4 résultats pour "redshifts"

• Redshift - astronomy.

  Astronomers can also use redshift to identify the oldest and most distant objects in the observable universe. Astronomers believe that quasars are the most distantobjects in the universe, because they have some of the largest redshifts. Quasars are objects in space that strongly emit radio waves. Astronomers originally namedthese objects quasars, which stands for quas i-stell ar (or starlike) radio source, because they appear as points of light, like stars, in photographs of the sky. When astro...

• Redshifts anormaux

  4 D'autres fa~ sont rapprochés de ces •observations. Si l'on évalue les distances des pulsars d'après leur redshift, leur répartition dans l'espace présente des ano- 111811es dont l'explicatiOn est très litigieuse. Le Soleil lui­ même pose un problème. Son spectre montre ùn léger redshift, bien plus faible que celui des galaxies, mals néanmoins .. mesurable par les moyens actuels. On ne l'attribue pas à t'effet Doppler (car la distance moyenne...

• Cosmology - astronomy.

  In 1917 American scientist Harlow Shapley measured the distance to several groups of stars known as globular clusters. He measured these distances by using amethod developed in 1912 by American astronomer Henrietta Leavitt. Leavitt’s method relates distance to variations in brightness of Cepheid variables, a class of starsthat vary periodically in brightness. Shapley’s distance measurements showed that the clusters were centered around a point far from the Sun. The arrangement of theclusters was...

• Radio Astronomy - astronomy.

  equivalent to the apparent angular dimensions of a basketball at the distance of the moon. In 1984, the U.S. government appropriated funds for the construction of aninstallation called the very long baseline array (VLBA), a network of 10 radio antennas spread from the U.S.-Canadian border to Puerto Rico and from Hawaii to the U.S.Atlantic coast. The VLBA is expected to provide angular resolutions in the range of 200-millionths of an arc second. Canada and Australia are both planning similarprogr...