Sunday, May 29, 2011

Sunday Photo(s)

My blogging friend Dana Hunter is hosting a geology blogging festival called "Accretionary Wedge" today. The subject is "weird geology", which is yet another one that I have neither the background nor the discretion to try to write about. It's all weird to me - sinkholes, eruptions, diamond and gold mines, why is all that stuff where it is? I have no idea, really, and doubt I ever will. As I've already noted, stuff like this is pretty weird, too, but geologists seem to take it in stride.

Still, in a spirit of solidarity I thought I'd put up a few pictures of one of the more unusual geological features I've ever seen. It's the Meteor Crater, in central Arizona.

The Meteor Crater was formed, as you might have guessed by now, by a meteor that hit the Earth. At the time I wrote this:
Image credit: NASA

This was not the only asteroid or comet to ever hit what is now the United States, only the biggest. This is a photo of the meteor crater near Winslow, Arizona. It was formed by a smaller impact 20,000 to 50,000 years ago. That's a very short time in geological history, and came at a time when human beings were starting to spread out over the planet. The first humans came to North America only a few millenia later than the end of that estimated impact period.

What Geology Can Teach Us
I hadn't actually seen the crater, but the following year Dana and I visited it while we were touring the area. It's hard to think of this as weird, because there are lots of impact craters on the Moon and Mercury. As I've noted before, meteors have had a major impact on how life evolved on Earth, even if the events are mercifully infrequent.

So, it's not weird.

Still, it's a big honkin' hole in the ground, and so it's a good subject for a photo essay. The meteor that hit the area was a 150 foot (45 meter) wide ball of iron that struck the ground at more than 10,000 miles per hour (more than 15,000 kilometers per hour (NOTE1)), leaving a sizable hole in the ground. Go figure. Here's what's thought to be the largest piece of the meteor that survived the impact. It's less than three feet in its longest dimension. There wasn't much left of that 150 ft. meteor:

Image credit: All photos by Cujo359 unless otherwise noted

I took a few panoramas of the crater that day. It's really hard to get a sense of scale from them, though. This one is taken from the trail that runs along the rim of the crater:

That thing off to the right that looks a bit like a chimney is, in fact, a chimney. It was part of the house built by one of the earliest explorers of the crater.

This is the view from the lower observation deck near the visitor center.

It shows a good view of the small settlement at the bottom of the crater. No one lives there now, but it was used during the 1960s as a training ground for astronauts who were training for moon walks. Here's a close up of that area. At least, it's as close as I could get with a 3.5X zoom:

This is another view from the rim as we were taking the tour:

The crater is almost a mile wide. Had it been formed today, the impact probably would have devastated half the state. This is yet another reason why I think people who think that we don't need to have the government prepare for disaster and study the things that could create them are crazy. Just imagine what would become of Flagstaff, which is only about thirty miles away, or any of the other towns in that area. Now imagine it hitting New York or southern California, instead.

So it may not be weird, but it's certainly important.

Click on the pictures to enlarge. Have a good Sunday.

NOTE 1 Yes, I know that a mile is 1.602 kilometers. I'm rounding to the same kind of precision in both units.

UPDATE: Here's a way to judge the scale of the place. It's an aerial view of the Meteor Crater that I put together using Google images:

In the top part of the image is the visitor center, which is a rather large building with a couple of auditoriums and a gift shop. In the lower left hand corner is a scale. For those of you stuck in the English measurement system, 200 meters is about the same as 200 yards (within ten percent). Ignore that arrow, it's just the cursor arrow.

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