An international team of astrophysicists from Italy, Japan and the USA has discovered evidence of the most powerful sources of radiation known in the Universe in our Milky Way galaxy. Their energies are tens of millions of times higher than any particle accelerator on Earth can produce. The study was published in the scientific journal magazine Physical Review Letters (PRL).
Ultra-high-energy cosmic rays were discovered in 1962, but scientists still don’t know exactly where they come from. In the past, astronomers have found similar radiation coming from objects outside the Milky Way.
There may be at least three sources of ultra-high-energy cosmic rays in our galaxy, according to recent results obtained with the CALET Calometric Electron Telescope on the International Space Station. All of them are located 3 thousand light years from Earth.
CALET recorded its first event of this kind in October 2015. Among the seven million rays detected since then, the telescope was able to detect a range of cosmic ray energies up to 10 teravolts and beyond. Scientists say this is a significant improvement over previous studies, which only found cosmic rays with a power of about 4 teravolts.
The most likely candidate for the role of the source of ultra-high energy rays is considered to be a supernova remnant in the Vela constellation, 800 light-years from our planet. The star that gave birth to it exploded about 11 thousand years ago.
The team plans to continue measuring CALET cosmic ray sources until the ISS is retired; This will probably happen by the end of this decade.
Earlier astronomers warned About how life on Earth is threatened by the possibility of imminent collisions with neutron stars.