The Monster Black Loch lurks an absolute animal in the middle of the Galaxy M87. It is one of the largest near us and was the ideal first destination for the event horizon telescope. Scientists viewed the super massive black hole with this iconic event -horizon telescopic picture and have now found out how quickly this monster turns and how much material it devours.
The results are pretty stunning. This black hole, which weighs the mass of our sun 6.5 billion times, rotates at around 80% of the theoretical maximum speed that is possible in the universe. In order to put this in the right perspective, the inner edge of its accretion disk whipped at around 14% of the speed of light – that is around 42 million meters per second.
The team found this out by studying the “Lichtblick” in the original black hole pictures. This asymmetrical glow is not only for the show – it is referred to by something that is referred to as relativistic Doppler radiation. The material on one side of the window moves so quickly that it appears much brighter than the material that we remove from us. By measuring this brightness difference, the scientists were able to calculate the speed.
The galactic core of Messier 87, as the Hubble world space telescope mapped. (Credit: NASA)
But it gets really interesting here. The researchers also examined the magnetic field patterns around the black hole, which act like a roadmap for the inside of the material spiral. They found that the matter falls into the black hole at around 70 million meters per second – about 23% of the speed of light.
Using these measurements, they estimated that the black hole of M87 consumed between 0.00004 and 0.4 solar masss worth the value of material every year. That may sound like a lot, but it is actually quite modest for such a massive black hole – it works far below what scientists describe the “Eddington border”, which means that it is in a relatively quiet phase.
Simulated view of a black hole in front of the large Magellan cloud (loan: Alain R)
The most important thing may be that the energy from all of this in the falling material fits perfectly with the performance of the famous jets of M87-the spectacular beam of particles that stretch out at almost the speed of light that extends for thousands of light years. This supports the idea that these mighty jets are actually driven by the black hole feeding process.
The study represents an important step forward to understand how super massive black holes work. While earlier estimates of the M87 spin were between 0.1 and 0.98, this new method suggests that it is definitely at the top – at least 0.8 and possibly much closer to the theoretical maximum of 0.998.
While we are preparing for even more powerful telescopes and imaging techniques, the black hole of M87 probably remains a cosmic laboratory for testing our understanding of gravity, space -time and the most extreme physics in the universe. Every new measurement brings us closer to answering fundamental questions about how these cosmic monsters form entire galaxies and maybe even how they influence the ultimate fate of the cosmos itself.
Source: New estimates of the spin and accretion rate of the black hole M87 ∗
