lol. perhaps a Shakespearean insult.

4/9/2008 2:12:03 PM

I doubt we'll die off.

Evolving seems more likely.

The people of 3000 will be almost beyond our current imagination.

4/9/2008 2:15:13 PM

Here comes the transhumanism shit again.

4/9/2008 2:15:58 PM

Actually, transhumanism is the way to escape shit.

Literally.

4/9/2008 2:19:48 PM

What about a joke that kills?
Beyond that, maybe a bomb derived from string-theoretic physics. It'll be a few hundred years for that one. Think Star Gate bomb.

4/9/2008 2:27:45 PM

GoldenViper, I think I speak for many of us when I say that this vague futurist shit you've been tripping on so hard lately has gotten annoying. You never explain any of these supposed trends, never even offer any support for any of them except your own quiet confidence that they will all prove themselves, and fortunately for you, if they don't we'll all be dead and unable to point out how wrong you were.

So I'm begging you, please, start fleshing out these heretofore pointless responses or just stop altogether.

4/9/2008 2:34:37 PM

^ Looks like we were on the same page. (See below.)

^^ Seems like we didn't really go much farther than nuclear weapons in terms of devastation. I wonder whether we'd actually use any one weapon that would destroy us all.

Quote :

"Mr. Joshua: It would take one hell of a witty comment to put the whole earth at risk."

Nothing wrong with a little transhumanism. It's gotta make sense, though.

GoldenViper, what degree/manner of evolution do you expect of us in the next thousand years?

Also, why do you expect homo sapiens to disappear outright?

We could grow alongside our genetic overlords, right?

[Edited on April 9, 2008 at 2:38 PM. Reason : ...]

4/9/2008 2:36:52 PM

What ends humankind?

That's easy: Crake.

4/9/2008 3:15:09 PM

Some say the world will end in fire,
Some say in ice.
From what I've tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.
-Robert Frost

I hold with those who favor fire.

4/9/2008 3:41:53 PM

Quote :

"So I'm begging you, please, start fleshing out these heretofore pointless responses or just stop altogether."

Uh, Kurzweil's idea are freely available on the open web, comrade. Do you honestly want me to produce a futurist treatise here?

I try to be brief. Put simply, the coming advances in artificial intelligence and nanotechnology will change everything. We'll probably have human-level AI and molecular manufacturing within a few decades. We can safely assume human mind at electronic speed will quickly put the rest of the species to shame. With control over fundamental building blocks from nanotech, you get the Singularity.

That's why I say the year 3000 will be nearly beyond imagining.

For further reading:

http://www.kurzweilai.net/articles/art0134.html?printable=1

http://www.crnano.org/

Quote :

"GoldenViper, what degree/manner of evolution do you expect of us in the next thousand years?"

Shift to electronic minds, as stated above. They'll think a million times faster than we do, giving them plenty of time to improve themselves. If these posthumans take bodies, it'll be of extremely durability materials such as diamondoids. They'll be effectly immortal, surviving indefinitely.

Between fusion generators and Dyson spheres, they'll wield vast energies for whatever purpose they see fit. Space exploration seems likely. They could reach many other solar systems by 3000.

Quote :

"Also, why do you expect homo sapiens to disappear outright?"

I actually don't. I can think of many reasons why simple biological humans would endure. After the Singularity, though, they'll be utterly irrelevant. They sure won't be making important decisions.

However, it's also possible that everyone would want to become a posthuman, leaving no squishy meatbags. (Though they could be recreated if desired.)

4/9/2008 4:04:28 PM

A big enough body hits us and the entire surface becomes molten. So, no life.

But more realistic is a large asteroid. To actually fully exterminate man even with mans preperations for impact, or attempts at deflection, it would have to be a very very large asteroid. Or just have no time to prepare would be sufficient for a large asteroid

4/9/2008 4:07:57 PM

^^I just read some of that stuff by Kurzweil. What a fucking nutjob.

He's got lots of fancy graphs to support his rambling nonsense. It's pretty funny, actually.

4/9/2008 4:29:43 PM

^ That's not an argument.

4/9/2008 4:40:31 PM

Quote :

"Do you have anything to back up the claim that resources are scarce? Prices for resources such as gasoline are not much higher than they were in either 1980 or 1880, so are you suggesting that we have needed a massive die-off since before the industrial revolution?"

I still have this terrible tendency to argue from emotion/hearsay as opposed to linking to any evidence.

Quote :

"We have difficulty feeding them because of stupid or corrupt governments, not because of a lack of food."

Okay, conceded. Once again I got ahead of myself.

Quote :

""Resources are scarce enough as it is, and climate change and rising ocean levels is only going to make it worse." What exactly is that supposed to mean? Tell me, what would be a level of scarcity that didn't require a die-off? There is no resource we need to survive that we are in dire need of running out of."

I just mean that the ensuing climate change may make it more difficult to grow as much food as we already do, which will lead to problems to feeding even the people who already get the distribution.

4/9/2008 5:07:07 PM

Perhaps the more important question... What is the most realistic survival strategy for each of these theoretical threats? (Obviously some of the more heinous examples might not have a solution at all.)

Oh and, Prawn Star how could zombies possibly be less likely than damn dirty apes or evil aliens! (Unless of course you're an undead zombie purist who simply lumps rage-type viruses in with the global epidemic option, in which case... agreed)

4/9/2008 5:13:23 PM

Quote :

"We'd be able to see a planet on its way likely hundreds or thousands of years before it collides with us, if not more. That's plenty of time to put colonies elsewhere, or develop technology to divert or destroy a planet."

[Edited on April 9, 2008 at 5:31 PM. Reason : .]

4/9/2008 5:30:53 PM

^ Doesn't load in Safari?

Quote :

"Perhaps the more important question... What is the most realistic survival strategy for each of these theoretical threats? (Obviously some of the more heinous examples might not have a solution at all.)"

Ecological diversification. We gotta get off this rock and start planting seeds elsewhere.

I don't see any way around it. As an investor, nothing else makes sense.

4/9/2008 5:39:52 PM

Fuck, I want to be a diamondoid immortal

THERE CAN BE ONLY ONE!

4/9/2008 6:00:17 PM

^ Thankfully, there can be many.

But it'll be a long, hard road to get there.

I'm not quite as optimistic as Kurzweil about humanity's use of the coming technology.

4/9/2008 8:20:38 PM

Derek 'Stormy' Waters: Okay, okay. So, say I put my brain in a robot body and there's a war. Robots versus humans. What side am I on?
Debbie DuPree: Humans! You have a human brain.
Sparks: But... the humans discriminate against you. You can't even vote!
Marco: We'd better not have to live on a reservation. That would really chap my caboose.
Captain Murphy: Yeah, but... nobody knows you're a robot. You look the same.
Debbie DuPree: Uh, uh. Dogs know. That's how the humans hunt you.
Derek 'Stormy' Waters: They're gonna' hunt me? For sport?
Marco: That's why we have to CRUSH mankind! So you might as well get on board for the big win, Stormy.

4/12/2008 8:09:02 PM

I'm reading Isaac Asimov's Nemesis right now. It takes place about 250 years in the future where the entire solar system is occupied and overpopulated. One asteroid of scientists has developed an incredibly rudimentary ftl drive. They discover that Earth has a twin star (Nemesis) that will, in a few thousand years, most likely destroy Earth. Instead of telling anybody about it they just put an engine of their asteroid and get the fudge out of there.

4/13/2008 10:06:02 AM

So long and thanks for all the rocket fuel.

Neat-sounding story.

4/13/2008 11:55:43 PM

The return of Christ during the rapture

4/14/2008 12:37:18 AM

biological epidemic (run-away genetically engineered virus, new plague, etc)

2nd place... mmm... i dunno.. I think we're some resilient little fuckers, and its be tough for anything else to wipe out the human race. Christ, even a biological epidemic isn't a 100% guarantee, some ridiculously small percentage of the population is likely to be resistant or immune.

4/14/2008 9:18:35 AM

^ Resilient indeed.

Nothing actually ends humankind altogether, but I think the closest we'll get is the kind of scenario set up by Kuntsler in A World Made by Hand I have yet to read it, but it promises to be entertaining. It's basically the royal flush of worst case scenarios:

1. End of Oil
2. Climate Change
3. Global Pandemics
4. Resource Wars

The end result is a back to the basics small-town system of government, with all the typical problems of Post Apocalyptic World scenarios... scavengers, disease, etc.

[Edited on April 14, 2008 at 9:37 AM. Reason : .]

4/14/2008 9:37:23 AM

I don't see how a colliding planet wouldn't kill every human. With the exception of some astronauts who'd be dead within a very short time afterwards.

[Edited on April 14, 2008 at 11:09 AM. Reason : ?]

4/14/2008 11:09:27 AM

^ Touché, but what's the point of talking about the one in ten billion shot that is both a planet killer and completely incapable of being planned for? We can talk fantasy about putting colonies on other planets & moons so that "someone" would survive all day long... or the highly unlikely notion that we could in fact destroy said planet before it reaches us... but without a massive single world government... How are these multi-trillion dollar ventures to be achieved?

4/14/2008 11:19:37 AM

Dear Everybody

The singularity won't ever happen.

Why?

Because computers are dumber then shit.

4/14/2008 12:36:50 PM

The US and EU space agencies systems for discovering and tracking near-earth objects is pretty good. They can pick up and track meteorites (<50m wide) that orbit within 1.7AU of Earth. Additionally, once tracked for the sufficient amount of time, the orbits can be reliably predicted, and their chance of hitting earth evaluated effectively.

Assuming it was moving at speeds similar to those of other trans-system objects (ie: comets, other moving asteroids), an object the size of a planet moving through the system as a rogue body would be noticed long before it got close to earth. If it was moving at faster speeds, we'd likely detect it burning through the Oort cloud, have a few years to say some prayers, rape and pillage, then die in quite a spectacular cataclysmic event. This of course is assuming we get hit.

Its been a minute since I've crunched numbers like this, so please feel free to correct my mistakes.. but:

Assuming:

The volume of Earth is 1.0832x10¹² km³

1 AU =~ 150 million km

Neptune is 30AU from the sun OR about 4.5 billion km

So, if you calculate the volume of the solar system inside Neptune's orbit,

V = 4/3 ?r³ = 3.817x10^29 km³

Basically, what I'm trying to get at through all the numbers is that at any given moment, we occupy an infinitesimally small percentage of the volume of the solar system, and in that size lies relative safety.

My money is still on a virus.

[Edited on April 14, 2008 at 1:29 PM. Reason : n]

4/14/2008 1:06:13 PM

^ Do the EU and American space agencies routinely look for objects that do not orbit along or near the ecliptic? Also, aren't they just looking for asteroids?

Your math's pretty, but your conclusion doesn't necessarily follow. An impact appears unlikely. You make a good case for that. It has happened before, however. That's the operating theory on our moon.

In fact, when we factor in gravity, impacts aren't all that threaten our safety.

Our infinitesimal size makes vulnerable to more. Gravity can be a motherfucker. Imagine a speck of dust in a light breeze. A gas giant swings through, does not strike Earth but passes nearby, and we still all die.

How?

We're gravitationally flung from orbit.

A virus might work. Why would a virus kill all of its hosts, though?

^^^ I'll take issue with the "incapable of being planned for" part.

Fantasy?

Non-terrestrial colonization is today what intercontinental colonization was to nations hundreds of years ago. Don't act as if your own non-world-government isn't already making strategic plans to man Mars and colonize the moon.

[Edited on April 15, 2008 at 2:44 AM. Reason : ...]

[Edited on April 15, 2008 at 2:45 AM. Reason : ...]

[Edited on April 15, 2008 at 2:48 AM. Reason : ...]

4/15/2008 2:43:35 AM

To fling us out of orbit it would need to come very close to the Earth and it would need to pass us just right. Otherwise, the pull on the sun will match the pull on us and the net effect will be nothing. So, short of a black whole or cosmic string even having a major effect on our orbit is insignificant. Even a gas giant would need to pass just right, or the earth will simply settle into a new orbit.

That orbit could be hell, but the Earth's self regulatory systems are amazingly resillient. Florida might flood or freeze, but with human help to strategically relocate plants and animals while at the same time relocating ourselves and our irrigation systems, I suspect a large percentage of us would survive all but the worst possible catastrophies.

4/15/2008 9:36:38 AM

I like your questions sir, they make me go read stuff. Viva the revolution.

From what I can find, the NEAT program and its similar counterparts around the globe cover a decent (read: more than half of the viewable area) portion of the visible night sky. Areas which the program avoid are the galactic ecliptic plane as interference from stars make it hard/impossible for the computer software to track moving objects, and up to a certain inclination above our own in-system orbital plane (For those reading this who are unaware, the plane which the planets rotate around our sun is not the same as the plane that the stars in the Milky Way orbit around the center of the galaxy).

