Expansion of the universe - Wikipedia
Cosmic expansion is a key feature of Big Bang cosmology. It can be modeled mathematically with the Friedmann–Lemaître–Robertson–Walker metric (FLRW), where it corresponds to an increase in the scale of the spatial part of the universe's spacetime metric tensor (which governs the size and geometry of spacetime).
The Hubble Diagram - Sloan Digital Sky Survey
In 1929, Hubble compared his distances to Slipher's measurements of redshift and made a famous plot, which today is called a Hubble diagram. Hubble's diagram showed that a galaxy's redshift increased linearly with its distance from Earth. The farther away a galaxy is, the faster it moves away from us.
The Hubble Diagram and the Expanding Universe – Voyages
So how does the straight line imply that the universe is expanding? The line on the Hubble diagram that relates redshift to distance is expressed as. c z = H 0 d , where c is the speed of light, z is the redshift, d is the distance, and H 0 is called the Hubble constant. The value of H 0 depends on the units used to measure the distance d.
The Universe - The Hubble Diagram and the Expanding Universe
如果您问一个天文学家到某一星系的距离是多少, 他或她很可能是通过测量红移z然后利用上面的公式计算d。这并不是你要做的：你要试图证明这个公式是正确的, 你不能通过红移来估测d,而必需单独测量。但是在假定宇宙膨胀的情况下, 上面这个方程提供了一种测量到任何一个星系距离的简单方法?C但要知道哈勃常数H 0 的值。
The Expanding Universe - HubbleSite
This diagram shows how the universe slowed down and then revved up since the Big Bang. The concentric red circles denote that galaxies are migrating apart at a slower rate during the first half of the cosmos. Than a mysterious dark force overcame gravity and began pushing galaxies apart at an ever-faster rate, signified by the green circles.
The Hubble Diagram – Voyages - Sloan Digital Sky Survey
Now, you have only one task left: you must make a Hubble diagram, pulling together your data to learn something about the universe. The key breakthrough that led astronomers to the big bang picture was the linear relationship between distance and redshift on the Hubble diagram. Two important observations led astronomers to this picture.
Chapter 26 Section 26.5: The Expanding Universe
The red dots at the lower left are the points in the diagram in the 1929 paper. Comparison of the two graphs shows how rapidly the determination of galactic distances and redshifts progressed in the 2 years between these publications. ... A uniformly expanding universe is one that is expanding at the same rate everywhere. In such a universe, we ...
The Universe - Sloan Digital Sky Survey
Hubble's diagram showed that the redness of a galaxy's light, and thus the speed with which the galaxy moved away from Earth, increased with its distance from Earth, and that the increase graphed into a straight line. The farther away a galaxy is, the faster it moves away from us.
Model of expanding Universe | ESA/Hubble
2001年4月2日 · This diagram reveals changes in the rate of expansion since the Universe's birth 15 billion years ago. The more shallow the curve, the faster the expansion. Are you a journalist? Subscribe to the ESA/Hubble Media Newsletter.
2003年10月21日 · In this brief report, Hubble laid out the evidence for one of the great discoveries in 20th cen-tury science: the expanding universe. Hubble showed that galaxies recede from us in all directions and more dis-tant ones recede more rapidly in pro-portion to their distance.
- 某些结果已被删除