MadSci Network: Astronomy

Re: In outer spac where there is no gravity, will two magnets attract?

Area: Astronomy
Posted By: David Barlow, Private individual, Grad education in Physics/Astrophysics and Comp. Support
Date: Sun Feb 2 23:58:07 1997
Message ID: 854403997.As

Dear Nathan

Thank you for asking a very challenging question. The simple answer is that, yes, two magnets will attract in outer space. The point is though, how can they do this? You may have done this in school; if you put one magnet down and bring another close to it, the first magnet moves by itself. This is an example of what is called a Force. Gravity is another example of a Force. A force is something that forces a thing to move. Also, if you put paper over a magnet and sprinkle iron filings around, the iron makes a pattern like a dumbbell. The pattern represents the lines of magnetic force extending out around the magnet. These lines of force are also called a field, or a force field. This field actually extends out for a very long way, it just gets weak very quickly. The existence of these lines of force has nothing to do with whether Gravity is present or if there is vacuum. Forces are like that, they extend out in space and do not need a substance to exist.

In actual fact Gravity does exist in outer space. It is gravity that keeps the Earth fixed in orbit around the Sun and the Moon around the Earth even though space seperate us. The reason why a space shuttle (and the Earth) appears to float in space without Gravity is that its forward motion cancels out the rate it is falling to Earth. Imagine you are on a plane moving at several times the speed of sound. You drop a ball out of the window and expect it to fall, oddly it does not. As the ball tries to fall it moves forward by an equal amount so that it actually circles the Earth. This is called free fall and is why space is said to be `weightless', not gravityless. In the real depths of space between Galaxies Gravity still exists, its effect though is so weak that it takes many millions of years before somehting moves becuase of it.

This is probably a longer answer than was required but I felt a detailed description of what is happening was needed to answer your question. If you have any questions about this, please E-Mail me directly, or ask another question of the Mad Scientists

Dave Barlow -

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