4

6/3/2009 12:29:14 AM

can't let this gem be lost to the 49th post on a page

Quote :

"think of it as a rod made of marbles held together by glue, and take this rod and beat yourself in the head with it"

6/3/2009 10:17:24 AM

haha

6/3/2009 10:35:21 AM

this is the kind of shit i thought about when i was 5

A++

6/3/2009 10:36:28 AM

bump?

2/1/2013 1:48:55 PM

someone poke holes in this logic for me:

it's estimated that the universe is several light years wider than it is years old. if this is true, wouldn't that require the big bang or some other force exceeding the speed of light?

2/1/2013 1:51:38 PM

space its self expanded faster than the speed of light. (not the matter in space)

2/1/2013 1:55:47 PM

No, see, it's taller than it is wide so if the light just kind of bends a little bit it makes it in the right amount of time.

2/1/2013 1:58:10 PM

Quote :

"Since it appears there are a bunch of engineers in this thread, let me throw out a hypothetical perpetual motion idea I had a while ago. Picture 2 parallel rails raised a precise distance from the core of the earth in a complete circle around the earth. Basically, a big railway like a mile or two off the surface of the earth in a perfect circle. If you had a giant steel ball rolling on these 2 rails, would gravity keep it rolling along the curvature of the rails?"

The ball wouldn't roll. For an alternatively equivalent experiment, try placing a ball on flat ground. Does it move?

Unless your surface is frictionless, then you might as well be in orbit.

2/1/2013 2:52:50 PM

I too once constructed thought experiments believing that gravity wasn't a conservative field.

2/1/2013 4:56:50 PM