The Random Image Thread (keeping it PG-13 at the worst)

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Geesie Couldn't hit it sideways
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I remember those ads and wanting one of those. ;)
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TOS
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Stunning new technique to accurately map the ocean’s floor via satellites:

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So how does this map the seafloor? Get this: If there’s a mountain under the ocean, then it has more gravity than the water around it (rock is denser than water, so it has more mass per cubic centimeter, which means it has more gravity than the same volume of water). This slight increase in gravity draws in water on the surface around it, piling it up on the surface—water is incompressible, so it doesn’t just flatten out. So when the satellite flies over a seamount, it sees a little bump in the sea surface.

If there’s a chasm or trench in the seafloor, then it has slightly lower gravity than the rock around it, so there’s a corresponding dip in the sea surface above it.

Mind you, these bumps and dips in the water surface are tiny, on the order of a millimeter. This is usually completely swamped by currents, waves, chop, and the like. The only way to get good measurements is to take a lot of them, and then the bumps and dips that change over time will cancel out. It’s like flipping a coin; do it a few times and they might all come out heads, but do it a million times and you can be pretty sure you’ll get extremely close to half heads and half tails.

Mind you, these bumps are dips in the water are subtle: They may have a height of several meters, which sounds like a lot, but they’re spread out over a long distance, sometimes hundreds of kilometers. The slope of the water is incredibly small and difficult to measure, and this is complicated by currents, waves, chop, and the like. The satellites have to find that gently sloping trend up (in the case of seamounts) or down (in the case of trenches) despite all that noise. The only way to get good measurements is to take a lot of them, and then the noise that changes over time will cancel out. It’s like flipping a coin; do it a few times and they might all come out heads, but do it a million times and you can be pretty sure you’ll get extremely close to half heads and half tails.**

This was the first thing to amaze me: Scientists can measure the sea surface height to incredible accuracy. The map is based on new techniques that improve the measurements by a factor of two or so.

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** Correction, Jan. 14, 2016: Arg! OK, I made a mistake. When I originally wrote this, I said that the measurements had to be accurate on the order of a millimeter to measure the water piling up or flowing away from gravitational anomalies. However, the reality is subtly different: The satellites measure the slopes of the mounds or troughs in the water over great distances to map the topography beneath them. I have to admit: This is even more amazing to me. You're not just looking for a bump in your data that pokes up or down; you're looking for a looooong, slooooow trend, which is in many ways more difficult. So my admiration for this work stand; it just points in a slightly different direction. For more info, read this, and this, and my thanks to Peter Guth for his help.
[links omitted, italics and bold included]

EDIT: added the Bad Astronomer's correction.

Last edited by DEyncourt on Thu Jan 14, 2016 8:07 pm.

maurvir Steamed meat popsicle
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Stuff like that is why it is so exciting to be alive today. That would have been science fiction just 10 years ago.
maurvir Steamed meat popsicle
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jkahless Custom Title
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Heckuvaway to unload some logs eh?
We had that posted here many pages back I think.
ukimalefu want, but shouldn't, may anyway
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Kirk posted:
We had that posted here many pages back I think.


All of these have been posted before and will be posted again

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TOS
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i often see reposts in this thread

not terribly surprising considering it's been going for almost four years now
ukimalefu want, but shouldn't, may anyway
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ukimalefu want, but shouldn't, may anyway
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Joan Jett and Lita Ford

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TOS
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man, they were just kids
Geesie Couldn't hit it sideways
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TOS posted:
man, they were just kids


At least 22 in that picture.
ukimalefu want, but shouldn't, may anyway
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juice Inadvertently correct
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Big Wheel!

My brother and I rode the human waste out of the ones my grandparents got us one Christmas.
Geesie Couldn't hit it sideways
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maurvir Steamed meat popsicle
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Image

There are times when I really get jealous of Lee Hutchinson...
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obvs Social Distancing Grandmaster
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Geesie posted:
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What does this mean?
Rings of Saturn near equinox (back in 2009) display perturbations due to tiny moon Daphnis:

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This emphasizes the thinness of the rings: Daphnis is only about 8 km in diameter.
dv
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obvs posted:
Geesie posted:
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What does this mean?


1) Fake mustache.
2) Real mustache, fake fake.
3) Real moustake, fake fake fake, fake hand.
4) Fake girl.

Or, as I read it: If you're one of those mustache-worshipping douchebag hipsters, any girl who seems interested in you and your stick fiddling skinny jeans is probably a reptilian.
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Is that what was really intended?
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maurvir Steamed meat popsicle
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maurvir Steamed meat popsicle
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obvs Social Distancing Grandmaster
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Where can I get one of those?
You could 3D print that. ;)
The fixed parts I mean. Motors and slides to make it move are extra.
maurvir Steamed meat popsicle
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maurvir Steamed meat popsicle
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DukeofNuke FREE RADICAL
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obvs posted:
Where can I get one of those?


You're not talking about the cake cutter, are you ?
maurvir Steamed meat popsicle
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maurvir Steamed meat popsicle
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obvs Social Distancing Grandmaster
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DukeofNuke posted:
obvs posted:
Where can I get one of those?


You're not talking about the cake cutter, are you ?
Yes, actually I was.
Awesome truck driving there.

Hah, I figured TEOO was after the cake cutter. ;)
Donkey Butter jerk face
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wasn't that cheese that is was cutting?
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The Random Image Thread (keeping it PG-13 at the worst)

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