An international team of astronomers has discovered the first black hole to roam freely in interstellar space, according to an article published on Monday on the scientific platform arXiv.
The scientific community has long believed that there are many black holes roaming interstellar space, but until now none had been recorded. Due to their very nature, they are difficult to detect against the black background of space.
To do this, researchers need to look for gravitational lensing effects, that is, when starlight is bent by the pull of the black hole. However, due to the great distances, lensing is slight, making it almost impossible to detect even with the best modern telescopes.
However, in 2011 two teams of researchers studying this phenomenon found a star that seemed to shine for no apparent reason. Thus, they decided to analyze the data from the Hubble Space Telescope, so they spent six years observing how its light changed with the hope that it was due to the increase of a black hole.
Later, they noticed that the position of the star seemed to change. The new study suggests that the phenomenon can only occur by an unseen moving object that exerts a force that pulls on light as it passes by, i.e. an interstellar black hole.
Astronomers continued to study the star and its light. Ultimately, they ruled out the possibility of light coming from the lens and also confirmed that the magnification was long lasting. Both characteristics are considered essential conditions to confirm the existence of a black hole.
Experts believe the evidence is sufficient to confirm the sighting of a free-floating black hole in space. They even determined that its size is seven solar masses and that it travels at a speed of approximately 45 kilometers per second.