|Hubbles Top Science Findings|
ince its launch in 1990, the Hubble Space Telescope has provided remarkable new views of the universe, which have revolutionized astronomers thinking about many astronomical mysteries.
Hubble's powerful capabilities have allowed astronomers to peer into the outer limits of the universe and uncover a variety of never-before-seen galaxies. The observations clearly show that different types of galaxies evolved at different rates. The giant elliptical galaxies formed shortly after the Big Bang and changed little; spiral galaxies like our Milky Way took longer to form and have undergone dramatic changes; and dim dwarf galaxies quickly appeared and then mysteriously vanished.
Hubble has uncovered convincing evidence for the existence of super-massive black holes in space. By using Hubble to measure the whirlpool-like motion of stars and gas in the cores of galaxies, astronomers have calculated how much matter is packed into a galaxy's hub. In the three galaxies probed so far by Hubble, the mass of hundreds of millions or billions of suns is compressed into a region of space no bigger than our solar system. The Hubble results fit the definition of a black hole: an extremely compact and massive object. A black hole is the simplest explanation for the observed phenomena.
Hubble is helping astronomers precisely calculate the age of the universe by providing accurate distances to galaxies, an important prerequisite for calculating age. Hubble measures the distances to neighboring galaxies by finding accurate "milepost markers," a special class of pulsating star called Cepheid variables. These, in turn, are being used to calibrate more remote milepost markers. Preliminary findings suggest that the universe may be only 9 billion years old, younger than previously thought; other researchers using Hubble argue that the age is more like 16 billion years. The research -- and scientific debate -- will continue for some time.
Hubble has confirmed the existence of an elusive, long-sought class of object called a brown dwarf, an object too large to be a planet but too small to be a star. Astronomers using a ground-based telescope made the initial discovery. Hubble provided a sharper, follow-up image that clearly separated the brown dwarf from the star it was orbiting.
While surveying the Orion nebula, a nearby star-forming region, Hubble returned images of pancake-shaped dust disks around dozens of embryonic stars. These disks may eventually condense and form planetary systems, and their abundance alone suggests that the conditions necessary to form planets are common elsewhere in the universe.
Looking to neighboring stellar "maternity wards" to see a replay of the events that created our sun and planets, Hubble has uncovered remarkable new details of star birth. Hubble revealed an eerie scene, illuminated by nearby hot stars, of huge stalagmite-like towers of cold, dark gas with finger-like protrusions containing embryonic stars just emerging from their incubation.
Probing the inner edge of the dust disk around the star Beta Pictoris, Hubble found a curious warp in the disk, like the twist in an airplane propeller. The most likely explanation for the twist is that the disk is feeling the gravitational tug of an unseen planet, perhaps the size of Jupiter, orbiting the star at a slightly different angle from the disk. Astronomers have long suspected that the star Beta Pictoris has a planetary system.
Hubble has provided definitive evidence for the existence of a vast belt of primordial icy debris around our solar system, a reservoir for comets flying through interplanetary space. Though astronomers using Earth-based telescopes had previously identified some of the largest objects in the belt, Hubble uncovered evidence for an underlying population of more than 100 million comets.
Hubble offered a ringside seat to a once-in-a-millennia event when 21 fragments of comet Shoemaker-Levy 9 collided with Jupiter. As each comet fragment crashed into the giant planet, Hubble caught mushroom-shaped plumes along the limb of the planet, detailed views not possible using any other telescope. The largest fragment impact created an Earth-sized "bull's-eye" pattern on Jupiter.
Hubble provided the first direct look at the surface of the distant planet Pluto. The pictures show that Pluto has a remarkably varied surface, mottled with bright and dark regions. This will probably be our best look at the tiny planet until space probes venture to this "frontier outpost" of our solar system.
Hubble detected what may be ancient helium gas that produced galaxies in the early universe. The space telescope found gas older than most stars. The discovery confirms the Big Bang theory's model: helium was produced with hydrogen in the first three minutes after the Big Bang. In addition, Hubble found that certain light elements created in the primeval universe, such as lithium, are in the exact quantity in space as expected if the Big Bang really happened.
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