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true or fales gravity in space

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  • true or fales gravity in space

    ok its simple true or false is there gravity in space , im thinking no way, iam also woundering if say i was traveling to the moon and i was half way there and all the sudden stop my craft would i drift or fall back to planet earth,,


    oh and the best one does the sun heat hte earth or does gravity due to us being caught and draged around in the suns gravity pull/belt,,

    i have a guy i really need to show the truth to ,,

    now for me i say there is no gravity , and i say if i stoped my craft id just float away, i do think that the gravity from the sun is what helps heat up the planet . given the distance form the eart to the sun if the sun on its own just heated us up we would have been tourched millions of years ago , so i belive the gravity we are caught in and as thigs move we have friction and so on i think that along with the light from the sun heats us up here, i could be off to left feild but it kinda makes sence ,,

    given there is no air in space and its cold as hell how could hte sun just on its own give us heat with out the addition of the fact we go around the sun at 62,000 mPH and so there is friction there and we are in its orbit i guess you call it i dotn know this sun thing has got my mind bent on this part..

  • #2
    Given the mood of the board the past few days this is thread is going to look like bait to some here.
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    Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

    It is true, there is nothing free about freedom, don't be so quick to give it away.

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    • #3
      Yes, there is gravity. Every body (mass) has some gravitational effect - that is one of the reasons NASA will slingshot a deep space probe around the sun.

      My wife used to teach a college level astronomy class. One of the things the students had to do was calculate gravity between and among bodies.

      Solar heat is a radiation, kind of like that from an incandescent light bulb, but it is in several different wavelengths’. As long as the waves can travel, they will transfer energy. That is why as you go father from the sun the surface temperature on the planets gets cooler, more of the waves are block.

      So much for my limited understanding of Astronomy…

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      • #4
        Yes there is gravity in space it is extremely weak as it falls off with the square of distance.

        And yes the electromagnetic radiation from the sun directly heats the earth, the waves pass through the vacuum of space and only give up their energy when they hit matter, ie the atmosphere or the ground.

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        • #5
          Exactly half way between the earth and the moon, you would begin orbitting back to earth.

          The gravity at any point is a ratio of the mass of the orbitting bodies and the distance between them. So the earth, which is mucho heavy, and the moon, which is light. At some theoretical point, the gravity between you and each object will be equal, thus the differential will be zero.

          See Newton's law of universal gravitation.

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          • #6
            The question doesn't make sense. It is possible to ask questions that don't have any meaning such as "What colour is black?"

            Gravity is a property of matter. All matter has this property in proportion to it's mass. Space isn't an object, it is a place, a location. Gravity is a fundamental force of matter and extends for infinite distance in all directions from every single bit of matter. It diminishes with distance according to a simple formula, the inverse power of two. Go twice as far from the center of an object and the effect of it's gravity is diminished to one half. Go twice that distance again and the force felt is then one fourth.

            Space is simply the absence of matter and it has no effect upon gravity. Space has no effect on anything since it isn't a thing and it has no properties. Ascribing it properties is like calling black a colour.

            There is gravity everywhere and the amount of that gravity is the sum total of all the matter in the Universe according to it's distance and direction from any particular place.

            There is more to this story but I shall wait to see what ensues.
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            • #7
              Originally posted by airsmith282
              ..........
              given there is no air in space and its cold as hell how could hte sun just on its own give us heat with out the addition of the fact we go around the sun at 62,000 mPH and so there is friction there and we are in its orbit .......
              Friction with What???? Nothing in space equals no friction.
              And there is lots of gravity in space. The sun has enough gravity to keep all those ginormous planets from flying off into space. Not to mention all those comets that keep visiting us from waaay out there. They don't keep coming back because they like us. If you stopped in space, even out past Pluto (planet or not) with not relative motion to the sun you would be drawn straight to the sun.

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              • #8
                "Gravity is a myth. The Earth sucks"

                Don't you just love psudoscience?!
                Paul Compton
                www.morini-mania.co.uk
                http://www.youtube.com/user/EVguru

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                • #9
                  Originally posted by Evan
                  The question doesn't make sense. It is possible to ask questions that don't have any meaning such as "What colour is black?"

                  Gravity is a property of matter. All matter has this property in proportion to it's mass. Space isn't an object, it is a place, a location. Gravity is a fundamental force of matter and extends for infinite distance in all directions from every single bit of matter. It diminishes with distance according to a simple formula, the inverse power of two. Go twice as far from the center of an object and the effect of it's gravity is diminished to one half. Go twice that distance again and the force felt is then one fourth.

