini when that shot was taken, a little under half the distance of the Earth to the Moon. From this angle, Enceladus is lit in a gorgeous thin crescent, but we can see detail on the dark side, I suspect due to light reflecting off Saturn onto the moon. You can see ridges in the surface; the moon has a thick crust of ice presumably floating on an undersurface ocean of water (though there have been arguments about that), so the surface is a bit of a mess, looking for all the world(s) like ice floes seen at our own north pole.

The geysers are obvious too, blasts of light at the top of the moon’s limb as the water erupting from the south pole is lit by the Sun. Thumbing through the raw images is a delight (once there, set the target for Enceladus, choose both narrow and wide angle, and put in dates of October 30 through November 3 to narrow the search). You’ll see dramatic images of the moon, its limb, the geysers, and everything.

Stunning, and wondrous. And there’s better to come: as Carolyn Porco herself mentions on Twitter, the primary purpose of this flyby was not to get images; November 21st is the imaging flyby where we’ll see lots of spectacular shots of the moon. So stay tuned!

Image credit: NASA/JPL/Space Science Institute

Clearly, the artist behind The Stonemaker Argument is after my heart. And his daughter is an awful lot like mine…

[Click to see the whole thing...]

The link to this cartoon was left in the comments to an earlier post of mine, but deserves its on post, so tip o’ the Treknobabble to Andrew.

Hey, it’s been a while since we’ve had some good ol’ pareidolia — seeing faces in random patterns — here on BA, and since Halloween just passed, here’s a goodie: a demon in a door’s wood grain:

Hmmm, not bad. For what it’s worth, the father doesn’t claim it’s actually a demon, though he does claim it wasn’t there before Halloween and now it is. I suspect it’s more likely due to no one noticing it before, but hey! That’s just me.

And the instant I saw the face I knew it wasn’t a demon. There’s a far more likely explanation:

Better call Ahnold.

My favorite part was the father saying the face didn’t freak out the kids. I’m not surprised, since clearly they’ve gotten used to Bambi’s dad hanging on the wall.

Tip o’ the demonic alien cornrows to Fark.

What is the source of cosmic rays?

Seems like an easy enough question. Cosmic rays are little subatomic particles zipping across the Universe. We’ve known about them for decades, and just about any astronomer who has used a space telescope knows and loathes them; cosmic rays zap our detectors, leaving bright streaks in the images which need to be tediously cleaned out before we can do any real science. I spent a large fraction of my time with Hubble doing just that.

But what’s generating them? They seem to come from all directions in the sky, making it difficult to pin down their source. They’re moving at fantastic speeds, so they must have a huge energy source behind them. For years, astronomers have suspected that they are accelerated to high velocities in supernovae explosions as well as in the fierce solar winds from massive stars. Recent evidence has been making that supposition seem more likely.

And now new results from the VERITAS gamma-ray telescope array have added fuel to that fire. VERITAS stands for Very Energetic Radiation Imaging Telescope Array System, and it’s located atop a mountain in Arizona. When energetic gamma rays (a form of light) hit the Earth’s air, they create a shower of subatomic particle that rains down and can be detected by the telescopes.

If cosmic rays come from supernovae and massive stars, then we should see more of them coming from galaxies that have a lot of stars being born. That’s because massive stars don’t live long. A nearby galaxy vigorously cranking out baby stars will therefore have lots of massive stars making cosmic rays. As a happy by-product, those same massive stars are the ones that blow up as supernovae, giving us a two-fer as far as cosmic ray production goes.

Such a galaxy exists: M82, a weird-looking one located a mere 12 million light years away (it’s close enough to see in binoculars, in fact). The image above is M82 as seen by Hubble, Chandra, and Spitzer. Astronomers trained VERITAS on M82 and took a very, very long exposure. What they found is that is is a weak source of gamma rays, but definitely above the background level. The amount detected is consistent with cosmic rays being generated in the violent environment of the galaxy which then slam into the gas surrounding the stars, generating gamma rays. Another process, called inverse Compton scattering, is probably behind this as well: when a low energy particle of light called a photon hits a cosmic ray, its energy is pumped waaaay up, and it becomes a gamma ray. Think of it like gently throwing a rubber ball in front of a speeding truck on the highway; the ball suddenly and violently finds itself with a lot more energy.

This all may not seem like a big deal, but it is. For one thing, there are a lot of cosmic rays flitting about out there, so knowing what they are and how they formed is clearly a big piece of understanding the high-energy Universe. Also, these cosmic rays may have an effect here on Earth. Scientists have been studying how they may interact with the Earth… and while the effect, if any, is incredibly small (people still argue over whether there is anything to this at all, like cloud formation and such) it’s worth investigating.

And I want to add something that makes me smile. The cosmic rays (which, remember, are subatomic particles) from M82 were detected because while still inside that galaxy they make gamma rays, a form of light, which then travel straight to Earth. But once those gamma rays hit our air they create subatomic particles once again, which are what VERITAS detects. So there are several steps to this process, with cosmic and gamma rays going back and forth until we actually detect their effect. It goes to show that sometimes the key to our understanding the Universe can involve subtle processes piled one atop the other, and it’s up to us to carefully peel back those layers to get to the underlying processes underneath.