Astronomers Use Improved Hubble Telescope To Measure Expansion Rate Of The Universe


The universe, as we know it, is expanding at a faster rate. Researchers are suggesting a new science on accurately measuring this expansion.

The latest discovery using the Hubble telescope showed that the Universe is expanding at a faster rate compared to the expected rate when the expansion was first recorded more than a century ago.

Scientists are attempting to explain this discrepancy. They suggested that a new physics may be needed to finally resolve the varying results.

Accelerating Universe

Edward Hubble first proved the expansion of the universe in 1925.

For the past six years, astronomers have utilized NASA's Hubble telescope to measure the expansion of the universe accurately.

Two years ago, astronomers at NASA discovered that the universe is expanding five to nine percent faster than expected.

The force that is causing the said expansion is what scientists identified as the Hubble constant. The latest study measured the expansion of the Universe at a value of 73 kilometers per second per megaparsec.

The new result indicates that galaxies are now moving much faster.

The Planck satellite of the European Space Agency, which previously measured the expansion of the universe, estimated the Hubble constant at 67 kilometers per second per megaparsec. Planck's estimate is equivalent to 3.3 million years.

NASA's Wilkinson Microwave Anisotropy Probe of the Big Bang's afterglow also presented a different result.

The different predictions have a discrepancy ranging from 5 percent to 9 percent lower than that of the Hubble constant.

"The community is really grappling with understanding the meaning of this discrepancy," says Nobel Laureate Adam Reiss, lead researcher of the Space Telescope Science Institute and Johns Hopkins University.

Reiss won the 1998 Nobel prize for his study on the accelerating universe.

What Causes The Mismatch?

Reiss' team suggests several possibilities on the discrepancies.

According to the study, dark energy could be pushing galaxies away from each other. The presence of particles called dark radiation and sterile neutrinos in the universe are also seen as one of the probable reasons for different rates of expansion. Lastly, it is also likely that dark matter interacts with radiation much stronger than previously assumed.

Measuring The Hubble Constant

Information on the amount of dark energy and dark matter in the universe at the time after Big Bang could have helped predict the current rate of the expansion, but such information is lacking.

"However, if this discrepancy holds up, it appears we may not have the right understanding, and it changes how big the Hubble constant should be today," Reiss added.

The Hubble constant is the value that calculates how fast the universe is expanding through time.

Scientists use three steps to measure the Hubble constant.

The first step is measuring the distance of pulsating stars Cepheid variables in the Milky Way.

Second is the observation of galaxies with Cepheid and Type Ia supernovae. The brightness of Cepheid stars corresponds to their distance from Earth. Type Ia supernovae are exploding stars that emit brightness that can be seen from long distances.

The final step is to look for a supernova in galaxies that are much farther away from the Earth. Scientists compare the measured distances to the true and apparent brightness of the supernovae to calculate how fast the universe expands with time.

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