Universe expanded faster than the speed of light during inflation

In summary, the theory of inflation suggests that the universe underwent a rapid period of expansion in its early stages, causing space to expand faster than the speed of light. This is supported by observations of the cosmic microwave background radiation and the large-scale structure of the universe. The expansion of space during inflation does not violate the law of special relativity, as it is not a physical object traveling through space. Evidence for inflation includes the uniformity and flatness of the universe, the absence of magnetic monopoles, and the observation of gravitational waves. The exact duration of the inflation period is unknown, but it is estimated to have lasted for about 10^-36 seconds. Some theories propose that inflation may have occurred multiple times, but this is still
  • #1
travwg33
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How is it possible that the universe expanded faster than the speed of light during inflation when this is the "cosmic speed limit"?
 
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  • #2


The speed-limit means that nothing (i.e. no information) can travel THROUGH SPACE faster than the speed of light. During inflation, space (more accurately space-time) ITSELF was expanding.

Another way to think about it is: in no local region of space-time, was anything moving faster than the speed of light. Only in comparing very distantly separated locations, was there a net motion greater than c.
 

1. Why is it believed that the universe expanded faster than the speed of light during inflation?

According to the theory of inflation, the universe underwent a rapid period of expansion in the first fraction of a second after the Big Bang. During this time, the energy density of the universe was extremely high, causing space to expand faster than the speed of light. This is supported by observations of the cosmic microwave background radiation and the large-scale structure of the universe.

2. How can space expand faster than the speed of light?

Inflation does not violate the law of special relativity, which states that nothing can travel faster than the speed of light in a vacuum. The expansion of space is not limited by this law, as it is not a physical object traveling through space, but rather the stretching of space itself.

3. What evidence supports the theory of inflation?

Besides the observations of the cosmic microwave background radiation and the large-scale structure of the universe, the theory of inflation also explains the uniformity and flatness of the universe on a large scale, as well as the absence of magnetic monopoles. Inflation also predicts the existence of gravitational waves, which have been observed by the BICEP2 experiment.

4. How long did the inflation period last?

The exact duration of the inflation period is still unknown, but it is believed to have lasted for about 10^-36 seconds. This is an extremely short time compared to the age of the universe, which is currently estimated to be around 13.8 billion years.

5. Could the inflation period have happened more than once?

Some theories suggest that inflation may have occurred multiple times, with each episode causing a rapid expansion of the universe. This is known as eternal inflation and is still a topic of debate among scientists. However, there is currently no definitive evidence for multiple inflation events.

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