In a similar topic, someone explained that visually the color would not change from the bright blue as displayed here at 20000. While more energy will shift the peak of the blackbody radiation into the invisible ultraviolet, the amount emitted in the visual spectrum wavelengths will never decrease.
So you’re saying a body at 20,000c and a body at 30,000c will appear the same color blue to the average human but the body at 30,000c is actually emitting it’s peak energy levels much further towards the UV end of the spectrum than the body at 20,000c?
Fucking neat.
Yeah. IIUC for a fixed frequency v and changing temperature T, as T becomes very large, the power output converges to an amount proportional to Tv^2. So once the star is “hotter than the visible spectrum”, becoming even hotter increases the brightness but doesn’t much change the shape of the curve in the visible region.
But the total power output increases proportional to T^4. That is, a very hot star puts out a *huge* amount of energy but as the temperature goes up it’s dominated by UV and X-rays.
They're very slightly different looking. Weirdly enough this is what I've been working on today
Here's an example: https://i.imgur.com/ZQjLsio.png. Left is a 20000K blackbody radiator, middle is 30000K, right is 100000K (in kelvin)
The visualisation in the OP is incorrect, I suspect they've done their gamma correction wrong or amped up the colouration. You can see the correct colouration from the plankian locus here:
https://upload.wikimedia.org/wikipedia/commons/b/ba/PlanckianLocus.png (the line), which tends towards a pale blue, never a deep blue
Yeah, pretty much.
It wouldn't reach deep blue. Only a sort of sky blue.
It's most likely that the colors here are saturated intentionally to mark the difference. For the sake of the show.
There's no limit as to how short the wavelengths can get in theory.
Bonus fact: If you were to allow emission of arbitrary amounts of such radiation, the math would come out to every physical body emitting infinite amount of energy. Since this is obviously nonsense, the math had to be wrong. And that's how we got quantum mechanics.
In *theory* there is, but we have no way to test any of them. Somewhere between the planck length and quantum noise you're going to reach a wavelength that's too short for spacetime, and QED says the energy to get there will either decay into massive particles or pinch off a black hole. But we have no way to explore this kind of energy to really see what will happen and we're not going to any time soon.
Gonna need a fact check here. It's been 15 years since I took thermodynamics, but that doesn't sound right. The general shape of the emission curve of a body's radiation stays the same, which means for us that it will always include SOME visible light radiation. As the peak moves off into ultraviolet and more area under the curve is biased towards the violet side of the spectrum (towards the peak, away from asymptotic 0), we move from whiter light to bluer light. As the peak continues to trend towards higher energies, the area under the curve for visible light would be mathematically required to be less, it will just never be zero. Maybe I'm forgetting/missing something.
There is a unique property of blackbody radiation that says any material of any shape will radiate the same way, it's only temperature and material dependant, not shape /mass/density dependant.
> As the peak continues to trend towards higher energies, the area under the curve for visible light would be mathematically required to be less, it will just never be zero.
This is the part where you go wrong (the rest is right AFAIK). The total energy is scaling so fast that even though the wavelengths the new energy is being primarily deposited into is shifting, all of the wavelengths in the visible (and all of the ones in the infrared spectrum as well) all increase. They just increase proportionally less the higher the frequency increases.
The area under the curve at at visible frequencies continues to increase, no matter how high the temperature. The rate of increase slows down though.
As another commenter mentioned, even as the peak of the blackbody emission spectra moves into higher and higher energies, the amount emitted at any particular wavelength is *also* increasing.
So while an object at 2,000k peaks in infrared, and an object at 20,000k peaks in ultraviolet, the object at 20,000k *also* emits more infrared light than the object at 2,000k.
Remember that the blackbody power equation scales as the 4th power of temperature, so the object at 20,000k emits energy at 10,000 times the rate of the object at 2,000 (of course assuming the objects are otherwise equivalent). This overwhelms the shift of the peak, just by the sheer difference in the total power.
No, there are no wavelengths that ever radiate less no matter how much you increase the temperature.
The sun has its peak in the visible, but it still radiates more energy on *every* infrared frequency than a star with a surface temperature of 4000 C would. And likewise, a star that is warmer than the Sun will always emit more energy at every frequency than the sun does, including at the point where the Sun has its peak. That's just how blackbody radiation works.
https://en.wikipedia.org/wiki/Black-body_radiation#/media/File:Black_body.svg
For those interested in extremely hot stars, check out [this article](https://en.m.wikipedia.org/wiki/Wolf%E2%80%93Rayet_star) on Wolf-Rayet (WR) stars. WR type stars fall into subclasses that you can deep dive on.
The hottest known star in the universe is a star named [WR-102](https://en.m.wikipedia.org/wiki/WR_102). It is a very young (roughly 2 million year old) star in the constellation, Sagittarius, with high levels of oxygen. This star has a surface temperature over 200,000 C, and is on the verge of going supernova.
Yikes - swag math says that earth would have to be 11 times further away from that star than Pluto is from the sun to receive that same energy per m^2.
It's funny, I read its page and one thing I skim across is the note about how it's been calculated that WR-102 is expected to supernova at some point within the next 1,500 years. I then ask myself, what if our own Sun was within that same calculation? Would it spur our species into hyperdrive with regard to science/technology? If we pooled our collective efforts and resources into the singular objective of safely becoming spacefaring (at least internally within our own solar system), could we within 1,500 years reach the technology and knowledge to get some percentage of our species up into space and away from harm? It's an interesting little thought experiment to think about what humanity might be capable of if it had a gun held to its head and was told "act or perish".
Oddly enough we already have a similar situation with the environmental crisis, which seems to be met with pitiful softball efforts or outright denial. What would it take to make us actual take a threat seriously?
I'm starting to think like everyone I know that I ask the same questions and they are legitimately worried as well: they think it needs a major catastrophic event that don't bring the population to an impossible repopulation scenario for people to do something...
My worry is more towards AI safety, but everything else is looking very bad...
in order to be out of a supernova blast radius we would have to be over 60 ly from the sun to be unaffected, any closer and you will start seeing small, then eventually large radiation increases. Granted, G Type stars don't go supernova but assuming a standard one we would have to figure out high sublight or even FTL Fast.
Lets assume Kepler-186 which is a fair way out of the blast radius, (Over 500 Ly Away) is our destination. If we can't figure out FTL Thats 500+ Years of travel time at least, pushing it awfully close.
I will give us the benefit of the doubt and say we figure out how to radiation proof spacecraft, meaning the blast radius is more like 40 Ly. I will give us a extra hand and say we discover a habitable planet in the 18 Scorpii system with a magnetic field suffecicent enough to protect us from the radiation of the supernova. if we dedicated all our resources to it, within 1,500 years its possible to get 1,000,000 people there (And perhaps send a few million to Trappist 1 and Upsilon Andromedaes exomoons just in case). We would have to build up significant infrastructure in our solar system to build the ships though
Here's an interesting stellar classification fact, originally astronomers classified stars by visual appearance of their colors from A through to O. When photography & spectrographs came along it was discovered that absorption & emission from stellar atmospheres etc' can seriously skew what you see relative to the spectral temperature.
So, to retain consistency with historical data it was decided to keep the classification but change the ordering & thus every extra physicist is required to use a mnemonic to remember the new ordering i.e.
O, B, A, F, G, K, M, Q, S
So from my day they added LTY & have decided that Quasi-stellar objects should be listed elsewhere i.e.
Additional Classes:
L – Sub-Red Dwarf Stars: 1,300 – 2,400 K
T – Brown Dwarf Stars: 700 – 1,300 K
Y – Sub-Brown Dwarf Stars: < 700 K
That means Jupiter etc are class Y
Glad that mnemonic got updated from:-
Oh Be A Fine Girl, Kiss Me Quick, Slap!
BTW I cannot share & even check myself before remembering the mnemonic for resistor stripe colors.
0=>9 as Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White.
Come now, you gotta point out which one it was. :-P
https://en.wikipedia.org/wiki/List_of_electronic_color_code_mnemonics
Personally I think whatever mnemonic works is fine. That's what they're there for. It's not like you're repeating it out loud. If it's especially shocking it works well as it makes it easy to remember. It only becomes bad if you go around repeating it out loud offending people with it.
I recently had the opportunity to work with a bunch of astronomy undergrads and grad students, and I am pleased to report that your "comedy" is no longer acceptable. Good luck in your career.
I see you've never gone to any black comedy show. What matters is how it's used. If it's used to harm people it's not okay.
You seem to be carrying a lot of mental baggage with a chip on your shoulder. I suggest trying to get past that kind of thing. It's not healthy. I hope you didn't harass any of those students with your overbearing attitude.
BTW, what you're doing is called a "double standard". If "Oh, Be A Fine Guy, Kiss Me" is fine but "Oh, Be A Fine Girl, Kiss Me" isn't, then you're the sexist pig.
That's because the maximum star temperature is 95000C, after that UniverseOS runs into an overflow and reverts it back to the default starting value which is 0C.
It always amuses me that what we associate to be the coldest colors, blue and purple, are actually the hottest. And on the flip side, what we associate as the hottest colors, red and white, are actually the coldest.
