Giant Waves Over Iowa

October 19, 2007 5:15 AM

Undular Bore Waves
posted by geos (17 comments total)

Holy moly, that first video almost gave me motion sickness. (Also had a misleading title: "Gravity Waves"?) But very cool stuff indeed - thanks!
posted by not_on_display at 5:40 AM on October 19, 2007 [1 favorite]

Undular bores are a type of "gravity wave"—so called because gravity acts as the restoring force essential to wave motion. Analogy: "We're all familiar with gravity waves caused by boats in water," points out Coleman. "When a boat goes tearing across a lake, water in front of the boat is pushed upward. Gravity pulls the water back down again and this sets up a wave."

"Also," he continued, "deliberately confusing this weather phenomenon with a hot topic in astrophysics is a great way to bump up our funding."
posted by DU at 5:45 AM on October 19, 2007

Gravity waves isn't a misleading title I think. Gravity waves aren't the same as gravitational waves, if that's what you're thinking.

owl
posted by edd at 5:47 AM on October 19, 2007

Who knew that pressure differentials in a fluid could give rise to waves?
posted by tylermoody at 6:15 AM on October 19, 2007

One night at 1 am when I lived in Oklahoma my wife and I were relaxing in our hot tub, and we saw one of these things come in from the south... a long white tubular cloud extending across the sky. A few minutes later the cloud had departed to the north and the moon was back out again. No weather, no wind, just a strange cloud trying to get from point A to point B.
posted by rolypolyman at 6:16 AM on October 19, 2007

Owl, that's the point. People confuse them.
posted by futility closet at 6:16 AM on October 19, 2007

I think most of us in the midwest have seen these in the past 2 days. Yesterday, the wind was so bad, people were starting to talk tornadoes, even though the weather service hadn't issued any watches or warnings (as it turned out, it's not warm enough for that right now).

Looking out my office window right now, I can easily imagine that the whole house is moving, and the clouds are the stationary ones.
posted by thanotopsis at 6:52 AM on October 19, 2007

between mefi and slashdot poor science.nasa.gov is feeling the wave now.
posted by quonsar at 7:52 AM on October 19, 2007

Amazing.
posted by rtha at 8:29 AM on October 19, 2007

I'm not owl. Owl is the obligatory wikipedia link. And yes, I got the point.
posted by edd at 8:54 AM on October 19, 2007

Very cool. I study gravity waves in the ocean (they occur between two water layers of different densities), and it was great to see these atmospheric examples.
posted by sotalia at 9:22 AM on October 19, 2007

Yutube doesn't like me.

I'm also more familiar with ocean gravity waves (hi sotalia!) but your "Waves" link picture is awe inspiring.
posted by carmina at 10:26 AM on October 19, 2007

Imagine looking up at these gigantic ripples on the Sun (caused by flare-induced solar quakes):

The solar quake that the science team recorded looks much like ripples spreading from a rock dropped into a pool of water. But over the course of an hour, the solar waves traveled for a distance equal to 10 Earth diameters before fading into the fiery background of the Sun's photosphere. Unlike water ripples that travel outward at a constant velocity, the solar waves accelerated from an initial speed of 22,000 miles per hour to a maximum of 250,000 miles per hour before disappearing.

Interesting that they accelerated. Here's a photo sequence and video.
posted by cenoxo at 10:47 AM on October 19, 2007

"Gravity waves" (as opposed to pressure waves, shear waves, etc.) is only misleading to people who don't know the subject. AFAIK they've been called that since well before gravitational radiation became an active research topic.
posted by hattifattener at 12:10 PM on October 19, 2007

Giant Waves Over Iowa?

Sure, but how you gonna make the drop?
posted by Relay at 12:45 PM on October 19, 2007

I'm pretty sure several Bore Waves passed through the last meeting I was at ...
posted by eritain at 4:03 PM on October 19, 2007

This is the first sign of the Apocalypse.
posted by cjorgensen at 6:19 AM on October 21, 2007