 Named after Edwin Hubble, the astronomer who discovered the expansion of the universe. Launched in 1990 and contains a 2.4 m (95 in) mirror with which it can observe visible, near- ultraviolet, and near-infrared light.

 The HST has a variety of detectors:

 The HST’s main mirror is 2.4 meters in diameter and designed for visible, infrared, and ultraviolet radiation.  Notice the best ground-based image of galaxy M100 on the left in comparison to an image from the HST on the right.

 Mainly observes visual wavelengths, so its greatest advantage of being above Earth’s atmosphere is the lack of seeing distortion.  Has been visited a number of times by the space shuttle for maintenance and repairs.  Astronomers hope it will last until it is replaced by the James Webb Space Telescope expected to launch no sooner than  Will contain a segmented mirror forming a 6.5 m (256 in) diameter.

 Telescopes that observe in the far-infrared must be protected from heat and must get above Earth’s absorbing atmosphere.  The most sophisticated of the infrared telescopes put in orbit was the Spitzer Space Telescope, launched in 2003.

 High-energy astrophysics refers to the use of X-ray and gamma ray observations.  Difficult, but can reveal incredible phenomena.  Largest X-ray telescope to date, the Chandra X-ray Observatory, was launched in  Studies star formation and black holes.

 All of the radiation we have studied so far has been electromagnetic, but there is another form of energy raining down from space, and scientists aren’t sure where it comes from.  Cosmic rays are subatomic particles traveling through space at tremendous velocities.  Almost none reach the ground, they smash gas atoms in the upper atmosphere and rain down upon us all the time.