•The atmosphere also absorbs a large portion of the electromagnetic spectrum, preventing the radiation of many celestial objects from reaching us. Many observations are therefore simply impossible from the ground and we need to move out of the atmosphere to be able to lead them. (Figure 3)
•Another problem encountered by ground-based observatories is limited observing time due to Earths rotation. Space telescopes, free of the Earth's surface, can often spend much longer periods of time observing a target. (Kepler, for instance, will observe the same field of view for over three years!) (Figure 4)