Astronomers Find a Black Hole That was Somehow Pushed Over Onto its Side

Artist impression of the X-ray binary system MAXI J1820+070 containing a black hole (small black dot at the center of the gaseous disk) and a companion star. A narrow jet is directed along the black hole spin axis, which is strongly misaligned from the rotation axis of the orbit. Image produced with Binsim (credit: R. Hynes).

The planets in our Solar System all rotate on axes that roughly match the Sun’s rotational axis. This agreement between the axes of rotation is the typical arrangement in any system in space where smaller objects orbit a larger one.

But in one distant binary system, the large central object has an axis of rotation tilted about 40 degrees compared to its smaller satellite. This situation is even more strange because the main body isn’t a star but a black hole.

Continue reading “Astronomers Find a Black Hole That was Somehow Pushed Over Onto its Side”

Protoplanetary Disks Throw Out More Material Than Gets Turned Into Planets

When a young solar system gets going it’s little more than a young star and a rotating disk of debris. Accepted thinking says that the swirling debris is swept up in planet formation. But a new study says that much of the matter in the disk could face a different fate.

It may not have the honour of becoming part of a nice stable planet, orbiting placidly and reliably around its host star. Instead, it’s simply discarded. It’s ejected out of the young, still-forming solar system to spend its existence as interstellar objects or as rogue planets.

Continue reading “Protoplanetary Disks Throw Out More Material Than Gets Turned Into Planets”

Whether They’re Stellar-Mass or Supermassive, Black Holes Behave Pretty Much the Same Way

In anticipation of the first image of a black hole, Jordy Davelaar and colleagues built a virtual reality simulation of one of these fascinating astrophysical objects. Their simulation shows a black hole surrounded by luminous matter. This matter disappears into the black hole in a vortex-like way, and the extreme conditions cause it to become a glowing plasma. The light emitted is then deflected and deformed by the powerful gravity of the black hole. 

Astronomers recently caught a supermassive black hole gulp down a star. It flared in exactly the same way as its smaller cousins do when those black holes have a snack. It just took longer and was a million times brighter.

Continue reading “Whether They’re Stellar-Mass or Supermassive, Black Holes Behave Pretty Much the Same Way”

New Simulations Show How Black Holes Grow, Through Mergers and Accretion

Artist's impression of two merging black holes. Credit: Bohn, Throwe, Hébert, Henriksson, Bunandar, Taylor, Scheel/SXS

One of the most pressing questions in astronomy concerns black holes. We know that massive stars that explode as supernovae can leave stellar mass black holes as remnants. And astrophysicists understand that process. But what about the supermassive black holes (SMBHs) like Sagittarius A-star (Sgr A*,) at the heart of the Milky Way?

SMBHs can have a billion solar masses. How do they get so big?

Continue reading “New Simulations Show How Black Holes Grow, Through Mergers and Accretion”

Closest Black Hole Found, Just 1,000 Light-Years From Earth

This artist’s impression shows the orbits of the objects in the HR 6819 triple system. This system is made up of an inner binary with one star (orbit in blue) and a newly discovered black hole (orbit in red), as well as a third object, another star, in a wider orbit (also in blue). The team originally believed there were only two objects, the two stars, in the system. However, as they analysed their observations, they were stunned when they revealed a third, previously undiscovered body in HR 6819: a black hole, the closest ever found to Earth. The black hole is invisible, but it makes its presence known by its gravitational pull, which forces the luminous inner star into an orbit. The objects in this inner pair have roughly the same mass and circular orbits. The observations, with the FEROS spectrograph on the 2.2-metre telescope at ESO’s La Silla, showed that the inner visible star orbits the black hole every 40 days, while the second star is at a large distance from this inner pair. 

Black holes are invisible to the naked eye, have no locally detectable features, and even light can’t escape them. And yet, their influence on their surrounding environment makes them the perfect laboratory for testing physics under extreme conditions. In particular, they offer astronomers a chance to test Einstein’s Theory of General Relativity, which postulates that the curvature of space-time is altered by the presence of a gravity.

Thanks to a team of astronomers led by the European Southern Observatory (ESO), the closest black hole has just been found! Using the ESO’s La Silla Observatory in Chile, the team found this black hole in a triple system located just 1000 light-years from Earth in the Telescopium constellation. Known as HR 6819, this system can be seen with the naked eye and could one of many “quiet” black holes that are out there.

Continue reading “Closest Black Hole Found, Just 1,000 Light-Years From Earth”