Milky Way Had A Big Blast, Furious Explosion 6 Million Years Ago
The Milky Way galaxy is a peaceful place right now, but the center of the galaxy is home to a supermassive black hole that occasionally sucks small amounts of hydrogen gas from nearby objects. But this is not always the scenario since a new study revealed what possibly happened 6 million years ago when the galaxy's core blasted furiously, which explained why there is a huge missing mass on the galaxy.
Studies show that the Milky Way Galaxy weights about 1-2 trillion times heavier than our Sun, which is mainly composed of five-sixths invisible dark matter. The remaining one-sixth is made up of stars, planets, and other solar masses (150-300 billion). But it seems odd that counting up all gas, dust, and stars will only make up 65 billion solar masses and the rest will only be made of protons, neutrons, and electrons that are missing or unseen yet.
According to lead author Fabrizio Nicastro of Harvard-Smithsonian Center for Astrophysics, "We played a cosmic game of hide-and-seek. And we asked ourselves, where could the missing mass be hiding?"
"We analyzed archival X-ray observations from the XMM-Newton spacecraft and found that the missing mass is in the form of a million-degree gaseous fog permeating our galaxy. That fog absorbs X-rays from more distant background sources," he continued explaining.
In their study, they calculated the amount of normal matter using the amount of absorption and determined how the matter was distributed in the galaxy. They used computer models and simulations to observe the distribution of gas and discovered that there was a huge "bubble" in the center of the galaxy.
They believe that a tremendous amount of energy was required to make the bubble and it can only come from a feeding black hole. The activity led to a shock wave clearing 20,000 light-years of space six million years later. They think the black hole subsided after it runs out of objects to eat.
They calculated the timeline based on the age of stars found in the galactic center. And the stars were made of the same materials that once were sucked by the black hole. This million-degree gas sums up to 130 billion solar masses which might explain where the missing matter is since it could not be seen.
A proposed space mission called X-ray Surveyor that plans to map out the "bubble" to explain the missing mass. Phys.org reported a similar plan by ESA's Athena X-ray Observatory in 2028. The study was published in the Astrophysical Journal.