Furthermore, the program doesn't specifically look for asteroids per se. It specifically searches for any moving object above a certain size. The lower limit of the object size is pretty small (at least 50m) so I'd say there's a good chance at noticing a planet.

Yes, impacts have happened before (reference: our orbiting hunk of cheese). They'll probably happen again. Right now, from current tracking, the next significant scheduled impact/near miss is due sometime in 2880ish. However, as the solar system ages, the number of rogue bodies flying through the orbital plane in unstable orbits decreases. They've simply been reduced in numbers because they've been hitting planets for billions of years already.

Example, the K/T impactor came from the Baptistina asteroid family in the asteroid belt. However, it took that asteroid family millions of years to get to one of the few gravitational resonance points in the belt to eject debris into the inner system, and then millions of more years for the subtle gravitational influences to work their magic and get a rock to us.

As for being flung out of orbit.. it'd take a lot, A LOT of planet to do that. An object with that much mass moving through the system would destroy it, and there wouldn't be anything we could do about it. However, we are talking about an object much more massive than Jupiter, and again I'm back to the point that we'd see something that massive coming before it got here.

Assume an object the mass of Jupiter passes through the system, planetary orbits would be altered slightly, but no one would be flung from orbit around the sun. Best case scenario, massive global climate change. But I think humanity could survive that. At least, some of us.

[Edited on April 15, 2008 at 10:36 AM. Reason : .]

4/15/2008 10:34:46 AM

Quote :

"Non-terrestrial colonization is today what intercontinental colonization was to nations hundreds of years ago. Don't act as if your own non-world-government isn't already making strategic plans to man Mars and colonize the moon."

Are you serious? How are we as a so-called super power going to supposedly pay for this colonization while running ourselves bankrupt in our international affairs? The scope of a project the scale of which you're talking about would be what? How many trillions of dollars? We (mankind) spends a total of only about $50 billion a year in space exploration. Assuming the all this money could be pooled into one organized program how long do you suppose it would take to get the project off the ground? How long to get the first man there? How long after the initial landing could building begin? And how long after beginning could the colony be completely independent from earth?

I'm more than willing to bet that your numbers would be close, but possible... And the chances of a one-world space agency being formed in the next century are what? Short of a third world war, it seems that the chances of any kind of international coalition of that scale are slim to none.

And in the 800+ years between now that next significant scheduled impact/near miss... what do you think are the chances that one of the previously mentioned threats happens first?

4/15/2008 11:42:19 AM

To be completely fair, that 800ish years is the estimation of the threats we know of.. that's not to say there isn't something headed our way we don't know about that would hit us before then.

4/15/2008 1:16:53 PM

Quote :

"LoneSnark: To fling us out of orbit it would need to come very close to the Earth and it would need to pass us just right."

Define very close and just right please.

You think climate change is rapid and bad enough when we're in a stable orbit?

Quote :

"LoneSnark: Otherwise, the pull on the sun will match the pull on us and the net effect will be nothing."

WHAT?

No, really.

WHAT?

Gravity is not a zero sum force. The gravitational effect of a body tugging on our sun doesn't diminish its ability to tug on us. That's inconsistent with rudimentary physics.

Quote :

"LoneSnark: So, short of a black whole or cosmic string even having a major effect on our orbit is insignificant."

I think you drastically underestimate the impact of a short shift (in astronomical terms) away from our present orbit in either direction. Think of an Ice Age with exponential severity.

The habitable zones only cover life, generally. Human life has no "god mode." As the species on top, we'd be the most likely to perish in such a cataclysm.

Quote :

"LoneSnark: That orbit could be hell, but the Earth's self regulatory systems are amazingly resillient. Florida might flood or freeze, but with human help to strategically relocate plants and animals while at the same time relocating ourselves and our irrigation systems, I suspect a large percentage of us would survive all but the worst possible catastrophies."

Earth is flung from orbit and we suddenly reverse thousands of years of human instinct at once?

I'd call human help an anachronism at that point. I'm just speculating of course, but I think Earth would become Planet Bedlam.

Granted, I see many scenarios in which small bands of humans would survive a close pass. I'd call it lunacy to assert that there aren't many scenarios in which we don't survive, however. Especially given our spot on the food chain.

---

Quote :

"Sayer: From what I can find, the NEAT program and its similar counterparts around the globe cover a decent (read: more than half of the viewable area) portion of the visible night sky."

That is impressive (i.e. with respect to Billy Bob Thornton, "It's a pretty big fucking sky."), but what about the non-visible night sky? (Infared? Hot planetary bodies we can't see definitely exist.)

Or the daytime sky?

The rest of the limitations on observation lead me to think they need a lot more $texas. Very neat read!

But, here we are again, taking the Universal Webster approach and saying, "potential impact bodies can not come from the non-covered portion of the night sky, the daytime sky, or from orbits that do not parallel our own solar system's ecliptic. They also must be visible in the visible portion of the electromagnetic spectrum."

The Universe may have other plans.

Quote :

"Right now, from current tracking, the next significant scheduled impact/near miss is due sometime in 2880ish."

This is based on available data. Empircism breeds false confidence here. Similar to my comments in the aliens thread, the existence of a "falling body" with our name on it precludes our ability to observe, document, and categorize it.

We could wake up to an announcement tomorrow that NASA found something in the Southern Hemisphere that's only a few days away. Sour grapes. Earth's geologic record shows that impacts do not occur on a regular schedule.

Quote :

"Sayer: However, as the solar system ages, the number of rogue bodies flying through the orbital plane in unstable orbits decreases. They've simply been reduced in numbers because they've been hitting planets for billions of years already."

The effect you mention is real, but small. For every meteor that hits the moon or Mars or whatever, there's another one knocked out (gravitationally or directly) by a comet. All those asteroids in the belt must smack into each other/influence each other's orbits all the time. Ditto the Oort Cloud.

Quote :

"Sayer: Example, the K/T impactor came from the Baptistina asteroid family in the asteroid belt. However, it took that asteroid family millions of years to get to one of the few gravitational resonance points in the belt to eject debris into the inner system, and then millions of more years for the subtle gravitational influences to work their magic and get a rock to us."

We live on the 8 ball on a 4d (for simplicity's sake) pool table where everyone's got a cue stick and nobody takes turns. What you've described here is the equivalent of how one shot took place during a very long game.

Remember, rare doesn't count for much in a HUGE BIG GIANT ASTRONOMICAL universe.

Quote :

"Sayer: As for being flung out of orbit.. it'd take a lot, A LOT of planet to do that."

How much?

I wonder if a gas giant would really even be necessary.

Quote :

"Sayer: An object with that much mass moving through the system would destroy it, and there wouldn't be anything we could do about it."

Agreed.

Quote :

"Sayer: However, we are talking about an object much more massive than Jupiter, and again I'm back to the point that we'd see something that massive coming before it got here. "

Unless it wasn't visible...

Why would it have to be much more massive than Jupiter? Not that that's a deal breaker...

4/15/2008 1:19:58 PM

Quote :

"Unless it wasn't visible..."

Do black holes move? (serious question)

4/15/2008 1:32:54 PM

Yes, black holes do move. Some are moving rediculously fast. But there are only a few known black holes, so they are not very common. Again, the odds are slim.

And anything moving into our solar system would be visible: we have a giant light bulb in the center which tends to light up all objects within our solar system. And a black hole would be completely visible as it would distort the stars behind it, an effect we already use with luck to see black holes that are on the other side of the galaxy.

So, yes, short of a black hole or cosmic string travelling at inter-galactic speeds we are likely to see it.

Quote :

"Gravity is not a zero sum force. The gravitational effect of a body tugging on our sun doesn't diminish its ability to tug on us. That's inconsistent with rudimentary physics."

If it did work like that then we would have a problem. But, as you say, it does not, so we should be fine with most large objects. What matters is the orbit of the earth relative to the sun. If a black hole passes the solar system fairly far away then the Earth will be pulled towards it, but so will the sun. How much? Gravity is awesome that way: objects of differing weights fall at the same speed. So, if the distance to the black hole is many times the distance between the Earth and the sun then both the sun and the Earth will fall towards the black hole at the same rate regardless of orbital position, which means the Earth's orbit of the sun will be largely unaffected. Think of the Moon's orbit of the Earth: the sun does not pull the moon out of orbit even though the sun weighs far more than the moon.

