Destroying a Planet - How Much Energy?

[lpetrich]

How feasible is it to destroy a planet? ... So it ought to be evident that destroying a planet is very hard to do.

Right? You'd think if you have an illudium q-36 explosive space modulator you'll be fine, but turns out it's harder than it looks...

Or at least a baryon-number-violating ray. If one can violate baryon number, one can make protons and neutrons decay, and one gets nearly all of their mass-energy.

 

[Jokodo]

In some science-fiction productions, we find the ability to destroy planets and sometimes even stars. Not just make planets' surfaces uninhabitable, but outright destroy them, turning them into expanding clouds of fragments and dust.

Mundicide | Wookieepedia | Fandom - lists several destroyed planets in the Star Wars universe, notably Alderaan: Destruction of Alderaan | Wookieepedia | Fandom near the beginning of the first Star Wars movie, A New Hope. There is a clip of that event at Star Wars A New Hope - The Destruction of Alderaan - YouTube

Star Trek also has some destroyed planets, like the victims of the Planet killer | Memory Alpha | Fandom (TOS "The Doomsday Machine") and in the Kelvin timeline, the Destruction of Vulcan | Memory Alpha | Fandom (first Star Trek film in that timeline)

How feasible is it to destroy a planet? One must give it more than its  Gravitational binding energy or self-energy.

For the Earth, that is a LOT. I calculate that it takes 2.35*10³² joules to destroy it. Using E = mc^2, that's about 2.62 trillion metric tons of energy. But it is only 4.38*10^-10 times the mass of our homeworld, however. Nevertheless, it is roughly 1/300 of the mass of the Big Island of Hawaii, and it is roughly comparable to the mass of Mt. Everest.

Humanity currently consumes energy at about 18 terawatts, and it would take 400 billion years for us to destroy our homeworld at that rate of consumption.

Using all the sunlight that falls on the Earth's surface would give some 43 million years, however.

For chemical reactions, close to the best case in energy per unit mass of reagents is hydrogen and oxygen, often used as a rocket fuel for that reason. The total amount needed, at 100% efficiency, is about 3 times the Earth's mass. That's because the mass-energy fraction of this reaction is 1.49*10^-10.

Nuclear reactions do much better. Nuclear fission typically releases about 10^-3 of its fuel's mass as energy, meaning that one would need nearly 3 quadrillion tons of uranium. The total production of uranium has been only 3.06 million tons, however, a billion times less. So one would need a cube of uranium 50 km on each side, while the amount that has been mined is only 50 m on each side.

So it ought to be evident that destroying a planet is very hard to do.

I may have missed it, but has no-one linked this gem from the early days of the internet yet? https://qntm.org/destroy

"Preamble
Destroying the Earth is harder than you may have been led to believe.

You've seen the action movies where the bad guy threatens to destroy the Earth. You've heard people on the news claiming that the next nuclear war or cutting down rainforests or persisting in releasing hideous quantities of pollution into the atmosphere threatens to end the world.

Fools.

The Earth is built to last. It is a 4,550,000,000-year-old, 5,973,600,000,000,000,000,000-tonne ball of iron. It has taken more devastating asteroid hits in its lifetime than you've had hot dinners, and lo, it still orbits merrily. So my first piece of advice to you, dear would-be Earth-destroyer, is: do NOT think this will be easy.

This is not a guide for wusses whose aim is merely to wipe out humanity. I can in no way guarantee the complete extinction of the human race via any of these methods, real or imaginary. Humanity is wily and resourceful, and many of the methods outlined below will take many years to even become available, let alone implement, by which time mankind may well have spread to other planets; indeed, other star systems. If total human genocide is your ultimate goal, you are reading the wrong document. There are far more efficient ways of doing this, many which are available and feasible RIGHT NOW. Nor is this a guide for those wanting to annihilate everything from single-celled life upwards, render Earth uninhabitable or simply conquer it. These are trivial goals in comparison.

This is a guide for those who do not want the Earth to be there anymore."

Read the rest at the link.

 

[Jokodo]

Also, I may have miscalcul

The whole business seems like overkill.

I agree.

Biospheres are fragile; Rendering a planet uninhabitable is pretty easy, and should be sufficient for almost any purpose.

I'll now consider how much energy is necessary to strip away a planet's atmosphere.

The Earth's atmosphere has a mass of 5.15*10¹⁸ kg, and its oceans a mass of 1.35*10²¹ kg.

Using the Earth's escape velocity gives energies 3.32*10²⁶ and 8.47*10²⁸ joules, or from E=mc^2, 3.59*10⁹ and 9.42*10¹¹ kg.

Using humanity's entire energy output gives 500 thousand and 130 million years, while using the Sun's light flux at the Earth gives 60 and 15,000 years.

This, I think, an overly pessimistic estimate, because the atmosphere and the ocean can be removed by heating them enough to evaporate into space: at least a few thousand K to around 10,000 K. With enough temperature, it becomes probable for air molecules to get kicked up to escape velocity near the top of the atmosphere.

You needn't strip off the atmosphere and oceans to destroy the biosphere.

Raising their temperature to a point above the temperature at which life can survive is sufficient.

If you want to kill all complex organisms, including humans, raising the temperature of our atmosphere above about 38°C should easily suffice. Killing the oceans would require more energy, but a lower temperature target, for complex life to be eliminated.

Killing everything, including extremophile bacteria, would require higher temperatures, but still lower than those needed to evaporate the entire oceans and atmosphere into space.

Life can survive at any temperature at which liquid water exists. They found life in the deep sea at volcanic springs at temperatures above 100° C (die to the pressure, water stays liquid). More relevantly, they found life in aquifers several km into the crust, at similar temperatures. Boiling away the oceans is trivial relative to baking the crust to 150° 5 or 10 km deep. I suspect even if we do boil the entire ocean, unless we keep adding energy a lot of the heat will dissipate into space before their habitat becomes to the critters adapted to such environments.

 

[Jokodo]

Wolfram alpha tells me the amount of water on the planets surface relative to the earth is about equivalent to 18 ml of water relative to my body mass. Just climb a flight if stairs in a haste and you are wetter on the outside than the earth

(((volume of ocean in cubic meters)*(1 tonne per cubic meter)/(mass of earth in tonnes)) *80kg - Wolfram|Alpha

Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.

www.wolframalpha.com

 

[Elixir]

Life on earth will endure in some form until it gets absorbed into the red giant that our sun will become in a few billion years.
At least that’s my guess. Sue me if I’m wrong.

 

[steve_bank]

Anybody who remembers the explisve space modulator is ok in my book.

You could start with two atoms bound floating in space not influenced by nearby gravity sources.

How much energy does it take to separate the atoms and overcome mutual gtravity? Then multiply by an estmate of the number of particles of moon. Pick a common element on the moon.

Simplistic but it may give you an idea of the amount of enrgy required to discombobulate the moon.

 

[Tigers!]

The more I look at this, the more it seems to require more energy and time than it's really worth.

Let's not do it.

At least, not this year.

You could do it to celebrate my 100th birthday. Admittedly that is a few decades yet.

 

[steve_bank]

One can say that mass extinctions,natural climate change, and natural events like asteroid strikes paved the way for the evolution of humans.

It would have been hard for humanoids to evolve when their ancestress were running around avoiding being a snack for T Rex.

 

[Jokodo]

The more I look at this, the more it seems to require more energy and time than it's really worth.

Let's not do it.

At least, not this year.

Yeah, let's wait out the current energy crisis.

 

[Tigers!]

The more I look at this, the more it seems to require more energy and time than it's really worth.

Let's not do it.

At least, not this year.

Yeah, let's wait out the current energy crisis.

Nordstream 2 is not busy at the moment.

 

[Loren Pechtel]

At one point, it attacks with a beam that is described as pure antiprotons. It would be hard to collimate such a beam, because antiprotons electrically repel each other. But that aside, antimatter is the most efficient choice for delivering energy to destroy a planet -- its energy yield is nearly twice its E = mc^2 value, since it annihilates with ordinary matter. I say "nearly" because a little bit of its energy comes off as neutrinos, and those are only weakly interacting. Those neutrinos are produced indirectly, from proton and neutron annihilation reactions producing charged pions, which decay into muons, which in turn decay into electrons. Decaying into muons and electrons is what makes those neutrinos.

