Help, Physics(?) question

[fratar11]

I want to run a zombie apocalypse campaign and I thought the reason of zombification of Earth would be another planet entering the Earth's atmosphere. But just entering, like so:

http://img802.imageshack.us/img802/2212/hhh.png

First off, I am fairly certain this is impossible to happen in real life. The question is; what would be the consequences if something like this happened. I guess that gravities would interfere and there would be a lot of flying cars and broken houses. What else?

Thanx

[Ashtagon]

I want to run a zombie apocalypse campaign and I thought the reason of zombification of Earth would be another planet entering the Earth's atmosphere. But just entering, like so:

http://img802.imageshack.us/img802/2212/hhh.png

First off, I am fairly certain this is impossible to happen in real life. The question is; what would be the consequences if something like this happened. I guess that gravities would interfere and there would be a lot of flying cars and broken houses. What else?

Thanx

The most likely result would be the two spiral in to each other and eventually collide. Rocks fall everyone dies (literally).

The second most likely is that the two planets slingshot each other, sending both of them in new directions. The PCs' planet will either go careening into deep space or into the sun. Again, game over.

[fratar11]

The most likely result would be the two spiral in to each other and eventually collide. Rocks fall everyone dies (literally).

The second most likely is that the two planets slingshot each other, sending both of them in new directions. The PCs' planet will either go careening into deep space or into the sun. Again, game over.

Thanx,

the second scenario gave me an idea :smallamused:

[Peregrine]

Also, it should be said that a miss by "a few miles" is unnecessary, and probably the most impossible part of the whole thing -- gravity gets stronger the closer two objects are together, so for two planet-sized bodies to be a few miles apart and not collide, they must be passing each other at absolutely insane speeds. (Or A Wizard Did It, but you did pose this as a physics question. :smallwink:)

I say unnecessary, because you would have enough disastrous results simply from passing within a few thousand miles. Earth's moon is the prime cause of our tides; a body larger than Earth (as it appears, from your diagram, is what you want) passing within the moon's orbit (about 240,000 miles) would cause colossal tides and flooding. And probably tidal stresses on the land as well as the water, leading to earthquakes or something.

If your "zombification" scenario involves something passing from Planet X to Earth, you still don't need to be that close. No atmosphere? Hard vacuum? Hey -- zombie. :smalltongue:

When you ask about "flying cars", do you mean the gravitational pull of Planet X lifting things away from Earth's surface? That's unlikely; basically, if it's close enough to pull you towards itself, it's pulling the Earth towards itself faster.

But yeah. Assuming no collision, worldwide devastation will still result, and the Earth's orbit will be drastically altered.

[Ashtagon]

Yep, there definitely won't be any objects "falling upwards". What you will have is something similar to marine tidal effects, but with the dial turned up to 11 (look up "roche limit"). Basically, imagine the entire spheroid planet being squished into an egg shape. Anywhere the stress gets too much, you'll have an earthquake. Too much stress, and the planet gets changed from solid rock to enough gravel to conform to that egg shape.

[fratar11]

Heh, OK thanx. I guess an asteroid will fall onto Earth then.

But i will have my electrical storm! :smallfurious:

[erikun]

Anything that would mess with the atmosphere would be capable of causing electrical storms. Even something like the Tunguska event (http://en.wikipedia.org/wiki/Tunguska_event), where a meteorite detonated mid-air, would deposit enough dust in the air to cause storms - perhaps even worldwide within a few days, if it was large and dusty enough. A meteorite impact wouldn't cause worldwide earthquakes, though.

[Evard]

Yeah watch Maximum Overdrive (awesome movie) ... Basically a zombie movie but with vehicles instead of human corpses :D

[BladeofOblivion]

Yeah watch Maximum Overdrive (awesome movie) ... Basically a zombie movie but with vehicles instead of human corpses :D

Better yet, read "Trucks," the Stephen King short story it was ripped off of. (It's in Night Shift)

[Aran Banks]

DUUUUUUDE!!!

The planet idea is awesome for a post-apocalyptic scenario. Imagine, floods and earthquakes have wrecked the world. stuff is everywhere. So many people have died.

