Researchers have discovered an exciting - and unkown - new object in the Milky Way.
It's seemingly both heavier than the heaviest neutron stars ever recorded from Earth, but also lighter than any black hole ever surveyed, placing it in a really interesting middle ground.
If that sounds baffling, don't hold your breath for it to get simpler - the entity was found orbiting around a millisecond pulsar 40,000 light years away in a dense group of stars known as a globular cluster.
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Millisecond pulsars are a type of pulsar (neutron star with pulses of radiation) that spin very rapidly – hundreds of times per second.
They throw radiation around them, making for a very volatile-sounding area - and we've never found one paired with a black hole, bringing up all sorts of questions for astrophysicists.
In particular, Ben Stappers, professor of astrophysics at the University of Manchester, said it will be an "important target for testing theories of gravity", which makes it sound like it could help to prove (or disprove) all sorts of assumptions that have been relied upon for a long time.
After all, one of our theories about the source of black holes is that they're the result of dead stars - these become what we call neutron stars and are ultra-dense with mass but, in turn, can collapse if they collect too much of that mass.
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This may be where black holes originate, but one massive gap in our understanding remains - the heaviest neutron stars are still far, far lighter than the lightest black holes.
This means that there's an unknown or little-understood area between the two, and the key question is how or whether a neutron star continues to get more massive, and at what point it becomes a black hole.
All these queries could get some small measure of clarity from this new discovery, although don't expect an instant resolution, as these things can take a long time to clarify.
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For the curious, the new entity was found in a star cluster named NGC 1851 using a telescope with the very fun name of MeerKAT. That cluster is so full of stars that it's one astronomers have had their eyes on for ages, since it frequently sees interactions between those stars.
Astronomers say it is so crowded that the stars can interact with each other, disrupting orbits and in the most extreme cases colliding.
They believe that a collision between two neutron stars may have created the massive object that now orbits the radio pulsar.
The findings are published in the Science journal.