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Across the Universe, a star exploded so violently that it annihilated itself
- geertj 7y agoPhotoid?
- ignorantguy 7y agonice one! three body problem reference.
- chongli 7y agoWow, it's impossible to Google that term. Every single result is related to "Photo ID."
- saagarjha 7y agoYou get a couple if you put it in quotes: https://www.google.com/search?hl=en&q=%22photoid%22 https://www.google.com/search?hl=en&q=%22photoid%22
- ivalm 7y agoSupernovae resulting from an impact by a large object moving close to the speed of light. Was used/popularized in a series called "Three Body Problem" as a weapon (book premise is the "black forest theory", which is since every sentient civ is a potential existential threat advanced civs would genocide any aliens they detect, photoids being one of the exotic weapons to accomplish this).
- perl4ever 7y agoAlso see "The Fourth Profession" by Larry Niven. Aliens didn't annihilate everyone out of fear, but they would cause a nova when there was profit in doing so.
- massanassa 7y agour mom farted
- the8472 7y agoAn interesting tidbit is that the region of stellar parameters where the explosion is so massive that it leaves behind no compact remnant borders directly on the region where stars can collapse into a black hole without a supernova, they just wink out of existence. https://upload.wikimedia.org/wikipedia/commons/1/18/Remnants_of_single_massive_stars.svg https://upload.wikimedia.org/wikipedia/commons/1/18/Remnants...
- FakeComments 7y agoAm I reading wrong, or is no remnant in the middle of a black hole formation region? It looks like “direct black hole” is on both sides of “no remnants”.
- wallace_f 7y agoI guess on both sides they start out as star -> collapse, but one either side the collapse continues into a hole. Within those parameters the star will stop collapsing and go supernova and never collapse back. I guess that's what it means.
- _Microft 7y agoYes, this most likely just means that different processes are responsible for the same outcome (i.e. becoming a blackhole), depending on the mass of the star. Edit: see https://en.wikipedia.org/wiki/Pair-instability_supernova#250_solar_masses_or_more https://en.wikipedia.org/wiki/Pair-instability_supernova#250...
- sandworm101 7y agoEven the direct black holes dont quietly wink out. Once an even horizon forms, anything outside in now in a forming accretion disk. As things contract they start spinning. Things get hot/loud/bright until that disk settles dow.
- perl4ever 7y agoSo that chart seems to imply it is unknown whether the Sun will end up with "electron capture collapse" or as a neutron star. That's news to me, because when I was younger, I had the impression that the accepted theory was it would become a white dwarf.
- rolltiide 7y agoScience Nonfiction channel?
- cronix 7y agoStuff like this just boggles my mind. Imagine if we could capture/store even a small fraction of that energy that was released in mere seconds. It could probably power Earth for millions of years. Sorry if my maths are off a bit.
- marcinzm 7y agoThe energies of even less exotic stars are insane. If we could capture 1 second worth of our sun's output then we could power earth for almost a million years.
- sametmax 7y agoThe earth already does that, we just call it our ecosystem. It's why we have clean water, carrots, coal and, and the end the chain, the internet to talk about it.
- maxerickson 7y agoThey are talking about capturing the full irradiance of the sun for 1 second. You are talking about the little sliver of it that smacks Earth.
- sametmax 7y agoTrue, but it's enough. We don't need more that what we already got. We don't even use most of it.
- human20190310 7y agoNo, we need more. The main barrier to achieving the dreams of science fiction is a lack of energy to accelerate human-scale amounts of material to high speeds (then slow them down later).
- behringer 7y ago
- jackyinger 7y agoTotal tangent.. but there’s no innate reason to be totally boggled by huge (or incredibly tiny) numbers. I think getting all in a huff about them is an anti-pattern in science writing. I mean, we deal with gigabytes of data on machines with clock periods of nanoseconds every day. What is cool is learning about new-to-you physical mechanisms.
- aasasd 7y agoCounterpoint: Graham's number. It's like the Emperor's “enough dakka,” but with digits.
- perl4ever 7y agoIt's faintly ridiculous to have all the over the top expressions of amazement about something a couple hundred times the size of the Sun. If you're the layperson this is aimed at, who doesn't have a clue about stellar physics, then why not imagine a star 1,000 or 1,000,000 times the mass?
- ajross 7y agoFor those interested in the science and less in the fluff: this is notable not because it's "bigger" but because it's the first really good observation that fits with a "pair instability supernova", which is a well developed existing theory but has never been observed. The basic idea (I'm not a professional here) is that the gamma rays produced in the stellar core provide the bulk of the pressure that holds up the outer star against collapse. But past a certain temperature, the energy of those gamma rays starts preferentially resulting in electron/positron pair production. And the effective pressure per energy of an e-/p+ pair is significantly lower than it is for photons. So the outer core layers start falling downward, picking up energy as they do, and getting hotter. And the still higher temperatures result in gamma production which is even more likely to result in pairs, so the pressure drops still further and the core contracts more, and you get a runaway reaction. But the runaway is of temperature and not so much density, so what's left after the outer layers of the star all get blown away is a comparatively low density core of extremely hot plasma, which simply diffuses without recollapsing into a neutron star of black hole.
- zazagura 7y agoWhy don't the e-/p+ annihilate back into photons? Where do the p+ go?
- whatshisface 7y agoSome do, but if they are moving apart fast enough they'll never meet again.
- zazagura 7y agoYeah, but I'm not talking about the original pair. Since there is way more matter than anti-matter, shouldn't the p+ eventually hit something and annihilate?
- ajross 7y agoIt will. But due to the way things work (and here I'm mostly ignorant of the actual physics) the likelihood of this happening (or really for it to scatter against anything else in the plasma) for a high energy lepton is much lower than for a photon of the same energy. So where the old, cooler photons were hitting things locally and providing pressure that was keeping the core from collapsing, the positrons are escaping farther out and allowing the core to collapse.
- blattimwind 7y agoHow do you explode without annihilating yourself?
- saagarjha 7y agoYou leave behind a collapsed core.
- peter303 7y agoPerhaps we are witnessing a war between Type II civilizations. A Type II civilization on the Kardashev Scale directly harnesses the energy of a star. https://en.m.wikipedia.org/wiki/Kardashev_scale https://en.m.wikipedia.org/wiki/Kardashev_scale Improbable, but an amusing hypothesis.
- CapricornNoble 7y agoCould have been a weapon's test gone wrong, like that recent Russian nuclear-powered cruise missile that blew up. A very amusing line of thought indeed.
- perl4ever 7y agoIf the brightness didn't go away, and that's unusual, why are people concluding it "annihilated itself"? I don't see why that would be the natural assumption. Maybe there is a black hole in the center and something about the dynamics is producing more radiation than usual from the stuff falling into it?
- YeGoblynQueenne 7y ago>> It was pretty much at this point reading the journal paper that my brain wanted to leap out of my skull and run around in panicked circles screaming. I’ve run out of adjectives to describe an event like this. Is it OK if I'm interested in science without acting as if I was watching a football game? Or do I lose my nerd cred for not expressing exuberant excitement with colourful language every time I hear how big the universe is, or how vast the cosmic scales, etc?
- gjm11 7y agoI don't remember Phil Plait being quite so breathless when he was blogging at, er, wherever he was before. (ScienceBlogs, RIP?) Is it a SyFy house style thing, perhaps?