A study using the NASA’s Chandra X-ray Observatory and other X-ray telescopes has revealed that "an exploded star can pose more risks to nearby planets than previously thought." The Chandra team explains.
Credit: NASA/CXC/A. Hobart
Credit: NASA/CXC/A. Hobart
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TechTranscript
00:00 [music]
00:02 Visit Chandra's beautiful universe.
00:05 Supernova Survey
00:08 An exploded star can pose more risks to nearby planets than previously thought,
00:15 according to a new study from NASA's Chandra X-ray Observatory and other X-ray telescopes.
00:21 This newly identified threat involves a phase of intense X-rays
00:26 that can damage the atmospheres of planets over 100 light-years away.
00:31 Although Earth is not in danger now, it may have experienced such X-ray exposure in the past.
00:37 Before this study, most research on the effects of supernova explosions
00:41 had focused on the danger from two periods,
00:44 the intense radiation produced by a supernova in the days and months after the explosion,
00:49 and the energetic particles that arrive hundreds to thousands of years afterward.
00:54 However, even these alarming threats do not fully catalog the dangers in the wake of an exploded star.
01:01 Researchers have discovered that in between these two previously identified dangers lurks another.
01:07 The aftermaths of supernovae always produce X-rays,
01:11 but if the supernova's blast wave strikes dense, surrounding gas,
01:15 it can produce a particularly large dose of X-rays that arrives months to years after the explosion,
01:22 and may last for decades.
01:24 The calculations in this latest study are based on X-ray observations of 31 supernovae and their aftermath,
01:31 mostly obtained from NASA's Chandra X-ray Observatory, SWIFT and New Star missions, and ESA's XMM-Newton.
01:39 The analysis of these observations shows that there can be lethal consequences
01:43 from supernovae interacting with their surroundings for planets located as much as about 160 light-years away.
01:51 If a torrent of X-rays sweeps over a nearby planet,
01:54 the radiation would severely alter the planet's atmospheric chemistry.
01:58 For an Earth-like planet, this process could wipe out a significant portion of ozone,
02:03 which ultimately protects life from the dangerous ultraviolet radiation of its host star.
02:09 As far as anyone knows, the Earth is not in any danger from an event like this now.
02:14 However, it may be the case that such events played a role in Earth's past.
02:19 There is strong evidence, including the detection in different locations around the globe of a radioactive type of iron,
02:25 that supernovae occurred close to Earth between about 2 and 8 million years ago.
02:30 Researchers estimate these supernovae were between about 65 and 500 light-years away from Earth.
02:37 Although the Earth and the solar system are currently in a safe space in terms of potential supernova explosions,
02:44 many other planets in the Milky Way are not.
02:46 These high-energy events would effectively shrink the areas within the Milky Way galaxy,
02:51 known as the galactic habitable zone, where conditions would be conducive for life as we know it.
02:57 Because the X-ray observations of supernovae are sparse,
03:00 particularly of the variety that strongly interact with their surroundings,
03:04 the authors would like to see follow-up observations of interacting supernovae for months and years after the explosion.
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