Astronomers Fix the Astronomical Unit

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Astronomers Fix the Astronomical Unit

Posted by Soulskill on Friday September 14, 2012 @05:23AM from the and-changed-the-oil dept.

gbrumfiel writes "The Astronomical Unit (AU) is known to most as the distance between the Earth and the Sun. In fact, the official definition was a much more complex mathematical calculation involving angular measurements, hypothetical bodies, and the Sun's mass. That old definition created problems: due to general relativity, the length of the AU changed depending on an observer's position in the solar system. And the mass of the Sun changes over time, so the AU was changing as well. At the International Astronomical Union's latest meeting, astronomers unanimously voted on a new simplified definition: exactly 149,597,870,700 meters. Nobody need panic, the earth's distance from the sun remains just as it was, regardless of whether it's in AUs, meters, or smoots."

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let's not waste significant digits! by markhahn · 2012-09-14 05:30 · Score: 4, Funny

you'd think they could have rounded up to 150 gigameters.
if politicians can be SD-conservative, why can't astronomers? we all know that significance is precious and rare...
1. Re:let's not waste significant digits! by girlintraining · 2012-09-14 05:34 · Score: 5, Funny
  
  if politicians can be SD-conservative, why can't astronomers? we all know that significance is precious and rare...
  It was decided by committee. I'm sure it was a compromise of several possible values, with concessions on each side, a few attempts to filibuster it until Pluto was given recognition again, etc. No, I'm not trying to be funny.
  
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2. Re:let's not waste significant digits! by cffrost · 2012-09-14 06:43 · Score: 4, Funny
  
  If you are constantly somewhere between 2.328 and 2.347 feet from me, I'm not going to define the distance between us as 2.000 feet simply because "it's a nice round number."
  Agreed; I'd define that distance as "all up in my grill," and I'd define that trajectory as "cruisin' for a bruisin'."
  
  --
  Thank you, Edward Snowden.
  
  "Arguments from authority are worthless." —Carl Sagan
3. Re:let's not waste significant digits! by Antipater · 2012-09-14 06:55 · Score: 4, Funny
  
  1 AU = 42
  Has anyone here noticed that? Why, when someone picks a random number, 12 and 42 come out so often? Has there been some research done on that?
  I wouldn't panic about it.
  
  --
  Everything is better with chainsaws.
No, panic. by girlintraining · 2012-09-14 05:31 · Score: 4, Funny

Nobody need panic, the earth's distance from the sun remains just as it was, regardless of whether it's in AUs, meters, or smoots."
I'm more concerned about the fact that the distance changes depending on where we are. That means that the Earth is moving, and I don't believe in that. It's more heliocentric non-sense by the astronomical community. What next; astronomical bodies that aren't perfectly spherical? The madness of the commoners, I tell you.

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Re:Distance remains the same? by mblase · 2012-09-14 05:37 · Score: 5, Funny

Since the Earth's orbit around the Sun is eliptical it's _never_ the same, is it?
Even an elliptical orbit is right twice a year.
The new AU ... by PPH · 2012-09-14 05:38 · Score: 5, Funny

... will be established by machining a bar of pure platinum to a length of exactly 1 AU. It will be stored in a vault in Paris.

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Have gnu, will travel.
1. Re:The new AU ... by wonkey_monkey · 2012-09-14 05:47 · Score: 3, Funny
  
  But they won't be able to shut the door unless the bar is moving at relativistic speeds.
  
  --
  systemd is Roko's Basilisk.
2. Re:The new AU ... by jmv · 2012-09-14 05:47 · Score: 4, Funny
  
  Apparently they decided to define it by sticking a large rock in orbit around the sun.
  
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  Opus: the Swiss army knife of audio codec
3. Re:The new AU ... by Anonymous Coward · 2012-09-14 07:48 · Score: 2, Funny
  
  It's already there, but you got the length wrong. It's exactly 1/149,597,870,700 AU
Eve nav problems by Anonymous Coward · 2012-09-14 05:39 · Score: 2, Funny

Great, everyone in Eve is going to be missing jump gates, plowing through asteroid fields at warp. Going to be chaos.
Re:They should mesure it in miles. by GodfatherofSoul · 2012-09-14 05:57 · Score: 5, Funny

92,955,807.3 miles
Your answer is SOO 8 minutes ago...

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Thank you, Bob Barker. by Minwee · 2012-09-14 06:26 · Score: 4, Funny

Now that it's "Fixed", it's technically an Astronomical Eunuch.
How much is that in Cesium atom wavelengths? by jfengel · 2012-09-14 06:29 · Score: 3, Funny

Or more correctly, units of c times the period of "radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom". Let's get this down to fundamentals and not muck about with intermediate convenience units like "meters".
Re:They should mesure it in miles. by RabidReindeer · 2012-09-14 07:38 · Score: 3, Funny

Don't mix speed and distance.
Hey, I can do the Kessel Run in 17 parsecs!