Plausible cosmic event that could annihilate the earth

[proggprod]

I am writing a screenplay that hinges around the imminent destruction of the earth. Can somebody describe a scientifically plausible cosmic event that could obliterate the earth. The only criteria I need to fill is that it can be identified four years before it reaches us. My first thinking was an exploding star, but could that be identified as a threat four years before it actually effects us? I am not keen on the idea of an asteroid. I am looking for something that would totally obliterate us into dust. Any ideas?
(It would be great if you could describe the event, but also how it could be discovered on Earth by scientists).

 

[mfb]

A medium to large black hole is possible, and with a bit of speculation you can get only 4 years of warning time (we had some threads discussing that in the past). The Earth would simply vanish in the black hole.

A supernova... hmm. I think is not completely impossible to predict such an event, but it is hard to kill all life on the surface with that. 50% of the Earth is always in the "shadow" when the initial radiation arrives.

The big asteroid will not destroy Earth completely, but it can make life on the surface impossible.

 

[StrayCatalyst]

If you're looking for a non-asteroid way of ending all life on Earth -grey goo, bioweapons, or just plain old nukes would do the trick. If you're looking for something more science fiction (but still plausible) then asteroids are the simplest - there really aren't that many ways to cause that serious a change to a planet. We've had near-misses by several asteroids in the past year - if a massive one at high speed hits the moon, not the Earth, then there are a number of ways it could make life on Earth difficult for decades or centuries - either by bombardment of particles, or altered orbit, or even by ejecting enough material from the moon to reduce the amount of sunlight that can reach the surface of the planet.

There's also plenty of other man-made causes that could sterilize the planet. Remember STUXnet? If a beefier version of it got out, geared to send reactors into meltdown, and robust enough to spread like informational wildfire, there'd be nothing left on the surface more advanced than cockroaches within a generation. Enough "dirty" bombs would accomplish the same purpose. "White Plague" was a story of bioweapons gone wrong.

 

[rustytxrx]

You could start an issue with the sun. four year period resulting in extraordinary mass expulsion pointed at the earth. it could be caused by the interaction with a "white hole" (here to unknown but evidenced by an area of high energy particles that seem to destabilize gravity).

as a writer it is your universe. make it fit your story. just enough detail (no math :) ) to sale the idea.

 

[proggprod]

Thanks for the responses.
The reason I am asking you guys about this and not just creating my own total fiction, is that I think the best science fiction is only one or two steps away from truth.
I like the idea of the sun destabilising. But it's still a bit local for my liking.
This has to be something beyond the control of humans. So bombs and human stupidity are out.
I also want total obliteration, sterilising the planet isn't quite enough :)

How about this:
in a cluster of 20 or more stars, one dies and explodes. This forces out 2 of the nearest stars which begin to orbit each other. These two stars pick up speed, and as they pass by the other stars in this cluster, they pull along up to 15 more stars. This entire group of stars then steak through our solar system destroying every planet and the sun.

Could someone describe this situation in a believable way? Using authentic scientific jargon.
Is there a real cluster of stars anywhere near our solar system where this might happen?
If these stars were orbiting each other, could they accelerate? Up to almost the speed of light?
What methods would we have on Earth that could detect this? If this is impossible, can anyone imagine a device or method that is currently beyond our current technology, but still sounds plausible?
Would a planet that was swallowed by a star explode or vaporise/melt? would rocky planets and gas planets react differently?

The biggest problem I have with this idea is the speed of light. How could we detect something traveling towards us at the speed of light (or close to), and still have a 4 year warning?

Thanks for your input everyone!

 

[phyzguy]

The problem with your star cluster scenario is that stars just don't move fast enough. Even at speeds of 1000's of km/sec, we would see them coming hundreds or thousands of years before they arrived. I think you need a dark body so you don't see it until four years before it arrives.

How about a large asteroid or small planet that plunges into the sun, heating it up to the point that the Earth becomes uninhabitable?

The supernova idea could work. We could discover a faint, nearby star that suddenly flares up due to interaction with some other star, and we realize that it will go supernova in a few years. I think mfb's objection is not valid - the radiation from supernovae lasts for weeks, so all part so fthe Earth could be sterilized.

