Searching for the supernova neutrino background of the universe

This is a sobering statement that stars are like the sun, or rather all stars will eventually die, even the sun. Don’t panic though, we still have a few billion years to go, so you’ll make it to the end of this article. The most massive stars die as dramatic supernova explosions occur, and when they do, they send a burst of neutrinos into space. Astronomers now believe that it is likely that there is a neutrino background in the universe, and that one day we will be able to map the historical distribution of supernova explosions, possibly even as far back as 2035.

The death of stars can be compared to bubbles; some simply turn out to be a disappointing “pfffft” like lower-mass stars like our sun, while others give off a crisp, satisfying glow like stars eight times the mass of the sun. When these massive stars appear, it’s actually a fascinating process in itself. The forces inside a star are balanced for most of a star’s life, with an inward force balanced by an outward thermonuclear force, the result of nuclear fusion in the star’s core.

Massive stars appear because they usually reach a stage at the end of their lives where the core is rich in iron, and the fusing iron doesn’t produce energy, it absorbs it. With an iron core, the thermonuclear force ceases and the core collapses, leading to a massive supernova explosion. Now, when atoms split or fuse, they emit neutrinos; even lowly fruits like bananas produce them from the natural radioactivity of potassium.

The same goes for supernova explosions. When they occur, the explosions, or neutrinos, are scattered across space on the order of 10.^58:. Throughout the history of the universe, neutrinos have been scattered throughout the universe, so they are now among the most abundant particles with mass in the entire universe. They are so abundant that trillions of neutrinos pass through our bodies every second.

It’s hard to know how many stars have gone supernova since the Big Bang 13.8 billion years ago, but it’s just possible that studying the background “buzz” of neutrinos, the so-called diffuse supernova background (DSNB), may provide the answer. : The DSNB has not yet been discovered, but if we can find it, we can determine the rate of collapse of the historical core since the beginning of time.

This intriguing concept is being explored with a number of existing and upcoming instruments, notably the Jiangmen Underground Neutrino Observatory (JUNO), which will begin collecting data in 2023, and the Super Kwmiokande neutrino detector in Japan, which has been collecting data recently. eight years. These and other tools examine DSNB and improve models.

The team (Nick Ekanger, Shunsaku Horiuchi, Hiroki Nagakura, and Samantha Reitz) used data from these and other instruments to refine their estimates of DSNB and conclude that it should be detectable, and concluded that it is possible in their paper, posted arXiv: preprint server. Although it has not yet been detected, it is an exciting prospect that within the next decade we may be able to infer from observations the rate of supernova explosions as the universe evolves.