{"id":19416,"date":"2016-04-07T00:34:03","date_gmt":"2016-04-06T16:34:03","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/scientists-say-supernovae-spread-fallout-when-human-ancestors-walked-the-earth\/"},"modified":"2016-04-07T00:34:03","modified_gmt":"2016-04-06T16:34:03","slug":"scientists-say-supernovae-spread-fallout-when-human-ancestors-walked-the-earth","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/scientists-say-supernovae-spread-fallout-when-human-ancestors-walked-the-earth\/","title":{"rendered":"Scientists say supernovae spread fallout when human ancestors walked the earth"},"content":{"rendered":"
\"Supernova
An artist\u2019s impression shows a supernova explosion in its prime. (Credit: Greg Stewart \/ SLAC)<\/figcaption><\/figure>\n

Researchers say they\u2019ve found evidence of supernova explosions that spewed radioactive fallout over Earth during the age when humanity\u2019s ancestors were evolving into upright-walking, big-brained creatures.<\/p>\n

One of two studies published in the journal Nature identifies deposits of radioactive iron-60 in deep-sea cores extracted from the bottom of the Indian, Pacific and Atlantic oceans. The deposits were traced back to one time frame ranging from 1.5 million to 3.2 million years ago, and another period 6.5 million to 8.7 million years ago.<\/p>\n

The researchers behind that study, led by Anton Wallner of Australian National University, say the iron-60 was blasted toward us by \u201cmultiple supernova and massive-star events\u201d that occurred within 325 light-years of Earth.<\/p>\n

Today, this region of space is known as the Local Bubble. The region was given that name decades ago, because even back then, scientists surmised that the \u201cbubble\u201d of hot, diffuse gas in our celestial neighborhood was created by a cluster of supernova explosions.<\/p>\n

https:\/\/www.youtube.com\/watch?v=f-NJMRuYxWc<\/p>\n

The other study in Nature, conducted by Dieter Breitschwerdt of the Berlin Institute of Technology and his colleagues, took a closer look at the more recent iron-60 deposit to trace its origins.<\/p>\n

They say it\u2019s most likely that that two supernovae were responsible: One would have occurred 2.3 million years ago, involving a star 9.2 times as massive as the sun. The other would have happened 1.5 million years ago, when a star 8.8 times as massive as the sun blew up.<\/p>\n

The supernovae would have been as bright as the full moon, and could have been seen during the day, the researchers say.<\/p>\n

\u201cThis research essentially proves that certain events happened in the not-too-distant past,\u201d Adrian Melott, an astrophysicist at the University of Kansas who was not involved in either study, said in a news release.<\/p>\n

\u201cThey make it clear approximately when they happened and how far away they were. Knowing that, we can consider what the effect may have been with definite numbers. Then we can look for events in the history of the Earth that might be connected to them.\u201d<\/p>\n