Australian scientists from the University of Queensland have performed time travel for the first time, by sending 2 photons to the past and bringing them back successfully to the present.
A photon is an elementary particle that is a carrier of energy, it travels at the speed of light and distinguishes itself from other particles by the fact that it has 0 mass at rest.
After the successful experiment, the physicists proclaimed that this proves that time travel is fully possible. Details surrounding the scientists' study has been published in Nature Communications journal.
In the experiment, they sent 2 photons to the past using a computer, then brought them back to the present. One of the particles in the past even encountered its own self, without this causing a catastrophe in the present.
In the past, the theory of time travel clashed with the paradox of the space time continuum - if one were to go back to the past, they might meet one of their ancestors and disrupt the flow of events.
Using the theory of relativity and quantum mechanics as a launch point, the scientists proved that time travel is possible in practice as well.
The general theory of relativity states that there exist tunnels in the space time continuum, which connect different areas of space.
Albert Einstein's equations allowed for the possibility of traveling from one year to another using a space time tunnel.
Even so, it is believed that creating a time machine at this point in our technological development is impossible.
Some believe however, that there have already been travelers between different periods and that various pieces of evidence are a testament to this.
During archaeological digs, experts have found objects which cannot in any way be assigned to the time period they had been studying.
For example, during the 80s, while drilling, a metal coin 400 000 years old was uncovered. Keeping in mind that humans appeared on the planet much later, so far the only explanation for this is that the object was "dropped" by a stranger from the future.