Until now. “Stuart’s remarkable photograph of the collision gave us an excellent starting point in our search,” said Dr. Bonnie J. Buratti of NASA JPL. She and Lane Johnson of Pomona College teamed to do a Mulder and Scully. “We were able to estimate the energy produced by the collision [about 0.5 megatons or 35 times more powerful than the Hiroshima atomic bomb]. Using Stuart’s photograph of the lunar flash, we estimated the object that hit the moon was approximately 20 meters (65.6 feet) across, and the resulting crater would be in the range of one to two kilometers (.62 to 1.24 miles) across. We were looking for fresh craters with a non-eroded appearance,” Buratti said. “But we calculated that any crater resulting from the collision would have been too small to be seen by even the best Earth-based telescopes, so we looked elsewhere for proof.”
They started with 1960s Lunar Orbiter photos and found nothing. Then it was on to records from the 1994 Clementine mission. Voila. Buratti and Lane’s search of images from Clementine uncovered a remarkable find: a very special 1.5-kilometer (0.93 mile) wide crater. It had a bright blue, fresh-appearing layer of material surrounding the impact site, and it was located in the middle of Stuart’s photograph of the 1953 flash. The crater’s size is consistent with the energy produced by the observed flash; it has the right color and reflectance, and it is the right shape. A report of their research appears in the latest issue of the space journal Icarus.
Dr. Stuart died in 1968. His son Jerry Stuart offered some thoughts about Buratti and Lane’s findings. “Astronomy is all about investigation and discovery. It was my father’s passion, and I know he would be quite pleased,” he said.
There’s a common feeling that we know just about everything there is to know about the Moon – since Apollo anyway. And it’s up there in our backyards shining brightly on its monthly rounds – we’re so used to that nearest celestial neighbor that we don’t realize – scientifically we have barely scratched the surface.
Our telescopes are incredibly good at finding extremely faint and distant objects, but they’re not so good when it comes to resolving things. From Earth’s surface the best resolution images of the Moon have a pixel size of several kilometers across. Hubble can do no better, from Earth orbit. The only way to do much better with realistically sized instruments is to actually go there – either robotically or in person; the resolution scales mentioned in this article are evidence of that. Clementine did a wonderful job – unfortunately it was only there briefly, and the viewing angles it used relative to the sun did not produce the best possible images; moreover the resolution of the best Clementine images is still only 100 meters or so. Apollo images were better (down to 1 meter) but covered only small strips of the surface.
At least our photographic lack of knowledge should be greatly lessened later this year when the commercial TransOrbital craft reaches lunar orbit: it will provide images of higher resolution and better quality than Clementine over the whole surface, and will photograph points of interest at resolutions almost as high as was done during Apollo.
Now if only we could actually put together a mission with people on it, to really find out about that mysterious neighbor up there!
Just curious, had you ever even heard about this 1953 photo before this week? I hadn’t, and that kind of surprised me. This crater was right on the equator and could have been an Apollo landing target…if they had known about it in the 1960s, which they didn’t. Would there be any scientific value in going to such a FRESH crater?
There’s a lot of talk about “transient” events on the Moon – before the Apollo project the consensus was that the craters were mostly volcanic, and people claimed to have seen what they thought were eruptions over the years. In fact it is still not known whether the Moon may have a molten layer in its interior right now – there definitely was volcanism associated with Mare formation (when the great basins filled with lava) but that was billions of years ago. The Apollo mission that was supposed to have made the closest investigation of the regions that may still have traces of volcanic activity, Apollo 14 which landed in the Fra Mauro area, unfortunately became a joy-ride for Alan Shepard (of the famous golf swing) when crews were switched at the last minute – and that crew was not geologically prepared and didn’t do the sort of investigation the geologists were hoping for. So we still know a lot less than we should.
One of the criteria for Apollo landing sites was that they wanted to be reasonably sure of a level position to bring the lunar module down in. Even so, it was up to the human pilots to actually find a suitable spot when they got there, because the imagery wasn’t good enough to pinpoint where would be good to land or not. But they deliberately avoided the regions expected to be worst, the “highlands”, which occupy most of the moon’s surface, and I believe that’s where this crater was just found.
Yet more to convince us we know a lot less about the Moon than we should!
These collisions and other locations are all vary
interesting. It was mentioned that TransOrbital plans on getting atlas images of the full moon. Also on this Transorbital missions page,they say “Once we have finished acquiring the surface atlas images, we will command the spacecraft to lower the periselene to approximately 10 km. This will enable us to take very detailed images of selected portions of the lunar surface, with resolutions of better than 1 meter per pixel. Candidates for these high-resolution images include the hardware left over from the Apollo (U.S.) and Lunakhod (Russian) lunar missions, the polar regions, and proposed sites for lunar colonization.”
However I see no mention of looking at other interesting sites.
Any ideas on this?