How Large is the Universe?

Do not feel lonely, the entire universe is within you

Rumi

How big is the universe? Why even ask or attempt to answer that question? We’re all living our lives in our own little bubble, so why even think about something so abstract? I believe that we should explore and get a better understanding of the universe because it’s about self-discovery. Learning more about the universe tells us more about ourselves because in essence, it is us, we are the universe, we are not separate from it – we are literally it…. as Alan Watts said, “We are an aperture through which the universe is exploring itself.”

The observable universe (just the part we can see) is 93 billion light years in diameter. When I say 93 billion light years in diameter, that doesn’t really mean much. We know it’s big, but we can’t really conceptualize a number that large. Large numbers are difficult to visualize, so, let’s start with something we all know; Earth, and we will work our way up from there.

Our pale blue dot, is bigger than most people give it credit for. If you could drive around the entire earth at 60 mph, it would take just over 17 days to go around it. If you were to fly around it in a standard airliner, it would take you just over 2 days. So, yea, this rocky dirt ball we call earth is pretty big. It’s taken humanity thousands of years to traverse the globe, to develop it, and to map it all out. Also consider that those are all pretty recent accomplishments in the grand scheme of things.   

Now, we’ve all seen pictures like this and this makes it seem like the earth and moon are pretty close.

But they are very far apart.

The moon is 238,900 miles away.  Even a number this small is hard to conceptualize (at least for me it is). We all understand the speed of a car, so we’ll use that to show just how far away the moon is.  Imagine getting into your car and driving at 60 mph for 6 months. No sleeping or bathroom breaks either. That’s how long it would take to drive to the moon.

This moon, this satellite that orbits the earth, is the furthest humans have made it into space. 12 people have walked on the moon and that’s an amazing feat, but really not very far when you consider what else is out there! We have some probes and robots that have made it further, but this is the furthest, we as a species, have made it. We really are at the infancy stage of space exploration.

Now, we’ve all seen graphics of the solar system that show the planets to be quite large and close together. Obviously, this is done for practical purposes, otherwise we wouldn’t be able to see any detail.

The problem though (just as is done with the earth and moon in many cases) is people assume that’s what it’s really like out there. This really gives a false impression of the immense size of the solar system.

If you were to look at the solar system to scale from this distance, this is what you would see.

Nothing! The planets are so small and the space so big, you literally wouldn’t see anything. That’s how small they are in comparison to the vastness of our solar system.

Speaking of the planets, here is the true scale of the planets compared to each other.

There is our sun.. which you could fit 1 million earths inside of.

The average distance between the earth and sun is 93 million miles. This distance is referred to as an Astronomical Unit (AU).  How far is that if it were a road trip? It would take 177 years to drive to the sun. If you’re in a hurry, you can get there in about 19 years via commercial airliner.

What about driving to Neptune? How long would that take? 5,133 years by car and 600 years by plane.

So, yea, the solar system is immense. And I want to give you one more visual to really drive home how big the space is between planets. Let’s shrink the solar system down to the size of a football field.

At this scale, our sun is just over 1 inch in diameter and sitting on the goal line. The inner planets – Mercury, Venus, Earth and Mars are smaller than the ball in a ball tip pen. The outer planets, or the gas giants would be smaller than BB pellets.

The solar system is huge and it’s easy to see why we haven’t made it very far.. there is a lot of empty space out there. Hope is not lost though…

We’ve sent several probes and robots into space, and they can go much faster than a car or a plane. Our furthest probe, Voyager 1, was launched in 1977 and has been traveling for over 42 years. It’s going about 38,000 mph and is now over 13 billion miles away. It is the most distant man made object in space. It passed all the planet’s orbits back in the 1980’s and it’s still going. Voyager 1’s official departure from the solar system occurred in August 2012.

You may be wondering where the boundary of our solar system is. Great question and a bit tricky to answer. Some define the edge of the solar system using Neptune’s orbit (which is 5.6 B miles in diameter), some use Pluto’s orbit, others use the heliosphere and some others define the border of the solar system at the outer limits of the Oort cloud. The Oort cloud is made up of billions of comets (basically, dirt ice balls) and they orbit the sun, way, way beyond the orbit of Neptune. 

So, there are several ways to define the edge of the solar system. In one (where Neptune is the outer boundary), it takes light 4 hours to go from our sun to the edge of the solar system. In the other scenario (with the Oort cloud), it takes light over a year and a half to go from the sun to the edge of the solar system (that’s over 3,000 times larger than the Neptune’s orbit).  So, quite a big difference between them. For the sake of simplicity, I will be using Neptune as the boundary of the solar system.

