Tag: Carolyn Porco

The staring eye of a crescent moon

By Phil Plait | February 10, 2012 10:39 am

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.


Related posts:

- Enceladus sprays anew!
- Enceladus fires on Alderaan
- Saturn weather forecast: rings, with light rain from Enceladus
- Icy moon and distant rings

Symphony of Science: Onward to the Edge

By Phil Plait | November 9, 2011 5:20 pm

A new Symphony of Science has come out today, in honor of Carl Sagan’s birthday. And I’m pleased to see it features three people I call friends: Neil Tyson, Brian Cox, and Carolyn Porco:

Isn’t that wonderful? Symphony of Science is the work of musician John Boswell, who takes the words of scientists and creates these lovely videos. You should watch them all.

I mention that Neil, Brian, and Carolyn are all friends for two reasons; one is that sharing a love of science is not a zero-sum game, a conserved quantity. The more we share it, the more people who are heard and seen doing it, the more desire there is for it. Each of us broadens the audience for all. There is no fixed capacity for learning and wonder.

But also, it’s more than that. It’s a reason I think Sagan would’ve agreed with as well: we’re all in this together. Paupers and kings, famous and infamous, men, women, black, white, all flavors of humanity. We are all riding this planet, and where we go is largely up to us. We can make the most of it, or we can squander it.

I am personally inspired by pieces like this. Like most people, I sometimes lose sight of my own goals, I sometimes get mired in the day-to-day business of life. But when I see Neil and Brian and Carolyn and, yes, Carl Sagan, letting their passion show, mine returns as well.

Keeping the passion is what drives the personal thirst for learning. Showing that passion is what instills it in others.

Show a little passion now and again. Who knows who you’ll inspire?

CATEGORIZED UNDER: Cool stuff, Piece of mind, Science

Peeking past Rhea

By Phil Plait | February 28, 2011 10:00 am

If I had to pick a single word to describe the system of moons swarming around Saturn as seen by Cassini, it would be "bizarre", "amazing", "exquisite", "jaw-dropping", and "Holy Haleakala!"

See for yourself:

[Click to enchronosenate.]

Wow! I love these shots showing perspective! The moon at the top is Rhea, which is about 1500 km (950 miles) across. We’re looking past its south pole here. The moon farther away is Dione, which is 1100 km (700 miles) in size. And since Cassini was very nearly in the plane of Saturn’s equator, the rings are nearly edge-on. Note that Dione is on the other side of the rings as seen by Cassini, so the bottom of the moon is obscured by the rings. We can’t see Saturn itself, but it’s off to the left in this shot.

Rhea is only a little bigger than Dione, but is a lot closer in this shot: 61,000 km versus 924,000 for Dione! That’s why Dione looks so much smaller. As seen by Cassini in this shot, it’s actually more than twice as far as our Moon is from the Earth. Both moons are composed of mostly water ice, with some rock. Both have been heavily battered by impacts, as you can see.

What a gorgeous, spectacular picture. I never get tired of these.

Image credit: NASA/JPL/Space Science Institute

Tip o’ the rings to Carolyn Porco on Twitter.


Related posts:

- The more distant moon
- Dione and Rhea, sitting in a tree
- Two alien worlds, superposed
- Midnight on a ringed world

CATEGORIZED UNDER: Astronomy, Pretty pictures

The bringer of fire, hiding in the rings

By Phil Plait | June 23, 2010 12:04 pm

After yesterday’s depressing picture, how about one that will make you smile?

The ever-amazing Cassini spacecraft sent back this pretty nifty shot of Saturn’s icy moon Rhea playing peekaboo in the rings:

cassini_rhea_prometheus

Beautiful, isn’t it? You can see that Rhea was on the other side of the rings from Cassini when this image was taken, and that the spacecraft was almost, but not quite, in the plane of the rings, too.

But there’s more to this shot… Read More

CATEGORIZED UNDER: Astronomy, Pretty pictures
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