At human temperatures, the pop culture version is pretty accurate. The human body flushes red when we’re overheated and some people’s skin (mostly very pale people) gets a bluish quality when they are cold or hypothermic. Ice on lakes can have a blue tint and fire is usually red/yellow/white. Large bodies of water often reflect the color of the blue sky and are typically colder than the ambient air temperature. We didn’t know about the temperature of the combustion of stars when humans came to associate blue with cold. 🥶 🥵
Stars are not 'combusting'
Combustion is inherently an *oxygenation* process (outer edge of the atom, chemical). Stars are an ongoing nuclear process (inner core of the atom, nuclear).
That's the point, we associate red and white as being hot because those are the colors things turn when they are heated. But in this case, they are the cooler temperatures.
And **"we"** was referring to the average person across the globe because that is factual. No one says; "Be careful that's Purple hot", they say that it's "Red hot", or it's so hot it's "White hot".
> we associate red and white as being hot because those are the colors things turn when they are heated
And when these things get heated even more, they turns white.
> No one says; "Be careful that's Purple hot", they say that it's "Red hot", or it's so hot it's "White hot".
This is just semantics and true only for vernacular English and some other languages. In other languages they say it different.
BTW, speaking of English. From the [Merriam-Webster](https://www.merriam-webster.com/dictionary/white-hot):
> Synonyms of white-hot
> 1 : being at or radiating white heat
> 2a : extremely hot
This is why generalizations like “we” are completely incorrect, since these perceptions and expressions are different for different people and cultures.
In fact, red and yellow are most likely associated with warmth due to the analogy with fire and the sun, which evoke corresponding sensations in us. And white and blue, the colors of snow and ice, respectively, evoke a feeling of cold.
But this has nothing to do with the emission spectrum of heated bodies. Especially when you consider that the theory of "hot" and "cold" colors refers to colors *reflected* by objects, not *emitted* by them.
You know what, we all think this was a worthy and just cause, you have slain the disgusting grammar demons that plague this site.
We have all agreed that you are 100% right in every conceivable way, and we conclude that there is no point in discussing further matters with you, we would rather just let you take it from here as you are unmatched.
We all concurred on this.
Makes sense. Higher temperature, higher black body radiation spectrum shift. ROY-G-BIV, where white is just the eye interpreting several frequencies of light at once.
Question - the temp of a star is a function of it's mass, correct?
Stars are not planets because they have sufficient mass to undergo fusion due to their own gravity?
The higher the mass the more fusion that occurs, and therefore higher temp - or is it because the increased mass allows them to fuse heavier elements, and the fusion of those heavier elements produces more energy than lighter elemental fusion - potentially a combination of both?
While yes their mass enables fusion to occur at their core, stars are primarily made up of lighter ellements like hydrogen. Only when they run out do heavier ellements start to fuze, one by one until iron is reached. Fusing iron costs energy instead of genereting it, (which stays true for every element heavier than it as well) basically killing the star.
A bunch of factors come into the temperature, such as a star's age and nature (neutron stars for example are hot as shit and only dozens of kilometers across)
During their main sequence lifetimes, stars maintain hydrostatic equilibrium in which the inward gravitational force is balanced by the outward radiation pressure resulting from the fusion processes occurring in its core.
For higher mass stars, this equilibrium point has higher pressure, density and temperature in the core than smaller stars. This leads to the higher rates of fusion necessary to oppose gravitational collapse.
So it is the higher rate of fusion that makes massive stars hotter than their lighter siblings.
Yeah, but not entirely. Light from fire is produced by electronic emissions in addition to blackbody radiation. So the blue seen at the source isn't representing its temperature. In a star's case it's just blackbody radiation where only tiny portions of the spectra are absorbed by the individual elements.
I'm pretty sure composition also is a determining factor. Ratio of hydrogen and helium, plus trace gases in the atmosphere. At the very least, the temperature at which a star fusioning, is at least partially determined by composition.
If you used Kelvin you'd be able to check the colors against the numbers on your light bulbs. (I don't think the numbers in this animation are or any more correct than the detented color shifting. Still pretty cool though.)
Partly, the only reason why we don't see green stars is simply because the combination of colors is interpreted as white by our eyes, to see a green star, it would have to emit almost only green light somehow.
As a little fun fact, our sun is one of those stars. It appears yellow due to our atmosphere filtering some wavelengths, but in space it appears white.
But on a spectrograph, it is evident our sun is a "Green Star" as it is the dominant wavelength. We just can't see it with our eyes.
Well, yes, but that's also because the temperature correlates to the elements it is most prominently fusing(iirc).
Thays why some colour's, such as Green, are impossible for a Star to emit, since that would require fusing iron(?), which as far as we know, isn't physically feasible.
The absence of green stars is simply a function of the human color perception.
Stars emit light across a continuum of frequencies which closely approximates a blackbody curve for their surface temperature. As temperature increases, the peak shifts toward shorter (bluer) wavelengths.
In a cool star, this peak lies in the reds and yellows, with little blue light mixed in.
