A visual comparison of space travel and human history

Even at light speed, the trip to the Andromeda Galaxy would take 2.5 million years AS MEASURED on Earth. According to Einstein’s theory of special relativity, time passes differently for observers moving at different speeds. If a spacecraft could travel extremely close to the speed of light, time dilation would cause far less time to pass for the astronauts onboard. From Earth’s perspective, the journey would still take 2.5 million years. But from the travelers’ perspective, the trip could feel dramatically shorter — potentially years or decades. Both perspectives are correct; they simply come from different reference frames.

According to Albert Einstein’s special relativity, in the traveler’s own reference frame time flows completely normally — their watch ticks, their heart beats, and they age just as they would on Earth. What changes dramatically isn’t their time, but the distance: due to length contraction, the space between Earth and the Andromeda Galaxy shrinks along the direction of travel, so while observers on Earth would measure a 2.5-million-year journey, the traveler could experience only years or decades. Both perspectives are equally valid because they come from different reference frames. However, relativity doesn’t make anyone immortal — the extreme radiation, collisions with interstellar dust at near-light speed, staggering energy requirements, and life-support limits mean the traveler likely wouldn’t survive in practice. Relativity changes how time and distance are measured; it doesn’t shield humans from the realities of physics

Milky way as compared to other galaxies in universe ✨

This video misunderstands relativity. If you can accelerate to close to the speed of light, then you can reach Andromeda in a short amount of time, for you. For those left behind on Earth, millions of years will pass, indeed.

If the traveler experienced, say, only 10 years while Earth aged 2.5 million years would their biological clocks, cellular decay, and entropy follow their proper time or coordinate time?

Fascinating perspective!

If you could actually travel close to light speed: For YOU inside the ship → Andromeda could feel like just a few years (or even months at crazy speeds) Meanwhile Earth ages 2.5 million years while you’re gone Relativity is wild — you basically time-travel one way 🚀⏳

1) You clearly haven't read the Theory of Relativity--at the speed of light, FOR YOU, the journey would be basically INSTANTANEOUS. Yes, millions of years would pass on EARTH...but not for YOU. 2) The speed of light is NOT the only or fastest way to travel interstellar...

Contemplating these things kind of blows your mind. It’s a little depressing and also makes me think that the only way we have any reasonable chance of discovering any life, much less intelligent life is to survive for millions more years and constantly keep sending out exploration satellites, advanced space telescopes and other technologies. Barring new technology that allows wormhole travel or new ways to dramatically exceed the speed of light, it will be a long long time before we reach another galaxy. Just our nearest star, Proxima Centauri is over 4.2 light years away. 💫

No one said we live in cramped quarters, and your documentary was interesting, but they forgot to tell the folks that the universe goes on forever with no stops at the end because there is no end!🤔

No, it would not take 2.5 light years for you to reach there , on earth it would be that much amount of time while you're gone but for you it will take some minutes if you travel to speed of light as relatively states that as you travel near the speed of light distances shrink.

@DeluriaD

The universe feels endless, and we’re just getting started.

This is the technology of the future of transportation: plasma energy. Believe it or not, I've experienced this moment. In the future, it was an amazing experience. But I don't know when it will become a reality. Will it be in 200 years, less, or more? But it's possible.

No need to travel to another galaxy, as we have more than enough planets in our own galaxy where life could exist.

Modern humans have only excited for about 300,000 years

Humans are like 'ants' on a galactic scale. We are the only 'ants' who may someday reach the stars.

The solution to this doesn't lie in raising the speed but in preservation of yourself. It doesn't matter how long it takes when you can be put in cryosleep

Maybe we weren't meant to travel between galaxies.

If this is true why does Stephen Hawkins not came back and remove his name from epistine file.

Non locality works for the same reason that space travel to other Galaxies will be possible... The underlying dimension has its own coordinates. "TDM" FTW!!!

Great

"i aM aThEisT!"...

Alhumdo Lilah I have the complete answer with Equation that how could I travel to an other Galaxy in only, just in one year travel time according to planet earth 🌎. I will do it Inn Sha Allah Very Soon.

This shows real clarity: humanity has brutal cosmic limits. Musk’s vision of expanding consciousness across the galaxy smacks straight into reality—louder than any Star Trek cliffhanger. Even shipping just our DNA across space? We’d likely be long extinct before it ever got read.

And when you got there you’d have to slowdown which would take a while I bet

2.5 M years to travel a ship would have to stop and repair

Ha-ha haaa, good imagination.

If human history were one day, space travel started at 11:59:58 PM. We evolved 300,000 years ago; space exploration began in 1957. Perspective is everything.

Why worry of traveling? In a few billion years #Milkyway and #Andromeda will comingle.

Echoing @sciencegirl—Andromeda’s two million light-years out. Light barely makes it here. Warp there? Relativity bends time, dust shreds hulls, physics spits. We’re ants in infinity. @neiltyson @ProfBrianCox @AstroKatie @skdh—your take? Are we explorers or just dreaming loud?

Imagine how vast and complex the solar system is,— also imagine some Being outside creating it from the beginning just boggles the mind. Our God is Great, He is Great, GREATER THAN ALL FAR ABOVE ALL.