End of Earth

[3488]

Hi Wayne,

Got a link here.

Earth's Future with a brightening Sun.

It does not say that the Earth as a planet will end in 1 GY, it says that the Sun's energy output will have risen enough to drive off the Earth's atmosphere & oceans in about that time, leaving the Earth more like the Moon or a hot Mars.

There's another here that says the Earth will resemble Venus in less than 1GY due to the brightening Sun.
Earth to become like Venus in the future due to a more powerful Sun.

Andrew Brown.

 

[ZenGalacticore]

Are you saying that all the yellow, G-2 Class main-sequence stars out there that are comparable to the Sun's mass increase to such intensity after 5.8 or so billion years that anything within one AU is going to get fried?

In 5.8 billion years, earth will probably be inside the surface of the sun, so yes.

You misunderstood me here, or I didn't pose the question properly. The Sun is about five billion years-old. You're saying that within one billion years, the Sun's increasing intensity will make the Earth uninhabitable. I'm saying, that do we see similar sun-like stars rising to such inhospitable intensities after about 5.8 billion years? Meaning, within a billion years after the 5 billion year milestone of middle age?

IOWs, before the Sun reaches the age of 6 billion years. (Of course, you are, or should be, well aware that I am at least familiar with G-Class stellar evolution and the red giant phases of such stars.)

And as I said before, while I've read that such stars increase in intensity as they age, I don't ever remember reading that the increase is so rapid as to render planets like Earth at one AU uninhabitable within 6 billion years. I just don't think we can say for sure on something like that that will unfold over a billion years.

I hope that clears up the misunderstanding here.

 

[MeteorWayne]

Zen, yes we missed each other on the 5.8 GY, I thought you meant 5.8 more not 5.8 total. Thanx for clearing that up.

But, see Andrew's links above.

"The Sun's energy output will have risen enough to drive off the Earth's atmosphere & oceans in about that time, leaving the Earth more like the Moon or a hot Mars."

Wayne

 

[neilsox]

Hi Wayne: I confess, I like numbers, so I make some up when I can't find any. Sometimes someone supplies a number that isn't someone else's guess. Most of the time not. So the average temperature of Earth will be 100 degrees c = 212 degrees f warmer one billion years from now, unless we put up some sun shades? Are sun shades incredibly improbable? Why do you think advanced humans can't cope if the equatorial ocean is boiling? Won't the poles of Earth continue to be at least 50 degrees c lower average temperature than the Equator/more if the tilt decreases from 23 degrees to near zero? My guess is one billion years is worst case scenario and the worst of the heating will occur much later. If Earth was moved to the position of Venus, how soon would the equatorial ocean surface reach 100 degrees c? Begin boiling vigorously, most afternoons?
Does hydrogen loss due to dissociation of water vapor double in the upper atmosphere if the solar constant doubles? Is oxygen and nitrogen loss still negligible?
If a high speed neutron star or solar mass black hole passes thought the diameter of our sun, would that not deliver fresh hydrogen to the core of our sun, thus reducing the fusion energy output for about a billion years? The density of our sun's core is very low compared to a neutron star or black hole, so the speed might be reduced very little by the passage though the diameter our our sun? Neil

 

[adrenalynn]

Hi Wayne: I confess I like numbers, so I make some up when I can't find any.

You jest, right? Please say yes...

 

[Yuri_Armstrong]

cant the astronauts improve the spaceships.

Well, yes, but interstellar technology is still a long ways off. Sending a robotic probe to another star system is one thing, but sending a manned mission is completely different. Especially if you're talking about going to Andromeda, which is 2 and a half MILLION light years away. Even with it approaching the Milky Way you're talking about unbelievably vast distances.

Doesn't the shape of the ship begin to distort as you reach higher fractions of light speed also? That would probably have a big effect on its systems.

 

[adrenalynn]

Doesn't the shape of the ship begin to distort as you reach higher fractions of light speed also? That would probably have a big effect on its systems.

Don't get bit by Relativity here. Make sure you pay attention to reference frame.

 

[neilsox]

Hi adrenalynn: I hope my guesses have some bases in reality, but I suspect some of our PHDs are believed because they are prestigious, instead of careful analysis. This is particularly likely when the PHD is over specialized in a different area, than that in which he is speaking as one with authority.
The first link by Andrew Brown = Universe Today had summaries of 4 talks, two of which suggested big trouble as soon as 1/2 billion years in worst case scenarios, but the other two suggested 5 billion and 7 billion years. If this is typical, consensus is poor. Neil

 

[adrenalynn]

So you're saying you just make stuff up and hope that someone somewhere has published something in agreement with it?