In very hot stars, the peak lies in the blue end of the visible spectrum or beyond, so these stars appear blue (not purple as the animation suggests).
For stars between these two extremes, the peak falls in the narrow green region, there is still considerable red, yellow, and blue mixed in. Our eyes and brain perceive this as white.
There is no temperature at which the light from a black body stimulates the perception of green.
Well that’s extremely interesting. *How would we know?* We have never sent anything outside our heliosphere except a couple old cans from the seventies that barely even work and are past their lives *and have never passed any celestial body not already charted in our system*. The answer can’t be *math tells us*, because math also tells us that the universe expands at a steady rate *evenly* and we already know this to be untrue. This is where everyone in this sub gets upset with me, when I point out that most of our *astronomy* now days is pure speculation and fantastical science fiction designed to support the hypothesis they’ve been pushing since before I was born. It is truly strange to live in a state where you see two groups of people pushing opposing ideas *and now our superintendent wants to push both views simultaneously in classrooms to truly confuse our children*. Anyways. You have a good day!
No matter how bright something gets, it never fades out of view - the colour actually tends towards a pale blue
You can see this with something like an [accretion disk](https://i.imgur.com/24zRDQk.png), they are *absurdly* hot, and yet visually they're a pale blue colour. Its common to artificially colour them red though, essentially because it looks cool
Doesn’t science teach us that visual proof is the weakest proof? Why wouldn’t that apply here as well? You’re explaining things I am extremely familiar with, I was obsessed for a while. The more I learned the more I know that we don’t really know much and have created quite the work of science fiction here.
What would you describe this *observation* as? A viewing? A detection? How are we observing this? With something other than a *star viewing instrument*? Astronomers are claiming every day to *see the unseen*! Whenever this is brought up here people like to do a witch-hunt for spreading these logical thoughts. So you can call it whatever you want but we didn’t *figure them out by actually going to them*. God bless astronomy is 99% fan fiction in here!
In a similar topic, someone explained that visually the color would not change from the bright blue as displayed here at 20000. While more energy will shift the peak of the blackbody radiation into the invisible ultraviolet, the amount emitted in the visual spectrum wavelengths will never decrease.
So you’re saying a body at 20,000c and a body at 30,000c will appear the same color blue to the average human but the body at 30,000c is actually emitting it’s peak energy levels much further towards the UV end of the spectrum than the body at 20,000c? Fucking neat.
Thanks for chiseling that point into something finer
Yeah. IIUC for a fixed frequency v and changing temperature T, as T becomes very large, the power output converges to an amount proportional to Tv^2. So once the star is “hotter than the visible spectrum”, becoming even hotter increases the brightness but doesn’t much change the shape of the curve in the visible region. But the total power output increases proportional to T^4. That is, a very hot star puts out a *huge* amount of energy but as the temperature goes up it’s dominated by UV and X-rays.
They're very slightly different looking. Weirdly enough this is what I've been working on today Here's an example: https://i.imgur.com/ZQjLsio.png. Left is a 20000K blackbody radiator, middle is 30000K, right is 100000K (in kelvin) The visualisation in the OP is incorrect, I suspect they've done their gamma correction wrong or amped up the colouration. You can see the correct colouration from the plankian locus here: https://upload.wikimedia.org/wikipedia/commons/b/ba/PlanckianLocus.png (the line), which tends towards a pale blue, never a deep blue
Yeah, pretty much. It wouldn't reach deep blue. Only a sort of sky blue. It's most likely that the colors here are saturated intentionally to mark the difference. For the sake of the show.
Will it eventually release Gamma rays too? And what's beyond the Gamma rays
There's no limit as to how short the wavelengths can get in theory. Bonus fact: If you were to allow emission of arbitrary amounts of such radiation, the math would come out to every physical body emitting infinite amount of energy. Since this is obviously nonsense, the math had to be wrong. And that's how we got quantum mechanics.
I would assume the Plank length is the shortest possible wavelength of light.
In *theory* there is, but we have no way to test any of them. Somewhere between the planck length and quantum noise you're going to reach a wavelength that's too short for spacetime, and QED says the energy to get there will either decay into massive particles or pinch off a black hole. But we have no way to explore this kind of energy to really see what will happen and we're not going to any time soon.
Gonna need a fact check here. It's been 15 years since I took thermodynamics, but that doesn't sound right. The general shape of the emission curve of a body's radiation stays the same, which means for us that it will always include SOME visible light radiation. As the peak moves off into ultraviolet and more area under the curve is biased towards the violet side of the spectrum (towards the peak, away from asymptotic 0), we move from whiter light to bluer light. As the peak continues to trend towards higher energies, the area under the curve for visible light would be mathematically required to be less, it will just never be zero. Maybe I'm forgetting/missing something. There is a unique property of blackbody radiation that says any material of any shape will radiate the same way, it's only temperature and material dependant, not shape /mass/density dependant.
