Skating across the image is a trail of light left by an artificial satellite that passed through the telescope's field of view during one exposure. Scientists cite the streak as an example of how light pollution affects astronomical observing, even under dark skies in the best possible locations. La Silla sits high atop a mountain bordering the remote southern extremity of Chile's Atacama desert. Such artifacts can be removed by computers, experts say, but always at the loss of some scientific information. A cluster of galaxies and dark matter appears to be sucking other galaxies, including our own, inward.
New research confirms the four most distant white dwarf stars ever found.
They are thought to have formed shortly after the Big Bang. Nests of up to five galaxies each seem engaged in multiple collisions that lead to fiery pileups. More sources found for radiation that permeates the Universe. Two will eventually become one, researchers say. Clusters of stars reveal that our galaxy builds much of its bulk by borrowing from other, relatively smaller galaxies.