Author Topic: Our Miserable Future (Read 7283 times)

RandallS · « **Reply #45 on:** April 11, 2016, 07:36:09 am »

Quote from: DIASPORA-1963;189773

Ah, thank you ... I'd been given a rather different time line - are you sure about the 6-7 billion years? How long before the Earth becomes uninhabitable? Certainly much sooner.

6-7 billion years is the current estimate for when the sun will be at its largest size (i.e. full red giant stage). The sun has been getting hotter since it was formed and will continue to do so. About 3-4 billion years from now it will be hot hot enough to wipe out most life on Earth. about a billion years later, the surface temperature of the Earth will probably be around 600 degrees. Things will just get worse when the sun goes into its red giant stage after that. When the sun is at its full red giant size, the remains of the Earth will probably be orbiting within the sun as the sun will probably expand to about 1.2 AU in diameter (Earth is 1 AU away from the sun now).

DIASPORA-1963 · « **Reply #46 on:** April 11, 2016, 07:45:30 am »

Quote from: RandallS;189882

6-7 billion years is the current estimate for when the sun will be at its largest size (i.e. full red giant stage). The sun has been getting hotter since it was formed and will continue to do so. About 3-4 billion years from now it will be hot hot enough to wipe out most life on Earth. about a billion years later, the surface temperature of the Earth will probably be around 600 degrees. Things will just get worse when the sun goes into its red giant stage after that. When the sun is at its full red giant size, the remains of the Earth will probably be orbiting within the sun as the sun will probably expand to about 1.2 AU in diameter (Earth is 1 AU away from the sun now).

Thank you.
From what I gathered, our sun is rather smallish - medium sized at best. It's not quite large enough ever to do the supernova thing. Instead, it will simply implode. Is this correct?

SunflowerP · « **Reply #47 on:** April 11, 2016, 08:43:08 am »

Quote from: DIASPORA-1963;189884

Thank you.
From what I gathered, our sun is rather smallish - medium sized at best. It's not quite large enough ever to do the supernova thing. Instead, it will simply implode. Is this correct?

You're correct about it being too small to become a supernova, but 'implode', while it might seem to make sense from a layperson's perspective, is a poor word choice, because it's a technical term in astrophysics that has to do with larger stars.

What the sun will do is expel mass and cool off, and become a white dwarf with about half the mass it currently has. (The ejected mass will become a planetary nebula, which is IMO a not-as-miserable part of our future.)

Sunflower

DIASPORA-1963 · « **Reply #48 on:** April 11, 2016, 09:48:34 am »

Quote from: SunflowerP;189886

You're correct about it being too small to become a supernova, but 'implode', while it might seem to make sense from a layperson's perspective, is a poor word choice, because it's a technical term in astrophysics that has to do with larger stars.

What the sun will do is expel mass and cool off, and become a white dwarf with about half the mass it currently has. (The ejected mass will become a planetary nebula, which is IMO a not-as-miserable part of our future.)

Sunflower

White dwarf, with the potential to last trillions of years ...

A lot of people I've discussed this with think that we'll've found a new home by then ... Huh? By time we find a new home - our descendants won't be us! They will evolve into somebody different. They probably won't even remember us.

RandallS · « **Reply #49 on:** April 11, 2016, 10:08:42 am »

Quote from: DIASPORA-1963;189884

Thank you.
From what I gathered, our sun is rather smallish - medium sized at best. It's not quite large enough ever to do the supernova thing. Instead, it will simply implode. Is this correct?

You are right, it will not supernova as it does not have enough mass. However, in its last million years or so before collapse to a white dwarf, it with blow off its outer layers (forming a planetary nebula) -- one blow off every time it reignites helium fusion (which the blow off stops). 4 or 5 such blow-offs with about 100,000 years between them is what is predicted with current knowledge.

If you are interested in all of this, try googling things like evolution of the sun -- looking for pages from university astronomy (or astrophysics) departments.

DIASPORA-1963 · « **Reply #50 on:** April 11, 2016, 10:20:35 am »

Quote from: RandallS;189888

You are right, it will not supernova as it does not have enough mass. However, in its last million years or so before collapse to a white dwarf, it with blow off its outer layers (forming a planetary nebula) -- one blow off every time it reignites helium fusion (which the blow off stops). 4 or 5 such blow-offs with about 100,000 years between them is what is predicted with current knowledge.

If you are interested in all of this, try googling things like evolution of the sun -- looking for pages from university astronomy (or astrophysics) departments.

Oh, I do so much reading in mathematics - and in 3 languages - that I like to ask questions in other subjects that interest me, like astronomy. I enjoy having other people tell me what they know, and I get to remain a lay-person who can enjoy it w/o feeling the need to do all sorts of research. It's nice just being a member of the audience for a change. I don't have to read through the proofs, check the equations to see that they balance - none of that stuff. And other people enjoy talking about the things that interest them, I find. It's a nice way to get them to relax and open up and be warm towards me: mathematicians scare people, you know. Dentists, mathematicians, morticians - we're not high on the social register ...