The universe is expanding faster than we thought, study finds

The universe is expanding quicker than we expected from observations of the cosmos soon after the Big Bang, according to new data from the European Space Agency’s Gaia space telescope.

If the Gaia data has been interpreted properly, scientists would have to lower the age of the universe by a few hundred million years or so.

Gaia researchers came to this conclusion by looking at a particular subset of stars referred to as cepheid variables. These pulsating stars inflate and deflate in a very regimented fashion and glow with a known energy output. They are fairly low on the “totem pole” astronomers use to identify the divide between the Milky Way and the locations of galaxies that sit billions of light-years away.

Knowing the cepheids’ exact distance, their behavior can be used to calibrate markers higher up the totem pole, explicitly, a class of supernovae, that also shine in a conventional way. By searching a big enough volume of space, it is feasible to track the pace at which the modern cosmos is growing.

Using light from distant galaxies

To perform these calculations, scientists use the light from increasingly remote galaxies, which becomes extended to longer wavelengths. This is referred to as the Hubble Constant and defining its value is among the great unsolved tasks in astronomy.

Using a group of 212 Gaia cepheids, ESA scientists arrived at a Hubble Constant for today’s Universe of 73.0 kilometers per second per megaparsec, or per 3.26 million light-years. This means the expansion rises by 73.0km/second for every 3.26 million light-years we peer farther into space.

This constant is significantly bigger the widely-accepted constant established using a very different technique. Using the known physics associated with the Big Bang, the Hubble Constant has been found to be 66.9km/s per megaparsec.

“Gaia is going to be a very important, really revolutionary, way to measure distances,” ESA team member Adam Riess from Johns Hopkins University, told BBC News.  “Ultimately, when Gaia is done, we ought to be able to measure the Hubble Constant to 1 percent precision. That’s the same precision that is predicted by the Cosmic Microwave Background. That will be really powerful.

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Image credit: ESA

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