 

[Bandersnatch]

Sorry, proggprod, that's a rather unlikely scenario.
IIRC, fastest peculiar(i.e. not related to orbital movement)velocities of individual stars in the galaxy are in the vicinity of a hundred kilometres per second. Moving at any sort of appreciable fraction of light speed is out of the question.

There are no nearby clusters of stars. As mentioned before, relatively slow velocities mean that it would take thousands of years to travel just the distance between the Sun and Alpha Centauri(4,5ly).
The nearest are Hyades, at 150 ly.

The mechanism for inducing velocities that you've proposed, is implausible as well.
Additionally, even if the Sun passed through a cluster, the event would not cause its destruction. At worst it would eject the planets into interstellar space.


The major problem with the possible scenarios is your insistence on "total destruction". It's surprisingly hard to destroy a planet. For example, the Earth will probably survive the Sun exploding in a few billion years.


The closest to it would be probably a collision with a large planetoid, so that the surface of our planet ends up molten or heavily volcanic. But I don't see any sensibly plausible way to actually vaporise the Earth.


If sterilisation is, after all, going to be acceptable, then I'd go for a nearby supernova. Betelgeuse is, for example, kinda sort of looking as if it was soon(in astronomical terms) to collapse. With a bit of stretching the reality, it could serve as the doomsday machine(make it enter the last stages of life now; pretend it's close enough to affect us; maybe make it rotate poles-on as seen from Earth, so that the gamma ray burst hits our planet; make it last long enough to catch all of Earth's surface). The actual state of the star is uncertain enough that you could simply go with better instruments allowing us to see the danger.

 

[rustytxrx]

The goal of fiction is to take us where we have not been. Take Steven Kings _Dome_. Not very plausible in a physics class but seems real in King's book. the disaster could come from an accidental intrusion of another multiverse. all you need is some way to disrupt local gravity.

maybe the multiverse has leaned how to mine other universes for something they need :)

 

[mfb]

The major problem with the possible scenarios is your insistence on "total destruction". It's surprisingly hard to destroy a planet. For example, the Earth will probably survive the Sun exploding in a few billion years.

As far as I know, recent calculations indicate that the Earth will probably fall into sun. Mars can survive it.Hmm... I found some supernova lightcurves.
10⁴⁰ erg/s X-rays for ~100 days.
-19mag brightness for a few days.
-19mag brightness for a few days.

The visible light does not help, however. Absolute -19mag in a distance of 10 pc (too close to stay undetected until now, if the star is massive enough for a supernova) gives apparent -19mag. Brighter than the moon, but still not enough to give dangerous effects.
I am not so sure about the x-rays.

Anyway, it could just kill some life on the surface.

How about this:
in a cluster of 20 or more stars, one dies and explodes. This forces out 2 of the nearest stars which begin to orbit each other. These two stars pick up speed, and as they pass by the other stars in this cluster, they pull along up to 15 more stars. This entire group of stars then steak through our solar system destroying every planet and the sun.

Could someone describe this situation in a believable way? Using authentic scientific jargon.
Is there a real cluster of stars anywhere near our solar system where this might happen?
If these stars were orbiting each other, could they accelerate? Up to almost the speed of light?
What methods would we have on Earth that could detect this? If this is impossible, can anyone imagine a device or method that is currently beyond our current technology, but still sounds plausible?

There is no way to make anything like this plausible, unless you introduce aliens with magic.

The biggest problem I have with this idea is the speed of light. How could we detect something traveling towards us at the speed of light (or close to), and still have a 4 year warning?

If it starts very far away... yes.

Would a planet that was swallowed by a star explode or vaporise/melt?

It would evaporate inside the star. Unless you have a really freaking dense planet (nearly 6 times the density of lead).What about small black holes? I think they look like a perfect solution.

 

[Decimator]

How about an impending collision with a hypervelocity planet?

This is what such an impact would do.

 

[phyzguy]

Hmm... I found some supernova lightcurves.
10⁴⁰ erg/s X-rays for ~100 days.
-19mag brightness for a few days.
-19mag brightness for a few days.

The visible light does not help, however. Absolute -19mag in a distance of 10 pc (too close to stay undetected until now, if the star is massive enough for a supernova) gives apparent -19mag. Brighter than the moon, but still not enough to give dangerous effects.
I am not so sure about the x-rays.

Anyway, it could just kill some life on the surface.

