supernova explosion 41,000 years ago, at a distance of 250 lightyears, could have killed off the mammoth<\/a>.<\/p>\nMammoth 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)<\/span> \u2013 velocities typical of supernova ejecta.<\/span><\/p>\n\u00a0<\/p>\n
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.<\/span><\/figcaption><\/div>\nAlso, 13,000-year-old archaeological sites in North America show evidence of a large impact.<\/p>\n
This could have been debris from a supernova explosion that may have caused the final extinction of the mammoth and other large mammals.<\/p>\n
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>\n
So perhaps the safe distance for a supernova is as much as 250 lightyears from Earth.<\/p>\n
DEM L249, remnant of a Type 1a supernova. Credit: ESA\/Hubble & NASA, Y. Chu<\/span><\/figcaption><\/div>\nAre there any potentially dangerous supernovae within 250 lightyears of Earth?<\/p>\n
The white dwarf HR8210, only 150 lightyears<\/span> away, is hovering near the critical Chandrasekhar limit (the maximum mass for a white dwarf), but as part of a binary system it is gradually accreting matter and gaining mass.<\/p>\nShould it reach 1.44 solar masses, it will explode as a Type Ia supernova, with potentially devastating effects for Earth.<\/p>\n
The timescale for this may be hundreds of millions of years, but its discovery suggests there may be other potential killers out there.<\/p> <\/body><\/html>\n
By Paul Roche Published: Thursday, 12 January 2023 at 12:00 am It\u2019s often stated that a supernova explosion would have to be within about 25 lightyears of Earth to cause significant environmental damage. However, scientists at Lawrence Berkeley National Laboratory reported in the mid noughties that a supernova explosion 41,000 years ago, at a distance […]<\/p>\n","protected":false},"author":24,"featured_media":40454,"template":"","categories":[1],"acf":{"readingTimeMinutes":"2"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/01\/how-close-would-a-supernova-have-to-be-to-affect-life-on-earth.jpg",1500,1069,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/01\/how-close-would-a-supernova-have-to-be-to-affect-life-on-earth-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/01\/how-close-would-a-supernova-have-to-be-to-affect-life-on-earth-300x214.jpg",300,214,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/01\/how-close-would-a-supernova-have-to-be-to-affect-life-on-earth-768x547.jpg",768,547,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/01\/how-close-would-a-supernova-have-to-be-to-affect-life-on-earth-1024x730.jpg",800,570,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/01\/how-close-would-a-supernova-have-to-be-to-affect-life-on-earth.jpg",1500,1069,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/01\/how-close-would-a-supernova-have-to-be-to-affect-life-on-earth.jpg",1500,1069,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"By Paul Roche Published: Thursday, 12 January 2023 at 12:00 am It\u2019s often stated that a supernova explosion would have to be within about 25 lightyears of Earth to cause significant environmental damage. However, scientists at Lawrence Berkeley National Laboratory reported in the mid noughties that a supernova explosion 41,000 years ago, at a distance…","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/40453"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/40454"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=40453"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=40453"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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