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Betelgeuse captured by ALMA

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Re: Betelgeuse captured by ALMA

#21

Post by throwanem »

seren wrote: post #16
mabbo wrote: post #13

Since I had to look it up out of curiosity/paranoia, I figure someone else might also be interested/relieved to know: Betelgeuse has frequently been the subject of scare stories and rumors suggesting that it will explode within a year, leading to exaggerated claims about the consequences of such an event. The timing and prevalence of these rumors have been linked to broader misconceptions of astronomy, particularly t…

However according to Wikipedia this is: >the star where the Elder Gods came from to battle the Great Old Ones [...]. Betelgeuse is also mentioned as the homeworld of the 'Ithria, a star-faring fungoid race.

Sure - if you take Derleth's mankind-involving Manichaeism as canon. That's something I don't recommend doing, because it rather misses the point, which is that we are as ants under the careless tread of powers far older, far greater, and far stranger than anything we can possibly imagine.

Re: Betelgeuse captured by ALMA

#22

Post by nkrisc »

kmm wrote: post #18

I wonder what it looks like up close. Betelgeuse's mean density is a few milligrams per cubic meter, probably way less so in the photosphere, comparable to the density of the atmosphere at the edge of space. And yet it still gives light. What would it look like up close? Wispy and ghostlike? Would you even notice you're inside the star?

That's only the mean density. I doubt its mass is evenly distributed. You'd probably see through the wispy outer layers and mostly be able to see the denser interior. Much like looking at Earth from space, you don't see the atmosphere (mostly so, anyway) and see the point where the atmosphere transitions to solid planet.

Re: Betelgeuse captured by ALMA

#23

Post by sqeaky »

seren wrote: post #16
mabbo wrote: post #13

Since I had to look it up out of curiosity/paranoia, I figure someone else might also be interested/relieved to know: Betelgeuse has frequently been the subject of scare stories and rumors suggesting that it will explode within a year, leading to exaggerated claims about the consequences of such an event. The timing and prevalence of these rumors have been linked to broader misconceptions of astronomy, particularly t…

However according to Wikipedia this is: >the star where the Elder Gods came from to battle the Great Old Ones [...]. Betelgeuse is also mentioned as the homeworld of the 'Ithria, a star-faring fungoid race.

That is all in the Pop culture and mentions lovecraft right there, this isn't some prank or defacement. This is just real references to literature.

Re: Betelgeuse captured by ALMA

#24

Post by privong »

kijin wrote: post #6

What's with the weird shape in the bottom left? I don't suppose stars can get squished like that, so it must be some sort of optical artifact?

> What's with the weird shape in the bottom left? I don't suppose stars can get squished like that, so it must be some sort of optical artifact?

It's possible that it could be something physical, as some of the other commenters have mentioned. But it also could be a result of the response of the telescope. Interferometers like ALMA do not directly measure the distribution of emission on the sky. Instead they sample the fourier transform of the sky brightness. Because there are discrete pairs of antennas, the full fourier transform cannot be measured. When images such as this are created, the sampling of the fourier plane is deconvolved. But that process does not create a perfect recovery of the sky emission distribution. One would need to look at the raw data, but another explanation for that extension is that it is an artifact of the fourier plane sampling (e.g., analgous to Gibbs Ringing; https://en.wikipedia.org/wiki/Gibbs_phenomenon).

Re: Betelgeuse captured by ALMA

#25

Post by aruggirello »

kmm wrote: post #18

I wonder what it looks like up close. Betelgeuse's mean density is a few milligrams per cubic meter, probably way less so in the photosphere, comparable to the density of the atmosphere at the edge of space. And yet it still gives light. What would it look like up close? Wispy and ghostlike? Would you even notice you're inside the star?

> And yet it still gives light. ... Would you even notice you're inside the star?

I bet at between 90K and 150K times the Sun's luminosity, you'd be too busy boiling away (OK, perhaps exploding in half a millisecond?) to notice :)

Re: Betelgeuse captured by ALMA

#27

Post by placebo »

At the risk of uncovering my ancientness, I remember reading astronomy books as a kid which specified that stars are so far away that they can't appear as anything more than dots of light even when viewed through the largest telescopes. Always makes me wonder what can be achieved in the future, especially since we're probably somewhere on an exponential progress curve. Of course, assuming a lot of optimism about not cutting off the branch we're sitting on before that happens...

Re: Betelgeuse captured by ALMA

#29

Post by aruggirello »

0xFFC wrote: post #26

> When that happens, the resulting explosion will be visible from Earth, even in broad daylight. How much visibility are we talking about?

IIRC we're talking about it reaching apparent magnitude ~ -12, given or taken a couple magnitudes (or about as bright as the full Moon - Just imagine that much light coming from an infinitely tiny dot instead). BTW with a declination of ~ +7° Betelgeuse is very close to the celestial equator, so the supernova will be visible from anywhere on Earth, save a very small region within 7° from the South Pole.

Re: Betelgeuse captured by ALMA

#30

Post by iamgopal »

jcims wrote: post #17

A 1.64 billion km diameter sphere 600 light years away will have an apparent width of 2.9 x 10^-7 radians. That's roughly equivalent to looking at an object 250nm wide at arm's length. A red blood cell is approximately 8000nm wide. Crazy resolving power.

How many photons ?
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