{"id":57509,"date":"2024-04-10T08:38:02","date_gmt":"2024-04-10T08:38:02","guid":{"rendered":"http:\/\/3a6ddfef-1b1d-4215-bec8-c06f657318a1"},"modified":"2024-04-10T10:08:23","modified_gmt":"2024-04-10T10:08:23","slug":"how-close-would-a-supernova-have-to-be-to-affect-life-on-earth-should-we-be-worried","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/how-close-would-a-supernova-have-to-be-to-affect-life-on-earth-should-we-be-worried\/","title":{"rendered":"How close would a supernova have to be to affect life on Earth? Should we be worried?"},"content":{"rendered":"

Could an exploding star have a devastating effect on planet Earth and its inhabitants? <\/p>

By <\/p>

Published: Wednesday, 10 April 2024 at 08:38 AM<\/p>

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It’s often stated that a supernova<\/a> explosion would have to be as close as about 25 lightyears of Earth to affect life and cause significant environmental damage.<\/p>

However, scientists at Lawrence Berkeley National Laboratory reported in the mid noughties that a supernova explosion 41,000 years ago, at a distance of 250 lightyears, could have killed off the mammoth<\/a>.<\/p>

Mammoth tusks dated at 34,000 years old were found to contain tiny impact craters, apparently produced by slightly radioactive, iron-rich grains moving at 10,000km\/s (22 million mph) \u2013 velocities typical of supernova ejecta.<\/p>

Mammoth tusks have been found to contain evidence that the species may have been wiped out by a supernova. Photo by Tim Boyle\/Getty Images.<\/figcaption><\/figure>

Also, 13,000-year-old archaeological sites in North America show evidence of a large impact.<\/p>

This could have been debris from a supernova explosion that may have caused the final extinction of the mammoth and other large mammals.<\/p>

Impact ejecta at these sites contained magnetic spherules, produced by the impact of a large meteor, and radioactive potassium-40, formed in supernovae explosions.<\/p>

So perhaps the safe distance for a supernova is as much as 250 lightyears from Earth.<\/p>

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DEM L249, remnant of a Type 1a supernova. Credit: ESA\/Hubble & NASA, Y. Chu<\/figcaption><\/figure>

Are there any potentially dangerous supernovae within 250 lightyears of Earth?<\/p>

White dwarf HR8210, 150 lightyears away, is hovering near the critical Chandrasekhar limit (the maximum mass for a white dwarf).<\/p>

But as part of a binary system it is gradually accreting matter and gaining mass.<\/p>

Should it reach 1.44 solar masses, it will explode as a Type Ia supernova, with potentially devastating effects for Earth.<\/p>

The timescale for this may be hundreds of millions of years, but its discovery suggests there may be other potential killers out there.<\/p>

Video interview: What is a supernova?<\/strong><\/h2>