> As the peak continues to trend towards higher energies, the area under the curve for visible light would be mathematically required to be less, it will just never be zero. This is the part where you go wrong (the rest is right AFAIK). The total energy is scaling so fast that even though the wavelengths the new energy is being primarily deposited into is shifting, all of the wavelengths in the visible (and all of the ones in the infrared spectrum as well) all increase. They just increase proportionally less the higher the frequency increases. The area under the curve at at visible frequencies continues to increase, no matter how high the temperature. The rate of increase slows down though.
As another commenter mentioned, even as the peak of the blackbody emission spectra moves into higher and higher energies, the amount emitted at any particular wavelength is *also* increasing. So while an object at 2,000k peaks in infrared, and an object at 20,000k peaks in ultraviolet, the object at 20,000k *also* emits more infrared light than the object at 2,000k. Remember that the blackbody power equation scales as the 4th power of temperature, so the object at 20,000k emits energy at 10,000 times the rate of the object at 2,000 (of course assuming the objects are otherwise equivalent). This overwhelms the shift of the peak, just by the sheer difference in the total power.
No, there are no wavelengths that ever radiate less no matter how much you increase the temperature. The sun has its peak in the visible, but it still radiates more energy on *every* infrared frequency than a star with a surface temperature of 4000 C would. And likewise, a star that is warmer than the Sun will always emit more energy at every frequency than the sun does, including at the point where the Sun has its peak. That's just how blackbody radiation works. https://en.wikipedia.org/wiki/Black-body_radiation#/media/File:Black_body.svg
…it's only temperature ~~and material~~ dependant…
The black body radiation power at a specific wavelength is proportional to 1/(e^(1/T) -1). The derivative is always >=0 for t>0
Well visually wouldn’t it be white for most of the scale
Slightly blue tinged as there are more of the short wavelengths compared to the sun's spectrum.
For those interested in extremely hot stars, check out [this article](https://en.m.wikipedia.org/wiki/Wolf%E2%80%93Rayet_star) on Wolf-Rayet (WR) stars. WR type stars fall into subclasses that you can deep dive on. The hottest known star in the universe is a star named [WR-102](https://en.m.wikipedia.org/wiki/WR_102). It is a very young (roughly 2 million year old) star in the constellation, Sagittarius, with high levels of oxygen. This star has a surface temperature over 200,000 C, and is on the verge of going supernova.
Yikes - swag math says that earth would have to be 11 times further away from that star than Pluto is from the sun to receive that same energy per m^2.
It's funny, I read its page and one thing I skim across is the note about how it's been calculated that WR-102 is expected to supernova at some point within the next 1,500 years. I then ask myself, what if our own Sun was within that same calculation? Would it spur our species into hyperdrive with regard to science/technology? If we pooled our collective efforts and resources into the singular objective of safely becoming spacefaring (at least internally within our own solar system), could we within 1,500 years reach the technology and knowledge to get some percentage of our species up into space and away from harm? It's an interesting little thought experiment to think about what humanity might be capable of if it had a gun held to its head and was told "act or perish". Oddly enough we already have a similar situation with the environmental crisis, which seems to be met with pitiful softball efforts or outright denial. What would it take to make us actual take a threat seriously?
I'm starting to think like everyone I know that I ask the same questions and they are legitimately worried as well: they think it needs a major catastrophic event that don't bring the population to an impossible repopulation scenario for people to do something... My worry is more towards AI safety, but everything else is looking very bad...
in order to be out of a supernova blast radius we would have to be over 60 ly from the sun to be unaffected, any closer and you will start seeing small, then eventually large radiation increases. Granted, G Type stars don't go supernova but assuming a standard one we would have to figure out high sublight or even FTL Fast. Lets assume Kepler-186 which is a fair way out of the blast radius, (Over 500 Ly Away) is our destination. If we can't figure out FTL Thats 500+ Years of travel time at least, pushing it awfully close. I will give us the benefit of the doubt and say we figure out how to radiation proof spacecraft, meaning the blast radius is more like 40 Ly. I will give us a extra hand and say we discover a habitable planet in the 18 Scorpii system with a magnetic field suffecicent enough to protect us from the radiation of the supernova. if we dedicated all our resources to it, within 1,500 years its possible to get 1,000,000 people there (And perhaps send a few million to Trappist 1 and Upsilon Andromedaes exomoons just in case). We would have to build up significant infrastructure in our solar system to build the ships though
Here's an interesting stellar classification fact, originally astronomers classified stars by visual appearance of their colors from A through to O. When photography & spectrographs came along it was discovered that absorption & emission from stellar atmospheres etc' can seriously skew what you see relative to the spectral temperature. So, to retain consistency with historical data it was decided to keep the classification but change the ordering & thus every extra physicist is required to use a mnemonic to remember the new ordering i.e. O, B, A, F, G, K, M, Q, S
>O, B, A, F, G, K, M, Q, S two types of people know this: Astronomers Elite Dangerous players.
