1000 Things You Didn’t Know About The Universe #1: The Universe is Huge

Welcome to a new series of posts that will characterize 1000 amazing facts about the Universe.  There is so much out there that we have yet to learn, and every day, astronomers across the globe are using their research to reveal the deepest secrets of the cosmos.  This series will look at the strangest, coolest, most exciting facts that we have discovered in hundreds of years of modern science.

Fact #1: The Universe is Far Larger than you Can Possibly Imagine

Scales in the Universe. Credit: Andrew Z. Colvin

Let’s start with the fastest speed ever travelled by a human being, about 11 Km/s (40,000 Km/h).  This is incredibly fast right? Imagine moving at 11 kilometres every second; it would be very easy to get anywhere you’re going.  That is, unless you’re going into space.

If you were travelling to the Moon at this speed, it would take you about 9.5 hours to get there.  This is like a long drive for a vacation.  I drove for 9.5 hours to get from Toronto, Ontario to the New Brunswick border this summer, and it was tiring.

How about to our nearest neighbour, Venus? At this speed it would take 274 days, about 9 months!  And that is at our fastest speed ever.  Space is big.  To get to Pluto as this speed it would take 14 years – so now things are getting a little unrealistic.  We couldn’t just sit tight for 14 years at that speed without some way to survive and keep ourselves entertained.  This is a significant portion of our life to spend in a tiny capsule, and it will only take us to the outer reaches of our own solar system.

Credit: NASA / New Horizons

So we don’t waste so much time, let’s presume that our technology has advanced to the point where we can travel at the speed of light, which is the fastest anything in our universe can possibly travel.  this speed is 300,000,000 meters per second, or about 1,080,000,000 Km/h.  Pluto is only a decent 5 hour drive away in our light speed car. But how about stars?

The closest star to the Sun is Proxima Centauri, part of the Centaurus constellation in the southern hemisphere.  It’s just over 40 Trillion Km away, which would take our light speed ship just over 4 years!

Four years.  At the fastest speed anything can travel. To the closest star. Jeez.

At this point there is no sense using Kilometres any more.  Everything we talk about will now be in terms of light years, ie the distance travelled by a beam of light in one year.  Proxima Centauri, our closest star, is 4 light years away.

Most stars in the sky that we see with our eyes are less than 1000 light years away.  But this is only a tiny fraction of the Milky Way Galaxy.  The entire Milky Way is about 100,000 light years across, and it contains as many as 400 Billion stars.

But once we leave the galaxy, we are truly on the edge of a vastly empty cosmic ocean, with other galaxies acting as islands that take millions of years to reach.  If we were travelling at the speed of light, it would take us 2.5 million years just to reach our nearest neighbour, Andromeda.  We are now talking about distances that are incredibly difficult to fathom.

But Andromeda is like a quick hop across a river compared to other galaxies and the immense clusters they form.  The coma super cluster is the nearest neighbour to the super cluster formed by our own galaxy and several thousand others, and it is a titanic 300 Million light years away.  As an analogy, if the Milky Way were reduced to the size of a penny, the Coma super cluster would be 57 meters away!

The most distant objects we can see are quasars, bright galaxies with a super massive black hole that is actively swallowing up gas and dust, creating super hot material that glows and radiates across the universe.  The most distant quasar is approximately 29 Billion light years away.  If we go back to our penny analogy, this quasar would be five and a half kilometres from our Milky Way Penny.

Finally, the observable universe itself, estimated to have a diameter of 90 Billion light years.  To cross it would take 90 Billion years if we could travel at the speed of light.  It would be 17 Km away from our Milky Way penny. If we had our old reliable super fast spaceship at 11 km/s, it would take us 2.5 quadrillion years, ie 2,500,000,000,000,000 years, or about 190,000 times the entire age of the universe from the Big Bang to present.

The universe is so large, it is beyond anything related to human experience.  Time and Space intermingle at these incredible distances in ways that are strange and exotic to us.  Einstein said ‘the most incomprehensible thing about the universe is that it is comprehensible.”  The sheer fact that we can understand our place in the vast cosmic ocean is a testament to our species.

And it’s a great #1 for this list.

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