The Hubble telescope is one of the most potent space-based observatories which has helped scientists understand and solve many cosmic mysteries. In its 30 years of service, the telescope has snapped more than 1.3 billion photographs of intriguing events. It is now focusing on one of its most challenging missions – finding out how quickly the universe is expanding. The findings so far suggest that something unusual is happening in our universe, NASA says.
The technological advancements over the years meant that scientists were able to study the universe's expansion more precisely. There seems to be a discrepancy. NASA said there is a difference in the rate of expansion of the universe as it is around us and observations right after the Big Bang, suggesting "something weird" is going on in the universe.
This has sent scientists scratching their heads. To understand the strange phenomenon, they are studying the data gathered by Hubble on a set of “milepost markets” in space and time, which can be used to track the expansion rate of the universe as they move away from us.
NASA said Hubble has calibrated more than 40 “milepost markers” since its launch in 1990.
“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 and the Johns Hopkins University in Baltimore, Maryland.
The study of the expansion of the universe began in 1920 with measurements by astronomers Edwin P Hubble, after whom the telescope is named, and Georges Lemaitre. Hubble said that galaxies outside of ours appeared to be moving away from us, adding the further they are from us the faster they are moving away. Since then, scientists have been trying to understand and measure this expansion.
When the Hubble telescope started gathering data, it turned out that the rate of expansion was quicker than models had predicted so far. Models predicted the rate at 67.5 kilometers per second per megaparsec, but observations showed it is around 73.
This discrepancy has made scientists assess their understanding and start over. They are now waiting for the new James Webb Space Telescope to start sending data, so that they can go deeper to solve this mystery.