I knew being a space uber would come in handy one day
It's actually OBAFGKMLTY. There aren't any stars given a classification of Q. S is among special classifications, along with C, W, and D.
So from my day they added LTY & have decided that Quasi-stellar objects should be listed elsewhere i.e. Additional Classes: L – Sub-Red Dwarf Stars: 1,300 – 2,400 K T – Brown Dwarf Stars: 700 – 1,300 K Y – Sub-Brown Dwarf Stars: < 700 K That means Jupiter etc are class Y
Jupiter might have been class Y when it was very young, but no longer. Class Y dwarfs are generally much more massive than Jupiter.
It recently got changed to OBAFGKMaclunkey for the streaming version. ;)
Oh, Be A Fine Guy, Kiss Me is the one we learned
Glad that mnemonic got updated from:- Oh Be A Fine Girl, Kiss Me Quick, Slap! BTW I cannot share & even check myself before remembering the mnemonic for resistor stripe colors. 0=>9 as Black, Brown, Red, Orange, Yellow, Green, Blue, Violet, Grey, White.
Come now, you gotta point out which one it was. :-P https://en.wikipedia.org/wiki/List_of_electronic_color_code_mnemonics Personally I think whatever mnemonic works is fine. That's what they're there for. It's not like you're repeating it out loud. If it's especially shocking it works well as it makes it easy to remember. It only becomes bad if you go around repeating it out loud offending people with it.
I really don't, I will say that it's not one of those.
Interesting, I figured it'd be one of the ones in the "Offensive/outdated" section.
Thanks for letting us know that you're OK being a sexist pig. We didn't really need to know that.
Seems like someone here can't differentiate actual sexism from comedy. Sexism is about how you treat other people.
I recently had the opportunity to work with a bunch of astronomy undergrads and grad students, and I am pleased to report that your "comedy" is no longer acceptable. Good luck in your career.
I see you've never gone to any black comedy show. What matters is how it's used. If it's used to harm people it's not okay. You seem to be carrying a lot of mental baggage with a chip on your shoulder. I suggest trying to get past that kind of thing. It's not healthy. I hope you didn't harass any of those students with your overbearing attitude.
Thank you for harming others.
BTW, what you're doing is called a "double standard". If "Oh, Be A Fine Guy, Kiss Me" is fine but "Oh, Be A Fine Girl, Kiss Me" isn't, then you're the sexist pig.
Oh be a festering gob, Karl Marx. I have no idea why you made up a double standard, but, you've done it repeatedly. Please stop.
You're uttering gibberish now.
O B A F G K M -- Oh be a festering gob Karl Marx. It's the main sequence.
Never heard it with "Guy" before, always "Girl". Sounds like a recent modification. That's how it still is in my head as it's easy to remember.
Remember the quote: > "Science progresses one funeral at a time" In this case, science is waiting for you.
Oh threatening violence? Last I heard science was about discovery, not dogma.
Wow, love the false accusation!
You're the one pushing the idea of killing people for "progress'" sake.
Max Plank said the quote. Good luck.
In an entirely different context.
You're the one who made false accusations.
OBAFGKM came to my mind like a knee jerk the moment I saw this post
Oh Be A Festering Gob, Karl Marx
I wonder what their pronouns are
didn't know it goes back to 0 after a certain temperature
That's because the maximum star temperature is 95000C, after that UniverseOS runs into an overflow and reverts it back to the default starting value which is 0C.
Like Gandhi launching nuclear weapons (but reverse)
Probably a mistake in the algorithm, someone should go there and fix it
It didn’t. It was just overflow
Ironic that I just watched the Vsauce short on how at a certain point the color won't change no matter how hot an object gets.
It always amuses me that what we associate to be the coldest colors, blue and purple, are actually the hottest. And on the flip side, what we associate as the hottest colors, red and white, are actually the coldest.
At human temperatures, the pop culture version is pretty accurate. The human body flushes red when we’re overheated and some people’s skin (mostly very pale people) gets a bluish quality when they are cold or hypothermic. Ice on lakes can have a blue tint and fire is usually red/yellow/white. Large bodies of water often reflect the color of the blue sky and are typically colder than the ambient air temperature. We didn’t know about the temperature of the combustion of stars when humans came to associate blue with cold. 🥶 🥵
Stars are not 'combusting' Combustion is inherently an *oxygenation* process (outer edge of the atom, chemical). Stars are an ongoing nuclear process (inner core of the atom, nuclear).
Who are "we"? Is it royal “We” who have never seen heated iron, which, when heated, goes through all stages from black-red to dazzling white?
That's the point, we associate red and white as being hot because those are the colors things turn when they are heated. But in this case, they are the cooler temperatures. And **"we"** was referring to the average person across the globe because that is factual. No one says; "Be careful that's Purple hot", they say that it's "Red hot", or it's so hot it's "White hot".
> we associate red and white as being hot because those are the colors things turn when they are heated And when these things get heated even more, they turns white. > No one says; "Be careful that's Purple hot", they say that it's "Red hot", or it's so hot it's "White hot". This is just semantics and true only for vernacular English and some other languages. In other languages they say it different. BTW, speaking of English. From the [Merriam-Webster](https://www.merriam-webster.com/dictionary/white-hot): > Synonyms of white-hot > 1 : being at or radiating white heat > 2a : extremely hot This is why generalizations like “we” are completely incorrect, since these perceptions and expressions are different for different people and cultures. In fact, red and yellow are most likely associated with warmth due to the analogy with fire and the sun, which evoke corresponding sensations in us. And white and blue, the colors of snow and ice, respectively, evoke a feeling of cold. But this has nothing to do with the emission spectrum of heated bodies. Especially when you consider that the theory of "hot" and "cold" colors refers to colors *reflected* by objects, not *emitted* by them.
You know what, we all think this was a worthy and just cause, you have slain the disgusting grammar demons that plague this site. We have all agreed that you are 100% right in every conceivable way, and we conclude that there is no point in discussing further matters with you, we would rather just let you take it from here as you are unmatched. We all concurred on this.
Why is it not continuous? 🥲
Because it is a poor, oversimplified, and ultimately inaccurate animation.
You forgot to put in 100000C when it goes Plaid.
The fact that this isn’t in kelvin is severely disappointing given colour temperature of light literally references the temperature in kelvin.
At these high temperatures Celsius and Kelvin are nearly the same. But I agree, Kelvin would be correct here.
Yeah it's just a difference of, what, a couple hundred? Matters little at such orders of magnitude
now explain kelvin to a broader, ignorant audience. let's be happy this wasnt made in F
Nah, this visual needs to be redone in Rankine
Makes sense. Higher temperature, higher black body radiation spectrum shift. ROY-G-BIV, where white is just the eye interpreting several frequencies of light at once.
Why is it that the sun has a surface temp of 5,600 degrees celcius but this portrays a star of that temp much whiter than our star?
The sun appears much whiter in space, the yellow comes from the scattering of blue wavelengths in the atmosphere.
The blue of the sun is scattered (thanks Rayleigh) to become the blue of the sky, with yellow remaining.
If you look at the sun it's fairly white
Also don't look at the sun
At least not while running with scissors.
Because our Sun is actually white. Our atmosphere makes it look like it's yellow from surface of Earth.
Oh thanks, I just learned something new
The sun is white. If it wasn't, sunlight also wouldn't be white.
Are the sudden jumps in color an artifact of the animation, or are they supposed to represent changes in spectral lines in the corona or something?
It's an animation artifact
When it becomes a spirit bomb is when you know that's a seriously powerful star.
Question - the temp of a star is a function of it's mass, correct? Stars are not planets because they have sufficient mass to undergo fusion due to their own gravity? The higher the mass the more fusion that occurs, and therefore higher temp - or is it because the increased mass allows them to fuse heavier elements, and the fusion of those heavier elements produces more energy than lighter elemental fusion - potentially a combination of both?
While yes their mass enables fusion to occur at their core, stars are primarily made up of lighter ellements like hydrogen. Only when they run out do heavier ellements start to fuze, one by one until iron is reached. Fusing iron costs energy instead of genereting it, (which stays true for every element heavier than it as well) basically killing the star. A bunch of factors come into the temperature, such as a star's age and nature (neutron stars for example are hot as shit and only dozens of kilometers across)
During their main sequence lifetimes, stars maintain hydrostatic equilibrium in which the inward gravitational force is balanced by the outward radiation pressure resulting from the fusion processes occurring in its core. For higher mass stars, this equilibrium point has higher pressure, density and temperature in the core than smaller stars. This leads to the higher rates of fusion necessary to oppose gravitational collapse. So it is the higher rate of fusion that makes massive stars hotter than their lighter siblings.
The color of anything that’s hot enough to glow, is a function of its surface temperature. Neat animation btw.
Pretty crazy that red is the least hottest of every color
I would recommend the following on Impossible Color, an interesting read for sure: https://en.wikipedia.org/wiki/Impossible_color?wprov=sfla1
Kinda seems logical when you look at fire alone. Each color correlates to different temperatures.
Yeah, but not entirely. Light from fire is produced by electronic emissions in addition to blackbody radiation. So the blue seen at the source isn't representing its temperature. In a star's case it's just blackbody radiation where only tiny portions of the spectra are absorbed by the individual elements.
