Did any other Brits read this in the Sunday Telegraph on Sunday?

The end is not as nigh as we thought. Scientists have found a mistake in the standard account of the future fate of the solar system and now believe that the Earth will not be destroyed when the Sun runs out of fuel.

For decades, astronomy textbooks have insisted that the Earth will be engulfed in an inferno billions of years from now as the Sun burns up its nuclear fuel and swells to become a gigantic red star.

Surrounded by the searing gas of the Sun's outer atmosphere, the Earth was expected to be dragged down to its doom deep within the Sun.

Now a team of astrophysicists at Sussex University has uncovered a significant flaw in the standard view of how the Sun will evolve, with dramatic consequences for the fate of our planet.

According to the conventional wisdom from astronomers, the Sun has been kept alight for the past 4.5 billion years by burning up hydrogen at the rate of several million tons every second.

As this fuel runs out, the theory predicts that stars such as the Sun will start to expand and cool into red giants.

Calculations based on this standard theory suggested that it would balloon out and engulf the Earth about 7.5 billion years from now.

According to the team from Sussex University, however, these calculations missed out a crucial effect: the loss of mass by the ageing Sun as it expands and its gravity weakens.

Taking this effect into account, the team found that the Earth would manage to dodge a fiery fate, its orbit expanding away from the swelling Sun.

According to Dr Robert Smith, one of the team that made the discovery, the dying Sun will make two attempts to destroy the Earth. In the first, about 7.7 billion years from now, it will expand to about 120 times its current size, engulfing the two innermost planets, Mercury and Venus.

The Sun's weakened gravity will allow the Earth to escape a similar fate, however, with our planet settling down in an orbit about 25 per cent bigger than the one it now follows - well clear of the Sun's outer atmosphere.

About 100 million years later the dying Sun will have another go at the Earth, but will fail again, with our planet having moved out even further.

According to Dr Smith, the Sun will then collapse into a harmless white dwarf star, about 10,000 miles across. "The Earth won't wander off into space," Dr Smith said. "But whether it will be anything like we see today seems pretty doubtful."

The team reports its findings in the current issue of the journal Astronomy and Geophysics. "They differ from the standard conclusion by taking account of mass loss and including the latest data based on studies of real stars," said Dr Smith. "To that extent, the textbooks will have to be rewritten."

He added that although the Earth is safe from destruction, life on the planet still faces some formidable challenges in the far future. The new calculations suggest that the surface of the Earth will become too hot to sustain human life for a few million years about 5.7 billion years from now.

This is about 200 million years later than previously thought - an extra period of grace that humans could use to develop technologies for living on a hotter Earth, such as building communities deep underground.

Alternatively, the human race could move to another planet for a while. "Unfortunately none of the surviving planets, such as Mars, are warm enough at the time we will need them - though we could think about altering conditions on them," said Dr Smith. "We might not have to leave the solar system."

The findings are likely to rekindle the age-old debate about the ultimate fate of humanity. Sir Patrick Moore, the astronomer, said: "In the end, no one really knows what is going to happen. But my message would be `don't panic'."

The original article is here - http://www.dailytelegraph.co.uk/conn...2Fecnsun08.xml

Well, that gives me another 200 million years to put my affairs in order...

__________________
Red

"Go to Blue Alert!"
"Is that really necessary Sir? It will mean changing the bulb..."

An extra 200 million years on top of the already 5.5 billion. As Sir Patrick Moore says at the end of that article, "Don't panic."

I always find it amusing when articles like this one blithely assume that human beings will still be around 5.7 billion years from now.

I'd be pretty surprised if we make it another 5.7 thousand. By that time, if we don't destroy ourselves directly (or indirectly by environmental degradation), we'll probably have created our own replacements.

[Doh! fixed my numbers...]


<font size=-1>[ This Message was edited by: Donnie B. on 2002-01-11 10:42 ]</font>

What I find baffling about this press release is that this idea has been around for years! I know I talked about it with someone at a meeting in 1998, and it was old then.

One question that I have about this whole thing: if the Sun looses enough mass to have the Earth's orbit swing out to 1.25AU, wouldn't the drag from the large amount of solar wind serve to slow our orbital speed, partially or totally negating the effect of the Sun's leaky mass?

Also regarding the ultimate fate of humanity: yes, I don't think that the human race will be around as we know it a few thousand years from now. But I think that it is more likely that we would have evolved into something completely different through technological means than have something terrible happen that would wipe us all now.

While I think it is likely that we will see full scale nuclear war and a partially wrecked biosphere in the next few thousand years, the fact of the matter is that humans as a species are resilient. If me manage to establish self-sufficient colonies on other worlds, that will simply make us all the harder to wipe out.

However, the benefits of combining human flesh and machine may pressure the rest of humanity to likewise evolve or be left in the lurch. Resistance is futile. [img]/phpBB/images/smiles/icon_smile.gif[/img]

_________________

The husband of the future borg queen--
--Azpod... Formerly known as James Justin

<font size=-1>[ This Message was edited by: Azpod on 2002-01-11 18:06 ]</font>

Surely we'll be creamed by an asteroid long before the sun dies. Here's a report on the latest close approach:

http://news.bbc.co.uk/hi/english/sci...00/1746330.stm

We're not gonna get creamed... and don't call me Shirley!

[img]/phpBB/images/smiles/icon_biggrin.gif[/img]

(Sorry, couldn't resist)

This should be plenty of time for humans to have at least gotten somewhere else in the universe. Considering that we have gotten from the horse and buggy to almost the edge of space in about 110-130 years, we should have something going by then. Provided we haven't blown ourselves out of existance by then.

__________________
"You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep seated need to believe." [Carl Sagan]

Isn't the solar wind blowing us away from the sun? Wouldn't that offset its drag?

I'm not so sure that technology will change us into something inhuman. Science is advancing faster now than in past centuries, but will it advance even faster in the future or will it level off as we reach the limits of our engineering ability or the limits of our understanding?

It would take a lot of wind to make any noticable change in Earth's orbit, and I suspect that any wind that powerful would have other effects that wouldn't be too nice.

For sure, though, it wouldn't make our orbit bigger. I'm no expert in orbital mechanics, but I do know that to attain a larger orbit you have to increase the satellite's orbital speed... that is, give it a push forward along its orbit. I don't see any way the solar wind could do that. On the contrary, it would slow the Earth's orbit frictionally.

An intriguing question indeed! My initial response is that we probably haven't approached either limit yet, but I can't say there are no such limits. After all, we know you can't teach a flatworm to do calculus, no matter how hard you try or how much time you devote to the attempt. By analogy, at least, there must be concepts too advanced for our brains to encompass.

However, humans have short-circuited a number of natural limits by using tools. Maybe there's a meta-calculus we can't grasp, but perhaps we can build machines that can. Now, do the results those machines produce count as human achievements? Are we still homo sapiens if we depend on our tools for any further advancements?

In any case, I still argue that any trace of mankind that survives to AD 5,700,000,000 (or even AD 7700) will not be people.

Because of the solar wind, the earth is not in a free fall orbit. If another force is acting on a body it can be closer to or farther from the body it's orbiting than its velocity would normally allow. Even if its effect is small it will have billions of years to work.

Whilst it is late at night where I live and I am quite muzzy-brained, I feel impelled to say that I think it's possible that the universe sets limits that we cannot surpass, no matter how rapidly we have advanced from stone-splitting to spaceflight. For example, I don't know that interstellar migration will ever be anything but a multi-century longshot because FTL travel may be quite impossible and conventional rocketry, even with matter-antimatter engines, may be limited to small fractions of lightspeed.

This runs counter to optimistic sci-fi scenarios and to extrapolations of the rate of mankind's past achievments, but I offer it as a possibility anyway.

--Don

Speaking of light travel, I watched K-Pax last weekend and I remember Prot saying that his "species" had traveled at light speed. Not in craft that increased speed to FTL speed, but they had hopped onto something that was already going FTL. Given enough time(say a couple billion years and provided we don't blow ourselves up), does anyone think it's possible? Or were the writers just using a creative license?

