2007-01-31 05:19:00 · 6 answers · asked by Saddgal 2 in Science & Mathematics ➔ Earth Sciences & Geology
The most obvious is that stars 'twinkle' and planets do not.
Stars produce their own light and the planets reflect the light off of themselves. The stars light is distorted through the Earth's atmosphere causing this twinkle affect.
Planets move about the sky in different patterns than the rest of the celestial bodies. Since they orbit around our Sun, they are the 'roamers' of the sky by which the name planet is derived from.
2007-01-31 08:54:11 · answer #1 · answered by GARY G 2 · 0⤊ 0⤋
Early astronomers were able to tell the difference between planets and stars because planets in our Solar System appear to move in complicated paths across the sky, but stars don't.
That is, if you observe the sky night after night, the stars will all appear in fixed positions with respect to each other. They will rise and set a few minutes earlier each night (an effect that is due to the Earth's motion around the Sun), but otherwise nothing will change. This is why the background stars are sometimes referred to as the "celestial sphere" -- from our point of view, it looks like the stars are "painted" onto a gigantic sphere that surrounds Earth and therefore are unable to move with respect to each other.
Planets, on the other hand, are observed to move in very complicated paths with respect to the background stars, sometimes even appearing to go "against the grain" and reverse their directions. Therefore, they are easily distinguishable from stars if you look at the sky night after night. Although ancient astronomers did not have a correct explanation for this phenomenon, we now know that the complicated motion is just a projection effect -- it is due to the fact that Earth and the other planets are physically moving in orbits around the Sun, so the planets' relative positions as seen from Earth (with respect to the fixed background stars) change as time goes on.
2007-01-31 05:28:03 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Because of their great distances, stars are seen as only 'points' of light. Any turbulence in the air will cause distortion of this very narrow beam. The result is that they "twinkle" or seem to flicker on and off.
Planets, on the other hand, are close enough to be small disk sources of the light that they reflect from the sun. The resulting beam is wider than that for true stars. As a result the turbulence in the air is not able to disrupt the beam as easily and planets do not flicker or "twinkle" to any great extent.
2007-01-31 07:38:30 · answer #3 · answered by sternsheets 2 · 0⤊ 0⤋
Get out a celestial map (I like StarCalc...you can download it to your computer at the link below for free).
Alternatively, keep track of the position from day to day. If it moves with respect to other stars, it's a planet.
2007-01-31 05:35:02 · answer #4 · answered by gebobs 6 · 0⤊ 0⤋
well i see so many people wrote so muh scientific things. it's not really hard. it's just that the stars are always twinkling and planets are not.
2007-01-31 08:38:37 · answer #5 · answered by umyxyz_rockstar 2 · 0⤊ 0⤋
stars twinkle planets don't
2007-01-31 05:27:00 · answer #6 · answered by cd 2 · 0⤊ 0⤋