Blogs / Bad Astronomy

The hi-res Lunar Reconnaissance Orbiter’s camera captured a pretty cool image of a (what I’m guessing is an ancient) landslide on the Moon. Check this out:

[Click to embrobdingnangate.]

The slide is down the steep slope of a crater called Marius, located in Oceanus Procellarum, a vast smooth-surfaced area on the Moon (generally called "maria" — singular is "mare" — and easily visible to the naked eye). The crater itself is pretty old; the floor is covered with the same smooth surface as the mare around it, so it predates Oceanus Procellarum which we know is pretty frakkin’ old.

The slide is very interesting; what could have caused it? A moonquake, or a nearby impact? Either way, the ground shook, knocking loose rubble at the crater rim which then rolled downhill. And just to give you an idea of the scale here, the image is 510 meters across: you could walk that distance in a few minutes. The fingers of debris are only a few dozen meters across at most! The smallest objects you can see in this image are less than a meter across.

Features like this on the Moon yield a lot of information. Better, as the LROC page notes, this feature can be compared to similar ones on Mars, giving scientists insight into both worlds.

And? It’s just really cool. Landslides on the Moon! Look out below!

Ever since the Hubble upgrade a few months ago I’ve been waiting to see the results of it getting back to routine science observations… especially for the new Wide Field Camera 3, which promised to return gorgeous imagery.

Well, the wait’s over. The first image is out, and it’s a nice one: star formation in the spiral arm nurseries of the nearby galaxy M83:

[You know the deal: click it to embiggen, or go here to grab a delicious 15 Mb 3900x3900 pixel version.]

M83 is about 15 million light years away, making it practically a next door neighbor for the Milky Way, as well as a tempting target for telescopes. Proximity = clarity in most cases, and with M83 we have a great view of its lovely spiral arms. This new image from Hubble’s WFC3 shows unprecedented detail, too. There are star clusters everywhere, factories cranking out baby stars by the millions. There are also something like 60 supernova remnants, the expanding gaseous debris from exploded stars, five times the number previously seen in this galaxy.

The colors are interesting. This picture is not quite true color. Sure, blue is blue, green is green, and red is red, but they also added a second version of red coming from the light of warm hydrogen gas (called Hα in astronomical parlance) as well as a fifth color: cyan (turquoise) coming from the light of warm, tenuous oxygen. That light is typically emitted from gas clouds making stars as well as the gas emitted from stars when they die (in fact, my PhD thesis was based on observations of this oxygen-light glowing from a ring of gas around an exploded star). You can see that this teal-like glow pervades the entire image: oxygen is everywhere! But it’s so thin it’s more like a hard laboratory vacuum than anything you could breathe.

Also, if you look closely at the pockets of red clumpy gas, you can some that are edge-brightened, like a soap bubble. These are where stars are being born in vast numbers. Their mighty winds expand outwards, carving huge cavities in the gas. My favorite is the one in the middle left of the image, zoomed in here for your viewing awesomeness. The stars are so closely packed they blur together, and each that you can see here would dwarf the Sun in mass, size, and brightness. You can also see that the rim of the bubble is more pronounced below the star cluster, which means that the surrounding gas in the environment of the cluster is thicker there, and has piled up more as the expanding winds have snowplowed it.

And everywhere in this picture are the dark ribbons and filaments of dust, dust, dust. These are long molecules (usually with lots of carbon) which are created by new stars and dying stars. They litter galaxies like M83 as well as our own. And while they make life difficult for optical astronomers who struggle to penetrate the thick veil and see what lies beneath, the dust is interesting all by itself… and adds a certain depth and grace to images like this one.

And, on the right of the big image, is the white glow of the galaxy’s nucleus. You can see detail of the dust, stars, and gas all the way down to the very center. It’s an amazing image, and I’m sure will keep astronomers busy for a long, long time.

What a great start to the return of the Hubble! And, as always, I can’t wait to see what’s next.

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.]

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

This is very, very cool: The Lunar Reconnaissance Orbiter, currently orbiting the Moon just 50 km off the surface, has taken more shots of the Apollo 17 landing site… and has seen the actual U.S. flag!

Behold (and salute):

[Click to boldly embiggen.]

Well, lookit that! It’s fuzzy and small and hard to be sure it’s the flag in the picture, but there it is. It does match maps made of the Apollo 17 landing site, so it’s definitely the flagpole we’re seeing there.

Cooool.

Compare this picture to that taken by the 16mm movie camera on the Ascent Module right after Apollo 17 lifted off the Moon; you can see many of the same features. I spent a minute looking for the rover in the LRO picture, then remembered that the astronauts moved it well off to one side, about 100 meters, before they left the Moon so that the video camera on board could record their ascent (it was remotely controlled from Earth by an operator named Ed Fendell, who had tried to film the launch of Apollo 15’s and 16’s Ascent Module but missed; with Apollos 15 and 16 technical issues prevented the ascent from being filmed, but with 17 he made it, and that’s the movie you always see in documentaries). However, you can see it in this larger overview from LRO:

[Again, click to make a giant leap.]

Incredible. The LRO page on this has more details, including comparisons of the images from LRO to ones taken in situ from Apollo 17. Remember too that these LRO images have a resolution of 50 cm (18 inches) per pixel!

Wow. Wowee wow wow.

Back to the flag, there’s a curious thing about it. The flag itself was nylon, and that tends to get brittle when exposed to ultraviolet light — which is relentless and plentiful on the airless Moon (the thermal pounding it’s taken between day and night can’t help either). I’ve often wondered what we’ll find when we go back to the Apollo landing sites; I half-expect to see red, white, and blue powder off to one side of the flagpole, and no actual flag left on the pole. This picture, as frakkin’ amazing as it is, is still just barely too low resolution to be able to say for sure, I think. The shadow is only a pixel or so in size and so it’s hard to say what’s what.

Still, Holy Haleakala. Apollo 17’s flag. I wonder what Gene Cernan and Jack Schmitt thought when they saw this picture. And I wonder when we’ll go back.

Tip o’ the spacesuit visor to Guillermo Abramson. [Edited to add: Apparently I am late to this game. While catching up on other blogs just now, I saw that both Emily Lakdawalla and Nancy Atkinson already wrote about this!]

Need some pretty for today? Then you should feast your eyes on this exquisite picture of the cluster of stars known as the Jewel Box:

[Click to encaret].

Gee, I can’t imagine why’d they name it the Jewel Box! In fact, this is a large cluster of stars located in the southern constellation of Crux, also called the Southern Cross. It’s bright enough to be seen with the unaided eye, in fact (though when I was in the Galapagos last year, Crux didn’t get high enough off the horizon to see the cluster very well).

This image, taken by the Hubble Space Telescope, shows the multicolored stars dwelling in the cluster. But not for long, I’ll add. Those bluish stars are O and B-type supergiants, massive stars that scream through their nuclear fuel thousands of times faster than the Sun, meaning their lives are far shorter. The red beacon there at the upper right is a red supergiant, a star right on the edge of disaster (literally, since the word means "bad or ill star"). It won’t be long, maybe a few million more years, when all the bright stars in the Jewel Box will go supernova, detonating in titanic explosions each of which, from the Earth, will outshine Venus!

The image is one of three from three different telescopes, taken to examine the core of the cluster (with Hubble) as well as the outer regions. The picture on the left is from the Very Large Telescope in Chile, and shows a larger area around the cluster (the bright red star is the same as in the Hubble picture). Incredibly, due to the huge telescope’s light-gathering abilities, this picture is actually only a 5.2 second exposure! It’s composed of three images: one in blue (2.6 seconds), one in yellow (1.3 s) and one in red (1.3 s). When you use a telescope with a mirror 8 frakkin’ meters across, bright stars don’t take long to show up.

Astronomers aren’t sure if the Sun was born in a cluster like the Jewel Box, or if it was formed in a smaller cloud by itself; both types of birth occur in the galaxy. I know it’s not scientific, but a part of me rather hopes that once upon a time, a few billion years ago, the Sun did in fact see its first light inside such a cluster. Imagine the sky, festooned with stars so bright they outshine the Moon, easily luminous enough to read by, and each glowing blue, red, yellow… that would have been a fantastic sight.

Some people think that science takes away the romance and wonder of the Universe, but I don’t think not knowing is romantic, especially when knowing gives us such lovely vistas to explore.

BABloggee Mauro Mello Jr. from Sydney, Australia sent me this wonderful picture.

That pretty much sums it up, doesn’t it?