Now, if a large planet named X travelling very fast passes very close to the Earth then on the way in it will accelerate the Earth towards it, but if you follow the effects through you should realize they largely cancel out. If it is passing in the same direction as the Earth rotates then it will slow down the Earth during approach (transferring kinetic energy from the Earth to X) and then re-accelerate the Earth as it departs (transferring kinetic energy back from X to the Earth). The net effect upon the Earth's speed (and thus its orbit) would be minimal (although during the actual process the effects could be large as X's gravity causes tidal effects similar to our moon).

The only disaster scenario's include if one of the objects captures the other. For example, if a rogue planet larger than Jupiter passes close enough then it could capture the Earth, turning it into a moon. The tidal effects of such a transfer would devastate our planet as the oceans washed over the continents from absurdly strong tidal forces and then freezing over as the two planets left the sun.

Now, if the Earth captures a large object going the opposite direction from its orbit, say another planet of equal size travelling a direction exactly opposite from our orbit, then after the two planets settled into orbit of each other, with the requisite oceans washing over continents, the two bodies would in effect stop orbitting the sun, instead falling straight out of orbit. In a matter of months the Earth and its partner would be vaporized.

Of course, there is always in-between: if the planets are travelling the same direction or their masses are substantially different, then after settling into orbit of each other they will simply settle into a different solar orbit.

4/15/2008 2:50:13 PM

LoneSnark, reading your post is painful because where you say weight, you mean mass.

-----

Gamecat

Quote :

"Unless it wasn't visible"

As mentioned by someone else above, the sun visually illuminates all objects in the solar system, and heats objects in the infrared spectrum. Tracking efforts use mainly infrared, as the thermal energy radiated gives clues to the objects composition. Additionally, I would point out that Saturn is visible in the night sky to the naked eye. With the number of amateur astronomers constantly scouring the night sky for their various projects, along with all the professionals conducting research, the chances are quite high that an object of planetary size at least as far away as Saturn would be noticed by someone no matter what the inclination.

Quote :

"Why would it have to be much more massive than Jupiter?"

Think of it as a balanced equation. For Earth to be ejected out of the system, an object of at least equal mass of the sun would have to be positioned in a very specific point in the system for the forces of gravity acting on Earth to cancel out and free Earth from its rotation around the Sun.

If an object of less mass moved along any path through the system, it would alter the orbits of all bodies in the system. The amount each objects orbit is altered is completely dependent on the mass of the object in question. The orbit of Mercury or Venus would move away from the orbital plane more drastically than the orbit of Jupiter, simply because less force is needed to move an object of less mass.

Furthermore, we can assume (acknowledging there are no 100%s in science) that the scenario we are discussing has probably never occurred since the orbits our Sun's planets are still on the ecliptic plane (ie: not altered by a massive body passing through the system).

Quote :

"But, here we are again, taking the Universal Webster approach and saying, "potential impact bodies can not come from the non-covered portion of the night sky, the daytime sky, or from orbits that do not parallel our own solar system's ecliptic."

True, but given the evidence we have on Earth, Moon, and Mars impacts, there is nothing to suggest that we or anyone else in-system has ever been hit by anything NOT from the ecliptic plane. I'm not saying its not possible for something outside the ecliptic to hit us, I'm simply justifying why they are tracking the area that they are.

Quote :

"Earth's geologic record shows that impacts do not occur on a regular schedule."

In fact, there is a regular period for impacts. It's referred to as Impact Flux, and according to research it has been decreasing as the system ages gracefully. Astronomers can examine the impacts on the moon and Mars (neither having erosional forces to erase impact data), extrapolate the age and frequency across the geologic timescale, and then compare that to the frequency of impacts on our own planet. Surprisingly, it matches up.

Here is excellent literature on Impact Flux, the three definied periods of IF activity, and a bit of explanation as to why the IF has been decreasing/leveling off:
http://www.lpi.usra.edu/meetings/chron2006/pdf/6019.pdf

This is a good summary on research of the origin of the K/T Impactor at Chicxulub. The actual paper was recently published in Nature and is unfortunately unavailable for free online. However the NCSU library has the issue if you want to dig into the meat of their argument:
http://www.geotimes.org/sept07/article.html?id=WebExtra090607.html

[Edited on April 15, 2008 at 4:49 PM. Reason : ..]

4/15/2008 4:48:52 PM

Quote :

"If an object of less mass moved along any path through the system, it would alter the orbits of all bodies in the system. The amount each objects orbit is altered is completely dependent on the mass of the object in question. The orbit of Mercury or Venus would move away from the orbital plane more drastically than the orbit of Jupiter, simply because less force is needed to move an object of less mass."

You are absolutely wrong, as Galileo Galilei demonstrated long ago. While the force is substantially less, so is the amount of force needed to move the planet. The mass of an object (what those in the American tradition often refer to as Weight, or the force exerted by the object at sea level) determines the rate at which other objects fall towards it, but this rate is irrespective of the mass of the falling objects.

For example, we take a space craft and place it X distance from Jupiter, which has been relocated to the void between galaxies. Jupiter will fall towards the space craft very slowely. Conversely, the spacecraft will fall towards Jupiter very quickly. Now, we replace Jupiter with Pluto, a tiny planet by comparison, at the same distance X. The spacecraft will now fall towards the planet at a substantially slower rate in proportion with the mass difference between the two planets. However, because the mass of the spacecraft has not changed, the rate pluto falls towards the spacecraft will match the rate Jupiter fell towards the spacecraft. This is because if Jupiter has a mass 100 times that of pluto then the gravitation pull between it and the spacecraft will be 100 times greater. As the rate of acceleration is force over mass, 100 times the force and 100 times the mass means the rate of acceleration would be unchanged. As such, the rate a planet falls towards any object is solely dependent upon the mass and distance of the object, regardless of the mass of the planet.

As such, a black hole sufficiently far away would pull an entire solar system equally, sun and all.

[Edited on April 15, 2008 at 5:33 PM. Reason : .,.]

4/15/2008 5:21:27 PM

The Earth hasn't been hit by another "planet" in the last 4 billion years. It's not something we need to worry about. Planets typically stick to their own solar systems, and it doesn't appear that Mars or Jupiter are in any hurry to try to attack us.

As far as large interstellar bodies go, the "nemesis star" is a theory that some astrophysicists have expounded on. Basically there have been many mass extinctions in the last 250 million years or so, and they follow a roughly cyclical pattern when shown on a graph. The idea is that a red or brown dwarf circling in the Oort cloud comes around every 26 million years or so and kills off a good portion of life on Earth via radiation. Even if this were true, we'd still probably survive such an event by turning into troglodytes.

Climate change is probably the biggest risk we'll face. If the ice caps melt off, ocean currents will stop and oxygenated water will no longer get circulated deep into the ocean. At this point most marine life will die off and basic organisms that thrive in oxygen-free environments will flourish. These proto-plankton would produce large amounts of hydrogen sulfide into the air, killing land organisms. Of course, this process would take hundreds of millions of years, so it's not something we need to worry about right now.

[Edited on April 15, 2008 at 5:36 PM. Reason : 2]

4/15/2008 5:29:54 PM

Seems at its root, even the left brainers have a lot of faith. At least when it comes to the long term odds of human survival.

I wish we'd evolve quicker.

4/16/2008 10:35:08 PM

idk.. i really liked the grey goo, cancerous self-replicating nanomachines suggestion earlier.

4/17/2008 12:58:29 AM

4/17/2008 1:14:26 AM

right now the best bet is massive global climate change

4/17/2008 1:24:15 AM

^ are you kidding?

We might lose some people, but that's going to be a slow enough occurrence where it has practically no possibility of ending mankind.

[Edited on April 17, 2008 at 1:29 AM. Reason : ]

4/17/2008 1:29:01 AM

we're perturbing the system in a completely unnatural way

who knows what may happen?

4/17/2008 1:37:44 AM

A regional nuclear war, perhaps expanding into a global nuclear war, followed by a nuclear winter that will starve humanity to the brink of extinction

4/17/2008 1:56:11 AM

^^ yeah, but the responses are fairly slow. In the WORST case you'll have significant problems a year down the road, more than likely the significant problems take 10 years to happen.

And we are actively looking out for them.

Considering we can prepare for a hurricane a week in advance, we can look out for climate change a year or more in advance.

4/17/2008 2:11:42 AM

Hurricanes go away.

4/17/2008 2:40:31 AM

So does climate change if we change our habits (more than likely).

4/17/2008 2:48:23 AM