Time travel is something that is often presented as a fantasy. The idea that a human being can travel into the future is believed to be impossible. However, you may be surprised to know that a Russian cosmonaut has already traveled into the future.
The time traveler
Sergei Krikalev is a veteran space traveler who has spent 803 days, 9 hours, and 39 minutes on the International Space Station (ISS). The ISS orbits the Earth at a speed of around 7.66 km/s. Due to the extended stay in space, scientists theorized that when Krikalev came back to Earth from his last mission, he was actually 0.02 seconds ahead of Earth time.
“When astronauts and satellites orbit the Earth, they are slightly further away from the center of the planet — compared to people on the ground — and so they actually experience less gravitational time dilation. This means the astronauts’ time would run slightly faster, and when they return to Earth, they’d have to ‘come back’ to the past compared to when they were in space,” according to Universe Today.
Krikalev retired from spaceflight in 2007. At present, he is the Vice President of Space Corporation Energia, a Russian manufacturer of space station components, spacecraft, and ballistic missiles. Though being ahead of everyone by 0.02 seconds does not confer Krikalev with any significant advantage, he definitely has etched his name in history as someone who has traveled through time. So, can we go further into the future? Physicists theorize that it is possible.
According to current theories, traveling further in time can only be done if one were to spend some time near a black hole. “You hang out [next to a black hole] for a while, you come back, get out of your ship, and it will be any number of years into the future, whatever you want all depending on how close you got to the edge of the black hole and how long you hung out there. That is time travel to the future,” Brian Greene, theoretical physicist and string theorist from Columbia University, said in a statement (Express).
GPS satellites often “travel” into the future since they orbit the Earth at a speed of 14,000 km/h. This essentially cuts off several microseconds from their clocks compared to the clocks on Earth. As such, both clocks have to be synchronized quite often to ensure they follow the same time.
Simulating time reversal
Recently, a team of scientists from the Moscow Institute of Physics and Technology (MIPT) succeeded in simulating the reversal of time. The simulation was done using a quantum computer of two qubits in which the computer was subjected to four stages — a starting point, degradation, time reversal, and chaos.
In the time reversal phase, the researchers launched a program that enabled the computer to evolve backward from chaos to order. As such, instead of degenerating into chaos, the qubits ended up being restored to their original state, essentially coming back to the past.
“During the research, scientists who took part in the study tried to analyze the possibility of violating the second law of thermodynamics. This second law states that the entropy or disorder of a closed system will increase over time. This increase in entropy establishes the ‘arrow of time,’ which is basically the irreversible progress from the past to the future,” according to IB Times.
The researchers stressed that what they had done was only a simulation of time reversal and that it does not mean humans now have the capacity to travel to the past. However, the experiment will definitely have some serious ramifications in our understanding of time.