Is Hubble Constant Inconstant? Scientsts Baffled With Mystery

Hubble's estimates of today's growth rate differ from what was predicted based on how the Universe looked immediately after the Big Bang about 13 billion years ago.

Washington Post said astronomer Edwin Hubble demonstrated nine decades ago that the Universe is an order of magnitude larger than previously thought - and that it is expanding. The Hubble Constant is a number that represents the rate of expansion.

Any hypothesis regarding the Universe's evolution and final fate must have the Hubble Constant. This number may have no bearing on everyday life, but cosmologically, there is a lot at stake.

Light flowed across hydrogen early in the Universe's history - there were no stars yet. Scientists calculated the Hubble constant to be about 67 based on oscillations identical to sound waves generated by this. Per 3.26 million light-years, the Universe expands at a rate of around 67 kilometers per second higher. However, it's a tricky figure.

Astronomers began debating the true value of this constant. Over time, they discovered that there was a difference in this amount between early and late universe measurements.

Different methods have shown further findings, and even as researchers refine their results, the data show no evidence of convergence.

Experts Suggest Fixing Cosmological Cornerstone For Hubble Constant

Now, a multinational team led by a physicist from the University of Michigan has studied a sample of over 1,000 supernovae bursts, confirming that the Hubble constant isn't necessarily constant.

Enrico Rinaldi, a research fellow in the U-M Department of Physics, and his team discovered that the Hubble constant shifting with redshift helps them "link" the constant value from early universe probes to the value from late universe probes. ESA said redshift happens when light spreads as the Universe extends.

The derived parameters, Rinaldi said, are still consistent with astronauts' standard cosmological understanding. But this time, he said that the parameters vary slightly as the gap changes and that this slight shift is enough to understand why the shift exists.

According to the researchers, there are various reasons for the sudden shift in the Hubble constant, one of which is the probability of data sample observational biases.

"The tension of the Hubble constant can be explained by some intrinsic dependence of this constant on the distance of the objects that you use," Rinaldi told Science Daily.

Instead, it could shift in response to the Universe's growth, growing as the Universe expands. To understand the growing rate of expansion, modern physics, such as an updated version of Einstein's gravity, is possibly needed.

Researchers uploaded their study, titled "On the Hubble Constant Tension in the SNe Ia Pantheon Sample," in The Astrophysical Journal.