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Harvard, MIT scientists propose new method to measure universe’s expansion

This image obtained from NASA on May 31 shows thousands of black holes that astronomers have discovered located near the center of our Milky Way galaxy.
AFP/Getty Images/File
This image obtained from NASA on May 31 shows thousands of black holes that astronomers have discovered located near the center of our Milky Way galaxy.

A pair of scientists from Harvard University and the Massachusetts Institute of Technology have proposed a new way to gauge the rate at which the universe expands — information that could help them discover how the universe began 13.8 billion years ago, and whether it will continue to get larger or eventually collapse, according to a statement from MIT.

Salvatore Vitale, an MIT assistant professor of physics, and Hsin-Yu Chen, a fellow at Harvard’s Black Hole Initiative, say researchers can determine the rate of expansion by studying rare binary pairings consisting of a neutron star and a spiraling black hole.

These systems will eventually collide, producing flashes of light and space-shaking gravitational waves, Vitale and Chen say in a paper to be published Thursday in the academic journal “Physical Review Letters.”

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Researchers could study the flashes to estimate how fast the pair is moving away from the Earth, and whether the gravitational waves created by the impact are detectable on Earth, they would provide an exact measurement of the system’s distance from our planet, the scientists propose.

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Those two parameters are key to estimating the rate of expansion.

Though black hole/neutron star pairings are rare, observing even a few could give scientists their most accurate value yet for the rate of expansion, Vitale and Chen say.

“Black hole-neutron star binaries are very complicated systems, which we know very little about,” Vitale said in the statement. “If we detect one, the prize is that they can potentially give a dramatic contribution to our understanding of the universe.”

Jeremy C. Fox can be reached at jeremy.fox@globe.com. Follow him on Twitter @jeremycfox.