Sometimes, the images from the Cassini Saturn probe are so cool it’s tempting just to post them and say, "Look at THAT!"

See what I mean? [Click to gigantesenate.]

But of course, I can’t just leave it at that. This image, taken on January 4, 2012, is a bit different than most. Sure, we see Saturn’s magnificent rings, nearly edge on from this perspective. And we’ve seen this icy moon Enceladus many, many times (see Related Posts below for tons more pictures). Look at the bottom of the moon: see those fuzzy streaks? Those are geysers of water spewing from cracks in the moon’s south pole! Cassini has been studying them intently ever since they were discovered; they are proof that liquid water exists under the surface of Enceladus, though it’s still being argued over whether it’s in pockets, like lakes, or the whole moon has an ocean of water under the surface.

Despite all that, I keep getting drawn to the crescent shape itself. We can never see that from Earth. Saturn is much farther out from the Sun than we are, and geometry demands that from home we always see these worlds nearly fully lit by the Sun. The only way to see them like this is to go there.

But also, that giant circular feature is really interesting. It’s big, maybe 200 km (over 100 miles) across, and a bit darker than the surrounding surface. I tried locating it on an atlas of Enceladus, but it wasn’t obvious at all. I thought it might be an impact basin, but a little scrounging online led me to a paper by Cassini imaging team leader Carolyn Porco, which says there are no large impact basins on Enceladus! So what is it?

Well, why not go to Dr. Porco herself? I sent her a note, and she kindly replied. That region is called Diyar Planitia, and it stands out among the surrounding terrain because it’s much smoother. It does have narrow surface features, but they’re too small to be seen at this resolution. At the low angle at which we’re seeing it here, it looks a little bit darker than the rougher terrain around it, so it’s easier to see (which is why on an atlas it’s harder to find). It is roughly circular, but that may simply be coincidence. Enceladus has been massively resurfaced, with some areas much older than others, due to various forces under the surface — looking this all up I learned a new one, called diapirism, where lower density material underneath higher density material can rise up and break through. That’s one process that’s helped change the surface of Enceladus over the eons.

That’s pretty nifty. And think about that! Today I learned of what is to me a new region of the solar system, one that has an interesting and complicated history, molded by vast forces over long-stretched times, one of which was also new to me. How wonderful to get all that from what’s otherwise just a pretty picture!

But of course, in science, there’s no such thing as just a pretty picture. Science is a tapestry, a vast complex fabric interwoven with countless threads. Each of those threads is amazing, each important, and each leads to another. And that’s where the true beauty of science lies.

Photographer Maik Thomas posted this time lapse video on Google+, and it made me chuckle. The bright object is the Moon, and as it sets it turns red, looking like a missile from space curving right into a church.

I love the star trails effect. It’s just a way of adding the individual frames together to show motion, but it does give the video an oddly other-world feel to it. And in this case it really makes the Moon look like some sort of re-entering rocket!

Sometimes, I like to think of a photon of light as a car on a road. As the road dips and curves, a car has to follow that path, dipping and curving as well. It might be weird to think of space as curving, but it does. Gravity from massive objects warps space, and a beam of light moving through that curved space curves along with it.

This is the principle behind what’s called gravitational lensing. A beam of light passing by an object — a big galaxy, say, or a cluster of galaxies — bends one way. A beam headed in a slightly different direction bends a slightly different way. This can really mess with what we see… which I can prove! Check this out: a Hubble image of the galaxy RCSGA 032727-13260.

What a mess! All those arcs and blue smudges are images of that one galaxy. The light from that galaxy traveled nearly 10 billion light years to get here! But when it was halfway here, that light passed by the big cluster of galaxies — the red fuzzballs — in the middle of the image. As it did, the curvature of space distorted and warped the light from the galaxy, and by the time it reached us here at Earth the image looks like this. The outstretched, smeared-out arc is amazing; I’ve never seen one that long and well-defined before.

Not only that, but the image gets broken up into several separate images. There are no fewer than four different repetitions of the background galaxy in the big image. To show that, I put three of them together here. It’s goofed up, to be sure, but you can kinda sorta see they are the same galaxy, flipped over and/or smudged out.

The cool thing about this is we can learn about the more distant galaxy by examining these images. (more…)

I love science. OK, duh, but I really do. And when I go on vacation, I can’t help but see science everywhere, and in every case it makes the trip more fun for me. Seeing local geology, biology, how the stars might look different at a different latitude… it adds to the vacations, makes it better.