                  Space is simply the absence of matter and it has no effect upon gravity. Space has no effect on anything since it isn't a thing and it has no properties. Ascribing it properties is like calling black a colour.

                  There is gravity everywhere and the amount of that gravity is the sum total of all the matter in the Universe according to it's distance and direction from any particular place.

                  There is more to this story but I shall wait to see what ensues.
                  Ah, but according to some of the latest theories, gravity is simply a curvature in space-time. Hence, it is a property of space (space-time) and objects (and radiation like light) just follow straight lines in this distorted frame.

                  Sorry Evan, you were trying to hold back, but I just couldn't resist.

                  As for friction, that is a resistance to motion or acceleration. While there is little matter in space to resist anything, there is some matter there. So, actually there is a small amount of resistance to motion or acceleration. Observe the fact that the satellites we put in orbit will eventually fall back to earth due, at least in part, to frictional forces.

                  As for what would happen if you "stopped" "half way between" the earth and moon, that would really depend on what you mean by by both of the terms I have included in quotes.

                  First, since the earth is a lot larger than the moon, at the half way point the earth would attract you a lot more than the moon. But it would be possible to find a point where the two forces would be the same. It would be a lot closer to the moon than the earth. But even this would not insure that you would just float there. This would be a point of unstable equiblibrium, like a pencil balanced on it's point. Many other things, including the gravational force from every other object in the universe, would influence you and in short order you would be moving somewhere.

                  Second is the really troubling word "stopped". Motion is a relative term and you didn't say what you are going to use as your frame of reference to determine that you are "stopped". The earth? The moon? Both together? The sun? The local group of stars? The Milky Way galaxy? Each of these choices would produce a different result as each of them moves with respect to all the others and hence if you stopped relative to one of them, you would still be moving in relation to the others. So, the very idea of "stopping" in space is not easy to define and there are really multiple ways to do so.

                  Someone above said it, the question is really not a good one because it is hard to assign real meaning to it.

                  From a practical point of view, it would be impossible to find a point between the earth and moon where you could "stop" and stay stopped. Satellites orbit the earth or moon or other body. They are in constant motion in a path around this other body. This is quite stable but it is not "stopped". But even this is not perfect stability. Comets are actually objects that had their "stable" orbits disturbed, causing them to "fall" towards the sun.
                  Paul A.

                  Make it fit.
                  You can't win and there is a penalty for trying!

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                  • #10
                    I suppose you could say that gravity is what makes 'space" INTO "space".

                    Without gravity, (and other attraction forces), matter might be spread out more-or-less evenly everywhere.

                    "space" exists (the vacuum where almost nothing is) because gravity caused the material that would otherwise have been there to gather into stars and planets and black holes etc.
                    1601

                    Keep eye on ball.
                    Hashim Khan

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                    • #11
                      The orbiting space station, for example, actually does receive substantial gravity from the earth because its orbit is so close. The reason things on the station are weightless, is because, due to its orbiting speed, the centrifugal and centripetal forces are balanced. One could say that the station is "falling around" the earth.

                      There is gravity in space.
                      There is no friction in the vacuum of space.

                      --Doozer
                      DZER

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                      • #12
                        The ISS officially is in space since the "legal limit" is 100 km above the surface of the Earth. In reality the ISS orbits in the upper fringes of the Earth's atmosphere. Because of this it experiences a significant amount of friction as it plows through the thin upper reaches of the ionosphere.

                        This is this years orbital profile of the ISS. The station is periodically reboosted by supply freighters and the SSTS which accounts for the upward spikes. If it was not reboosted it would reenter within a year or two depending on the solar weather.



                        Even in intergalactic space there are molecules of hydrogen and helium with a density of a few hundred atoms per cubic centimetre. There is no place in the universe that is truly "empty" on the macroscale.
                        Free software for calculating bolt circles and similar: Click Here

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                        • #13
                          After being sucked into looking at this thread I now know why I put
                          the OP on an "ignore" list. :-)
                          ...lew...

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                          • #14
                            Originally posted by Berniep
                            Not to mention all those comets that keep visiting us from waaay out there. They don't keep coming back because they like us.


                            Aw, man, you just harshed my self esteem.


                            Rex

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                            • #15
                              The reason the ISS has so much air friction is it's size. Just for fun I put together this composite to show just how big it is.

                              Free software for calculating bolt circles and similar: Click Here

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