Word: nebula
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
...Chinese astrologers recorded a brilliant "guest star" supernova that suddenly exploded one night in the constellation Taurus. Located near the tip of the left horn, the star remained visible even during bright daylight. This same supernova's remains can be seen today as the Crab nebula, a diffuse, glowing gas cloud 3,500 light years away, which continues to expand at 800 miles per second...
...vague shapes in the sky contracted until it became possible for radio observers to direct optical astronomers to smaller and more manageable areas. In 1949, astronomers using these directions spotted the first visible object outside the solar system that was associated with a discrete radio source: the Crab Nebula, the remnant of a star explosion (or supernova) in the earth's Milky Way galaxy. Shortly afterward, they identified the first visible source outside the Milky Way: a large galaxy 50 million lightyears* from earth. In the next decade, as radio and optical astronomy continued their fruitful alliance, about...
...first serious project with the new antenna was begun early this past summer. Dennis N. Downes '65 and Michael P. Hughes, Dr. Maxwell's research associate at the station, observed the passage of the solar corona in front of the Crab Nebula. In late June the Crab Nebula, the gaseous remnants of a star which exploded in 1054, was in the daytime sky near...
Most scientists believe that the solar system-sun, planets and all-condensed out of a vast nebula of gas and dust. Graduate Student Craig M. Merrihue of the University of California at Berkeley is even convinced that some of the first objects that condensed are still around and can be identified. They are "chondrules"-round, pea-sized or even smaller globules of stony material. When they happened to be embedded in meteorites, the tiny pebbles were preserved by the cold and vacuum of interplanetary space and lasted for billions of years...
Xenon 129 is a rare xenon isotope that is the descendant of iodine 129, a radioactive form of iodine that was created with the rest of the elements that formed the solar nebula and became extinct not many million years later. Since chondrules contain xenon 129, Merrihue argues that they must have acquired it from the decay of iodine 129. This means that they condensed as droplets during the infancy of the solar system, when everything else in the nebula was dust or gas-and they must be older than the earth...