Wormholes – we love them in science fiction novels and movies, and we wish they existed more than just about anything else created by the fertile minds of the Bradburys and the Roddenberrys. Wormholes are especially enticing and frustrating because they offer such a nice clean way of traversing space and time while being impossible under the General Theory of Relativity. Or are they? Two physicists have proposed a loophole that would allow humans to safely pass through wormholes without destroying themselves, the universe, life and everything. Is it true or have they been in quarantine too long?
“Traversable wormholes are a staple of the science fiction literature. In classical general relativity, they are forbidden by the average null energy condition [1, 2, 3]. Interestingly, they are allowed in the quantum theory, but with one catch, the time it takes to go through the wormhole should be longer than the time it takes to travel between the two mouths on the outside.”
That opening paragraph is the last one understandable by non-theoretical physicists in the paper, “Humanly traversable wormholes,” written by Juan Maldacena, Princeton professor of theoretical physics, and Alexey Milekhin, Princeton graduate student of astrophysics. Fortunately, Universe Today breaks it down into terms this humble writer can understand. The key sentence is the one about the time it takes to travel between the two mouths on the outside – anything else would violate the General Theory of Relativity, which science fiction does all of the time. Even worse, wormholes are short-lived and volatile, so you might not make it to the other side before being crushed out of existence. Finally, this would only seem to work with matter at the particle level – no starships can fit nor shrink that small.
“The Randall-Sundrom II model was based on the realization that this five-dimensional spacetime could also be describing physics at lower energies than the ones we usually explore, but that it would have escaped detection because it couples with our matter only through gravity. In fact, its physics is similar to adding many strongly interacting massless fields to the known physics. And for this reason it can give rise to the required negative energy.”
Maldacena and Mikekhan propose using a quantum physics model with a fifth dimension (yes, we’ve entered a new Age of Aquarius) to provide the negative energy (the fifth dimension) required to keep the wormhole stable and maintain the tunnel until the body passes through the other end. They used charged massless fermions (particles like the electron but with zero mass) which exist in black holes and travel in circles. That would make the wormholes look like black holes, but all of that negative energy would require the ship to exert a sudden boost of energy to pass the midpoint in the tunnel. Finally, this wormhole would allow speeds far greater that the speed of light, allowing a ship to cross the Milky Way in ten seconds.
Oh, and one more thing (maybe two) …
“[F]or astronauts going through the wormhole it would take only 1 second of their time to travel 10,000 light-year distance (approximately 5000 billion miles or 1/10 of Milky Way size). An observer who does not go through the wormhole and stays outside sees them taking more than 10,000 years. And all this with no use of fuel, since the gravity accelerates and decelerates the spaceship.”
No fuel and no violation of the General Theory of Relativity! That’s not exactly good news – the Enterprise arrives 100,000 years too late to stop the Romulan fleet from destroying Earth. But it keeps wormholes in the realm of the possible – at least the quantumly possible. Maldacena and Milekhin admit traveling them is well beyond current technology and protection against exposure to massive amounts of cosmic radiation. But it’s something to strive for.
Quite a challenge for a species that still can’t get flying cars flying at the speed of cars.