And then the electrical storm comes, born of the strange atmosphere from Planet X. The dead rise as zombies. Some have been torn apart by the destruction (resulting in crawling torsoes and such) and others have frighteningly awful-looking wounds. Zombies that attacked the characters could come at them with ceremonial swords or big pieces of wood sticking out of their chests.... it's awesome.

And if you want to play the "slingshot into the sun" thing, say that the planet was orbiting a pair of binary stars (rare, of course, but this is D&D...) and that earth has been slingshotted from one star to the next (again, rare... still awesome). You can say that the earth grows colder as you leave from one star and approach the other. In the middle of the campaign, temperatures could be below freezing all the time. Then, as the campaign gets closer and closer to its finish, the temperature begins to increase... or it could just get progressively colder, if you substitute the second star for a BLACK HOLE!!! (the final battle with the BBEG could involve reality slowly unraveling and time slowing down)

Of course... you'd need something to prevent the planet from being totally wiped out. Like a time-reversal spell (or machine or something).

Honestly, this is an awesome idea. It's totally cool to fudge what goes on to make a good story (since everything's possible, just ridiculously uncommon). Anyways, a slingshotting planet seems cooler by far when compared to a simple meteor.

[Eldan]

How about, instead of a planet, you take a large planetoid and make it orbit the planet, like a second small moon? The results could still be pretty catastrophic, and you could still include impacts from smaller asteroids.

[Zeta Kai]

How about this: instead of a planet or an asteroid, how about a magnetar (http://en.wikipedia.org/wiki/Magnetar) fragment? Not the whole thing, because even though they are only 12 miles wide, they are more massive than the Sun. But a tiny fraction of one would still carry the same electromagnetic charge, IE 10 gigateslas. With a magnetic field that powerful, at a distance halfway to the Moon, every credit card on Earth would be wiped, & hard drives would be useless. Any closer, & paperclips would start to float away, followed by coins, Hot Wheels cars, & any other small ferro-magnetic metal objects. Like loose bullets.

Then it gets hits the Earth, with enough force to emulate the most powerful nuclear blast. The Earth is thrown into a mild nuclear winter. The sky dims for years, crops wither, & anything that gets within 1,000 miles of the blast site boils & dies (the magnetic field is powerful enough to diamagnetize the water in a body, pulling it apart at the molecular level). The effect on creatures a little further away is even worse: the intense magnetic rediation is sufficient to drive any living creature insane. The plants grow into mad elongated shapes, all the animals act like hyperaggressive feral demons. And the people...

...They no better than zombies. Their higher brain functions eroded by an elemental force thousands of times more powerful than gravity, the water in their bodies pulling apart, wracking them with pain, they are reduced to animals. Hungry, violent animals. Taking them away from the blast radius doesn't help them; the damage has been done to their bodies & their minds. To go nearer to the blast site means more pain followed by death, so they have only one way that they can go: Outward, away from the magnetar, & towards the rest of humanity, who are trying to pick up the pieces of their shattered world.

They are not dead, but nor are they truly alive. No pain can compare to the agony of the magnetar's pull, so blade & bullet do no phase them. They must feed, & they care not what they eat.

After the Info-Wipe...
After the Fragment fell...
After the Long Winter set in...


...The Zombies Rose.

[hamishspence]

A tiny fragment normally wouldn't be stable- it would break apart- due to neutron repulsion needing a massive gravity field to keep that material together.

Which is the big problem with anything "Made of neutronium"

That said, it's a very cool idea.

[Zeta Kai]

A tiny fragment normally wouldn't be stable- it would break apart- due to neutron repulsion needing a massive gravity field to keep that material together.

Which is the big problem with anything "Made of neutronium"

That said, it's a very cool idea.

Why would neutrons repel each other? They have no charge. I'm off to Wiki for more info...

[hamishspence]

http://en.wikipedia.org/wiki/Neutronium

The Pauli exclusion principle explains why neutron matter can't be compressed past a certain point- in effect, the neutrons are "repelling" each other- which is what I meant by that.

