Observations made with the rejuvenated Hubble Space Telescope are providing important information on supernovas, galaxies in the early universe, comet Shoemaker-Levy's collision with Jupiter, and the search for evidence of black holes in active galaxies, according to speakers at a Tuesday afternoon session. The faint, fuzzy lumps which previously were our only access to galaxies at such ancient eras have, for the first time, become distinct, sharply delineated individuals. H.C. Ford of Johns Hopkins University reported on the recent observation of small disks of gas and dust in the centers of four bright radio galaxies, one of which seems to carry the gravitational signature of a black hole with a mass equivalent to two billion stars like our sun. And STSI's Mario Livio reported on recent Hubble images that reveal that many planetary nebulae produced by stellar explosions are remarkable similar in morphology, contrary to expectations. Grun and colleagues C. Manka and B. Ripin focused a laser onto the surface of a foil placed in an ambient gas to heat the foil to a few hundred eVs, creating a powerful miniature explosion.
Cosmic rays constitute a constant stream of particles raining down on Earth.
At energies around 1018 eV, they seem to be heavy nuclei. While shock acceleration in our galaxy has been thought to be responsible for the bulk of cosmic rays up to about 1014 eV, at the highest energies above 1019 eV, the particles again appear to be protons and may be extragalactic in origin. He added that propagation of the highest energy cosmic rays from extragalactic acceleration sites through the cosmic background radiation also results in predictable changes in composition, spectral shape, and anisotropy, as well as the production of accompanying diffuse gamma-ray and neutrino background that must not exceed those observed. Previous efforts relied on a static magnetic trap to avoid limiting wall recombinations of atoms. However, as temperatures were lowered and atoms approached BEC conditions, they reverted to a ground spin barrier state and were ejected from the trap.