NASA’s Hubble Space Telescope reveals that the universe is actually expanding five percent to nine percent faster than previously thought. Scientists estimate that the universe expands at a rate of 73.2 kilometers per second per megaparsec (megapersec= 3.26 million light-years), doubling the distance between cosmic objects within the next 9.8 billion years.
The team of scientists called Supernova H0 for the Equation of State at NASA (or SH0ES team) investigated 2,400 Cepheid stars and 300 Type Ia supernovae in 19 galaxies. Cepheid stars and Type Ia supernovae emit light that stretches in space, which can be used to calculate the rate of expansion of space.
“This surprising finding may be an important clue to understanding those mysterious parts of the universe that make up 95 percent of everything and don’t emit light, such as dark energy, dark matter, and dark radiation,” adds the study’s lead researcher Adam Riess in a statement. Reiss is a Nobel Laureate who works with the Space Telescope Science Institute and The Johns Hopkins University.
As of now, no one knows what exactly causes this expansion. However, two theories have been suggested: dark energy and dark radiation.
Dark energy is believed to push galaxies away from each other with increasing strength. Dark radiation is speedy subatomic particles that were created when the universe was still young. Although not much is known about dark radiation, scientists believe that it somehow plays a role in the expansion.
The newest estimation could also mean that Einstein’s theory of gravity needs some improvements. The findings will be published in the forthcoming issue of The Astrophysical Journal.
The discovery was made possible through the Hubble’s sharp-eyed Wide Field Camera 3 (WFC3). The SH0ES team is currently conducting further investigations regarding the exact rate of the universe’s expansion. More accurate expansion rate can be determined using the European Space Agency’s Gaia satellite, the Wide Field Infrared Space Telescope (WFIRST) and the James Webb Space Telescope (JWST).