‘
I got an interesting phone call yesterday morning. It was from a man who claimed he saw something odd. On October 22 of last year he was driving along Interstate 50 in California, heading east away from Sacramento. The Moon was rising over the mountains, and he saw what looked like a giant asteroid impact on the Moon. He described it to me in some detail, with rising plumes arcing away from the Moon and everything. He said he saw people stopped by the side of the road, watching, with some taking pictures.
I told him I was sure it wasn’t something that had actually hit the Moon. If it had been, every astronomer on the planet would have been going nuts, especially the amateur astronomers (who, in truth, would be more likely to see it before any professional astronomers). We’re talking major impact here, and the whole planet would have seen it.
If what he said is true then I suspect what he saw was an atmospheric effect, given that it was only seen locally. Since the Moon was rising at the time, that makes it even more likely; when the Moon is low there you see it through more air, and this can cause all kinds of weird effects.
However, out of scientific honesty, I’ll add that he claimed the Moon was full that night, when it was actually full five days earlier. Either he got the date wrong, or the phase wrong. I suspect it was the phase: on October 22 the five-days-past-full Moon would have risen at 9, and by 11:00 p.m. would have been low over the Sierra Nevada mountains. To be fair, it’s been my experience that people commonly think a less-than-full Moon is full, and even though this was really not full, it was rising and may have looked distorted.
Anyway, if anyone saw this event last October, please leave a comment here! I’d like to know.
Now, stuff like this does in fact happen. Just look at the Moon’s surface: it’s a testament to a history of very seriously pummeling. Even now it still gets hit, though really big impacts are very unlikely. Still, a ton or so of asteroid shrapnel and dust hits the Moon every day.
By coincidence, I was literally reading an article about lunar impacts when I got that call! Weird. Anyway, give that a read; it’s fascinating. It says that something massing 1100 kg (over a ton!) hit the Moon back in 1972. If it was a rock, it would have been about a meter across, and with a typical impact speed of 30 km/sec, it would have released about as much energy as 100 tons of TNT. Not bad for something smaller than a washing machine. I had no idea there had been an impact that large in the recent past. Pretty cool.
If you’re interested in this, check out the page on Wikipedia about transient lunar phenomena. They have good links from there, too.’
June 6th, 2006 at 12:26 am
More TNT than that!
KE = 0.5 * m * v^2
m = 1100
v = 30,000
yields 5 * 10^11 Joules.
One Megaton is 4*10^15 Joules.
So it would be 1.2*10^-4 Megatons, or 120 tons.
June 6th, 2006 at 2:19 am
we could always nuke the Moon for entertainment on a boring evening.
June 6th, 2006 at 5:02 am
I posted the following in a previous thread about the “comet hitting the Atlantic Ocean”, but since this item is about the moon I thought I’d repeat it.
I went to see Poseidon the other day (on an IMAX screen no less) and noticed a bit of Bad Astronomy. It’s New Years Eve and everone is celebrating at midnight on the huge luxury liner Poseidon. Except Richard Dreyfus, who is outside by the rail hoping to receive a very important call on his cell phone.
He doesn’t receive the call and in despondence is about to jump over the rail, when he sees a giant wave blotting out the full moon which is low on the horizon.
Full moon on the horizon at midnight? Wow, that really is a disaster!
June 6th, 2006 at 5:50 am
A full moon on the horizon could be possible, although both may be ruled out be the specifics of the journey in the film (not seen it, no interest in seeing it).
Two scenarios spring to mind:
1) The ship is quite far north (i.e. artic circle), in midwinter. The path of the moon (and sun) across the sky could be very low and near to the horizon.
2) Time zone differential. The ship starts from, say Southampton UK, sailing to New York. Ship maintains UK time on board until it arrives at New York. But geographically the ‘time’ on board could be up to 5 hours different from the time to observers. So midnight as noted by Mr Dreyfuss could be close to 7pm New York time, so again full moon near the horizon is again possible.
Okay scenario 1 is quite weak and not sure about the journey specifics in the film for 2.
Just some random thoughts, feel free to shoot them down in flames if I’m wrong.
June 6th, 2006 at 6:50 am
Sure would be nice to see the pictures the people on the side of the road were taking.
June 6th, 2006 at 8:53 am
Sounds like the fun carnival game, Whack-a-Moon.
June 6th, 2006 at 9:22 am
D’oh! I wrote pounds when I meant tons. I’ll fix that right now.
June 6th, 2006 at 9:34 am
Tim G, you’re assuming that the meteorite hit the moon full on, but it is more likely it hit the moon at a slight angle. Some of the kinetic energy would then have transformed into potential energy of bits flying off. Considering 120 tons is in the same ball park as 100 tons, this is probably what happens.
June 6th, 2006 at 9:57 am
Yikes! Now my first post looks anal.
BA, feel free to delete it.
Thanks.
