Physicists call them “wormholes” and in fact, they are the Einstein’s field equations for gravity.
Theoretically, wormholes are tunnels that connect different points in spacetime. In simple words, if someone enters a wormhole located, for example, in our solar system, he can get to a remote location of the galaxy or the universe in time dt, which would normally require thousands or millions of years.
A few weeks ago Luke Butcher, Professor of Physics at Cambridge University, garnered the spotlight with a new theory about wormholes. According to Dr Butcher, wormholes can act as a cosmic server for message transfer in time. The scientist believes that anyone can send messages through a wormhole either in the past or in the future, which will be transferred with the help of light pulses containing the message.
There are two basic types of wormholes: Lorentzian wormholes (general relativity) and Euclidean wormholes (particle physics).
Lorentzian wormholes are essentially shortcuts through space and time. They are studied mainly by physicists who deal with Einstein’s equations, and if we could see them in real life, they would be more or less similar to the wormholes we see in sci-fi movies and series.
Euclidean wormholes are even more bizarre. Since they have properties of quantum mechanics, their chaotic nature will not be easy to study.
The one who made wormholes known to the public was the American astronomer and astrophysicist Carl Sagan. He wrote a science fiction novel in which aliens communicate with humans. Sagan wanted to bring humans and aliens together in a way based on the existent scientific data, and not by a method that would be a product of his imagination. Therefore, he asked the help of Kip Thorne, Professor of Theoretical Physics at MIT, who along with two graduate students studied such possibility.
They concluded that a wormhole could be a transfer passage for the heroine of the book only if the negative energy was produced in a quantity sufficient for keeping its mouths open. Of course, it was the novel that became a base for the movie «Contact» with Jodie Foster.
The good news for Lorentzian wormholes is that scientists cannot prove whether they exist or no.
The bad news is that all the studies conducted till now show that even if there are such wormholes, they are completely unstable cosmic objects that open and close in a split second. So if they exist, large amounts of negative mass are required to keep them open and prevent them from collapsing.
It is possible to get small amounts of negative energy in the laboratory (the Casimir effect), but we cannot get large amounts of negative energy required to keep a Lorentzian wormhole at a normal size and for sufficient time.
However some time ago a group of physicists from Germany and Greece conducted a study which suggested that the construction of a wormhole may be possible without using negative energy.
“Even the normal matter with positive energy is not required,” said Burkhard Kleihaus of the University of Oldenburg in Germany. “Wormholes can stay open with nothing,” said the researcher opening a new topic for studies and discussions on whether travel in spacetime is possible.