We know for sure that the Universe is expanding firstly due to what the American astronomer Edwin Hubble discovered about a century ago. He found out that there are many other galaxies besides our own, and judging by the Doppler effect, he concluded that they are moving away from us at very high speeds. Therefore, scientists later gave the name “the Hubble Constant” to describe the expansion rate of the Universe. The Bible has also been speaking a lot about the expansion of the Universe in a rudimentary language, long before scientists discovered it for their own.
But just how fast is this expansion going on? Some scientists believe that the Universe expands even faster than the speed of light. And no, that wouldn’t be a violation of the laws of physics. Einstein said that the speed of light could never be surpassed, and he’s totally right. He was referring to the speed of light throughout space and time, which doesn’t exclude that the spacetime itself can grow even a lot faster.
67.5 kilometers (42 miles) per megaparsec is the actual number
A team of scientists from the University of Clemson came to this conclusion after studying data from multiple telescopes on gamma-ray attenuation and models on extragalactic background light. Their discovery is contradicting the old Hubble Constant estimation, which is set at 500 kilometers (310 miles) per second per megaparsec — that is, per 3.26 million light-years, approximately.
Alberto Dominguez is the study’s lead author, and he stated:
Our technique allows us to use an independent strategy – a new methodology independent of existing ones – to measure crucial properties of the universe … The analysis that we have developed paves the way for better measurements in the future using the Cherenkov Telescope Array, which is still in development and will be the most ambitious array of ground-based high-energy telescopes ever.
Why is the expansion happening?
The “fuel” is the dark energy, a mysterious form of energy that helps our Cosmos to expand faster and faster. We would like to know more about it, but perhaps science can’t simply know everything. One other factor is that we are practically living inside the “explosion” of the Big Bang itself. The Universe is in constant expansion since then, and it doesn’t show any signs that it wants to slow down. The Big Bang was the beginning of the Cosmos, but also the trigger of its expansion.
Perhaps the next big step in science is to find out what is the Universe expanding into.