The role of star explosions in the Earth’s climate history may be greater than scientists thought.
nearby Supernova A new research report claims that in the past 40,000 years, they have left a series of possible fingerprints in the tree ring records on the earth, which may have destroyed the earth’s climate many times during this period.
Study author Robert Brakenridge, a senior researcher at the Arctic and Alpine Institute at Boulder University in Colorado, said: “These are extreme events, and their potential impact seems to match the tree-year record.” Said in the statement.
Supernova photos: great photos of star explosions
Breckenridge compiled a list of 1
Carbon 14 is a radioactive isotope of carbon, and its nucleus contains eight neutrons instead of the usual six neutrons. Carbon-14 is rare on the earth, and it will not occur naturally here without external influence-that is, high-energy radiation flows in from deep space, which will convert some “normal” carbon in our atmosphere into carbon-14 (This explains why this isotope is also called radiocarbon).
Breckenridge said: “Usually there is a stable number every year.” “Trees picked up carbon dioxide, Some of the carbon will be radiocarbon. “
However, the amount of radiocarbon is not always stable.Scientists found peaks in tree ring records, which are usually attributed to powerful Flares from our own sun. But Breckenridge suspected that supernovas might be involved, so he researched possible connections.
He made a tempting but tentative discovery: Eight of the closest supernovae on his list occurred near short-lived radiocarbon peaks. The association is particularly strong for four supernovae, including one that ended the life of a star in the constellation Vela about 815 light years from Earth 13,000 years ago.
Breckenridge discovered that shortly after the explosion, the radiocarbon content in the earth’s atmosphere rose briefly by about 3%.
Taking into account the various uncertainties involved, the results are still uncertain. For example, it is difficult to accurately determine the age of a supernova. Brakenridge said that the estimated time of the Vela explosion may be as long as 1,500 years.But he believes that the new results were posted online last week in International Journal of Astrobiology, Indicating that more research on the supernova-radiocarbon link is necessary.
Breckenridge said: “What makes me move forward is when I look at the ground records, I say,’My God, the effects of predictions and simulations do exist.”
He is not the only scientist to suggest that supernovae may have a significant impact on life on Earth.Other studies assume that nearby stars explode Caused or caused the mass extinction of some species, By changing the earth’s atmosphere and causing climate change.
Mike Wall (Mike Wall) is “outside“(Grand Central Press, 2018; Karl Tate illustration), this is a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook .