spaceSpace and Physics

Doomed gas cloud could give clues about black hole inner workings

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Lisa Winter

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239 Doomed gas cloud could give clues about black hole inner workings
ESO/S. Gillessen/MPE/Marc Schartmann

The supermassive black hole in the middle of our galaxy is about four million times more massive than our sun. Black holes have been studied extensively, yet there is not a clear consensus about the origins and internal structure. Astronomers could get a unique chance to peer inside the the black hole over the next few decades, depending on the composition of a gigantic gas cloud called G2. 

G2 has been a topic of great interest since its discovery in 2011. There has been some speculation that a star is hidden within the cloud, holding it together. If this is the case, when the cloud makes its closest approach to the black hole in a couple months it will be fairly uneventful. While some of the cloud would be consumed upon approach, the internal star will continue on its course relatively unscathed. If there isn’t a star and G2 is an ordinary gas cloud, there will be a wealth of information obtained from its demise. However, there has not been an observed increase in heat as the cloud has started to get pulled apart, so it is becoming doubtful that G2 is harboring a faint star.


In 2013 the cloud grew closer to the black hole and the immense gravitational pull began ripping it apart and pulling it into thin threads. The first bits of the cloud will be consumed by the black hole within the next couple of months as it makes its closest approach. Assuming the cloud is indeed just a gas cloud, the results will be spectacular. As the massive cloud is ingested, it will kick out x-rays which astronomers will be able to observe. This will give a never-before-seen view of the black hole’s core. The cloud is three times more massive than Earth and it will take decades for the black hole to consume it entirely, producing invaluable information every step of the way.

The x-rays emitted from the cloud will allow astronomers to learn more about how black holes like ours consume matter, which may also give clues about how it formed in the first place. The progression of G2 as it approaches the black hole is currently being monitored by the ESO’s Very Large Telescope and NASA’s Swift telescope. The research team from Swift posts new information daily, so researchers will know when the cloud reaches the black hole as soon as possible. Additionally, the Swift team presented their current body of research at the 223rd Meeting of the American Astronomical Association last week.

The ESO has produced this simulation of what G2 looked like as it approached the black hole, and what we can expect to see over the next few decades:


spaceSpace and Physics
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  • black hole,

  • g2,

  • gas cloud,

  • xray,

  • swift telescope,

  • very large telescope