Ancient Code

In Brief: Astronomers have recently found that radio jets from the supermassive black hole located at the very center of the Milky Way could be pointed almost directly towards the Earth.

New observations of the supermassive black hole located at the center of the galaxy Sagittarius A*(around 25,000 light years away from Earth) have revealed fascinating new details.

Sagittarius A* is believed to weigh around 4 million solar masses. Its apparent size in the sky is less than 100 millionth of a degree, which corresponds to the size of a tennis ball on the moon as seen from the Earth, explains an article detailing the discovery at the website of the University of Radboud in the Netherlands.

Scientists used radio telescopes around the world to observe Sagittarius A* and found that the emissions coming from the black hole originate in a very small area, smaller than scientists had previously expected.

Since the black hole is surrounded by an extremely foggy cloud of hot gas, we can’t really observe it using traditional methods or telescopes. The huge distance it is from Earth also doesn’t help experts.

But scientists have come up with a new technique and found unprecedented details about Sagittarius A*.

The bottom right image shows Sgr A* as seen in the data. The top images are simulations, while the bottom left is Sgr A* with the scattering removed. Image Credit: (S. Issaoun, M. Mościbrodzka, Radboud University/ M. D. Johnson, CfA).

Based on a number of observations, and using a technique dubbed very long baseline interferometry (VLBI) scientists have identified a relativistic jet angled towards Earth.

VLBI combines the power of various telescopes into one, massive virtual telescope.

The resolution achieved was twice as high as in previous observations at this frequency, and produced the first image of Sagittarius A* that is completely free of interstellar scattering, an effect caused by density irregularities in the ionized material along the line of sight between Sagittarius A* and the Earth, notes an article by the University of Radboud.

“The galactic center is full of matter around the black hole, which acts like frosted glass that we have to look through,” astrophysicist Eduardo Ros of the Max Planck Institute for Radio Astronomy in Germany explained in an interview with New Scientist.

The discovery is detailed in a new scientific paper led by University of Nijmegen Ph.D. student Sara Issaoun and published in the Astrophysical Journal.

The paper explains that scientists have managed to penetrate for the first time ever, the cloud of hot gas that obscured the black hole, and discovered that the radio emission originates from a small region in space, that looks as though the jet is pointed towards our planet.

Scientists successfully mapped out the exact properties of the black hole and believe that the black hole may be lying on its side.

“This may indicate that the radio emission is produced in a disk of infalling gas rather than by a radio jet,” explained Issaoun.

“However, that would make Sgr A* an exception compared to other radio emitting black holes. The alternative could be that the radio jet is pointing almost at us.”