how many satellites are currently in orbit around the earth, and what happens when they break/nolonger useful?
151403
Orbits are stable. If you have a little rocket in orbit and you suddenly jetteson the boosters, the boosters will stay in orbit even though you're not using them. The only reason objects eventually fall back to earth and burn up in the atmosphere is the atmosphere itself. The (very very tiny amount of) air friction the orbiting object is exposed to slows the oblect down. This lowers the altitude slightly, exposing the object to even more resistance. This is a runaway affect, causing the object to eventually fall out of the sky.\nOh, for your first question: Not counting junk, the earth posseses 1 natural sattelite (the Moon) and thousands of artifical sattelites (for TV, GPS, phone, etc.). Counting junk, the number extends into the billions. That's right, I said billions - that's not a typo of millions.
652664
The length of the earth's orbit (orbital circumference) is 924,375,700 kilometres according to wikipedia.
600116
Lets see now, Earth rotates aproximately once every 24 hours, thats one over 60 x 60 X 24, thats one over 86400 rotations per second. All the time we are doing that, consider this, we are also going around the sun at aproximately 66500 miles per hour.
122132
United States Strategic Command tracks objects orbiting earth. An AN/FPS-85 phased array radar, located at Eglin Air Force Base, is the primary sensor used to track these objects. The radar is capable of tracking objects the size of a soccer ball at 20,000 miles. The quote following is from USSTRATCOM's website (see first link). The second link provides additional information on the Eglin RADAR. \n\nFWIW, the Eglin RADAR is now receiving a major hardware and software upgrade under the SENSOR contract. ITT is the prime contractor and Northrop Grumman is the major sub.\n\n"USSTRATCOM tracks about 8,500 man-made space objects, baseball-size and larger, orbiting Earth. The space objects consist of active/inactive satellites, spent rocket bodies, or fragmentation. About 7 percent are operational satellites, 15 percent are rocket bodies, and about 78 percent are fragmentation and inactive satellites."
80397
About 2,270 orbit the Earth.
140242
There are no live satellite images of your house available on the internet.  This is because imagery satellites fly in low earth orbit.  They circle the earth in two hours or less.  The images available on websites are collected over time.  Satellites in geosynchronous orbits circle the earth once in twenty four hours.  Because the earth also rotates about its axis in twentyfour hours, these appear to stay over the same spot on the equator.  But, these satellites are too high to provide detailed imagery.
83795
There are literally thousands of satellites in orbit capable of both receiving and transmitting radio signals. Some of their names are Telstar, Comsat (Communication satellites), Cosmos 1602, GOES 7, Landsat 5, NOAA 12, Radarsat, and Seasat 1 (weather satellites).
613963
How many moons does Saturn have? There you go- good question.
250001
The longest period artificial satellite I can think of is Ulysses, which orbits the Sun every 6.2 years.  If you're discussing one that orbits the Earth, I'm not sure.  There's SOHO which, at the L1 point, goes around the Sun with the Earth in one year.
322134
must be thousands, as strictly all satellites that have been launched and are still up there go round the sun by virtue of the fact that the earth and all other planets go round the sun
208174
Types of satellites? Well there are many ways of classifying satellites:\n\nStabilisation\nSatellites have to be stabilised so that they can always point in the direction they want to be pointed in and so that they can thrust in the right direction etc. You can have 3 axis stabilised or rotational stabilisation (where one bit spins, like the solar panels, and one bit is de-spun, like the dishes)\n\nFunction:\nMilitary, earth observation, solar observation, deep space exploration, communication (Satellite TV & cell phones) are some examples of different satellite functions\n\nOrbit:\nYou can have satellites in many different orbits. Near Earth Orbit, where it orbits at a low altitude (e.g. 200miles, time to complete 1 orbit = 90 minutes), Geostationary orbit (orbit period = 24 hours), Highly Eliptical orbit (for communications in high latitudes). Lagrange orbit (satellite stays in the same place relative to the sun&earth)\n\nYou can find out more on any of these with a simple google search on their names
496612
Some of it floats in space; much of it orbits Earth. You can find it on the surfaces of Venus and Mars and twenty tons of it is actually parked on the Moon! Some call it space trash, others refer to it as space junk or space debris. All three terms identify the same items -- man-made objects remaining in space though they no longer serve any useful purpose. Mankind¹s journey into space began in 1957 when the Soviet Union launched Sputnik, the first artificial satellite. Since that time more than 4,000 satellites have been launched into orbit. With so much traffic travelling into space, is it any wonder that a little trash has been left behind?
409966
A geostationary orbit is when a satellite circles earth in the EQUATORIAL plane in an orbit in the same direction of Earth's rotation and with a time period (time taken to complete one revolution) equal to that of the earth. In simple terms, the satellite stays over the same spot all the time.\n\nA geosynchronous orbit may have a different period, and may be over different spots at different times.
1022574
They move satellites in orbit all the time.  It depends how much fuel they have and what type of propulsion they have.  Satellites can not be stationary.  They CAN however take an orbit (very high) that allows them to orbit the earth once every 24 hours so they can remain above a certain point where they seem motionless to us on the ground.
774166
The same thing that keeps an artificial satellite in orbit around Earth -- Earth's gravity tries to pull the moon towards it, but at the same time the moon is trying to fly off in a straight line. The two vectors cancel, so the moon ends up going around Earth.
222144
Two objects will orbit one another indefinately unless disturbed.  The man made satellites that return to earth orbit to closely and are so small, atmospheric drag and solar wind eventually cause their orbits to decay.\n\nThe moon is large enough are far enough out, these factors don't come into play.  The primary force now is tidal friction, which causes the orbit to slow, and therefore expand, by a fractional amount each year.  \n\nDon't worry about losing the moon, though.  The sun will expand into a red giant, swallowing both earth and moon long before this happens.
46875
Approximately 93,000,000 miles.  The distance varies because our orbit is not perfectly circular.