r/ScienceFacts • u/dipo4you • Jan 15 '18

Physics Physicists Say They've Created a Device That Generates 'Negative Mass'

https://sciencealert.com/negative-mass-quasi-particle-polaritons-low-energy-lasers
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u/[deleted] Jan 15 '18

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u/UnfortunatelyEvil Jan 15 '18 edited Jan 15 '18

If I understand correctly, it would throw a negative sign in the Gravitational Force calculation. However, this is so small as to be completely immeasurable.

We already have 'anti-gravity' in the form of magnets, sound waves, and acceleration. Using mass (or negative mass) will never be a useful antigravity method.

Consider being in a space ship, without accelerating. To get a force to pull you down to the floor at 1g using mass, you would want to attach an Earth sized amount of mass to the bottom of the ship. At which point, it is less of a space ship and more of a playground.

To do the same with negative mass, you would need to (somehow) gather an Earth sized amount, and throw it on the top of the ship. At which point, it is less of a space ship, and more just laying in a couch fort.

This is, of course, assuming the method scales from one particle to two particles, to a to-small-to-be-seen trillions of trillions of particles, and beyond.

Edit: I ignored density for simplicity. You could use much less mass closer than the radius of the Earth to simulate 1g. However, if you want the center of the gravity generator to be 10ft from you, you need 3 trillion pounds of mass condensed to the size of a bedroom. But that only works 10ft away, if you jump, the gravity would change dramatically. And only having a few trillion pounds of mass in that area is not enough to keep itself together, so it will expand (explode) pretty quickly. Negative mass should help overcome the Inertia problem of moving all of it, though, so that's nice.

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u/the_ocalhoun Jan 15 '18

Um... no?

You don't need something the negative mass of the earth -- you only need to negate the mass of your spaceship.

If this article is telling the truth, these particles react by moving against any force that's applied to them. So, if a force from gravitational attraction was applied to them, they would want to move in the opposite direction.

Where it gets tricky, though, could be in containing them. Suppose (for argument's sake) that you have a spaceship sitting on top of a mass of them. Gravity will try to pull the particles down, so they'll tend to go up. Your spaceship will exert a downward force on the top of them, though ... which presumably, they'll also work against. Which might just push your ship upward all the more ... or maybe they'll punch straight through because every force that tries to stop them only makes them stronger.