Universe Expansion: How Fast Is It?

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SUMMARY

The universe is expanding at a rate of approximately 70 kilometers per second per megaparsec, as defined by the Hubble constant. This means that for every megaparsec of distance, galaxies are receding from us at this speed. To visualize this, it would take about 14 million years for the universe to expand by one-tenth of a percent and 140 million years for a full percent. Additionally, galaxies at varying distances are receding at multiples of the speed of light, with those 14 billion light-years away receding at speed c, and those 42 billion light-years away at speed 3c.

PREREQUISITES
  • Understanding of the Hubble constant
  • Basic knowledge of light-years and megaparsecs
  • Familiarity with concepts of cosmic expansion
  • Awareness of relativistic speeds
NEXT STEPS
  • Research the implications of the Hubble constant on cosmology
  • Explore the concept of cosmic inflation and its effects on universe expansion
  • Learn about the methods used to measure distances in space, such as parallax and redshift
  • Investigate the relationship between distance and recession velocity in the context of general relativity
USEFUL FOR

Astronomers, astrophysicists, students of cosmology, and anyone interested in understanding the dynamics of the universe's expansion.

Chris_Gottschal
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How fast is the universe expanding. Even an estimate would be a good enough answer.
 
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chroot said:
Roughly 70 kilometers per second per megaparsec of distance.

http://en.wikipedia.org/wiki/Hubble_constant

- Warren

another way to visulize it is as a percentage expansion over time.

at the present rate of expansion it would take about 14 million years for it to expand by a tenth of a percent-----or 140 million years to expand by one percent.

this is equivalent to what Chroot said

another way to say the same thing is that a galaxy which is at this moment 14 billion LY from us is receding from us at speed c.

a galaxy which is currently 28 billion LY from us is receding at speed 2c, and so on.

something 42 billion LY away is presently receding at 3c...

(this is just translating Chroot's figure into different units which may be more familiar to some people)
 

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