2007-06-14 16:01:24 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
It's caused by gravity. As things are drawn closer in they tend to whorl around the center of gravity between them. Like water going down a drain.
2007-06-14 16:08:49 · answer #1 · answered by Anonymous · 1⤊ 0⤋
The 'easy' answer is that the universe is 'warped' by gravity and objects simply follow the curvature of the warping.
However, 'circles' is not an appropriate description. Objects that do not have enough energy to escape the 'gravitational well' of another object (like the Earth compared to the Sun) is following an orbit which is basically elliptical (the circle being a special ellipse), but also deformed by the gravity field of other objects in the area.
Some objects are on hyperbolic orbits (they will escape). Some comets fall in from very far on orbits where their speed is very close to escape speed. As they pass near Jupiter (or any other planet), they may gain just enough energy to boost their speed and they escape the solar system.
The Galaxy is a very massive object. The Sun is in orbit around the Galaxy (one orbit in 220 million years).
The Local Group has enough mass that our Galaxy is in orbit around the centre of gravity of the Local Group. So is the Andromeda Galaxy. The two galaxies are not moving fast enough to be on circular orbits and, in a 'mere' 5 billion years (give or take a few years), the two galaxies will merge.
2007-06-14 23:11:44 · answer #2 · answered by Raymond 7 · 1⤊ 1⤋
Everything in the Universe doesn't turn in circles. Is this a trick question?
2007-06-14 23:16:13 · answer #3 · answered by Neil S 4 · 0⤊ 0⤋
Nature always takes the easy route: rivers flow downstream, bubbles are round, and things go around in circles. Although, it's not circles. They are eliptical, oval, in nature. Why? Because it's the easiest way to move. How else would a planet turn? Squares?
2007-06-14 23:05:49 · answer #4 · answered by Anonymous · 0⤊ 0⤋
It's actually quite simple. The objects in our universe formed from clouds of gas and dust. Each object that formed collected from this cloud. Thecloud collected about some center. Since on the average, every bit of mass didn't fall straight into the center, but entered usually at a grazing angle, the net was that the collection of mass had some rotational energy about the center of mass. Think of ice skaters randomly coming from different directions to hold hands at a center. That grazing angle energy converted to angular momentum which left things spinning.
2007-06-14 23:18:10 · answer #5 · answered by Gene 7 · 0⤊ 1⤋
You don't need to know anything about general relativity or warped space time to answer this question! Just Kepler's laws!
Objects don't orbit each other but orbit their center of mass. The resulting path is an ellipse.
2007-06-15 01:14:46 · answer #6 · answered by kennyk 4 · 0⤊ 0⤋
Nothing moves in circles; 2-body planetary motions are always ellipses. The reason is the energy remains constant, but it oscillates between potential energy and kinetic energy.
2007-06-14 23:20:08 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Virtually nothing turns in circles. All orbits are ellipses.
2007-06-14 23:26:25 · answer #8 · answered by Owl Eye 5 · 1⤊ 0⤋
The fastest way to get to a point in a curve is to travel a curved path. The effect of the geometry of space is what we call gravity.
2007-06-14 23:13:16 · answer #9 · answered by saosin 3 · 0⤊ 1⤋
Because circles and ovals are easier to manuever than triangles or squares.
2007-06-14 23:57:25 · answer #10 · answered by Anonymous · 0⤊ 0⤋