Breaking astronomy news!

The European Southern Observatory, in combination with other institutes, has discovered a black hole – and it’s a mere 1000 lightyears from Earth! 

This newly discovered Black Hole forms part of a triple system (called HR6819) that can be seen with the naked eye. Petr Hadrava, Emeritus Scientist at the Academy of Sciences of the Czech Republic in Prague and co-author of the research, points out how amazing it is that we can see this without a telescope on a clear night. Don’t get too excited though – it’s only observable from the southern hemisphere. The ESO witnessed one of the stars in the system orbiting an unseen object every 40 days – a black hole! 

A view from the Southern Hemisphere: Zooming into HR6819. Source: ESO

The black hole located in HR 6819 points to an exciting (or terrifying) possibility. Nearly all of the black holes discovered within our galaxy to date have been violent ones that absorb the stars and planets around them, creating powerful x-rays as a result. This black hole is different as it exists quietly in its own system, undetected for years. This could mean there are thousands of black holes relatively close to our solar system, but we just haven’t seen them yet! The astronomers involved also believe a second system, LB-1, could contain a similar black hole – however more research is needed to determine this.

On of our own Astronomers, Dr. Andreas Sander, has broken down what this discovery could mean for identifying future Black Holes.

“The discovery in the HR6819 system is a good example of how we extend our knowledge about stars and their lives and deaths. We know that Black Holes exist and that massive stars eventually end up collapsing into a Black Hole. But how massive do they need to be? And how exactly do they get to their final stage? As scientists, we don’t just want to draw nice cartoons of the principles, but we want to describe this with robust numbers and scenarios that we can test and model. That is why we need observations and good telescopes to get them, both on Earth and in space.  

The ESO’s MPG/ESO 2.2-metre telescope was used in the Black Hole discovery. Source: ESO

“While normal stars are emitting a lot of light, Black Holes are hard to find for Astronomers. When they are “active”, which means they are currently consuming matter from an accretion disk or a companion star, we can see them due to radiation resulting from their “feast”. But when a Black Hole is not active, which likely is the case for most of them, it is just what its name says: black. Therefore, the only way to find a Black Hole is essentially to identify that something is missing. This is what the team of ESO astronomers and collaborators did. They identified HR6819 as a system, where they see the light of two stars, but the moving pattern of those acts like there is at least another massive body. So basically, the observations tell that you should have a lot of mass in a place where you do not see anything, which is a strong indication of a Black Hole.

The famous image of Black Hole M87 – this is not a “quiet” Black Hole. The Black Hole located in HR6819 cannot be photographed like this. Credits: Event Horizon Telescope collaboration et al.

“Follow-up observations and studies are already underway and will be required to confirm the nature of the system and constrain the parameters of the visible components as well as the potential Black Hole. Unfortunately, stars don’t have labels attached to them and like small people can cast a large shadow, some stars can be quite crafty in hiding their true properties. This is why astronomers, including some of us here at AOP, develop complex analysis and model techniques to deduce stellar properties.

“Astronomers all around the world will now study the findings of the ESO team and their collaborators, taking further observations and providing theoretical models to get a better understanding of this interesting triple-component system with its mysterious hidden object that could be the nearest Black Hole known to date.

“But in case you are worried: “Near” is meant in astronomical terms. HR6819 is approximately 1000 lightyears away, far enough to not be any kind of threat for us here on Earth, but near enough to study it in detail.”

Earth can rest assured – the Black Hole in HR6819 won’t harm us! Credit: NASA

So there you go, this Black Hole is ideally placed for research but thankfully you can sleep easy tonight – it’s far too far to cause us any harm. The discovery of this Black Hole within HR6819 shows us that there is so much of our universe yet to understand. I for one am excited to see where this research will lead.


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