Why can't the Hubble Telescope observe from earth as opposed to space as most other telescopes do?
The reason for the Hubble Space telescope being in space is that from the Earth the telescopes have to look through the atmosphere. The atmosphere absorbs several kinds of light outside of the visible spectrum, which is why many space telescope missions must be done from space rather than on the ground. For Hubble, this is because of their desire to have capabilities of observing in the UV. Hubble also observes in visible light which can be done from the ground; however, turbulence in the upper atmosphere leads to images being somewhat distorted (you could compare it to look at stuff through ripply water). In space there is no atmosphere so you can get much more detail in the images without distorting effects. However it is difficult and very expensive to run telescopes in space, and ground telescopes can also be larger so they have some advantages too. There have been many recent advancements in correcting for atmospheric distortion effects in ground based observatories known as adaptive optics.
This page was last updated July 18, 2015.