How to destroy the world Jacob Schwartz, Society of Physics Students, Week 10, Fall 2011 Acknowledgements http://qntm.org/destroy Scope/Goals To make The Earth no longer be a planet Definitions IAU definition: Planet: a celestial body that 1. is in orbit around the Sun 2. has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, 3. has cleared the neighborhood around its orbit Ways not to destroy earth Hurling it into interstellar space, Moving it into orbit around a gas giant Moving it into a solar orbit whose neighborhood is not cleared These don’t count! Information on Earth Radius: 6371 km Mass: 5.9722 x 10^24 kg = 5972200000000000000000000 kg ball of rock and iron Semi-major axis of orbit: 149,598,261 km Average orbital speed: 29.78 km/s Calculations Rotational Angular Momentum: Assuming constant density, spherical earth L = I w = 2/5 M R2 w = 7.05 x 1033 T_rotation = ½ I w^2 = 2.56 x 1029 Energy output of sun over 11 minutes Calculations Orbital angular momentum: L = m r v = 2.66 x 1040 J s Orbital Kinetic Energy: T= ½ m v2 = 2.658 x 1033 J For comparison: Mean solar output = 3.846×1026 W 80 days of sun’s entire output Method 1: Annihilated by Antimatter Earth You will need: An entire planet Earth made from antimatter E= (2m) c2 = 1.07 x 1042 Joules 89 million years of sun output Method 1: Annihilated by Antimatter Earth Feasability: 2/10 Earth’s final resting place: gamma rays Method 2: Fissioned You will need: a universal fission machine (e.g. a particle accelerator), an unimaginable amount of energy Method: Take every single atom on planet Earth and individually split each one down to become hydrogen and helium. Method 2: Fissioned Solar wind carries H, He away Planet essentially evaporates Method 2: Fissioned Feasability: 2/10 Earth’s final resting place: gas cloud Method 3: Sucked into a microscopic black hole You will need: a microscopic black hole, mass > Mount Everest or so Method: Drop black hole into earth, wait Method 3: Sucked into a microscopic black hole Feasability: 3/10 Earth’s final resting place: A black hole orbiting the sun Method 4: Cooked in a solar oven Surface area of Earth: 5.112 * 1014 m2 Black-body temperature of Earth: ~287 K Power radiated by Earth: ~1.966 * 1017 kg m2 s-3 Black-body temperature of Earth after being completely boiled: ~3134K Power radiated by Earth at this temperature: ~2.796 * 1021 kg m2 s-3 Ratio of these two powers: 1 to ~14,000 Method 4: Cooked in a solar oven Need to have 14000 * Earth’s surface area worth of mirrors : 1.80 * 1018 m2 Method 4: Cooked in a solar oven Method 4: Cooked in a solar oven Feasability: 3/10 Earth’s final resting place: gas cloud Method 5: Overspun Increase rotation speed until Earth flies apart : centrifugal force > gravity r w2 > 9.8 m/s2 w > 0.00124 or Period of rotation < 84 minutes Increase rotational kinetic energy by 7.4*1031 J 2 days of solar output Method 5: Overspun Method 5: Overspun Feasability: 4/10 Earth’s final resting place: A new asteroid belt Method 6: Destroyed by Antimatter Bomb Gravitational Binding Energy of Earth: U = 3/5 G M2 / R = 2.24 * 1032 Need enough antimatter to overcome this m c^2 = U Only need half of that! m = 1.25 * 1015 kg of antimatter! ~ 200 Mt Everest Sun’s energy output over one week Method 6: Destroyed by an Antimatter Bomb Feasability: 4/10 Earth’s final resting place: a new asteroid belt around the sun Method 7: Sucked into a giant black hole You will need: a black hole, extremely powerful rocket engines. Nearest black hole: ~1600 light years from earth Method 7: Sucked into a giant black hole Feasibility rating: 6/10. Earth’s final resting place: Part of the black hole Method 8: Deconstructed You will need: a mass driver Method: Dig up a chunk of earth, launch it at escape velocity or more A million tonnes per second 189,000,000 years. Note that Earth’s mass increases at ~~~ 1000 tons/day Method 8: Deconstructed Feasibility: 6/10 Earth’s final resting place: Scattered throughout the solar system Method 9: Pulverized You will need: Something large and heavy Method: Smash it into earth Example: 5,000,000,000,000-tonne asteroid at 90% of light speed Note that a Mars-sized object once hit Earth … this led to the moon. Method 9: Pulverized Feasibility: 7/10 Earth's final resting place: a variety of roughly Moonsized chunks of rock Method 10: Hurled into the Sun You will need: Earthmoving Equipment Solar sails, giant rockets, large asteroid, gravity assist Method 10: Hurled into the Sun Feasibility: 9/10 Earth's final resting place: a small globule of vaporized iron sinking slowly into the heart of the Sun. Method 11: Tidal Forces Move Earth close to the Sun / Jupiter Tidal forces rip it apart. Method 11: Tidal Forces Feasibility: 9/10 Earth's final resting place: lumps of heavy elements, torn apart, sinking into the massive cloud layers of Jupiter, never to be seen again. Thanks!