2007-08-13 03:29:46 · 3 answers · asked by educator 1 in Science & Mathematics ➔ Astronomy & Space
That is a pretty broad question. The broad answer is Kepler's 3rd law, P^2=A^3. The time it takes to complete one orbit is P and the average distance form the Sun is A. P is in years and A is in Astronomical Units (AU). One AU is the average distance from the Earth to the Sun. So for Earth is it 1^2=1^3. For Jupiter is is about 11^2=5^3. Then to find where the planet will be at some time in the future, it is some fraction of an orbit. So in 3 years Jupiter will be 3/11 of the way around it's orbit from where it is now and Earth will be where it is now, but after having gone around the Sun 3 times.
But for exact predictions it is WAY more complicated. Kepler's first 2 laws say that planets orbit is ellipses and that they move at different speeds so that an equal area is swept out in equal time. And they orbit in different planes. And gravity of other planets causes interactions that require Newton's laws to account for. It gets really messy of you want exact predictions. Nobody even tries to do it by hand; it is all in computer programs now.
2007-08-13 03:42:23 · answer #1 · answered by campbelp2002 7 · 0⤊ 0⤋
Jean Meeus has written several books which contain everything you need to know to make any astronomical calculations, if you really want to do the calculations yourself. Most of us use computer programs like Starry Night, which already contain Meeus' calculations.
2007-08-13 04:08:38 · answer #2 · answered by GeoffG 7 · 0⤊ 0⤋
If you want to find out where they will be in the night sky, use stellarium. It's great!
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2007-08-13 03:54:41 · answer #3 · answered by beonny1 3 · 0⤊ 0⤋