the elegant universe question.?

Question

what does gravity explain?

what was the "problem" with the theory of gravity during newton's time?

what force keeps us from"sinking into the floor"?

what characterisitics do blakc holes have that make them so interesting to study?

Answer 1

Blackholes!? Interesting!?
You've got to be joking.
Blackholes SUCK!
Literally. lol

Answer 2

The problem with newtons theory of gravitation is that he said it was an attraction between two objects. Albert Einstein proved that gravity is actually when you sort of bend space around an object like a ball on a rubber sheet. If you put a sinker on a rubber sheet it makes a dent if you put a marble on the sheet it will roll towards the sinker this is the principal behind Einsteins theory
http://www.thebigview.com/spacetime/gravity.gif
if you paste this in your adress bar it will come up with a picture.
Basically Matter needs space to exist so it trys to get as much space as possible smaller objects want the space the big object has so they're attracted by it.

From what I can understand there is no force that stops us sinking into the floor and that there is simply a solid underneath you stopping you from moving towards the earths core.

Black holes are weird because they are when a star explodes it'sleft with a really heavy but small core. This core's own gravity actually pulls itself in to makeitself smaller and smaller and smaller and smaller forever and ever and ever untill there is a really massive dent in space which even light can't escape. At the bottom of this dent space and time are all jumbled up so weird things could happen there which we will probably neverf find out.
Follow this link for a picture of a blackhole'seffect on space
http://io.uwinnipeg.ca/~vincent/4500.6-001/Cosmology/embedding.gif

Answer 3

Gravity is a manifestation of space in the presence of matter,it did not exist when the universe came into existence.
Newton's gravity was at odds with Einstein's relativity but it worked perfectly for Newton's purpose.
You don't sink through the floor because of the Pauli exclusion principle.
This says no two pieces of matter can occupy the same space at the same time. So the floor seems solid.
If a black hole could exist it would be composed of 2.5 solar masses confined in a sphere 3 km in diameter.
A black hole in an elegant theoretical entity that cannot exist in reality.

Answer 4

There is no problem with Newton's theory of gravity, it has been shown as an approximation of general relativity when the masses concerned are not huge like neutron stars or black holes.

Newton's Third law : Every action has an equal and opposite reaction

They harbour singularities where the laws of physics as we know them, break down.