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pikapika!
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I know its in orbit but things like the Hubble telescope need fuel don't they?
pikapika! said:I know its in orbit but things like the Hubble telescope need fuel don't they?
Kinda irrelevant, but I'm curious: Does Hubble have fuel or does the Shuttle just give it a boost when it stops by for servicing? I know it doesn't use fuel for pointing...BobG said:The International Space Station and the Hubble telescope orbit at an altitude a little under 200 miles high, so the atmosphere does slow them down, causing them to lose altitude.
Oops. My bad. The Hubble orbits around 350 miles high. The atmosphere does have a very small effect on the orbit, but it degrades slowly enough that the shuttle raises it back again whenever other maintenance is performed on the Hubble. It would take around 10 years for the Hubble to re-enter the atmosphere if were left unattended.BobG said:Low orbiting satellites need fuel to stay in orbit because the atmosphere doesn't suddenly stop. Instead, it gets thinner and thinner until, eventually, there's so little left you can just disregard it. Around 300 miles high, the atmosphere is so thin that it would only affect satellites with an extremely high area to mass ratio. By around 600 some miles, you could disregard the atmosphere for virtually every orbiting object.
The International Space Station and the Hubble telescope orbit at an altitude a little under 200 miles high, so the atmosphere does slow them down, causing them to lose altitude.
pikapika! said:Ok, i have another question.
Do we see the same side of the moon and why? I seem to always see the face. although this could be an illusion.
That's still a shorter timeframe than I would have expected. Thanks for the info.BobG said:Oops. My bad. The Hubble orbits around 350 miles high. The atmosphere does have a very small effect on the orbit, but it degrades slowly enough that the shuttle raises it back again whenever other maintenance is performed on the Hubble. It would take around 10 years for the Hubble to re-enter the atmosphere if were left unattended.
pikapika! said:Ok, i have another question.
Do we see the same side of the moon and why? I seem to always see the face. although this could be an illusion.
I believe that this is an incorrect interpretation of the physical data. What is the evidence that the moon actually moves around relative to the em barycentre? It seems more likely to me that it is our position on the Earth relative to the em barycentre that changes.Glenn said:From Earth, we don't always have the EXACT same view of the moon. It wobbles a little; its called libration. Here is a link explaining it...
http://www.stargazing.net/david/moon/moonlibration.html
The moon does not fall to the earth because it is constantly in motion due to its velocity, which creates a centripetal force that counteracts the force of gravity. This keeps the moon in a stable orbit around the earth.
The moon's orbit is maintained by a balance between its inertia and the gravitational force of the earth. This creates a stable circular orbit, meaning the moon continues to revolve around the earth without falling towards it.
The moon is constantly being pulled in by the earth's gravity, but it also has a tangential velocity that creates a centrifugal force, which balances out the gravitational force and keeps the moon in its orbit.
While the moon's orbit is relatively stable, there is a slight decrease in its distance from the earth each year due to tidal forces. However, the rate of this decrease is so small that it would take billions of years for the moon to fall into the earth.
If the moon were to suddenly fall to the earth, it would have cataclysmic effects on the planet. The impact would cause massive earthquakes, tsunamis, and volcanic eruptions. It would also alter the earth's orbit and tilt, drastically changing the climate and potentially causing the extinction of many species.