Time travel and quantum physics to try to restore the world.

How can Avengers Endgame, which is in cinemas this week, try to bring these characters back?

Time travel is a tried-and-tested movie plot device. There’s also a surprising amount of scientific jargon, such as quantum physics, Deutsch proposals, eigenvalues, and inverted Mobius strips.

Read more: We did a breakthrough’ speed test’ in quantum tunneling, and here’s why that’s exciting.

But don’t think that everything you hear during the movie was created in the minds of some crazy screenwriter. Many of the time-travel concepts in Endgame are connected, at least in name, to recent scientific theory, simulation, and speculation.

Marvel Studios Avengers: Endgame official trailer.

We’ll dive into the science behind quantum time travel to see if eigenvalues are able to save the universe. But beware: there will be moderate spoilers.

Time Travel 101

The main premise is that only the powerful Infinity Stones can reverse the death of half of the universe.

The problem is that Thanos destroyed them in the present, and so they are only available from the past. The remaining Avengers will have to travel back through time and visit multiple locations in order to retrieve them.

Is Time Travel Possible? Since Albert Einstein’s Theory of Special Relativity was published more than 100 years ago, we have known that time travel is relatively simple.

You can travel into the future millions, or even billions, of years within your lifetime if you move close to the speed of light.

Could you return? This is a much harder feat. Here are some challenges and solutions.

The grandfather paradox

The well-known grandson paradox can be caused by time travel.

Disrespecting your elders doesn’t pan out well for you. iimages / 123rf.com / Michael Milford.

You could not have been born if you killed your grandfather in his youth. But how would you do it if you were never born?

Scientists have a number of theories on these time loops. (Physicists refer to them as closed curves). According to some ideas, such time loops are physically impossible. Therefore, traveling back in the past is not possible.

We also know, thanks to Einstein, that rotating black holes can twist both space and time. This is why the very first image of a black hole shows one side brighter than another.

Endgame: Time travel

The characters in the film first mock other time-travel films, such as Back to the Future or Terminator Series, where you can change your past and future.

Endgame instead goes with an alternative reality concept, whereby any change in the past causes a new universe to appear or a “splitting” of multiple timelines. This idea is known as the Many Worlds Theory in physics.