Cygnus X-1: The first black hole ever discovered is much larger and more massive than we thought

Cygnus X-1 is a high mass X binary file located in the Cygnus constellation. First discovered in 1964 thanks to a pair of Geiger counters aboard a rocket, it is the first candidate for a black hole discovered by scientists. Indeed, until the mid-20th century, black holes were simple mathematical predictions.

For the recording, the object had been the subject of a bet between two renowned physicists: Stephen Hawking and Kip Thorne, the latter having bet in 1974 that it was a black hole. Eventually, Hawking admitted defeat in 1990 when the first sighting data came out.

Measurements based on the Very Long Baseline Array

Recently, astronomers at the International Radio Astronomical Research Center (ICRAR) conducted a new study to get more accurate measurements from Cygnus X-1. To do this, they used the Very Long Baseline Array, a huge radio telescope consisting of 10 antennas distributed throughout the USA.

The team also used a technique where the object was viewed from different angles as the earth rotated. “If we can observe the same object from different locations, we can calculate its distance from us by measuring how far it appears to be moving from the background,” said Professor James Miller-Jones of Curtin University in Western Australia.

500 light years away

“If you hold your finger in front of your eyes and look at it eye to eye, you will find that it seems to jump from place to place. It’s exactly the same principle, ”Miller-Jones added, quoted by DigitalTrends. Thanks to these measurements, the researchers were able to make a comparison with the data collected a few years ago.

Cygnus X-1,500 light years away. Image credit: NASA

By doing this, they were able to determine that the system is actually further away than expected, being 7,200 light years away instead of 6,700 light years as previously suggested. And it turns out that Cygnus X-1 is spinning faster than any other object of the same species discovered to date. Its speed would approach that of light.

An underrated crowd

In addition to being further away than previously reported, the black hole is also heavier. The new data show that it has a mass about 21 times that of the Sun, which is 50% more than previously thought. Interestingly, Cygnus X-1 is home to a super-giant star 22 times the size of the Sun. This shining star and the black hole orbit each other very quickly, so their time of rotation is only five and a half days.