That’s why my wife and I started a company called Science Getaways. We figured there are lots of other folks out there like us who would really enjoy taking a vacation that has bonus science added in. Our first planned trip is to a gorgeous Colorado dude ranch called C Lazy U. Besides the usual amenities of such a place — horseback riding, great food, spectacular views of the Rocky Mountains — we’re adding SCIENCE! And scientists: we have a geologist, a biologist, and an astronomer — hey, me! — who will be on hand to give talks about the local nature scene, and then we’ll take hikes to put that new-found knowledge to practical use. I’ll be running a stargazing session every evening with my new 8" Celestron telescope, and I’m hoping to do some solar observing during the day as well.

IMPORTANT NOTE: We’ve negotiated a special rate — the price we’re offering is actually less than the usual ranch rate. We’re hoping to have the entire ranch for our group, but if we don’t have enough reservations by March 1 we can’t guarantee it. Space is limited, so please book now if you plan to come.

By the way, we’re also on Facebook and Google+ if you’d like to add us.

I hope to see lots of BABloggees there!

In the race to find the weirdest planet orbiting another star, we may have a front runner: GJ 667Cc, a super-Earth orbiting one star in a triple system that’s actually relatively closeby. And oh yeah: it just so happens to be in just the right spot to be potentially inhabitable!

Of course, I have some caveats, so don’t get too excited. But this is a weird and pretty cool one!

GJ 667 is a triple star system that’s right in our back yard as these things go: it’s only about 22 light years away, making it one of the closest star systems in the sky. It’s composed of two stars a bit smaller and cooler than the Sun which orbit each other closely, and a third, smaller star orbiting the pair about 35 billion km (20 billion miles) out. Stars in multiple systems get capital letters to distinguish them, so the two in the binary are GJ 667 A and B, and the third one is GJ 667C.

That third star is the interesting one. It’s a cool, red M dwarf with about a third the diameter of the Sun. Fainter, too: it only puts out about 1% of the light the Sun does. It’s been studied for years to look for planets around it, and while there have been some signs found, this new research is the first solid detection of planets that’s been published.

They used the Doppler method (sometimes called the Reflexive Velocity method): as planets orbit a star, their gravity tugs on it. We usually can’t see this motion directly, but a spectrum can reveal a Doppler shift, similar to the change in pitch you hear when a car or train goes by. If the spectrum has a high enough resolution, and the analysis very carefully done, there’s a lot you can tell by measuring it. You can get the planet’s mass, its period, and even the shape of its orbit.

In this case, the spectrum reveals GJ 667C may have four planets! Two very strong signals pop up with periods of 7 and 28 days, a third one at 75 days, and a possible trending shift in the spectrum that may point to a planet orbiting in a very roughly 20 year period.

It’s that second planet, GJ 667C with a 28 day orbit that’s so interesting. Its mass is at least 4.5 times that of the Earth, so it’s hefty. A 28 day orbit puts it pretty close to the parent star — about 7 million kilometers, or less than 5 million miles (Mercury is 57 million km from the Sun, by comparison). But remember, GJ 667C is a very dim bulb, so being that close means that the planet is actually right in the middle of the star’s habitable zone! The HZ is the distance where liquid water could exist on a planet — it depends on the size and temperature of a star, and also on the planet’s characteristics. A cloudy planet can hold heat better through the greenhouse effect, so it can be farther from the star and still be warm, for example.
(more…)

I really don’t think I need to add anything to this. Set it to HD, make it full screen, and turn the sound up.

Tip o’ the magnetometer to Tom Lowe, aka Timescapes.

Cerro Paranal, in the high, dry, Atacama desert in Chile, is where some of the best astronomy in the world is done. It’s graced with incredibly dark and steady skies, and a view of the southern hemisphere skies that, frankly, makes me jealous.

So it’s hard to argue with the title of this short time lapse video, An Astronomer’s Paradise:

This was taken by photographer Babak Tafreshi, who alerted me that he had put it online. Watch it to 1:30 in if only to watch Orion rise — upside down, to my northern hemisphere bias! — with colors and texture that are simply stunning.

Isn’t that awesome? And then a few seconds later, he shows a still image of the great Carina Nebula with the four domes of the Very Large Telescope Interferometer silhouetted against the sky. You can get a better look at that at The World At Night website, which has amazing shots of the sky.

I hope someday to make a trip to this part of the world. To see this for myself…

Credit: Babak Tafreshi