Scientists accidentally discover huge galactic structure in space

Astronomers have accidentally discovered a huge, previously undetected galactic structure that could change the way we think about how stars are made.

The structure, which is made up of a mind-boggling amount of gas, spans the entire Milky Way disk and possibly far into its periphery.

The discovery was made by a group of astronomers including Ron Allen, a professor in the Department of Physics and Astronomy at Johns Hopkins University.

It was only recently that astronomers also said that there may be many more Earth-sized planets orbiting other stars than previously thought.

When astronomers talk about the emptiness of space, they are referring to the empty space between stars and planets that is not filled with anything.

However, if one looks at the Universe on a sufficiently large scale, it becomes evident that even the emptiness of space is not entirely empty. Instead, it’s filled with what’s known as the interstellar medium, a collection of very low density gases and dust.

It is believed that this gas is mainly composed of molecular hydrogen (H2) and other molecules.

The problem is that H2 usually cannot be detected, so astronomers should instead look for other molecules mixed with interstellar gas that help infer its existence, such as carbon monoxide (CO) or OH gas, usually the carbon monoxide. These other molecules are called tracers.

In 2012, Allen accidentally found OH emissions but no CO emissions while working on something else. He thought this OH might hint at a massive cloud of H2.

He teamed up with Dave Hogg of the National Radio Astronomical Observatory in Virginia, as well as Philip Engelke and Michael Busch, both with doctorates. Johns Hopkins University students, to see if they could use OH as an H2 tracer by observing it with the Green Bank Telescope (GBT), the world’s largest fully steerable radio telescope.

They discovered that OH can indeed be used as a tracer for H2 gas. The Green Bank Observatory said in a statement: “Although it required long exposure times, OH observations began to fill in the gaps between previous observations of CO, showing molecular gas as a major component of structure of our galaxy. “

Then Engelke found a large and weak feature throughout the telescope’s line of sight. The researchers believed this was due to the telescope itself rather than something that was actually there.

However, after spending hundreds of hours staring again, using different techniques and even a different telescope, they determined that the huge feature was really there.

A study of the discovery, published in The Astrophysical Journal in June, describes the discovery as “fortuitous” – meaning it was found by chance – and describes the structure as “an extremely large and ubiquitous OH emission” located around the second quadrant of the other galaxy.

He adds: “Our results imply the existence of a thick disk of diffuse molecular gas in the outer galaxy previously undetected in CO readings across the sky.”

The team believes the existence of the structure has implications for theories about star formation as well as the structure of the interstellar medium.

Allen died in 2020 while the research was being written. Engelke said in a statement from the Green Bank Observatory: “We were very lucky to know him. Ron was really excited about this discovery, and I know he would have been proud of the result.”