Posted on by Matt Williams

Astronomers Get as Close as They Can to Seeing the Black Hole at the Heart of the Milky Way

This visualization uses data from simulations of orbital motions of gas swirling around at about 30% of the speed of light on a circular orbit around the black hole. Credit: ESO/Gravity Consortium/L. Calçada

Since the 1970s, astronomers have theorized that at the center of our galaxy,  about 26,000 light-years from Earth, there exists a supermassive black hole (SMBH) known as Sagittarius A*. Measuring an estimated 44 million km (27.3 million mi) in diameter and weighing in at roughly 4 million Solar masses, this black hole is believed to have had a profound influence on the formation and evolution of our galaxy.

And yet, scientists have never been able to see it directly and its existence has only been inferred from the effect it has on the stars and material surrounding it. However, new observations conducted by the GRAVITY collaboration** has managed to yield the most detailed observations to date of the matter surrounding Sagittarius A*, which is the strongest evidence yet that a black hole exists at the center of the Milky Way. Continue reading “Astronomers Get as Close as They Can to Seeing the Black Hole at the Heart of the Milky Way”

Posted on by Elizabeth Howell

Celestial Laser Show? Nope, These Are Trails Showing Off Star Colors

Star trails above the European Space Observatory's Paranal Observatory in Chile, showing three of the four auxiliary telescopes of the Very Large Telescope Interferometer (VLTI). Credit: ESO/B. Tafreshi

There are so many colorful streaks in that image above that you’d be forgiven for thinking somebody is shooting lasers around the European Southern Observatory (ESO) in Chile. Actually, though, this demonstrates a common technique for astronomy photo-taking where you do a time lapse to watch the stars moving as the Earth makes its daily rotation.

The image of auxiliary telescopes of Very Large Telescope Interferometer is not only pretty, but does have some scientific interest as well, ESO said.

“This technique … enhances the natural colours of the stars, which gives an indication of their temperature, ranging from about 1000 degrees Celsius [1,832 Fahrenheit] for the reddest stars to a few tens of thousands of degrees Celsius [or Fahrenheit] for the hottest, which appear blue. The sky in this remote and high location in Chile is extremely clear and there is no light pollution, offering us this amazing light show,” stated the European Southern Observatory.

According to ESO, these supplementary telescopes working together allow astronomers to “see details up to 25 times finer than with the individual telescopes.” You can read more about the VLTI at this ESO link, which includes some interesting facts — such as why the interferometers are named Antu, Kueyen, Melipal and Yepun.

Source: European Southern Observatory