By Tidal Effects
An orbit can also decay by tidal effects when the orbiting body is large enough to raise a significant tidal bulge on the body it is orbiting and is either in a retrograde orbit or is below the synchronous orbit. The resulting tidal interaction saps momentum from the orbiting body and transfers it to the primary's rotation, lowering the orbit's altitude until frictional effects come into play.
Examples of satellites undergoing tidal orbital decay are Mars' moon Phobos, Neptune's moon Triton, and the extrasolar planet TrES-3.
Read more about this topic: Orbital Decay
Famous quotes containing the words tidal and/or effects:
“And now it is once more the tidal wave
That when it was swept by, leaves summits stained.
Oh, blood will out. It cannot be contained.”
—Robert Frost (1874–1963)
“Upon the whole, necessity is something, that exists in the mind, not in objects; nor is it possible for us ever to form the most distant idea of it, consider’d as a quality in bodies. Either we have no idea of necessity, or necessity is nothing but that determination of thought to pass from cause to effects and effects to causes, according to their experienc’d union.”
—David Hume (1711–1776)