You'll get a bit of extra energy out of it--when that antiproton beam hits normal matter it will be moving things up the periodic table and some of the resulting isotopes will decay. I think an antineutron beam would be far more effective as a weapon, though.

 

[Loren Pechtel]

You needn't strip off the atmosphere and oceans to destroy the biosphere.

Raising their temperature to a point above the temperature at which life can survive is sufficient.

If you want to kill all complex organisms, including humans, raising the temperature of our atmosphere above about 38°C should easily suffice. Killing the oceans would require more energy, but a lower temperature target, for complex life to be eliminated.

Killing everything, including extremophile bacteria, would require higher temperatures, but still lower than those needed to evaporate the entire oceans and atmosphere into space.

I ran into an analysis a while back that showed it would be very hard to kill the extremeophiles. The problem is energy escapes to space faster than it soaks into the ground--you can put an awful lot of energy in at the surface (they were looking at impact events) without killing deep extremeophiles on the other side of the planet. I don't remember what they figured it would take but it was way beyond any event ever expected to happen to Earth.

 

[Loren Pechtel]

Can't you just place a large (very large) cast iron pan along it's orbit?

I'd imagine that it'd be easier to manipulate the Earth's orbit to fall into the Sun (or maybe even easier to eject from the solar system), than use energy to destroy the planet.

Depending on exactly what you count as "destroy" I think you found the minimum energy solution.

Lowest energy solution: Lower the periapsis until you get an impact with Venus.

If you don't like the big planet that results from that, second lowest energy solution: Send it to Jupiter, aimed for a grazing impact. It will pass within the Roche limit and be torn apart, but you'll still have big hunks of planet.

 

[Loren Pechtel]

I say we think bigger.

Let's blow up the Sun.

"For years, mankind has yearned to destroy the Sun" - C. Montgomery Burns

My plan is to use the hydrogen and other light elements already present to make a massive thermonuclear explosion.

Of course, the Sun is fairly big, so it might take a little while; I estimate around eight billion years. But the explosion should be close to being big enough to destroy the Earth (in about five billion years time). And it will destroy Mercury and Venus too, as a bonus.

I have actually seen a suggestion on how to blow up a star without totally insane tech: You need a very high speed impactor. Dump enough energy into a small enough space and you can cause rapid proton-proton fusion in the outer parts. A big enough initiation and this becomes a self-sustaining shockwave.

 

[Loren Pechtel]

Life on earth will endure in some form until it gets absorbed into the red giant that our sun will become in a few billion years.
At least that’s my guess. Sue me if I’m wrong.

Wrong. Even the "best" case projections leave the Earth completely sterilized by the red giant phase.

While the energy of a single event tends to radiate into space rather than cook the planet deep enough the energy from the red giant phase is continued--the heat will melt the surface and everything deeper will inherently be warmer. (I won't say it will melt the whole planet because there's the issue of things staying solid because of pressure even when they're above their normal "melting" point.) Nothing lives in lava.

 

[steve_bank]

"What the mind of man can concieve man can achieve"

Be careful what you ask for, yiu might get it.

Back in the 90s there was a theory that a collider experiment at Brookhaven might destroy the Earth. Back then I talked to a cousin who was working on RHIC. He assured me of course it was not likley. I was talking with him about it at my sister's house near Brookhaven, and she freaked out. The idea that scientists were tinkering with thngs that hold everything together.

Will the Large Hadron Collider Destroy Earth?

Whether the world's largest atom smasher will destroy Earth is just one question buzzing around on the eve of LHC's opening.

www.livescience.com

Another wild idea: The LHC might produce something called a strangelet that could convert our planet into a lump of dead "strange matter."

This hypothesis is equally unlikely, experts say, because the same worries were raised eight years ago before the opening of the Relativistic Heavy Ion Collider (RHIC), a particle accelerator at the Brookhaven National Laboratory on Long Island. Since RHIC has been operating safely for years, and it's set-up made it even more likely to produce strangelets if such creation were possible, then the LHC poses little risk of converting us into strangelings.