At pressures below that in a neutron star, the material is highly unstable. And these pressures need a massive gravitational field to be kept.

[Zeta Kai]

http://en.wikipedia.org/wiki/Neutronium

The Pauli exclusion principle explains why neutron matter can't be compressed past a certain point- in effect, the neutrons are "repelling" each other- which is what I meant by that.

At pressures below that in a neutron star, the material is highly unstable. And these pressures need a massive gravitational field to be kept.

Well, say a magnetar collided with the Moon & a few fragments hit Earth just before breaking into a degenrate mess of rads (neutron-degenerate matter, or NDM). You'd still get the nuclear winter, plus a radioactive burst, which could cause a one-time zombification effect like I described. Multiple fragments means multiple zombie hot zones cropping up at once, an instant worldwide zombie apocalypse. The proximity of the magnetar & its rapidly-decaying fragments (let's call them Wormwoods) would still wipe out credit cards & hard drives, leaving modern society wholly hosed just before the people near the fragment impacts got all loopy & bitey.

Plus you'd still have these weird craters at the impact sites, which would be very deep (as the NDMs burrowed into the earth due to their great mass) & full of twisted metal (every ferro-magnetic object in the area would be pulled toward the NDMs with a force than can scarely by imagined, stretching them into taught cables of metal). But the radiation would soon dissipate, leaving blasted wastelands devoid of life for PCs to explore. Win-win all around, really.

[hamishspence]

If it was possible for a collision to break off fragments of magnetar, maybe.

Chances are though, it would cut straight through the Moon like a hot knife through butter, without slowing down.

If it's a slightly more fantastical setting though, maybe it could work.

[Zeta Kai]

If it was possible for a collision to break off fragments of magnetar, maybe.

Chances are though, it would cut straight through the Moon like a hot knife through butter, without slowing down.

If it's a slightly more fantastical setting though, maybe it could work.

I can imagine a scenario where the shock of the impact would ripple through the neutron star, destabilizing it in parts & causing the whole thing to fly apart. The neutronium articles imply that only the intense gravitational pressure of the neutron star's mass holds the NDM (http://en.wikipedia.org/wiki/Neutron-degenerate_matter#Neutron_degeneracy) together. And we are talking about hitting the Moon at astronomical speeds here.

Sure, the Moon would be shredded to bits, but I'd bet the magnetar wouldn't fair much better.

Also, as a trump card, I will note that we are discussing a zombie apocalypse here. There's only so much science we can cram in a scenario like that. We're probably past the limit, but the plausible speculation is fun.:smallwink:

[hamishspence]

Maybe. I wonder if anyone's modelled what happens when a superdense object of this kind hits an ordinary one at high speed?

As an explanation for Zombie Apocalypse- it does have the merit of being unusual.

Given that D20 Modern already plays fast and loose with biology, why not physics?

[jiriku]

Bonus points: the moon turns into a ring of asteroids, eventually forming a planetary ring and continually dropping flaming chunks down on the planet's surface. Good times.

[TelemontTanthul]

I'd be more worried about the trajectory of the Earth changing, due to the massive planet that passed by. Earth could theoretically be flung straight into the sun. Not to mention the Earth's tilt would be effected, plus (If this mystery planet passed between the Earth and the Moon), it would be likely that this mystery planet (Being larger and temporarily closer), would effectively steal the Moon from Earth, which would be VERY bad.


I like your asteroid idea better. (MUCH SIMPLER) But what about plague? A human form of rabies? (From Quarantine) or a virus (from practically every other zombie movie).

:smallbiggrin:

[Zeta Kai]

Maybe. I wonder if anyone's modelled what happens when a superdense object of this kind hits an ordinary one at high speed?

Something like this (http://answers.yahoo.com/question/index?qid=20100416111913AAPvO7Z), from the the looks of it. Or this (http://www.physicsforums.com/archive/index.php/t-294122.html).

