On August 28, the Laser Interferometer Gravitational-Wave Observatory (LIGO) noted two separate gravitational waves, which came just 21 minutes apart. Gravitational waves, in this instance, were caused by two behemoth black holes merging, which sent ripples through the fabric of space-time. Scientists as LIGO were shocked to see the two separate mergers happen in such quick succession, as two gravitational waves have never been recorded on the same day – let alone within half an hour of each other.
Astrophysicist Robert Routledge from McGill University was shocked at the findings, and suggested it might be more than a coincidence.
He tweeted: “This is freaky. Perhaps the simplest explanation – barring an instrumental or data handling issue – is that this is the first gravitationally lensed gravitational wave detection.
“Non-scientists, this is a genuine ‘Uh, wait, what?’ We’ve never seen that before’ moment in gravitational wave astronomy.
“If you’d like to see how double-checks and confirmations and conclusions occur – pay attention, in real time. Happening now.”
Mr Routledge and others in the scientific community speculated that the two gravitational waves, known as S190828l and S190828j, came from the same source.
However, after analysing, and reanalysing, experts at LIGO discovered the localisations were extremely similar but not the same, suggesting it was two separate events.
Northwestern University Christopher Berry, a member of the LIGO Scientific Collaboration, said: “In case you were suspicious of two events close in time with S190828l and S190828j, they sky localisations are similar, but distinct (you might expect them to overlap for a gravitationally lensed signal, but that doesn’t seem to be the case).”
Gravitational lensing can be used if an object in space is massive enough, such as the Sun, its gravitational field would be so intense that its mass can bend light.
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Another way is when a large amount of matter, which can be in the form of a gas cloud or a star collapses in on itself through its own gravitational pull.
Finally, the collision of two neutron stars can cause a black hole.
The gist of all three ways is that a massive amount of mass located in one spot can cause a black hole.