i have a few questions about space. how do scientists find out the gravity of other planets without going there. also how do they know what a planets' gravity is wiht out being there
2007-04-25 06:44:37 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
sorry a friend messed with it before i put it on. what i meant to ask was how do they know what it is made of?
2007-04-25 08:04:52 · update #1
They dont actually find out, or know man. But theres alot of formulae and physics mathematics that help them determine how far the body is from other bodies, or the systems primary star. if its orbiting something, how fast it is moving, then all the math based on how fast our planet is moving and the distance to that object, which all factors in. After they eliminate all the factors based on the distance that could distort our readings, they are left with pretty raw numbers and can then ESTIMATE this or that. Nothing is set in stone, but remember this, which is never mentioned by anyone...
all their estimations are based on the periodic table that WE have, and the physics that WE know.
Out there, the physics might be different, may open up new understandings for us. Unexplainable things when we apply only what we know now. There might be elements on that planet that we dont have on our periodic table. That could effect the heat of the planet overall, how it absorbs the radiation hitting it, and things like that. Could be cooler than what our scientists predict, or hotter..
Most likely anything observed that far out, and estimated based on what we know, is WRONG!! somehow.
kind of like things never really turn out the way we think they will, or want them to... or something costs more than you think. The universe is too random.
2007-04-25 06:54:48 · answer #1 · answered by sbravosystems 3 · 0⤊ 0⤋
That's actually the same question.
Anyway, gravity is a function of mass. Scientists can discern a planet's mass by seeing how much it causes the star that it orbits to wobble. (planets make stars wobble - earth makes the sun shake a little bit as it spins around the sun). And stars' masses are known based on their color and chemical composition (which can be determined by looking at the light they emit, including Xrays, UV, and infrared).
So you know how much the star shakes, how big the star is, and from that you can discern the planet's mass. And since gravity is a function of mass, you can calculate the gravity.
2007-04-25 06:49:31 · answer #2 · answered by Brian L 7 · 2⤊ 1⤋
They can get an estimate on the size of the planet by measuring the dimming of the star as the planet obscures it. This information can be correlated to mass and the mass of the planet is easily converted into a gravitational pull.
2007-04-25 06:50:41 · answer #3 · answered by the.lilhb 2 · 2⤊ 0⤋
The more massive the planet, the more it tugs on the star it orbits, and that tug causes a small motion that can be measured by measuring the Doppler shift of the light it emits. Knowing the Doppler shift tells you the motion and the motion tells you the mass and the mass tells you the gravity.
2007-04-25 06:50:58 · answer #4 · answered by campbelp2002 7 · 0⤊ 1⤋
that is old information - they have been getting to correctly known those planets for some years, now that they know what to seek for. lots of the gasoline giants are in all possibility in closer to their suns by way of fact they are smaller suns - which might make the wobble led to by utilising the orbiting planet additionally extra straightforward to discover. no one photograph voltaic equipment is same to a distinctive, and we can be engaged on regulations to conceal all circumstances for a protracted time back.
2016-11-27 19:59:50 · answer #5 · answered by opp 4 · 0⤊ 0⤋
They can look at the orbital mechanics -- rotation around its star and infer the mass.
2007-04-25 06:48:33 · answer #6 · answered by Gene 7 · 1⤊ 0⤋