Could We Find a Door To A Parallel Universe?

p1234 writes "Though no direct evidence for wormholes has been observed, this could be because they are disguised as black holes. Now Alexander Shatskiy of the Lebedev Physical Institute in Moscow, Russia, is suggesting a possible way to tell the two kinds of object apart. His idea assumes the existence of a bizarre substance called "phantom matter", which has been proposed to explain how wormholes might stay open. Phantom matter has negative energy and negative mass, so it creates a repulsive effect that prevents the wormhole closing. 'US expert Dr Lawrence Krauss, from Case Western Reserve University in Cleveland, Ohio, points out that the idea rests on untested assumptions. He told New Scientist magazine: "It is an interesting attempt to actually think of what a real signature for a wormhole would be, but it is more hypothetical than observational. Without any idea of what phantom matter is and its possible interactions with light, it is not clear one can provide a general argument."'"

Comments

Sqrt(Negative energy) = head hurts

[G4from128k]

IANAP, but most "energy" variables can be thought of as the square of some other physical properties (kinetic energy is related to velocity squared, electrical energy is related to voltage or current squared, etc.) So to get "negative energy", it would seem that we need imaginary (as in the number i = sqrt(-1) ) values of velocity, voltage, current, etc. So now my brain hurts (and the real physicists on slashdot can enjoy ripping me to shreds or educating me as is their wont)

Re:Sqrt(Negative energy) = head hurts

[jonnyfish]

Negative kinetic energy happens all the time in quantum mechanics. That's what tunneling is. In classical physics, the total energy is E=T+V, where T is the kinetic energy and V is the potential energy. In tunneling, a particle can pass through a "barrier" where V>E, so that the kinetic energy E-V is negative.

I still think the claims in the article are ridiculous though.

Re:Sqrt(Negative energy) = head hurts

[rasputin465]

IAAP, although not in this field (and actually I don't know anything about "phantom matter"). The idea of imaginary physical quantities isn't actually as forbidden as you might think. The best example I can think of are tachyons. Non-physicists invariably hear about these particles in sci-fi (I seem to recall multiple references to them in star trek), but actually a number of current theories predict their existence. They are particles that travel faster than the speed of light, which means that their rest mass is imaginary. You need not worry, however, because they never travel slower than the speed of light. One example, supersymmetery, predicts a number of particles whose mass^2 is positive at high energies (read: very soon after the big bang), but goes negative at lower energies; hence their rest mass is imaginary and are tachyons.

Less esoterically, in the realm of electronics, the electrical impedance of capacitors and inductors is imaginary. However, one could argue that this is just a mathematical trick to aid computations.

I might also note (and probably other commenters have too) that Lawrence Krauss, who's mentioned in the summary, is the author of the famous The Physics of Star Trek, which is a great read.