June 6th, 2006 at 11:14 am
Lasers are better for moon messages.
June 6th, 2006 at 1:09 pm
One evening back in the seventies I had just stepped outside and looked up at a waxing gibbous moon in the eastern sky. In the twilight I saw a very bright streak heading west to east straight for the Moon. Just as the streak of light reached the illuminated face of the Moon there was a bright explosion followed immediately by a second explosion on the trailing edge of the Moon. For a split second, okay maybe a full second I thought I had seen an impact. Of course logic quickly took over and I knew that what I saw was a remarkable chance alignment of a bolide entering earth’s atmosphere with the explosions juxtaposed in front of the Moon. It was an event I will never forget.
As a side note I’ve always thought that the reported lunar impact witness by the group of monks may have been a similar chance alignment of a bolide exploding in front of the Moon.
June 7th, 2006 at 6:53 am
Just how well is Richard Dreyfuss’s cellphone going to work in mid-ocean, anyway?
June 7th, 2006 at 9:35 am
I did a Carribean cruise and had cell service (though I didn’t use it for fear of the charges) most of the time. A repeater on the ship shouldn’t be too hard to do. I guess the question is, what format would it be?
June 7th, 2006 at 12:16 pm
I know this is doubtful but could any of the Lunar Laser Ranging Experiment procedures have been visible in any way?
http://www.csr.utexas.edu/mlrs/dda.html
June 7th, 2006 at 12:20 pm
Post code error problem. It happened again. When I use normal HTML address I get the following error message, yet the post appears:
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I tried to educate myself on the xhtml code but need more work on it. Sorry for the blog post errors in the meantime.
June 8th, 2006 at 5:11 pm
Tom K said: “Full moon on the horizon at midnight? Wow, that really is a disaster!”
Maybe I’m just too much of an amateur (I haven’t even made it all the way through The Basics of Space Flight over at JPL) but what is so impossible about a full moon appearing on the horizon? If you look at the link to the phases of the moon that BA made in his post, you can see that full moons happen at all times of the day and night. In fact, there will be a full moon on December 5 at 25 minutes past midnight this year (2006).
Tom K may, admittedly, have been calling attention to the fact that the full moon doesn’t (usually?) fall right on the evening of the 31st of December, but it can fall very close to that day (there will be a full moon on January 3, 2007, and on December 24, 2007). Near-full moons often look like full moons (also as stated by BA).
Am I missing something? We don’t even seem to need Stuart’s somewhat complex explanations. Granted, Hollywood doesn’t seem to know that full moons don’t happen every night, but what can we expect? It doesn’t rain continually in Seattle, either, but every time you see Seattle in a movie, it’s pouring day and night.
June 8th, 2006 at 5:13 pm
P.S. I get the same error messages as appeared above in Beskeptigal’s comment. My post seems to have made it onto the board all right, but the “success” page told me all that garbage. Something wrong with the software, or something we’re doing wrong?
June 9th, 2006 at 8:42 am
About the Moon on the horizon for ZorkFox:
A full moon can be on the horizon (obviously, because it must rise), and the moon can be on the horizon at midnight (depending on where it is in its orbit relative to us), but Tom K’s point was that the moon can’t be BOTH full AND on the horizon at midnight.
When the moon is full, the Earth is on a line, roughly, from the sun to the moon. That means that when the moon is full, and the point on the Earth on which we are standing is opposite the sun (midnight), then the moon must be high in the sky.
The exception is the one Stuart points out where the moon could be near the southern horizon, although I can’t imagine a passenger on a cruise liner out for a stroll on the deck in the high arctic at midnight in, say, late December. Was Richard wearing a parka? Did his nose look waxy white?
June 9th, 2006 at 12:30 pm
Doesn’t really pertain to moon impacts, but today’s Earth Science Picture of the Day is a quite nice collection of full moon pictures over one year. Have a look at the animation, this shows the effects very well.
http://epod.usra.edu/archive/epodviewer.php3?oid=308256
June 10th, 2006 at 7:49 am
Tuesday, February 25, 2003
Moon Impact Confirmed, 50 Years Later
Back in 1953, amateur astronomer Leon Stuart photographed what he claimed was an asteroid-sized rock smashing into the moon. Now NASA says the crater has been found. Such a collision only happens about once every 50 years, they estimate, meaning that Stuart is probably the only person in history to witness and document the creation of a moon crater.
June 10th, 2006 at 7:52 am
Other evidence of witnessed moon impacts:
http://www.space.com/scienceastronomy/solarsystem/leonids_crash_000621.html
June 12th, 2006 at 3:33 pm
Just back from an Alaska Cruise. Didn’t see any good astronomical stuff, but did eat lunch with a guy using his satellite cell phone well away from any other cell phone source. Perhaps Dreyfuss had one of them.
June 14th, 2006 at 1:20 am
NASA is reporting a new crater formed on May 2 2006 — they have animated frames showing the event.