The NASA Hubble Space Telescope has spent 3 decades in space acting as the Earth’s watchdog and explorer of the universe. In its time spent observing distant galaxies and stars, it has also collected important information about the world which has helped scientists break records and reach new milestones. And now, Hubble is going to take on its toughest challenge yet. The NASA space telescope has been entrusted with measuring the expansion rate of the universe. What is it and why is it one of the biggest unsolved mysteries of the universe? Read on to find out. Also read: A gigantic 3,400-feet wide ‘potentially hazardous’ asteroid is headed towards the Earth What is the expansion rate of the Universe The popular theory about the origin of the universe is the Big Bang theory. The theory suggests that at the beginning of time, the universe was a dense “substance” which contained all the matter that has created the stars, planets, galaxies and the entire universe since then. At some point in time a huge explosion occurred which resulted in the birth of the universe. However, because the universe came into existence as a product of an explosion, it is constantly in motion- outwards. But it is not moving in a random direction, all things in the universe are actually moving away from each other like particles emerging from a single point explosion do. Also read: Looking for a smartphone? To check mobile finder click here. So, if this theory is to be believed, the universe should be expanding continuously as all the particles, which are the stars and the galaxies, are moving away from each other. And the expansion rate of the universe is the way to prove it all. According to the current theory, the rate of expansion of the universe should about 67.36 kilometers per second per megaparsec (a megaparsec equals 3.26 million light-years). But whether this theory is true or not, is dependent on physically proving this expansion. This is where NASA Hubble Space telescope comes in. Also read: A solar storm this big can destroy power grid in China! How can the NASA Hubble Space Telescope unravel the biggest mystery of the universe In recent years, using the data of the Hubble telescope, the scientists have found a strange twist. There is a discrepancy between the expansion rate as measured in the local universe and the independent observations from right after the big bang, which predict a different expansion value. While the cause of this discrepancy remains unknown, the data highlights something far more interesting – there is something exciting going on in the universe which may require new laws of physics. The astronomy community has not faced a situation like this ever since the discovery of dark matter in 1998. Now, there are two ways of looking at it. One, either the science that has been going on for decades is wrong, or the NASA Hubble Space Telescope is wrong. And scientists are betting on the Hubble. The expansion rate of the universe was predicted to be slower than what Hubble actually sees. But, given the large Hubble sample size, there is only a one-in-a-million chance astronomers are wrong due to an unlucky draw. “You are getting the most precise measure of the expansion rate for the universe from the gold standard of telescopes and cosmic mile markers,” said Nobel Laureate Adam Riess of the Space Telescope Science Institute. Riess also leads a scientific collaboration which is tasked with finding out the universe’s expansion rate. He, along with his team, is also soon going to publish a paper which more than doubles the prior sample of cosmic distance markers. These distance markers are different galaxies which Hubble has been observing over the years and recording how fast they move away from us. With the study doubling the sample size, it will also make Hubble virtually impossible to be wrong in the calculation of the expansion rate of the universe. It remains to be seen how scientists now decide to solve this new puzzle.