Is the moons orbit decaying?
85721
googled to find this:\n\n"The Moon, at first, will recede further and further from the Earth, but the two bodies will continue to orbit about their common centre of gravity. Around 600,000,000 years from now, the Moon will be too far away for total eclipses to occur.\n\nHowever, this process won't continue indefinitely - as Mike Sawicki points out in his Myths About Tides and Gravity:\n\nOnce the Earth becomes tidally locked with the Moon, the solar tides will tend to slow the Earth’s rotation even more, so the day will be longer than the month and the Moon will rise in the West and set in the East. The water spheroid generated by the Sun will cause the high tide to appear earlier than the time of highest moon ... Then the tidal force of Earth on the Moon will pull the Moon into a lower orbit and eventually inside the Roche limit (18500 km), whereupon the Moon will disintegrate producing a ring round the Earth."\n\nWhatever happens, we won't be around to know!
1018425
Yes, the Moon is receding from the Earth slowly. The reasons why have to do with tides and conservation of energy and angular momentum, and are about a college-junior-level homework problem to work out. \n\nThere is direct observational evidence for this. The Apollo 11, 14, and 15 astronauts left retroreflectors on the Moon, and the Soviets put retroreflectors on two of their unmanned lunar landers, just for this purpose. You can shoot a laser pulse through a telescope at one of these retroreflectors and some of the beam will be reflected back to the telescope. (The beam spreads out during the trip, 384,000 kilometers each way, so not all that much actually makes it back; you have to do this for a number of minutes to be sure that you got a good amount of measurements.) We know the speed of light with great accuracy, so if you measure how long it takes between your laser shot and the time the pulse returns, you get a very precise measurement of the distance between your telescope and the retroreflector on the Moon. A single good measurement gives an accuracy of about an inch. Measurements have been collected now for over 25 years. \n\nThe Moon's orbit around the Earth isn't a circle, so over the course of one month it moves towards and away from the Earth by a few per cent. This means a small number of measurements don't suffice to tell what's going on. If you track the Moon over time, though, it is clear that the Moon's orbit is slowly growing larger and that the Moon is moving away from the Earth. The net result is that the Moon is receding from the Earth at about 4 centimeters a year. \n\n(Incidentally, this isn't the only evidence for recession of the Moon from the Earth. The ancients observed and recorded solar eclipses pretty well, and those observations don't match what one would expect based purely on unchanging Twentieth Century orbital parameters for the Moon.) \n\nWe aren't limited to doing this laser ranging trick to retroreflectors on the Moon. Several satellites have been equipped with these also and laser ranging of artificial satellites has been going on for a long time as well.
133273
Probably not. It seem unlikely a moon could escape its orbit around a planet and end up in another orbit that is so eccentric as Plutos is.\nOn the other hand some of the moons of neptune and uranus may very well have begun as Kuiper belt objects that ventured a little too close to them and got captured by their gravity.
269567
Try the site below for information and the second link for a catalog of current orbits.  It's pretty technical but it should be fun deciphering.
627332
First of all i would like to say that you are some kind of good thinker.. well for 4 years old, this kind of question may too complex for you. But i try to answer it for our knowledge.\n\nWell the moon is not just go down when the sun is up. The world is rotating itself, while the world is rotating around the sun. In the same time, the moon is rotating around the earth and the sun. When you are at any part of the earth expecially near to the equator, you will see some kind of nice organized pattern of when sun is out, the moon is gone, otherwise vise versa. \n\nWell, actually this is not the true. The moon is still there rotating around the earth in 24 hour time, but when the part of the earth where get alots of sun shine, the brighness of the moon will dissphere like you shine a touch in a good shinine day. The light from the touch will not seen as in the dark. But we cannot say that the ligh is gone. The light is still there but, due to the brigher light of the sun (higher cendela - unit for light), the reflaction light of moon is not seen.\n\nThere are some infomation that i can help you. It's good to think!!!
1062163
I know how it will look.  The same side of the moon always faces us because its rotation rate and revolution rate are both the same - 27 to 28 days depending on whether you are looking at it from sidereal or solar time (that's technical lingo you can skip over).  But those two rates are tidally locked and there's no reason that would change.  We'll never see the other side from earth. One thing that WILL change is that is has been, and will continue to, slowly move farther away from us every year.  In the distant future it will appear smaller in the sky and will take a longer time to go around us, 30+ days in the future.  This is because conservation of energy and conservation of angular momentum must both be conserved.  I can explain that, but trust me, you don't want me to.
1105582
The eccentricity of earth's orbit varies over a period of about 100,000 years. Currently, we are in a phase of decreasing eccentricty, so the answer is YES, but not by much.
798233
The moon orbits the earth.  It does not 'rise'.  Look in any good newspaper to see what time it is visible in your area.  This information can be found in the weather section.
