Will the Impactor knock Tempel 1 out of its orbit, change its orbit or cause any debris to hit the earth?
No, the Impactor will not knock Tempel 1 out of it’s orbit. However, the impact will cause a slight change in the comet’s orbit, but that change is so small that it won’t be noticed. A good analogy is to imagine a small pebble hitting an 18-wheeler truck. Over time, the changes we introduce might become noticeable except for the fact that this comet also has close approaches to the planet Jupiter which exerts gravitational forces that change Tempel 1’s orbit more than the impact. Dr. Don Yeomans has written a detailed history about Tempel 1’s orbit. Finally, any material knocked off of Tempel 1 will continue along the comet’s orbit. Tempel 1 has an orbit that is larger than Earth’s so the two orbits do not cross. So debris from Tempel 1 will not hit Earth.
