Radiation appears to travel seven times faster than light – New Scientist

cosmic Jet, a combined, lightning-fast gas stream from two colliding neutron stars that appears to be traveling at seven times the speed of light. Fortunately, this does not mean the end of the laws of physics: it is an optical illusion caused by the relative positions of the Earth and the collision of two neutron stars.

Nothing can travel faster than light, so researchers can say with certainty that this is an optical illusion. Nevertheless, the observation provides important insights into gamma-ray bursts, extremely fast bursts about which many are still perplexed.

In 2017, astronomers at the Laser Gravitational Wave Observatory (LIGO) observed a gravitational wave, called GW170817, that was caused by the collision of two neutron stars. Dozens of (space) telescopes were pointed at him instantly, which picked up a flash of bright light, along with a powerful gamma ray: a gamma ray burst.

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The first measurements of this telescope grid, which used a so-called Very Long Interferometry (VLBI) technique, showed roughly in which direction the aircraft was moving, at least 95 percent of the speed of light. But because the Earth and the neutron stars are 130 million light-years away, and because the gamma-ray burst was relatively faint, there were still many doubts about the jet.

higher resolution

Kunal Muli, an astrophysicist at the California Institute of Technology in the US, and his colleagues now compared data from the telescope’s network with measurements from the Hubble Space Telescope from 8 to 159 days after the collision. This allowed them to set the speed with higher accuracy.

The team found that the plane appeared to be moving at seven times the speed of light. This is an optical illusion caused by the movement of light towards the Earth. A similar effect occurs when you aim a laser beam at the moon and move it sideways: the laser dot appears to move across the moon’s surface faster than light, even though no single photon can.

part of a pixel

However, this precise measurement does tell us important things about the plane’s true speed, position, and direction: it’s actually traveling at 99.97 percent of the speed of light, and it’s in a tiny part of the galaxy NGC 4993. One can do is zoom in on this event. Up to a thousand or ten thousand times to see local features,” says Molly.

She was not involved in this study, said Matt Nicholl, assistant professor of physics and astronomy at the University of Birmingham in the UK. “Seven times the speed of light sounds astounding, but it is equivalent to the motions of fractions of pixels over hundreds of days.”