What are past values of the Hubble constant and is there an archive for them?

[nick1o2]

Hello, I've been looking round trying to find a history of records, showing the speed of which the universe is expanding? Would this just be the hubbles constant? If so I'm looking for past Hubble constant values. Is there an archive for this? or is there a way to work past Hubble constant's to an exacte year (not right on the dot, but some where near that specific time area)?

 

[mfb]

We have a calculator that can do this.
Knowing past Hubble constant values is sufficient, right, but I think the scale factor is a better value (it directly shows how large the universe was compared to today).

 

[Chronos]

The expansion history of the universe is an unknown asserted on not altogether reliable assumptions. It remains a controversial issue in science, IMO. We do, however, have some good guesses as noted by mfb.

 

[Chalnoth]

The expansion history of the universe is an unknown asserted on not altogether reliable assumptions. It remains a controversial issue in science, IMO. We do, however, have some good guesses as noted by mfb.

The expansion history of the universe is measured. Those measurements aren't all that precise as of now, but I think calling it an "unknown" is significantly understating our understanding of the expansion rate.

 

[sardar]

Hello there, the expansion of the universe is a widely studied and debated topic in the scientific community. The Hubble constant is indeed a key factor in understanding the rate of expansion of the universe. It represents the current rate of expansion and is measured in kilometers per second per megaparsec (km/s/Mpc). However, it is important to note that the value of the Hubble constant is not constant and has varied over time.

To answer your question, there is a way to work backwards from the current value of the Hubble constant to estimate past values. This is done through various methods such as using data from the cosmic microwave background radiation or studying the distances and velocities of objects in the universe.

There are also archives available that contain past measurements of the Hubble constant. One example is the NASA/IPAC Extragalactic Database (NED), which contains a compilation of data from various sources. However, it is important to keep in mind that these values may have uncertainties and may not be exact.

Overall, the expansion of the universe is a complex and ongoing research topic, and scientists are constantly working to improve our understanding of it. I hope this helps answer your question.