DailyDirt: Measuring Important Stuff...

from the urls-we-dig-up dept

Thu, Nov 10th 2011 5:00pm — Michael Ho

Measuring natural phenomena isn't always easy. There are a lot of interesting things that can be measured without a lot of fancy equipment, but some things can't be measured without just the right conditions and materials. Here are a few links on measuring some cool (or actually kinda hot...) things.

Did you know that the speed of gravity is about equal to the speed of light with an error of less than 1%? It's a speed that's measured from the decay rate of binary pulsar systems. [url]
The Earth is radiating a lot of heat (forty-four trillion watts!), but the source of that heat isn't entirely obvious. About half of the heat seems to be accounted for (radioactive decay of elements, etc), but there's around 20 trillion watts that's still a bit of a mystery. [url]
Vikings probably didn't use magnetic compasses to help them navigate since magnet-based compasses weren't popular in Europe until the 1300s. Vikings might have used "sunstones" -- crystals of calcite -- and birefringence to determine the sun's position even in foggy conditions. [url]
To discover more interesting science-related stuff, check out what's currently floating around the StumbleUpon universe. [url]

By the way, StumbleUpon can recommend some good Techdirt articles, too.

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Filed Under: binary pulsar, birefringence, compass, gravity, speed, sunstones, vikings

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Anonymous Coward, 10 Nov 2011 @ 6:57pm

You failed to mention SOPA. Mike will be angry.
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Anonymous Coward, 10 Nov 2011 @ 7:19pm

"Did you know that the speed of gravity is about equal to the speed of light with an error of less than 1%?"

Yeah but the 1% a masses all the wealth!

Ba-da-bump
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Rekrul, 10 Nov 2011 @ 9:10pm

The Earth is radiating a lot of heat (forty-four trillion watts!), but the source of that heat isn't entirely obvious.

Really? Well send some of that heat this way so that I don't have to go broke buying heating oil this winter...
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- Pixelation, 10 Nov 2011 @ 10:13pm
  
  Re:
  "but the source of that heat isn't entirely obvious"
  
  Much of it comes from the trolls posting around here. Hot air to spare.
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- Michael Ho (profile), 10 Nov 2011 @ 11:35pm
  
  Re:
  Well, the other thing is -- how accurate is that 44 trillion watts figure? I'm not sure how they arrived at that amount, so maybe they have that part wrong...
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Lawrence D'Oliveiro, 10 Nov 2011 @ 11:40pm

"Speed Of Gravity" -- wow.
Is this Earth gravity that is almost equal to the speed of light? Which means that, say Jupiter gravity must be over two and half times the speed of light. So Einstein was wrong that nothing could exceed the speed of light!

Either that, or Jupiter is wrong about Einstein being a figment of its imagination.
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- Killercool (profile), 11 Nov 2011 @ 12:20am
  
  Re: "Speed Of Gravity" -- wow.
  As it says in the post, the number is based on a binary pulsar system.
  
  Think of gravity as a wave. The wave travels the same speed, no matter what. The amplitude, however, changes based on mass.
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- abc gum, 11 Nov 2011 @ 4:47am
  
  Re: "Speed Of Gravity" -- wow.
  Big G, not little g ... just in case,
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