What facts make it certain?
2007-06-03 19:36:51 · 7 answers · asked by Petrarch Socinian F 2 in Science & Mathematics ➔ Astronomy & Space
It's a proven fact. There are at least three clear indications that the Earth is moving:
1) The aberration of starlight, first observed around 1725. The apparent positions of stars shifts back and forth by about 20 arc-seconds depending on whether Earth is moving toward or away from the star. The shift is due to the finite speed of light; it's an effect similar to the way raindrops appear to be slanting down at you when you drive through rain.
2) Stellar parallax. Nearby stars can be seen to shift back and forth very slightly relative to more distant stars as the Earth moves around in its orbit and changes our point of view.
3) Doppler shift. We can measure the speed of Earth relative to stars by measuring the shift in the wavelengths of their spectral lines. Most of the shift is due to the motion of the star itself, but we can measure a cyclical change in the shift over the course of a year due to the Earth's motion in its orbit.
2007-06-03 20:36:12 · answer #1 · answered by injanier 7 · 1⤊ 0⤋
It is a fact. Measurements taken from different observatories in earth (and nowadays in space) show how the planets and many other celestial bodies move in relation to one another and around the sun. The sun is the body with the biggest gravitational field in the solar system, and its gravity holds all the other objects "captive". However, the sun (and hence the solar system) also rotates around the center of our galaxy.
All these facts have been proven, so it is not a theory, but a fact.
2007-06-03 19:50:37 · answer #2 · answered by ayante01 3 · 3⤊ 0⤋
It's an absolute fact that has been verified by who knows how many thousands (or millions) of observations of both the Earths position and the orbits of the other planets.
Doug
2007-06-03 19:48:57 · answer #3 · answered by doug_donaghue 7 · 1⤊ 0⤋
Well the fact that one of us circles the other is an unavoidable fact but since we've explored the solar system to an extent its a fact that we circle the sun. We can also look at what the other planets are doing for proof.
2007-06-03 19:43:58 · answer #4 · answered by Matt 1 · 1⤊ 0⤋
thats a absolute fact
2007-06-03 19:43:59 · answer #5 · answered by abhilasha b 2 · 1⤊ 0⤋
its an absolute fact
2007-06-03 19:46:33 · answer #6 · answered by Anonymous · 1⤊ 0⤋
it is an absolute fact.
although the correct term is orbiting.
since the detailed info is long,
check this website for a detailed explanation
http://en.wikipedia.org/wiki/Orbit
and
http://en.wikipedia.org/wiki/Centripetal_force
2007-06-03 20:23:41 · answer #7 · answered by Anonymous · 1⤊ 0⤋