hubble space telescope, impact site, Jupiter, planetary science

Debris-sweeper of the Solar System

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Jupiter

Jupiter as seen through HST's WF3. NASA, ESA, M.H. Wong (University of California, Berkeley), H.B. Hammel (Space Science Institute, Boulder, Colo.), A.A. Simon-Miller (Goddard Space Flight Center), and the Jupiter Impact Science Team.

By now, most people have heard that Jupiter got whacked earlier this month. The event was witnessed live by Anthony Wesley, an amateur astronomer living in Australia. Astronomers raced to observe the impact site to see if the debris plume could give them a clue to just what it was that hit the Jovian cloud tops. Among the telescopes trained on the site was Hubble Space Telescope and its Wide Field Camera 3. The results of that observation are in, and it seems that Jupiter was smacked by a giant meteor.  The image at left (on which you can click to massively enJovianate) shows where the meteor collided with the atmosphere on June 3 (the circle on the right-hand image). There’s no dark debris cloud as we’ve come to expect from other impact events.  This tells us that the meteor didn’t get very far into the clouds, since it didn’t explode and scatter dark debris around the region.

The flash of light recorded by Anthony Wesley during the event is created by the same type of activity that creates a “shooting star” in Earth’s atmosphere. The incoming object is moving at very high speeds and when it speeds into the atmosphere, a shock wave is generated by the resulting ram pressure. That shock wave heats the object to extremely high temperatures. That heats the atmospheric gases along the object’s path, and it also vaporizes a layer of the object’s surface. On Earth, what’s left of the object — if it makes it all the way through the atmosphere — falls to the ground as meteoritic material. On Jupiter, it just gets swallowed up by the clouds.

It used to be (back in the Shoemaker-Levy 9 days) that impacts into Jupiter were considered rare.  Not so much any more. We have 24/7 observations of the planets using vastly improved telescopes and sensors — and now, it turns out that Jupiter gets impacted by meteroids pretty frequently. Astronomers think this could be happening perhaps every few weeks or so.  We were lucky that someone was watching when this last one occurred, and I imagine that Jupiter-watchers will be keeping a close eye out for other impact events like this. Jupiter plays an important role in sweeping up debris in its path, and it very likely filtered out a lot of large debris early in solar system history — acting as a sort of protector for the inner planets. That means that Jupiter could have played a large role in shaping our solar system by lassooing many objects before they could whack into Mars, Earth, Venus, and Mercury.  If  so, and we didn’t have Jupiter, who knows what the inner solar system might look like now?  There’s no doubt that Jupiter has swept up much debris, but can it have other effects?

On the other hand, there is research supporting the idea that Jupiter’s presence might have increased the impact rate at Earth and the other planets over the history of the solar system (thanks to Daniel Fischer for reminding me of that research).  If that’s the case, you could still ask the same question:  if not for Jupiter, what would our solar system look like now — particularly the inner planets?  And, what role could Jupiter still be playing with the remaining solar system debris that still makes its way around the Sun in orbits that sometimes take it a little too close to Earth (and other worlds)  for comfort?  This is something that planetary scientists are seeking to understand as they map the orbits of solar system “stuff” and add what they find to their understanding of the complex mechanics of space debris and the worlds of the solar system.

stargazing, storytelling

Starry Tale? Starry Science? Both? Neither?

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Depends on How You Look at It

I spent last week at a planetarium conference held by the SouthEastern Planetarium Association (SEPA). It was held in Kingsport, Tennessee, and the host planetarium was at Bays Mountain Park — a great place to visit and the meeting was really enjoyable. The theme of the meeting was “Storytelling” and since Mark and I bill ourselves at Loch Ness Productions as “Storytellers of the Universe” we fit right in. We presented a show that Mark did the soundtrack for, called SpacePark360: Geodesium Edition — it’s really a production of Dome3D, and the story was “have fun!” — since it is a thrill park ride set on other planets. It was well-received and great to see in the fulldome theater at Bays Mountain Park.

Since the theme was about telling stories, several speakers, such as Lynn Moroney, focused on it with storytelling experiences — and stories — of their own. The keynote speaker was Dava Sobel, author of Galileo’s Daughter, Longitude, and several other well-written books.

Why storytelling? Because planetarium folk — indeed, anyone who teaches (formally or informally) — are storytellers. And, most of us who grew up in planetariums learned to be storytellers. It’s part of our shared heritage as planetarium folk. So, hearing from storytellers is a good thing at a meeting. Of course, the stories we astronomy types tell are focused on the stars, but there’s always some amount of the human experience in them. That shows up in the star legends that various cultures ell about what’s in the sky.

The star patterns are logical choices, and so you find lots of drama among the constellations. The other day I wrote about the very useful ways that The Big Dipper helps us find our way around the sky. If you find the Dipper and instead of using the curve to find Arcturus, use the Pointer stars to find the North Star — but keep going! Eventually you run into a W-shaped (or M-shaped, or 3-shaped, all depending on what time of year you look) pattern. It’s called Cassiopeia.

Of  course, there’s a story about Cassiopeia that involves her husband the king, a mythical hero,a fair maiden, and a monster or two. A long time ago, back when there were a lot more shepherds than there are now, the Greeks thought that pattern reminded them of that queen — who, incidentally,  had quite a reputation for being self-absorbed, vain, all “me, me, me” (in the modern parlance).  And, let’s not forget taht she had a penchant for making her daughter’s life miserable.  She was such a good object lesson in how NOT to behave that the Greeks put her up in the sky as a reminder to all people (of any gender) that vanity and other character flaws are not admirable traits — even acting all self-absorbed does get you a glittery star pattern to your name! (Run over here for some more background on the tales and science of Cassiopeia.)

Those star tales like the rather lenthy and involved one about Cassiopeia are the stock in trade of starry storytellers like me and my colleagues in the planetarium profession when we want to acquaint people with the rudiments of getting around the sky.  I could just show you five stars in the shape of a smooshed M (or W), but if I tie it to a story, it’s more memorable. The constellations we describe are the stuff of stargazing. Those patterns help us find our way around the sky and give us reference points to directions, time of year, season, and many other useful bits of knowledge. So, check ’em out!

Exploring Science and the Cosmos

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