According to a new study, The Milky Way center may be even more peculiar than astronomers have expected.
An unidentified barrier is preventing the highest-speed particles of the universe from getting inside our galaxy’s center, as Livescience reported.
The Invisible ‘barrier‘
A researcher group from the Chinese Academy of Sciences in Nanjing investigated a radioactive gamma-rays map.
In the universe, gamma rays, regarded as the highest-energy form of light, occur following the collision between immensely high-speed particles, named cosmic rays, into ordinary matter.
According to the journal, Nature Communications reported on Nov. 9 about the map, outside the galaxy’s center appears cosmic rays and gamma-rays in multitude due to the acceleration of particles to astonishing speeds, closely approaching the speed of light.
Something unidentified near the galaxy center is the acceleration’s cause.
The unidentified barrier prevents most of the cosmic rays from the universe from getting inside although the galaxy center itself sends a constant storm of high-energy radiation into space.
According to the researchers’ demonstration, the effect appears as an invisible “barrier” surrounding the galaxy center maintaining a lower cosmic rays density level at the center compared with the baseline level throughout the galaxy reported LiveScience.
In simpler terms, cosmic rays can easily escape the galaxy center but much fewer than would be expected can enter.
The cause of the cosmic barrier or its process is unknown at present.
The cosmic ray sea
Our galaxy center appears as a dense and dusty place, where more than 1 million times as many stars are found compared to the whole solar system.
They all hover around a super–huge black hole measuring around 4 million times the sun’s mass. Our galaxy center is a part of the constellation Sagittarius located around 26,000 light-years from Earth.
Scientists have long doubted that this black hole, called Sagittarius A*, or possibly the galaxy center’s other object, speeds up protons and electrons almost equivalent to the speed of light. It then creates and emits cosmic rays that disseminate throughout our galaxy and onward into intergalactic space.
The propagation of cosmic rays through our galaxy’s magnetic fields creates an ocean of high-energy particles known as the cosmic ray sea with nearly equivalent density throughout the Milky Way.
In their new study, researchers compared the density of cosmic rays in this sea with that of cosmic rays within the galactic center.
Although cosmic rays are invisible to the naked eye, scientists can detect them using gamma-ray maps of space, which productively exhibit the location of their collision with other types of matter.
Impacts of the ‘undefined‘
The research group stated that the undefined barrier in the galaxy center is acting as a massive particle accelerator, shooting rays out into the galaxy, based on data from the Fermi Large Area Telescope.
According to Live Science, Sagittarius A* is a possible candidate because certain particles could theoretically be shot into space by black holes even if these black holes swallow up everything else around them.
However, the unidentified “barrier,” as revealed by the map, appears as an obvious point where the cosmic rays decrease sharply at the edge of the galaxy center.
According to the researchers, the cause of this occurrence is challenging to explain, but it seems to be related to the magnetic field clutter near our galaxy’s dense core.
The group proposed in their research paper that dense clouds of dust and gas near the galaxy center, for example, could crumble onto themselves, squeezing the magnetic fields there before building a cosmic-ray-proof barrier.
Another possibility came with the myriad stars’ stellar winds at the galaxy center. They are thrusting back against the cosmic ray sea in the same way that the solar win does.
The peculiar and unexpected influence at the galaxy center begs further investigation.