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Scientists observed the spectacular sight of two neutron stars colliding in 2017 and collected a large amount of data, but it was not until recently that scientists analyzed and understood the data and made an interesting discovery: the material thrown into space after the two neutron stars merged, the jet stream The speed seems to be 7 times the speed of light.
The 2017 event, dubbed GW170817 (GW stands for gravitational wave), was the first time scientists have detected gravitational waves from the merger of two neutron stars. At the time, gravitational waves from a handful of black hole mergers had been detected, but collisions between neutron stars remained elusive.
Neutron stars are compact celestial bodies formed after the explosive death of stars. According to NASA, a teaspoon of neutron star matter would weigh 4 billion tons on Earth.
NASA said that this unimaginable density brings a huge gravitational force, enough to bring two neutron stars together in an explosive collision, and at the same time emit gravitational waves and gamma radiation into space. Both detected simultaneously from neutron star mergers.
The Hubble Space Telescope observed two neutron stars collapsing into a black hole after the explosion, which then formed a spinning disk around the black hole, ejecting matter into space at incredible speeds. When scientists combined this finding with the National Science Foundation’s findings, they were able to piece together the events, including the speed at which matter was ejected into space, with extreme precision.
According to Hubble Space Telescope observations, the jet of matter appears to be traveling at seven times the speed of light. Of course, this is impossible because it has broken through the physical limit of the speed of the universe. However, follow-up research has found that its speed can always rush very close to this insurmountable speed limit, at least reaching 99.97% of the speed of light, which is about 6.7 per hour. billion miles. Scientists attribute this seemingly faster-than-light motion to the phenomenon of “superluminal motion.”
NASA pointed out that because the material in the jet is flying towards the earth at close to the speed of light, when the material is closer to the observer on the earth, the light it emits needs to travel a shorter distance, which makes it appear to the observer than it actually is. The movement speed is faster.
The research has been published in the journal Nature. Scientists hope that more precise observations of neutron star mergers in the future will help calculate how fast the universe is expanding. ◇