 

[MeteorWayne]

Hi Wayne: I confess, I like numbers, so I make some up when I can't find any.

sigh... I've noticed

So the average temperature of Earth will be 100 degrees c = 212 degrees f warmer one billion years from now, unless we put up some sun shades?

I don't see anything that said that. As the temperature gets higher, evaporation increases, which increases the greenhouse effect, which raises the temp....

Are sun shades incredibly improbable?

No, but there might be many other consequences of a sunshade...do a google search.

Why do you think advanced humans can't cope if the equatorial ocean is boiling?

huh?

Won't the poles of Earth continue to be at least 50 degrees c lower average temperature than the Equator/more if the tilt decreases from 23 degrees to near zero?

Who konws how heat flow will respond. And by what possible mechanism would the obliqity decrease to zero?

My guess is one billion years is worst case scenario and the worst of the heating will occur much later. If Earth was moved to the position of Venus, how soon would the equatorial ocean surface reach 100 degrees c? Begin boiling vigorously, most afternoons?

Too much speculation to discuss

Does hydrogen loss due to dissociation of water vapor double in the upper atmosphere if the solar constant doubles? Is oxygen and nitrogen loss still negligible?

Don't know the answer, and I don't don't make stuff up.

If a high speed neutron star or solar mass black hole passes thought the diameter of our sun, would that not deliver fresh hydrogen to the core of our sun, thus reducing the fusion energy output for about a billion years? The density of our sun's core is very low compared to a neutron star or black hole, so the speed might be reduced very little by the passage though the diameter our our sun? Neil

If a high speed neutron star or solar mass black hole passes thought the diameter of our sun, it will be a moot point, since we won't be in the same orbit, and could be redirected into the sun, ejected from the solar system entirely, or be in any orbit at all, except the one we're currently in.

 

[csmyth3025]

In 1865 Jules Verne published "From the Earth to the Moon". !04 years later we actually went from the Earth to the Moon.

Today people talk about colonies on Mars and elsewhere. !00 years from now our progeny may well see such things themselves.

Can anyone imagine what travels we may undertake a thousand years from now - or a mere one million years from now?

If the Earth becomes uninhabitable 500 million years from now it will be a sad ending to what will be remembered as the first chapter of humankind. The chapters that lay ahead are the stuff that our dreams are made of.

Chris

 

[MrUniverse]

Won't the poles of Earth continue to be at least 50 degrees c lower average temperature than the Equator/more if the tilt decreases from 23 degrees to near zero?

Who konws how heat flow will respond. And by what possible mechanism would the obliqity decrease to zero?

My guess is one billion years is worst case scenario and the worst of the heating will occur much later. If Earth was moved to the position of Venus, how soon would the equatorial ocean surface reach 100 degrees c? Begin boiling vigorously, most afternoons?

Too much speculation to discuss

Does hydrogen loss due to dissociation of water vapor double in the upper atmosphere if the solar constant doubles? Is oxygen and nitrogen loss still negligible?

Don't know the answer, and I don't don't make stuff up.

If a high speed neutron star or solar mass black hole passes thought the diameter of our sun, would that not deliver fresh hydrogen to the core of our sun, thus reducing the fusion energy output for about a billion years? The density of our sun's core is very low compared to a neutron star or black hole, so the speed might be reduced very little by the passage though the diameter our our sun? Neil

If a high speed neutron star or solar mass black hole passes thought the diameter of our sun, it will be a moot point, since we won't be in the same orbit, and could be redirected into the sun, ejected from the solar system entirely, or be in any orbit at all, except the one we're currently in.[/quote]

F#@% it! We're moving the Earth. I'll do it myself if I have to.

 

[eburacum45]

No, but there might be many other consequences of a sunshade...do a google search.

I must admit, I'm one of the people who has recommended the use of a sunshade to ensure the habitability of a future Earth. There are some disadvantages, but in general it is a much more energy-efficient option than trying to move the planet.

A sunshade seems a very attractive option if our distant ancestors actually desire to maintain a biosphere in that far-off time. In all probability, if any intelligent life remains anywhere near the Earth in one gigayear's time we wouldn't recognise it as our own species, but in the unlikely event that we do want to maintain a biosphere on this old world of ours I'm pretty certain we could do so for most of the time that the Sun remains on the Main Sequence.

If humanity continues to advance technologically, and if we remain a biological species, I expect we will find ways of terraforming other terrestrial worlds. Venus would pose a greater challenge than the future Earth of one gigayear from now, but if it were desirable to terraform that world, then a sufficiently advanced civilisation could do it.

On the other hand an advanced civilisation which remains biological in nature might find it much more efficient to construct and use rotating space habitats of various kinds, which have the advantage of being movable and so can respond to the variation in a star's luminosity. A sufficiently advanced civilisation might decline to use planetary surfaces at all, mostly because they require so much effort to maintain in a habitable state.