Accelerated Expansion Of The Universe

[Little Bang]

https://www.sciencedaily.com/releases/2018/02/180222162005.htm

 

As we look back in time with our telescopes we see the Universe as it was in a denser state, more matter per cubic meter. This would suggest that time would be slower than at present. Would this seem to make the Universe be accelerating?

[bangstrom]

Yes, the transition from a gravitationally dense state to a less dense state would suggest that time was slower in the distant past and this would appear as an acceleration of space. I don't know but I suspect this is part of the calculations for the rate of expansion. An acceleration of time would necessarily accompany an expansion of space if c is to remain a constant.

[Little Bang]

An expansion of space would make  c slower, any change in space/time will change c. Unlike you I don't think they have ever considered it. In the first few seconds after the BB c must have been almost infinite because a change time would have been extremely slow .

Edited February 25, 2018 by Little Bang

[Little Bang]

BTW, Einstein even said that we would have to reconsider c in a gravitational field.

[bangstrom]

C slows in a gravitational field relative to an outside observer but locally c is a ratio that remains the same. Gravity is a space/time energy gradient where increasing gravity amounts to a region of shorter space and slower time. The expansion of space would make c slower if time did not change with space but expanding space is like the emergence from a BB gravity well where time quickens as space expands so locally c remains the same since c is a constant by definition.

 

In the BB theory, the changes in time that accompany the expansion of space are corrected for mathematically by the use of "co-moving coordinates." Co-moving coordinates assume that the universe is expanding like bits of ejecta from a grand, cosmic explosion where distant galactic redshifts can give us accurate readings for galactic recessional velocities that we can use to calculate the size and age of the universe. Anomalies such as the Guth's "inflation period" and accelerated expansion are telling us that the universe is not expanding like the typical explosion so the use of co-moving coordinate may not be valid.

[sophiewilson0191]

If only we can explore more universe.

We can maybe save our Earth.