__________________
"You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep seated need to believe." [Carl Sagan]

Nothing with mass can go as fast as massless particles (299,792,458 m/s). Superluminal movement is an optical illusion, even with massless particles. The particles might be coming near light speed at an angle, making them appear as if they had been going faster than light.

Folks who write science fiction for the media have to find ways for their characters to get from here to there quickly (rather than in many, many years), so they make up all kinds of methods for travel which are based only very slightly on scientific principles. Very, very slightly....

ljbrs [img]/phpBB/images/smiles/icon_biggrin.gif[/img] [img]/phpBB/images/smiles/icon_eek.gif[/img] [img]/phpBB/images/smiles/icon_rolleyes.gif[/img] [img]/phpBB/images/smiles/icon_wink.gif[/img]

Yes. We'll just have to figure out how to live a l-o-n-g...l-o-n-g time.

Or we'll have to pace ourselves as a human race and just accept gradual colonization over lifetimes, and human exploration of Mars, the out solar system, deeper space between stars, and eventually the area of the nearest star's solar system. On and on over time until there are human-like beings living on worlds and in space throughout this portion of the spiral arm, within the "short" time of just 10,000 years from now. This may sound impossible, but in reality it might be much more realistic and feasible than "warp drive."

It may not seem like we have the motivation to start right now, but we are in fact moving in that direction if one takes the broad historical view.

My personal opinion is that by then we'll have hollowed out the earth's core and stuck an engine in there, a la "The Dalek Invasion Of Earth".

Either that, or we'll all be crusing around in transdimensional Police Telephone Boxes and wearing ludicrously long scarves...

__________________
Red

"Go to Blue Alert!"
"Is that really necessary Sir? It will mean changing the bulb..."

Accompanied by attractive (if sometimes rather noisy) young ladies.

Larry Niven's solution:

Use magnetic fields, or possible superheavy bodies (mini-black-holes) to cause the Sun to form a jet from one of its poles. Go exploring, taking the whole solar system along for raw materials.

Optional: before you go, convert the mass of the outer planets into a ringworld so you have plenty of living space).

My only serious objection to living a l-o-n-g time is that I don't want to hear another round of media hype about the Y10K bug, or the Y100K bug or the Y10^nK bug.

Seriously though, whether we figure out how to stop aging or not, whether the human race is alive 1 billion years from now or not, the fact of the matter is that space is not a friendly place for humans, but is a much more friendly place for machines.

Sending humans to the nearest star would take a massive multi-generational starship, a small gas giant as a fuel reserve and a whole lot of $$$ to fund the thing. Even then, it would take hundreds if not thousands of years. However, a small probe, capable of self-replication given an energy suppy and the raw materials, could make the trip in less time with a whole lot less overhead.

Whether we evolve into these machines or simply create them to go ahead of us and prepare new solar systems for human habitation, the fact of the matter is that thousands of years from now, the dominant species in the worlds that we inhabit won't be human. They will be machines, and likely intelligent ones.

Here's to hoping that we stay on good terms. [img]/phpBB/images/smiles/icon_smile.gif[/img] Of course, if someone does come up with a Warp Drive, all bets are off!

__________________
If E = MC², why do I have less energy the more mass my body acquires?
That is all.

--Azpod... Formerly known as James Justin

Following on the machine thread, we need to address the question of whether we want the human race to survive, or are we talking individual humans. If the former, there's no reason to not believe that by then we will have perfected cloning, making a "seedship" a possibility - even if it takes millenia to reach it's destination, once it gets there it just needs to whip up a batch of human sauce, with machines to nurture and care for them initially... hell, it could even be possible to store the genetic material of the earth's population along with the contents of their brains, so the individuals would "live on", even if they had copped it back on earth... excuse me, I feel a bad sci-fi movie coming on...

_________________
Red

"Go to Blue Alert!"
"Is that really necessary Sir? It will mean changing the bulb..."

<font size=-1>[ This Message was edited by: Code Red on 2002-01-15 05:04 ]</font>