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> wouldn’t that mean that something with negative mass can then go faster than the speed of light? No. You can construct a theory of tachyons (particles that g
by pdonis 4y ago
> wouldn’t that mean that something with negative mass can then go faster than the speed of light?
No. You can construct a theory of tachyons (particles that go faster than light) using special relativity, but they have imaginary masses!
The key is that the quantity that actually appears in the equations you refer to in special relativity is the mass squared. So ordinary objects have positive mass squared, light has zero mass squared, and tachyons have negative mass squared.
(Note that this means that some of the things that the article under discussion here says about "negative mass" are only valid in Newtonian mechanics, not in relativity.)
- atonse 4y agoSo in your example with tachyons, the negative number squared becomes positive? Thanks for that explanation!
- pdonis 4y ago> So in your example with tachyons, the negative number squared becomes positive? No. The negative mass squared means the mass itself, the square root of the mass squared, is imaginary.