I agree that an ordinary supernova won't do it. Anything massive enough to supernova would be visible from far away, and I don't think we know of anything close enough to be dangerous. Even Betelgeuse if (when!) it goes off will probably not be dangerous. However, I was thinking about some dark remnant, like a dead neutron star, that interacts with a dark companion and then becomes massive enough to supernova. It could be nearby, maybe within a few light-years. If there were two dead neutron stars orbiting each other a few lightyears away that finally got close enough to start merging, that could do it. We migh get a few year's warning if they started interacting before they finally merged.

 

[Ryan_m_b]

May I ask why you want the Earth totally destroyed? Sufficient damage to the biosphere could easily wipe out all human life long before life itself was extinguished on earth.

 

[mfb]

Really cold neutron stars? Hmm.
It would be interesting to check if gravitational wave detectors are sensitive enough, but I guess that is not an issue for science fiction. Maybe there is even a direction where orbiting stars do not emit gravitational waves (?).

 

[DHF]

Main sequence stars coming our way would normally be easy to see coming more then 4 years away because as others have mentioned, they don't move fast enough to be speeding bullets in the cosmic sense.

However what about Black Dwarf stars? After a star such as ours dies it puffs up into a red giant then eventually cools into a white dwarf, a cooling ember of its former self. over time it will continue to cool until it no longer emits any light but it would be enormously dense comparatively to planets or asteroids.

Theoretically Black Dwarfs can exist but none have been confirmed because the math suggests the universe is not yet old enough for any white dwarfs to have cooled to that point...theoretically. The beauty of sci-fi is that you can bend the math a bit. we just haven't spotted any yet, we THINK none exist yet but what if they do? IF Black dwarfs Were out there and were on a collision course it would be very hard to spot because they are all but invisible, they admit no light so we could only detect them by their gravity. It is conceivable that we might not spot one until it was on our door step. If we were unlucky enough for something like that to be on a collision course with Earth we would be shredded. Even if it didn't smash it us but only grazed by us, the gravitational pull would destabilize our orbit and all sorts of unhappiness would ensue. Maybe it yanks us out of orbit, flings us around and tosses us into our own sun. who knows, its up to you.

Granted its similar to an asteroid impact but a lot more exotic because hey its a star corpse!

 

[chemisttree]

Still interested in this? If so, I've got what I believe to be a plausible killer. It won't explode the Earth but it will strip the atmosphere and sterilize.

 

[DHF]

The suspense is killing me Chemisttree, what is your idea? :)

 

[chemisttree]

It's something close... well, closer than you might think.

 

[Vanadium 50]

The problem with anything star-sized/massed is that it will perturb the planetary orbits once it gets within a few tens of billion miles of the sun. That means its moving above galactic escape velocity, so the question of how it got there in the first place opens up.

Does it have to be astronomical? How about geological - a supervolcano 100x larger than Lava Creek.

 

[mfb]

Hypervelocity stars that will leave our galaxy exist - binary systems where one partner exploded and 3-body mechanics are possible sources.

 

[Enigman]

A meteorite destabilizing the moon would probably get rid of earth.
L.H.C. might create a small black hole.
I think the collision of solar system/earth/sun with a hitherto invisible black hole could be plausible...

 

[DHF]

I like the idea of something destabilizing the moon, if it passed by there would be an initial sigh of relief that it was a near miss. only afterwards as scientists start realize the Moon's orbit is off slightly, as they run the figures they estimate that with within 4 years the orbit will be so unstable that it will collide with the earth. that is pretty much end game. an impact like that would likely revert Earth to a molten state.

 

[mfb]

Orbits in two-body systems are always stable* - that's why they are called orbits. To let the moon crash into Earth a while after the impact, you have to send it far away - so far that tidal forces from the sun are relevant (~1 million km). I guess this is not possible with a single fly-by, without ripping the moon apart.

*apart from orbits around black holes

 

[DHF]

I suppose rather then something passing by the moon and destabilizing it, something could also strike the moon and pulverize it, then send the remains of both the moon and the original projectile towards Earth. It would be a meteor shower the Earth had not experience since the Late Heavy Bombardment.