60264
Our moon is locked in what is known as a geo-synchronous orbit. For millions of years the angular momentum has stablized the moon to provide very little loss of energy between earth and moon. This does not account for the influences that the moon has upon our oceans though. (Tides) Our solar system has "moved about" for many millions of years to allow for efficient energy transfers between baryonic masses.  This is not unlike a person who sit's in a chair and move's about to become more comfortable.  Peace
723622
The phases of the moon are the same around the world. What varies is the rise and set time. The US Naval Observatory is a great site for this.
857195
While you do assume a perfectly circular orbit and zero drag force, your phrasing of the question does *not* rule out tidal effects. \n\nThis depends on the planet's oblateness, known as its "J2 moment".  Most planets are not perfect spheres, but slightly squashed along the axis of planetary rotation.  If the planet is oblate and its rotation axis is tipped to the axis of the object's orbit, then there will be tidal forces as the object experiences a net torque between the near and far sides of the planet.  Combined with lag from material stresses, there can be a transfer of rotational momentum...remember, the moon used to be much closer to the Earth and Earth rotated much more quickly a few billion years ago.\n\nIn general, this effect causes orbits which are prograde (orbit direction same as planetary rotation direction) to slowly migrate outwards, and retrograde orbits (orbit direction opposite to planetary rotation) to migrate inwards.  This is one theory for the creation of Saturn's rings: that a retrograde moon drifted inwards until it was ripped apart from increasing tidal stresses.
661026
No, there are just moons.
274178
mercury has no moons \nbut there are definitely things that orbit mercury
231237
The asymmetric nature of this gravitational interaction is also responsible for the fact that the Moon rotates synchronously, i.e. it is locked in phase with its orbit so that the same side is always facing toward the Earth. Just as the Earth's rotation is now being slowed by the Moon's influence so in the distant past the Moon's rotation was slowed by the action of the Earth, but in that case the effect was much stronger. When the Moon's rotation rate was slowed to match its orbital period (such that the bulge always faced toward the Earth) there was no longer an off-center torque on the Moon and a stable situation was achieved. The same thing has happened to most of the other satellites in the solar system. Eventually, the Earth's rotation will be slowed to match the Moon's period, too, as is the case with Pluto and Charon. \n\n Actually, the Moon appears to wobble a bit (due to its slightly non-circular orbit) so that a few degrees of the far side can be seen from time to time, but the majority of the far side (left) was completely unknown until the Soviet spacecraft Luna 3 photographed it in 1959. (Note: there is no "dark side" of the Moon; all parts of the Moon get sunlight half the time (except for a few deep craters near the poles). Some uses of the term "dark side" in the past may have referred to the far side as "dark" in the sense of "unknown" (eg "darkest Africa") but even that meaning is no longer valid today!)
310923
It's orbit is closer to a circle than any other with an eccentricity of less that 1%. It also has a retrograde motion (it rotates from east to west instead of west to east). It always shows the same face to earth in the same way the moon does.
57630
No.\n\nThe orbits are inclined slightly and I do not believe there is a place where they would all be *exacly* in a line.\n\nBut they get close together in the sky. The visible planets are within a couple of degrees every twenty or thirty years. (Holding your fist out will block about 10 degrees.) Such an alignment in the sky can last for a few days.
483617
Neat Question!!!!\n\nHere's your answer:\n\nIf the Moon disappeared then the tides would reduce in strength by about two thirds. There would still be tides, because the Sun causes tides, too (see the Conjunctions Page). \n\nThe Moon keeps the angle between the rotation axis of the Earth and the plane of the orbit of the Earth within a fairly narrow range, so that the strength of the seasons cannot differ too much from its current value. If the Moon disappeared, then the inclination of the rotation axis of the Earth would vary much more over periods of thousands of years and could get much further away from the upright position, with corresponding greater differences between summer and winter, and hence with great influence on the climate, such as Mars has experienced (without any large moon). See http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1993Natur.361..615L, http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2002A%26A...384..689E and http://arxiv.org/abs/astro-ph/0112399 (for http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2001EM%26P...85...61B). \n\nI've heard of kinds of animals that synchronize some rhythms of their lives with the phases of the Moon, and the sudden disappearance of the Moon could cause trouble for them. I believe I've heard of some kinds of turtles that come to lay their eggs on the beach at a certain Full Moon, and that the nightlife of deer and similar animals takes the phase of the Moon into account. In any case, fishermen and hunters seem to take the phase of the Moon into account, but perhaps that is because they would like to be able to see something at night. I am not a biologist, fisherman, or hunter, so I do not know the details of this. \n\nIt is highly unlikely that the Moon will just disappear. Only the very close passage of a celestial object of the size of a planet could wrench the Moon from the grip of the Earth's gravity, and such an event could also change the orbit of the Earth itself markedly, so then the disappearance of the Moon might not be the most important thing. Calculations of the future of the orbits of the planets show that such an event will not happen during the coming thousands of millions of years (at least not with one of the other planets of our Solar System as the disturbing object). See http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2002MNRAS.336..483I and http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1996CeMDA..64..115L.