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And We’re Off, To the Past

Looking into the past with light-years

Growing up, I fantasized time travel and if it would ever be possible. I watched cartoons and movies that made time travel seem so real. Of course, I got a little older and realized physical time travel would be a thing of the distant future, if it ever comes to fruition. I let the fantasy go and focused on “real life” as all the adults said. It wasn’t until I learned of the concept of a light-year that I realized a form of time traveling is already upon us.

One light-year is the distance that light can travel in one year. If an object is ten light-years away, then the light from that object will take ten years to reach me. If this distant object emitted light on January 1, 2010, I wouldn’t see the light until January 1, 2020. In a sense, since the light I’m seeing is ten years old, I am looking ten years into the past. Now, this is just a theoretical object. In reality, astronomers have observed plenty of objects (stars, galaxies, etc…) that are at extreme distances.

For example, our closest neighboring galaxy, Andromeda, is around 2.5 million light-years away. The light we observe today from Andromeda was emitted 2.5 million years ago so we’re 2.5 million years into the past! For me, the most interesting concept of light-years is the age of the universe which is estimated to be about 14 billion years old. If we can see to the “edges” of the universe, then we are looking back 14 billion years. Everything between our planet and the edges is known as the observable universe and all of the light we see from the objects is the light of the past. How’s that for time travel?

I may be stuck in the present for now but by looking up at the sky on a clear night to see the multitude of stars and other objects above, I can look back into the past to satisfy my childhood fantasy of time travel.

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