A five-part series on the ultimate limit on technology, and how that limit could help us find other civilizations: 1 2 3 4 5 [via]
posted by cthuljew
on Dec 12, 2012 -
Does dark matter exist?
Dark matter has been suggested as a solution to the galaxy rotation problem
where individual stars don't seem to rotate the way Newton's laws would predict. Now, some scientists are saying that observations fit with Einstein's general relativity, without any dark matter needed. I just find it amazing that no one has tried this yet.
posted by delmoi
on Oct 10, 2005 -
Does relativity have any practical significance? In fact, relativity had to be taken into account
by the designers of the Global Positioning System. The GPS satellites are affected both by special relativity
(since the satellites are moving, clocks aboard them appear to run slower as seen from the ground), and by general relativity
(since the satellites are farther away from the mass of the earth, clocks appear to run faster as seen from the ground). The net effect of both is that clocks aboard GPS satellites would gain 38 microseconds per day relative to the ground, if relativistic effects were not corrected for--a figure which can be confirmed by using Google calculator
posted by DevilsAdvocate
on Nov 30, 2004 -