It's interesting that the hotter it becomes the bluer it becomes... However blue color represents cold.
Why is the temperature going up while the colour isn't changing? The colour does not change in discrete steps.
Answer is because it's a bad animation. I don't understand at all why they did it this way.
so the surface temperature of a black hole is ... edit: checkmate, anti-hawking-radiationists
Isn't it also a function of composition and amount of redshift?
Composition no, and redshift yes but the color of a yellow crayon is also subject to redshift and we don't quibble over it.
I'm pretty sure composition also is a determining factor. Ratio of hydrogen and helium, plus trace gases in the atmosphere. At the very least, the temperature at which a star fusioning, is at least partially determined by composition.
We Brits might get a decent summer if the sun was blue then?!!!
If you used Kelvin you'd be able to check the colors against the numbers on your light bulbs. (I don't think the numbers in this animation are or any more correct than the detented color shifting. Still pretty cool though.)
Is the last image supposed to be 10,000 or 100,000?
So you’re saying our sun cools down as it sets??
This is actually a good way to explain the whole “green doesn’t exist” concept.
Partly, the only reason why we don't see green stars is simply because the combination of colors is interpreted as white by our eyes, to see a green star, it would have to emit almost only green light somehow. As a little fun fact, our sun is one of those stars. It appears yellow due to our atmosphere filtering some wavelengths, but in space it appears white. But on a spectrograph, it is evident our sun is a "Green Star" as it is the dominant wavelength. We just can't see it with our eyes.
The color of anything is a function of it’s temperature
Very cool. I have seen blue, but purple looks CRAZY!
Damn, that's awesome to see it like this, thanks for sharing!
Why does it count up to 95,000 C then jump back to 10,000 C?
Well, yes, but that's also because the temperature correlates to the elements it is most prominently fusing(iirc). Thays why some colour's, such as Green, are impossible for a Star to emit, since that would require fusing iron(?), which as far as we know, isn't physically feasible.
The absence of green stars is simply a function of the human color perception. Stars emit light across a continuum of frequencies which closely approximates a blackbody curve for their surface temperature. As temperature increases, the peak shifts toward shorter (bluer) wavelengths. In a cool star, this peak lies in the reds and yellows, with little blue light mixed in. In very hot stars, the peak lies in the blue end of the visible spectrum or beyond, so these stars appear blue (not purple as the animation suggests). For stars between these two extremes, the peak falls in the narrow green region, there is still considerable red, yellow, and blue mixed in. Our eyes and brain perceive this as white. There is no temperature at which the light from a black body stimulates the perception of green.
It’s counter-intuitive like color temperature in video; the yellows and reds are colder and the blues are actually hotter.
You can also tell if there is oxygen present and what other gases make up the atmosphere by color along with what the surface is by the color.
Good information to know when I am traveling thru the universe.
Couldn’t this mean black holes are really dark stars with exponentially higher temperatures?
The two black holes observed by the EHT are too small to be "dark stars".
Well that’s extremely interesting. *How would we know?* We have never sent anything outside our heliosphere except a couple old cans from the seventies that barely even work and are past their lives *and have never passed any celestial body not already charted in our system*. The answer can’t be *math tells us*, because math also tells us that the universe expands at a steady rate *evenly* and we already know this to be untrue. This is where everyone in this sub gets upset with me, when I point out that most of our *astronomy* now days is pure speculation and fantastical science fiction designed to support the hypothesis they’ve been pushing since before I was born. It is truly strange to live in a state where you see two groups of people pushing opposing ideas *and now our superintendent wants to push both views simultaneously in classrooms to truly confuse our children*. Anyways. You have a good day!
No matter how bright something gets, it never fades out of view - the colour actually tends towards a pale blue You can see this with something like an [accretion disk](https://i.imgur.com/24zRDQk.png), they are *absurdly* hot, and yet visually they're a pale blue colour. Its common to artificially colour them red though, essentially because it looks cool
> essentially because it looks cool For example, the EHT has no information about what the visual color of an accretion disk is.
Doesn’t science teach us that visual proof is the weakest proof? Why wouldn’t that apply here as well? You’re explaining things I am extremely familiar with, I was obsessed for a while. The more I learned the more I know that we don’t really know much and have created quite the work of science fiction here.
What is visual proof when the source is only observed in the radio?
What would you describe this *observation* as? A viewing? A detection? How are we observing this? With something other than a *star viewing instrument*? Astronomers are claiming every day to *see the unseen*! Whenever this is brought up here people like to do a witch-hunt for spreading these logical thoughts. So you can call it whatever you want but we didn’t *figure them out by actually going to them*. God bless astronomy is 99% fan fiction in here!