[Milskidasith]

Big question: Why are we trying to use physics to explain zombies? Just say "A wizard did it", drop an asteroid with the zombie virus on it, and be done with things. No need to add harder science to something that is decidedly a soft science campaign; that just breaks verisimilitude. While it obviously shouldn't be something obviously nonsensical (Earth being a few miles from a planet more massive than it), the more you put real science into explaining zombies, the stranger it is that zombies actually exist. Mysterious space virus caused by giant asteroid impact from some asteroid that came from the asteroid belt: Post apocalyptic, not many questions (only maybe "how did scientists not know this was going to hit us, since we do model all that stuff"), zombies are there but nobody really knows how they work.

Part of a Magneton: How did it fly all the way to the moon without anybody noticing? It would have to be moving faster than the speed of light. Why didn't it disintegrate? Why is it causing zombies? (Note: Crazy people aren't really zombies, since they lack the whole pack mentality, infecting others, rising from the dead, etc. stuff; the only real similarity between zombies and the proposal you had are that they are mindlessly aggressive) Why isn't the Earth in a massively different orbit? Etc, etc. All the same questions you could have about the asteroid, but since you're using real science explanations, they are a lot stranger, while for the asteroid, they can be explained away by its unique properties and other phlebotnium related efects.

Basically, when going for a zombie apocalypse, you don't want it to be harder science. If you want the radiation=crazy effect (which doesn't lead to zombie infection even in a loose reading), just go with an asteroid with a strange radioactive, zombie causing element in it. Fiat at all levels works better than trying to be realistic at one level (apocalypse caused by massive amounts radiation from a Magneton) while being fiaty at all the others.

[Draz74]

I say unnecessary, because you would have enough disastrous results simply from passing within a few thousand miles. Earth's moon is the prime cause of our tides; a body larger than Earth (as it appears, from your diagram, is what you want) passing within the moon's orbit (about 240,000 miles) would cause colossal tides and flooding. And probably tidal stresses on the land as well as the water, leading to earthquakes or something.

Quoted for truth.


Yep, there definitely won't be any objects "falling upwards". What you will have is something similar to marine tidal effects, but with the dial turned up to 11 (look up "roche limit"). Basically, imagine the entire spheroid planet being squished into an egg shape. Anywhere the stress gets too much, you'll have an earthquake. Too much stress, and the planet gets changed from solid rock to enough gravel to conform to that egg shape.

Hmmm, I don't think the Roche Limit's effects kick in so quickly. There are lots of objects in our solar system that defy Roche Limits, either because they're small enough or because they only pass within a Roche belt for brief intervals. I believe some of Saturn's moons do this, for example. So I don't think Earth would be forced into an egg shape in a brief pass.

It would sure get pushed towards doing so, though. Which could certainly cause planetwide earthquakes.


Why would neutrons repel each other? They have no charge. I'm off to Wiki for more info...

The weak nuclear force. If unopposed by sufficient gravity, it would cause many of the neutrons to go through beta decay (radioactivity), in which they "split" into a proton and an electron. The electrons would typically be ejected from the neutronium object in the process (and if they aren't initially, eventually they would leak away via quantum tunneling); and you're left with a big blob of protons and neutrons, in which the protons repel each other electromagnetically, which will cause the object to fragment until its pieces are small enough that the limited-range strong nuclear force can hold them together. At that point, you're back to ordinary atomic nuclei.

[fratar11]

Bonus points: the moon turns into a ring of asteroids, eventually forming a planetary ring and continually dropping flaming chunks down on the planet's surface. Good times.


Ohh yes!:smallbiggrin:

The magnetar idea is also awesome, but like someone pointed out, I don't actually need a highly scientific explanation because I call the shots and players can either go with the idea or go with the idea.

Thanx again

[flabort]

Why the moon? that would be close enough for the same fate to happen to earth, being turned into an asteriod ring.

Mars, on the other hand, is close enough for a chunk to hit us afterwards, and far enough away that the whole thing doesn't.

And for whoever asked wouldn't it put us into a dramaticly different energy level, have you ever seen an electron change energy levels when struck by a photon? same fun deal.

[hamishspence]

Problem is the time frame- would the chunk of magnetar last long enough to reach the Earth before decaying? Neutrons have a short half-life. So without the gravity, the chunk might not last long.