Over at The Planetary Society Blog, guest blogger David Seal (filling in for Emily Lakdawalla who just had a baby) has written a really good article about radar observations of Earth made from the Space Shuttle.
Normally that’s not my cup of tea, but David has a great and personable writing style that makes the topic fun, interesting, and yes, inspiring. He writes very convincingly about why we do science from space, and how it has an impact on us… in many ways, including mapping volcanic events, assessing the damage from the 2004 tsunami, seeing how the flooding affected New Orleans, and much more.
The coolest thing he wrote about, IMO, was about mapping the K/T impact crater in Chixchulub, Mexico. That’s the one that gave the dinosaurs a Really Bad Day. Here’s a radar image he mentions:
That arc in the lower right is part of the rim of the crater. It’s basically impossible to see from the ground, and invisible even from space using most normal methods of observation. But the very sensitive radar mapping technique reveals it clearly. Arguments have raged about how big the impact event was, spawned by uncertainty in the crater size. Was the asteroid big enough to wipe out the dinosaurs all by its lonesome, or was it not quite enough to do that, and instead just the start of a series of events that killed them all off? These sorts of questions — and face it, they are pretty important ones! — can be solved or at least helped along by observations like the ones David writes about in the blog.
He makes a pretty good case for science, and science from space. The next time someone asks you why we’re "wasting money" on space, you can send ‘em to that blog entry.
September 26th, 2006 at 2:57 pm
I played a small role on SRTM. I got to fly out to ACE-Abel and view the mast canister and witness a full extension and retraction. I also visited JPL and saw the rest of the payload being processed. That was an incredible design criteria. Think about this – they had to accommodate the flexibility of the boom and the vaccillation at the end of that 60 m boom to allow for that fluctuation in the calculations. And then they performed a particular thrust maneuver from the Shuttle to snap the fluctuations out.
Yes, that mission was a spectacular engineering and science achievement.
September 26th, 2006 at 5:39 pm
Judging from the image, the imact happened a bit out into the Gulf. Google Earth shows a small group of islands right about the point I’m guesstimating for the impact. Coincidence? Maybe. At the scale of the pictures compared to Google Earth, the islands would be just out of frame.
jbs
September 26th, 2006 at 5:53 pm
Map out the cenotes in the peninsula too. They follow an arc right along the arc shown in Phil’s posted image.
A good example here: http://www.lpl.arizona.edu/SIC/impact_cratering/Chicxulub/gpcenotes.jpg
September 27th, 2006 at 4:27 am
Can anyone provide the scale? A very similar image is visually descernable at the Vredefort impact site (circa 2023 billion years). It is visable on google earth – look approx 50 to 70 kilometers South South-West of Johannesburg adjacent to Parys. The concentric rock formations in that case turned out not to be the edge of the crater but the remnants of the central dome left by rebound!! The edge of the crater is now visually invisable and had a diameter of hundreds (300 to 500?) kilometers.
September 28th, 2006 at 12:02 am
[...] David Seal is guest-blogging at the Planetary Society Blog, and a coupla days ago he blogged about a mission close to my heart in the post entitled The Greatest Mission You’ve Never Heard About. [via Bad Astronomy] Except that readers of this blog have heard about it. A few times: The Shuttle Radar Topography Mission (or SRTM). Or, how we mapped the world in 11 days from the space shuttle. [...]