Although worrywarts have gone so far as to file suit in Federal District Court in Hawaii and in the European Court of Human Rights to stop the LHC (as they also did before RHIC), the project will go ahead as planned.

Sooner or later maybe somebody will press the start button on an experiment, and we are all destroyed....

 

[lpetrich]

(antiprotons for destroying a planet...)

You'll get a bit of extra energy out of it--when that antiproton beam hits normal matter it will be moving things up the periodic table and some of the resulting isotopes will decay. I think an antineutron beam would be far more effective as a weapon, though.

This is antiprotons, not ordinary protons. They will annihilate with a proton or a neutron in the nucleus and the resulting energy will go into boiling off nucleons and small nuclei.

Antineutrons will do the same thing when they annihilate, but they will have greater penetrating power, since they are electrically neutral, and they won't repel each other.

 

[lpetrich]

How to destroy the Earth @ Things Of Interest

1. Annihilated by an equivalent quantity of antimatter
2. Fissioned -- split every nucleus into its nucleons
3. Sucked into a microscopic black hole
4. Cooked in a solar oven -- reflect a few % of the Sun's output onto the Earth to make it hot enough for its material to blow off
5. Overspun -- until it splits in two
6. Blown up -- with enough antimatter to supply the energy for doing so
7. Sucked into a giant black hole
8. Meticulously and systematically deconstructed -- with a mass driver, a linear-motor gun, for shooting its material into space
9. Pulverized by impact with blunt instrument -- another planet colliding at >~ 10 km/s
10. Hurled into the Sun -- one would have to drag the Earth by about 30 km/s
11. Ripped apart by tidal forces -- one would have to use something more dense than the Earth and much more massive, like a stellar-mass black hole

Then some fallback methods

1. Total existence failure -- ???
2. Written off in the backlash from a stellar collision -- crash another star into the Sun, enough to make the combined star make a supernova
3. Swallowed up as the Sun enters red giant stage -- the Earth might squeak through if the Sun blows off enough of its material as a red giant.
4. Crunched -- from the Big Bang becoming a Big Crunch -- the Universe collapsing
5. Torn a new one -- from the Big Bang becoming a Big Rip -- the Universe's expansion becoming superfast
6. Decayed -- from protons and neutrons decaying into much lighter particles

Then some less probable ways

1. Whipped by a cosmic string
2. Gobbled up by strangelets -- if that's what they will do
3. The Supernova Method -- move the Earth to a start that will become a supernova, then wait for that star to do so
4. Shaken to pieces -- making it oscillate at a normal-mode frequency until it oscillates enough to break apart
5. Reduced to true vacuum -- this universe's vacuum must be an excited state for this to work
6. Wormholed
7. Existence negated via time travel -- go back to when the Solar System was forming, then keep the Earth from forming
8. Destroyed by God -- or some similar entity

 

[lpetrich]

Geocide in fiction @ Things Of Interest

Then things that won't work, like gamma-ray bursts and nanotechnology.

Earthmoving @ Things Of Interest

1. Electromagnetic influence -- by giving the Earth an electric charge
2. Direct rocket propulsion
3. Direct matter propulsion -- by using mass drivers
4. Disassemble, move the bits and pieces, reassemble
5. Solar sail method
6. Billiards method -- except that the Earth is not rigid enough for that to work
7. Gravity assistance -- send asteroids on near-collision paths and give the Earth momentum with their swerves

 

[lpetrich]

Star Wars vs Star Trek Essays: Planet Killers

Planet Killers (me: these make planets uninhabitable)

Asteroid or comet impact | Cobalt Bomb | Shadow planet-killer | Vorlon planet-killer | Imperial Star Destroyer | Republic Acclamator | Eclipse-class Star Destroyer | Genesis Device | ForeShadow

Planet Destroyers

Death Star | Death Star 2 | LEXX | World Devastators | Galaxy Gun | Doomsday Machine | Species 8472 | Drej Mothership | Supernova Weapons

Mostly discusses various movies and TV shows, like Star Wars and Star Trek.