The narrative describes a hypothetical scenario where a supernova event occurs in the future, impacting our understanding of the universe and potentially causing mass extinctions. It begins by discussing the constellations that ancient humans would have known, and how the stars have shifted over time.
The narrative then introduces the concept of a supernova, using Betelgeuse, a bright red star in the Orion constellation, as an example. It explains that supernovae are the death of a massive star, and can have different impacts depending on their type.
The narrative discusses the potential dangers of a supernova, including the destruction of the ozone layer, which could lead to mass extinctions. It also explains that the effects of a supernova can be felt even if it is not within a "kill zone" of 15-20 light years, due to the effects of cosmic rays and the muon flux.
The narrative then discusses the types of supernovae, including core collapse supernovae and hypernovae, and how they can have different impacts.
The narrative concludes by discussing the potential future of supernovae, estimating that a supernova of one type or another goes off on average every 50 years inside the Milky Way. It suggests that the next truly spectacular supernova will probably be Betelgeuse, which is not expected to happen in our lifetime, but will likely be seen by future generations.
The narrative emphasizes the importance of understanding supernovae and their potential impacts on Earth and the universe.
1. Around two and a half million years ago, a human-like creature observed a brightening star in a familiar constellation. This star became brighter than the full moon in a day and was visible during the daytime. After weeks, it faded and vanished entirely, leaving a void in the constellation [Source: Document(page_content='00:00:00.24: Thank you to Brilliant for supporting PBS...')].
2. Betelgeuse, a bright red star on the shoulder of Orion, is a red supergiant—a star 11 times the mass of our Sun and nearing the end of its life. The exact timeline of its death sequence is unknown [Source: Document(page_content='00:00:00.24: Thank you to Brilliant for supporting PBS...')].
3. Supernovae have lit up our sky recently on astronomical and geological timescales. A supernova is a star that has exhausted its nuclear fuel and collapses under its own gravity, releasing an enormous explosion of energy [Source: Document(page_content='00:02:58.20: carved out by supernova explosions over the...')].
4. Supernovae can have different impacts depending on their type and proximity to Earth. For instance, a type II supernova, also known as a core-collapse supernova, occurs when a star's core collapses. The energy released in a supernova is primarily carried away in neutrinos, which can pass through everything [Source: Document(page_content='00:03:03.06: Supernovae have lit up our sky recently on...')].
5. The shockfront of a supernova, which is a wave of particles, kinetic energy, and magnetic fields leading the expanding supernova remnant, can be potentially dangerous. It can take hundreds to thousands of years to reach us depending on the distance [Source: Document(page_content="have to be within 15-20 light years...")].
6. Supernovae can influence the Earth even if we're outside the kill zone. For example, the Pleistocene supernova is thought to have had a massive impact on Earth, causing a mass extinction event [Source: Document(page_content='00:07:17.58: Unlike most cosmic rays, this heavy cousin...')].
7. There are ways to extend the kill zone for an exploding star. In some cases, the gas surrounding the progenitor star can continue to radiate X-rays for hundreds to thousands of years after the initial explosion. Such a supernova could deplete our ozone layer from much further distances than a regular supernova [Source: Document(page_content='00:08:07.62: In a study that came out in April this year...')].
8. Betelgeuse is 640 light years away, and it's one of the few stars closer to us that will eventually go supernova. However, there is an impending supernova closer than these—IK Pegasi, which is within the maximum range of dangerous at 150 light years [Source: Document(page_content='00:10:41.58: Betelgeuse is 640 light years away, so no...')].
9. A supernova of one type or another goes off on average every 50 years inside the Milky Way. Most of these are many thousands of light years away. Supernovae occur in the 15-20 light years needed to directly roast our ozone layer on the order of a billion years or so [Source: Document(page_content='00:13:20.94: drifted to a much safer distance of a few...')].
10. The next truly spectacular supernova will probably be Betelgeuse. It’s not entirely impossible, but we’re unlikely to catch that one ourselves, despite its recent rumblings. It’s more likely that this spectacle will be enjoyed by a distant future generation [Source: Document(page_content="see with your own naked eye could well happen...")].