Mysterious object in space may have been swallowed by a black hole

A screen grab from an artist's animation of the object.
A screen grab from an artist's animation of the object. © @Alex Andrix / Virgo / EGO - European Gravitational Observatory / AFP

Scientists have announced the discovery of a puzzling astronomical object that’s smaller than a black hole, but bigger than a neutron star – and exists in the so-called "mass gap” between the two.


Detected by gravitational waves antennae as a tiny vibration of space-time, the object – 800 million light years away – is 2.6 times heavier than our sun.

It appears to have merged with a black hole 23 times heavier than the sun, setting off gravitational waves that were able to extrapolate its mass.

The mysterious object could be a small neutron star that was "swallowed" by the black hole, says the team behind the research, which was published in The Astrophysical Journal Letters.

In theory a neutron star cannot exceed 2.5 solar masses, while the lightest black hole ever recorded weighs about five solar masses. This quandary has led to scientists to rethink how these two phenomena are formed.

They say the presence of this object - discovered in August by the LIGO-Virgo gravitational wave detectors in the US and Italy – cannot be explained without challenging our understanding of extremely dense matter, or what we know about the evolution of stars.

Whether the object is the heaviest known neutron star or the lightest known black hole, scientists say that either way, it’s broken a record.

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