Closest Black Hole to Earth:
The existence of black holes dates back to 1939 by Oppenheimer.
The closest known black hole to Earth is Gaia BH1, located about 1'600 light-years away in the constellation Ophiuchus. This dormant black hole is roughly 10 times more massive than our Sun.
Gaia BH1 is accompanied by a star. It's a binary system where the black hole and the star orbit each other.
The star orbiting Gaia BH1 is similar to our Sun in size and mass, which makes this binary system particularly interesting to astronomers.
Discovered in September 2022, BH1 was not originally detected via xRay signals but was rather discovered by examining data from the Gia survey and analyzing the orbit of its visible companion star ☀️.
The Gaia BH1 black hole is a dormant black hole, meaning it isn't actively consuming any material from its companion star. It is not attracting solar matter and accelerating it to high orbital speeds thus causing this material to glow hot or produce any xRays or emit jets of plasma at its polar magnets.
Gaia BH1 formed from the collapse of a massive star at the end of its life cycle. This collapse left behind the black hole, which now orbits with its companion star in a binary system.
The star and the black hole in the Gaia BH1 system are separated by a distance similar to the distance between the Earth and the Sun. This means they are relatively close in astronomical terms, allowing them to orbit each other in a stable binary system.
Given its Sun-like size, the companion star is more likely to end its life as a white dwarf rather than another black hole. Only very massive stars become black holes.
Currently, there is no evidence of any planet orbiting Gaia BH1. Observations have not detected any planets in this binary system.
The Gaia BH1 black hole is not known to cause significant dimming to its companion star. The system's orientation does not create eclipses from our vantage point, so we don't observe dimming due to transit. The orbit's orientation doesn't align in a way that causes eclipses from our perspective.
The star and black hole in the Gaia BH1 system complete an orbit around each other approximately once every 185 days.
Knowing this orbital period (185 days) and their approximate distance (similar to Earth-Sun), we can estimate their relative orbital speed which comes out to be around 100 kilometers per second.
The Earth orbits the Sun at about 30 kilometers per second. Comparing this to the 100 kilometers per second for the Gaia BH1 system, the ratio is roughly 3.33. Thus the Gaia BH1 system's orbital speed is over three times faster than Earth's around the Sun.
The Talman-Oppenheimer-Volkoff limit:
There is an upper mass limit to how massive the following objects can grow and remain stable before collapsing into a black hole:
- white dwarf = 3 x mass of our Sun
- neutron star = 2 x mass of our Sun
- Black hole = ...
