Wait so space is flat?

I think that gravity is a product of inertia, and inertia is a product of opposites. Take subatomic particles as an example. Also I think space time is not effected by a planet but by it's gravity. I have seen this demo where they place a ball in a sheet and say that the sheet is space. So that would mean space is flat then? I could not disagree more. If space was flat then all galaxy's would sit on that plane and we would see nothing.

So to me that means no gravity. Space does not have it. This is why sugar or salt clump together in space right?

DLM2011-06-16T10:12:39Z

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You are submitting a common misconception.

When cosmologists say that the universe is flat, the are referring to a curvature along a higher physical dimension.

Think about the surface of the Earth. It most certainly is not flat. It is a 2-D surface, but it shows curvature. This can easily be determined by measuring the angles of a triangle along the surface of the Earth. It the angles add up to 180 degrees, it is flat. If not, which they don't, then that surface is curved.

Think about a person who is on the south pole. He walks 1 kilometer (due north, obviously), then turns 90 degrees to his left. Walks one more kilometer. Turns 90 degrees to his left again. When he walks one more kilometer, he is back where he started. He completed a triangle, but the sides add up to 270 degrees.

In space, we measue very little curvature, now, that could mean the universe is flat, or it could mean it is so enormous, that within our observable horizon, there is not enough curvature to measure a triangle with anfles that add up to something other than 180 degrees.

To argue that gravity doesn't exist because you do not understand the space-time fabric metaphor, is ludicrous.

Space and time ARE curved under gravitational prescenses, but they are curved in three physical and one temporal dimension. This was PROVEN in the early 1900s.

Buddha2011-06-16T10:09:46Z

First of all, gravity is relative. That's what Einstein was talking about in the Theory of Relativity. As for the subatomic particles, since size is also relative, gravity has almost no affect on them at all. Inertia is the random element here because it wasn't invented until Steven Hawking's third year at Princeton. As we all know, Christopher Columbus of Oxford University in England proved that space is shaped like a Mobius Strip. That's why galaxies "look" like they are in three dimensions. If space was smaller, all the galaxies would fall to the bottom. That's how Einstein proved gravity is relative.

I hope that helps.

Anonymous2011-06-16T09:59:00Z

If you look up "flat" as an astrophysics term you'll see it is not about round or flat but more about a line on a graph or scope, like "flat lining" on a hospital scope registering heart beat, etc.. And it's about whether the universe has enough momentum to keep expanding forever (line goes up on the chart) or not enough so it will collapse (line goes down on the chart) or just even energy to keep the way it is forever (flat line). To learn more though you can check out the flat terms on wikipedia and other definition sites related to astronomy and "flat" term, also referred to as "open or closed" universe. And also the idea that the unverse is expanding in every direction the faster the farther away everything is ...is a theory, and The Big Bang Theory is not all there is to think about in Cosmology. Here is just one example of the many many videos and articles you can see online, this one by the great Carl Sagan; http://www.youtube.com/watch?v=oZxzvdQ85zU&feature=related
Have fun looking around the universe.

Anonymous2011-06-16T10:42:17Z

The space-time continuum is technically curved only by mass. It's mathematically ALMOST three dimensionally "flat" at large distances from masses that create gravity wells in the space-time continuum. Scales of size AND time are VERY important. Most people grasp the concept of "scale" only with considerable mental effort.

quantumclaustrophobe2011-06-16T09:43:45Z

Well... the sheet is representative of just an gravitational demo... it's a 2-dimensional visual of 3-d space. It *could* be on a plane, but it's not necessarily so - and, in fact, isn't.

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