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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00:00Visit Chandra's beautiful universe.
00:05Supernova Survey
00:10An exploded star can pose more risks to nearby planets than previously thought,
00:15according to a new study from NASA's Chandra X-ray Observatory and other X-ray telescopes.
00:22This newly identified threat involves a phase of intense X-rays
00:26that can damage the atmospheres of planets over 100 light-years away.
00:31Although Earth is not in danger now, it may have experienced such X-ray exposure in the past.
00:37Before this study, most research on the effects of supernova explosions
00:41had focused on the danger from two periods,
00:44the intense radiation produced by a supernova in the days and months after the explosion,
00:49and the energetic particles that arrive hundreds to thousands of years afterward.
00:54However, even these alarming threats do not fully catalog the dangers in the wake of an exploded star.
01:01Researchers have discovered that in between these two previously identified dangers lurks another.
01:07The aftermaths of supernovae always produce X-rays,
01:11but if the supernova's blast wave strikes dense surrounding gas,
01:15it can produce a particularly large dose of X-rays that arrives months to years after the explosion,
01:22and may last for decades.
01:24The calculations in this latest study are based on X-ray observations of 31 supernovae and their aftermath,
01:31mostly obtained from NASA's Chandra X-ray Observatory, Swift and NuSTAR missions,
01:36and ESA's XMM-Newton.
01:39The analysis of these observations shows that there can be lethal consequences
01:43from supernovae interacting with their surroundings
01:46for planets located as much as about 160 light-years away.
01:51If a torrent of X-rays sweeps over a nearby planet,
01:54the radiation would severely alter the planet's atmospheric chemistry.
01:58For an Earth-like planet, this process could wipe out a significant portion of ozone,
02:03which ultimately protects life from the dangerous ultraviolet radiation of its host star.
02:09As far as anyone knows, the Earth is not in any danger from an event like this now.
02:14However, it may be the case that such events played a role in Earth's past.
02:19There is strong evidence, including the detection in different locations around the globe
02:23of a radioactive type of iron,
02:25that supernovae occurred close to Earth between about 2 and 8 million years ago.
02:30Researchers estimate these supernovae were between about 65 and 500 light-years away from Earth.
02:37Although the Earth and the solar system are currently in a safe space
02:41in terms of potential supernova explosions, many other planets in the Milky Way are not.
02:46These high-energy events would effectively shrink the areas within the Milky Way galaxy,
02:51known as the galactic habitable zone,
02:53where conditions would be conducive for life as we know it.
02:57Because the X-ray observations of supernovae are sparse,
03:00particularly of the variety that strongly interact with their surroundings,
03:04the authors would like to see follow-up observations of interacting supernovae
03:09for months and years after the explosion.
03:16Transcription by ESO. Translation by —