It’s a fact that the universe keeps on expanding, but researchers have gathered observations from Hubble Space Telescope and they’ve discovered that the universe is expanding faster than we thought.
Our universe was formed in the Big Bang 13.8 billion years ago and it kept expanding, so galaxies that are distant appear to move away from us.
Using Hubble parameter, astronomers measure the distance to the objects that are the most farter and that value is called a Hubble constant. But the thing is that Hubble hasn’t had the same value, and the last results suggest that the universe keeps on expanding, but it’s faster than expected.
Adam Riess, the Lead researcher of the Space Telescope Science Institute and Johns Hopkins University stated that the community hasn’t been able to understand the discrepancy. He and his team have used Hubble the last six years in their studies and they’ve discovered that the Hubble constant has changed.
In the previous studies, the constant value should have been 67 kilometers per second per megaparsec (3.3 million light-years). This means that if we’re watching a galaxy that is 3.3 million light-years away, it will expand away from ours at 67 km/s. But recent measurements point that the value increased to 73 kilometers per second per megaparsec. This means that galaxies are moving farther away from us at a faster rate. And if you’re wondering if there’s been a mistake in the measurements, Riess stated that:
‘Both results have been tested multiple ways, so barring a series of unrelated mistakes. […] It is increasingly likely that this is not a bug but a feature of the universe.’
So, what’s the researchers’ explanations? An important factor for the expansion of the universe is the dark energy that creates about three-quarters of the universe. This discovery brings a new point of view over how universe changes in time: the universe doesn’t have a constant value of expansion, and its value changes over time.