• Question: is time travel possible

    Asked by neck520easy on 9 Jun 2025.
    • Photo: Alistair Glasse

      Alistair Glasse answered on 9 Jun 2025:

      Tycho Brahe, because he had a silver nose.

    • Photo: Amal Lavender

      Amal Lavender answered on 9 Jun 2025:

      i dont believe so currently or in existence now or we’d see evidence of it? 🙂

    • Photo: Caroline Roche

      Caroline Roche answered on 17 Jun 2025:

      Yes. It is possible to travel into the future, if you leave earth and travel at the speed of light, time will pass slower for you than those on earth. So that when you return you are now in earths future compared to when you left. (e.g. if you are in space for 6 years, when you return the time measured on earth that you were away for would be measured as 10 years.)
      It is a bit trickier to travel into the past (possibly even impossible) and one that people aren’t sure how to do. It also raises lots of questions on what happens when you go back and you change something i.e. does it affect the future you’ve come from or does it just generate a new timeline, can you ever return to your original time.

    • Photo: Charlotte Slade

      Charlotte Slade answered on 1 Jul 2025:

      This is one of the biggest and most exciting questions in all of science! It’s the kind of question that makes being a physicist so much fun. The answer is a surprising “Yes… and no.”

      Let’s split it into two parts: travelling to the future, and travelling to the past.

      1. Travelling to the Future (The “Yes!”)

      The amazing thing is, you are already time travelling into the future right now! You’re just doing it at a rate of one second per second. But physics, specifically Albert Einstein’s brilliant ideas, proved that we can change that rate.

      There are two main ways to do it:

      i. Go really, really fast: The faster you move, the slower time passes for you compared to someone who is standing still. If you were an astronaut on a spaceship travelling near the speed of light for a year, when you came back to Earth, many, many more years would have passed for everyone you left behind. You would have effectively jumped into their future! Astronauts on the International Space Station are doing this right now, just on a tiny scale. They age a fraction of a second slower than we do on Earth.

      ii. Go near something with a lot of gravity: Gravity can also bend time. A clock at the top of a skyscraper actually ticks a tiny bit faster than a clock at the bottom, because the gravity is slightly weaker up there. If you could hang out near something with incredibly strong gravity, like a black hole (from a safe distance!), time would slow down dramatically for you.

      2. Travelling to the Past (The “Probably Not”)

      This is where things get really tricky. As far as we know, travelling to the past is not possible.

      Think of it like trying to un-bake a cake. You can mix flour, eggs, and sugar to bake a cake, but you can’t take the finished cake and separate it back into raw eggs, flour, and sugar.

      Physics has rules, and one of the biggest ones is “cause and effect.” The cause (mixing the batter) always has to happen before the effect (the cake). If you could travel to the past, you could break this rule. You could see the cake before you’d even bought the eggs!

      So, while we can’t build a machine to visit the dinosaurs, we know that time is much weirder and more flexible than we think. And asking these huge questions is exactly what science is all about

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