 

[brenan]

Right now the Earth's magnetic field is about due to flip.
Most scientists seem to be ignoring this. And certainly there is little popular talk.
But consider what could cause that - the Earth's centre is believed to be a huge
liquid magma dynamo with a (recently established) solid core.
Now the Earth spins. What happens if the you spin a ball with a liquid core?
The liquid sploshes about inside - heats up tremendously and expands.
(yes - global warming occurs deep under ground)

This expansion causes the rock around it to heat up melt and crack.
Deep fissures occur and expand. The molten magma bangs and flows into the fissures
putting further perssure on the rock. Heat and earthquakes increase in
frequency and intenisty.
And suddenly - bang - the crust cracks wide open and the ball explodes into a mess
of cooling rubble.


Any good ?

 

[mfb]

No.
The magnetic field of Earth switches all the time in geological timescales. It could be bad for some satellites, it could increase the level of ionizing radiation on Earth a bit, but it is not a catastrophe.

What happens if the you spin a ball with a liquid core?

With gravity holding it together: nothing special.

 

[brenan]

No.
The magnetic field of Earth switches all the time in geological timescales. It could be bad for some satellites, it could increase the level of ionizing radiation on Earth a bit, but it is not a catastrophe.

With gravity holding it together: nothing special.

yes it switches all the time which is how we deduce its time for another - the real question is why
To posit a situation that fulfills the thread originators requirements I merely extrapolated. I'm suggesting it's plausible because no one can say otherwise because no one has even a vague
understanding of what's really going on down there.
I didnt suggest magnetic flux change was a catastrophe - but the cause of it could be.
Gravity wouldn't help under the proposed conditions - kinetic energy is the force in control - but for a fictional construct - I think its good enough.

 

[mfb]

yes it switches all the time which is how we deduce its time for another

The time between switches does not follow any known pattern. We can just see that the dipole component of the field is getting weaker.

To posit a situation that fulfills the thread originators requirements I merely extrapolated. I'm suggesting it's plausible because no one can say otherwise because no one has even a vague
understanding of what's really going on down there.

You don't need detailed knowledge about a sandbox to understand that it won't explode. The same is true for Earth's core. There is simply not enough energy to make anything more catastrophic than volcanoes and earthquakes.

 

[brenan]

The frequencies are mapped quite specifically. The issue was first discovered by measuring the
magnetic properties in ancient pottery which threw up the anomaly. Since then the dates have
been traced back to a regular pattern. The fields are not "getting weaker" - they move - physically.
We are currently overdue for a north-south flip by the dating.
Not enough energy in the Earth's core to fracture the planet?
I'd like to see a justification for that. We just don't know but the analysis of viscous fluids
applied to what we believe the core components are made of and how they are assumed to behave
does allow for "creative" asssumptions. Insufficient energy wouldn't be one I'd gamble on.

 

[mfb]

The frequencies are mapped quite specifically. The issue was first discovered by measuring the magnetic properties in ancient pottery which threw up the anomaly. Since then the dates have been traced back to a regular pattern.

Please post a source for the claim that there would be a regular pattern. "It happens on average every x years" is not a pattern, even if the average time is well-known.
This does not look very regular (source: U.S. Geological Survey ).

Pottery does not exist long enough to see even a single geomagnetic reversal.

The fields are not "getting weaker" - they move - physically.

The dipole component both gets weaker and changes its direction.

Not enough energy in the Earth's core to fracture the planet?
I'd like to see a justification for that.

Where should the additional energy come from?

"creative" asssumptions

Please note that we do not allow discussions of personal theories in this forum. This is science fiction, so fiction is possible, but if you claim that something would be based on actual science it has to be verifiable.

 

[brenan]

magnetic anomoly in pottery is how the field flip was discovered. Really - you should read up - its fascinating work. I wrote about it when the discovery was announced. I'm guessing the year but I think it would have been about 1990 or perhapsa little earlier - I'd need to check my records.

As for the the rest - I'll just point you to a link on todays physicsforums.com
http://blogs.physicstoday.org/newspicks/2013/09/deep-earthquakes-may-caused-mineral-changes/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+physicstoday%2Fpt2+%28Physics+Today+News+Picks%29

Remember the question is for a "plausible" explanation for fictional purposes. I'd say this link confirms
the idea I suggested as plausible for this purpose.

Really I think you are very confused about what fiction is and what science is.
And not for the first time.