Taking the temperature of the far cosmos.Score another point for the Big Bang big bang Model of the origin of the universe, which holds that it emerged from a state of extremely high temperature and density in an explosive expansion 10 billion–15 billion years ago. . In a celebrated confirmation of cosmology's most popular theory, a spacecraft 4 years ago measured the temperature of the cosmic microwave background Noun 1. cosmic microwave background - (cosmology) the cooled remnant of the hot big bang that fills the entire universe and can be observed today with an average temperature of about 2. (SN: 1/20/90, p.36). Astronomers believe this faint glow represents radiation left over from the fireball that spawned the expanding cosmos. The universe has cooled considerably since its birth, and the temperature of the relic radiation in nearby regions of space, 2.73 kelvins, exactly matches the predicted cooling. But scientists have tried for years, with little success, to examine a related facet of the microwave background: Probing more distant reaches of the universe, which reveals the way the cosmos looked at earlier, presumably pre·sum·a·ble adj. That can be presumed or taken for granted; reasonable as a supposition: presumable causes of the disaster. warmer times, should yield a higher temperature for the microwave glow. According to the Big Bang, the temperature of the microwave background increases linearly with redshift redshift Displacement of the spectrum of an astronomical object toward longer wavelengths (visible light shifts toward the red end of the spectrum). In 1929 Edwin Hubble reported that distant galaxies had redshifts proportionate to their distances (see , a measure of the distance to faraway objects. Using a high-resolution spectrograph and the 10-meter W.M. Keck Telescope atop Hawaii's Mauna Kea, researchers have now taken the temperature of two distant gas clouds observed as they appeared at 25 percent of the cosmos' current age. Antoinette Songaila and Lennox L. Cowie of the University of Hawaii (body, education) University of Hawaii - A University spread over 10 campuses on 4 islands throughout the state. http://hawaii.edu/uhinfo.html. See also Aloha, Aloha Net. in Honolulu and their colleagues report their work in the Sept. 1 NATURE. The measurements "are strikingly consistent with the Big Bang theory big bang theory n. A cosmological theory holding that the universe originated approximately 20 billion years ago from the violent explosion of a very small agglomeration of matter of extremely high density and temperature. Noun 1. ," comments David M. Meyer of Northwestern University in Evanston, Ill. The two clouds studied lie directly in the path of light from a quasar quasar (kwā`sär), one of a class of blue celestial objects having the appearance of stars when viewed through a telescope and currently believed to be the most distant and most luminous objects in the universe; the name is shortened from and contain carbon atoms. Analyzing the quasar light absorbed by these atoms, the team calculated the relative number of carbon atoms occupying either of two closely spaced energy levels. The atoms in each level serve as a sensitive probe of the energy imparted to them by the microwave background, providing a measure of its temperature. Within experimental errors, the team found that one cloud-- at 7.58 kelvins -- matches the temperature predicted for the microwave background at that distance. The other cloud has a temperature some 3 kelvins higher. Cowie notes that the numbers give only an upper limit on the microwave background. Local effects also contribute to the excitation of carbon atoms in each cloud, and this may explain the higher temperature in the second cloud. |
|
||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion