What disasters could destroy Earth in under a couple of years?

That's true. The same could be said for a black hole.

 

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An oversized asteroid to Earth, is compared to a black hole to our Solar System.

 

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How about two supermassive black holes colliding in five billion years? Andromeda and the Milky Way for starters. That kind of event should thin out the troops a little and everything else I would think..........

Yob Atta

 

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Suppose a mini-black hole, with a mass only about that of large asteroid (and therefore smaller than a rollerskate ball bearing) collided with Earth maybe a thousand years ago. The actual impact went completely unnoticed - it would've looked like an ordinary meteor. The hole, dense enough to sink through Earth's mantle like a stone through air, settled at the very centre - and has been slowly eating our inner core ever since.

As the core shrinks and grows denser, the uranium it contains will gradually differentiate towards the hole and become more pure. Eventually a point will be reached where a spontaneous fission chain reaction can occur.

The Earth's core explodes like a giant atomic bomb. The tremendous shockwave blasts the entire mass of the crust into space, leaving a globe of lava orbiting the Sun amid a new asteroid belt.

 

If the earth stopped spinning for some reason i'd say that would be pretty devastating, not much chance of it without some outside force though.

 

The British Astronomer Royal Martin Rees wrote a book about the ends of the world;
http://www.brothersjudd.com/index.cfm/fuseaction/reviews.detail/book_id/1319/

he came up with some good scenarios, including the Nanoswarm idea we use in OA;
http://www.orionsarm.com/historical/nanodisaster.html
similar disasters include an omniphage genetically modified organism, and advanced antihuman artificial intelligence killing humans on sight.

Also included are gamma-ray bursters and hypernovae

one interesting scenario is the Vacuum phase shift, based on his own research; the vacuum has shifted phase before, during the inflationary era; it could change again, totally altering the laws of physics in our universe. But this wouldn't help your scenario, as the destination of your refugee ship would be destroyed too.

 

I think the bottom line is if "GOD" get's pissed off with at the planet Earth, then watch out!

Yob Atta

 

before all this happens, the jedi knights will return.

 

Someone else posted a highly improbable, if not physically impossible, disaster in which a very small black hole plunges through the Earth “as if passing through air” but for unexplained reasons stops at Earth’s center instead passing all the way through. It then proceeds to concentrate uranium leading to a nuclear explosion. How it enriches the U235 /238 fraction high enough to support a chain reaction with fast (unmoderated) neutrons is not explained. A slow reaction might be possible if some suitable moderator and elements with large neutron capture cross sections could be excluded, but I don’t see how a black hole could cause this. Long ago in Africa nature did run a sustained, water-moderated, fission reaction. (We know because a large uranium ore body there has the U235 percentage considerably reduced.) Even if a slow nuclear reaction did happen at the center of the Earth, it would have less effect than the African near-surface one did and probably the increased heat-induced convection in the core would extinguish the reaction more quickly than the surface one burnt itself out of fuel. (Thousands of years if memory of articles about it serves me correctly.)

If the idea was that the black hole at the center of the Earth captured the Uranium and thus prevented this self extinction by convective mixing, then we would not be able to even detect the reaction as nothing comes out of a black hole. Instead of a nuclear explosion, a rapid massive global cave in is the danger a black hole magically placed at Earth’s center presents. The gravitational energy released as Earth is swallowed, not nuclear energy release, is the danger, but even that would not happen as the poster has described. Instead, the small black hole would be “eating earth” and growing in mass as it passes through the Earth. As it acquires mass it would slow down and the exit hole on the other side would be bigger that the entrance one, much like a blunt nose bullet. (Much larger than its own diameter as it accelerates earth towards it.) How the Earth would react to a tunnel punched through it would not be safe to watch unless you were on the moon. (I have not taken the time to carefully think through the physic of all this but enormous earthquakes, volcanoes and a poisonous, steam-bath atmosphere is my initial view. In view of all this, I am not concerned about the poster’s nuclear reaction even if it were / is possible.)

But I want to describe a more probable, physically possible, black hole disaster. Unlike an asteroid, a small black hole need not even come close to the Earth to do us in quickly. Consider:

The most common black holes (not counting the very small ones Hawkins has speculated about and the poster may be considering) have a few solar masses and formed when stellar cores of larger stars imploded in supernova events. This happened very often in the early universe because it had more hydrogen, was smaller and thus had denser gas clouds for star formation. Consequently, it tended to form larger stars which aged quickly. Most stars, back then as now, formed in pairs to conserve the gas cloud’s angular momentum without excessive spin. Some paired stars were initially so close that the first black hole formed captured the other star as it slowed down while orbiting through the expanding nebula of the supernova and a quasar, rather than a pair of black holes, was the result. Some black hole pairs have merged by radiating gravity waves, but most are still slowly approaching each other. Thus, before the sun was born, many generations of black hole pairs formed and it is possible that more pairs of small black holes now exist than all the current stars!

It is also possible that in the late 1920s one member of a black hole pair passed by our solar system and tilted then unknown Pluto’s orbit plane and perturbed Neptune’s orbit. Pluto and Neptune were in the same small sector of the sky and near their minimum separation (17 AU) back then. Percival Lowell used perturbation of Neptune observed in the late 1920s to predict Pluto’s existence, founded the Flagstaff observatory, and hired Clyde Tombaugh to search for “Planet X.” Clyde found Pluto on 18 February 1930 by the new "blinking technique”, which compared two plates taken some time apart.

To produce the observed perturbations, Lowell’s calculations required Pluto to have a mass about 7 times that of the Earth, but now it is known that Pluto is smaller than the moon. Thus, what perturbed Neptune is a still unanswered question. If it was the first of a pair of black holes, then the second should / could arrive about now. The thesis of the book Dark Visitor is that the second black hole, which is now 130 AU away, will pass about 12AU from Earth in 2008. Perturbation by its 2.2 solar mass increases Earth’s eccentricity to 0.0836, which is still less than that of Mars, but sufficient to rapidly plunge the Earth into an ice age. Dark Visitor’s details are speculative but entirely possible with accurate physics and climatology. (I am a retired physic professor.) Dark Visitor is so called because black holes do not reflect sun light and we would not know it is coming until the perturbations start. Dark Visitor is really a vehicle to teach a lot of physics in a unique style (as part of a scary story). For more information, including how to read for free, see www.DarkVisitor.com. If you know a young student and want to interest them in a science career, Dark Visitor makes a cheap gift that could change a life.

 

Thanks Billy, you seem to have a knack for reviving recently-deceased threads. Thank you also for debunking my mini-black hole/georeactor disaster idea - nice to know it could probably never happen!

This natural, water-moderated fission reaction in prehistoric Africa: what might its environmental effects have been like? Would it have been obviously visible?

And yes, I was thinking of small, Hawking-type black holes, which I believe can theoretically come in any mass down to about 0.005 grammes (is that right?)

Your Dark Visitor scenario does, ironically, resemble my earlier post about a neutron star passing through the Solar System. Could such an object possibly be lurking as close by as 130 AU?

 

Republicans

 

Once you confirm it, an update would be greatly appreciated.......

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http://survive2012.com/geryl1.php

what about that :|
That guy was deadly serious.

 

What a nutter. How can anyone claim to predict a geomagnetic reversal with such exactitude?

 

Hmmm...maybe that's our nemesis...

 

Your welcome, and thanks for not responding childishly to a factual corrects as some have.

I don't know much about that african fission, forget even where it was. Sorry.
I live in Brazil, with dial up ISP connection and here even local calls increment in cost everry 3 seconds, so I don't search internet much. (I like www.sciRus.com when I do as I can restrict search to journal articles only and don't need to wade thru the crap that proves anything you want.)

book, Dark Visitor, considers about five objects that could be the approaching "dark visitor" (not reflecting sun light) and assigns probability to each. (four or five different origin black hole types collectively get 0.5 probability) Your neutron star idea is one, but it is very old to not be detecable as a pulsar - It would be, if only 130 AU away, even if beam is not pointed at Earth. Also it is not "dark." In book it is estimated that approximately 100 telescopes exist that could see it now and I explained fact they have not by noting these large insturments are all doing cosmological work at high magnification, not routine sky serveys. Perhaps most innovative candidate for dark visitor is an agregate of magnetic monopoles. They are very heavy (each about 10^16 times a proton, if memory is not failing me, maybe it was 10^7 ?) a crystal of them like:

NSNSNS
SNSNSN
NSNSNS
SNSNSN

might not collapse if their attractive force law has a repulsive short range term, if not, they collapse and are one of several black hole sources considered. All now in small black holes could explain why none have been found. - I liked that idea.

The effect on Earth's orbit is computed in book. The finite-time-step code used is given in an appendix. Yes, currently the effect is a small perturbation in Pluto's orbit - that is how the book's astronomer was able to to predict a rough trajectory for it and that year will become 378 days in an orbit with eccentricity 0.0836 after the dark visitor is back in deep space.

Perhaps you can help me. I am new to this group and because of connect time cost, I normally work off line, (also helps spelling as I am poor and type badly) but today is Sunday and they turn off the charge clock at telephone company for local calls so I am on line. I need to know how to find my own posts to see if there is a reply. Tried "Billy T" and then "list msg" but ended up in my private mail. There must be a better way to see if I need to respond to a post - send me a private msg - I now know where they are stored. (This forum needs a "new members userr's guide" I can download once and print.)

 

Hmmm true... but then again it is far enough away for it to only disturb the Oort cloud (very very outer ring of metorites, half way to the nearest star) so it is possible it wouldn't affect the orbits of the planets.

 

alty in your free thoughts thread, can you solve it, can you tell us the answer thankyou.

 

what abouit a near enough gamma ray burst i'm not sure but i think that would ruin our shit pretty bad

 

america has enough nukes to blow the entire world 10 times