I mentioned a light year, so let’s touch on that briefly.. A light year is the distance that light travels in 1 year.  Light travels at 186,282 miles per second.

Here are the earth and moon to scale. It takes light 1.3 seconds to get from the earth to the moon. It would take you 6 months to drive that far and light is traveling that far in 1.3 seconds.. That’s fast.

186,282 miles every second,

11,176,920 miles every minute (21.25 years of driving),

670,615,200 miles every hour,

16 billion miles every day,

And just about 6 (5.879) trillion miles every year.

Everything is so far away in space, and we don’t want to have to write down these huge numbers, so we use the term light year to make it a bit easier on us.

In terms of light speed, we are just 8 minutes from the sun. That’s how long it takes for light to travel from the sun to the earth. Neptune is 4.1 hours away, in terms of light speed. If I haven’t said it enough, let me say it one more time – the solar system is really big! Which is really why we haven’t made it too far just yet. But when you compare our solar system it to the milky way, it’s just ridiculously small.

The nearest star to us is Proxima Centauri. I’s about 4.2 light-years from Earth… that’s 25 trillion miles from earth.

Great, huge numbers again. Let’s simplify it a little. If you scaled down our solar system to the size of a quarter, how many quarters (or, how many of our solar systems) could you fit between us and the nearest star? Go ahead, give it a guess – 1, 5 10?

You could fit 4450 of our Solar Systems (Neptune diameter of 5.6 Billion miles) between us and the nearest star. At this scale, the nearest star is 350 feet away from our little quarter sized solar system.

Just to humor you, it would take 47 million years to drive there or 5 million by plane if you’re in a hurry.

Now, if you were going the speed of a space probe like Voyager 1, which is traveling at 38,000 mph, it would take about 73,000 years to travel to the nearest star (4.24 light years away). Which isn’t too bad, but that is still over 2,500 generations.

Obviously we are not getting there until our technology improves.  It’s not even worth pursuing the nearest star with current technology because it will simply take too long.  You would literally pass by the previously launched spacecraft.

Our interstellar neighborhood is about 50 light years across. With our current technology (going the speed of Voyager), it would take almost a million years to travel across this region in space.

Just beyond our interstellar neighborhood, we get to the radio sphere.

This sphere represents the extent of all human broadcasts since about the time of WWII, when we became radio bright as a species. At about 200 light years across, this area is filled with approx. 3-5 thousand stars. Again, not all are pictured here because only the brightest stars can actually be seen from this distance.

As we get close to 1,000 light years away, which is just 1% the diameter of the Milky Way, it becomes apparent that the milky way is larger than we can even imagine. There are at least 100 billion stars in the milky way. That’s 100,000 millions.  But big numbers kind of go in one ear and out of the other.  When we hear the term a billion, we don’t visualize it… we simply can’t.

So let’s take a second to talk about big numbers. To count to 1,000 would take 17 minutes. To count to 1 million would take 12 days. To count to 1 billion would take 32 years!

Ok, one last example. We’ll use distance this time.  If 15’ were to represent 1,000, then 1,000,000 would be 3 miles, and 1 billion would be from Cape Canaveral to Seattle. Oh, and a trillion, that would be 12 time further than from here to the moon!!!

I just want to stress this point so we can appreciate what a huge number 100 billion is before we get deeper into this because the universe is about to get a whole lot bigger.

Let’s zoom out to the entire galaxy, full of billions of stars… Remember that blue sphere that was 200 light years wide? That’s it.

That’s the speed of light radiating from our planet for the last 100 years or so. We haven’t even made a dent…

Some astronomers even believe there are as many as 400 billion stars in our galaxy alone. ..  That’s absolutely mind numbing.  The Milky Way is home to hundreds of billions of stars. Each one potentially having it’s own planets and possibly its own life forms. In the last 20-30 years we have studied very small sections in the Milky Way and discovered that other stars have planets too. Based on this data, scientists now believe that most of the stars in our Milky Way actually have a family of planets orbiting them. By extrapolating this data, that means there are billions of other planets out there in our milky way alone.

The milky way is about 120,000 light years across and 1,000 light years thick on average. Alright, if that still doesn’t make much sense, let’s forget huge numbers for second. Let’s use another comparison to bring things down to a scale we can relate to.

Let’s go back to our solar system being shrunk down to the size of a quarter. If our entire solar system was the size of a quarter, our Milky Way galaxy would be about the size of North America.

I can’t even find a quarter in my own couch and if you said to find this one particular quarter in North America, it would be pretty much impossible! Trying to see our solar system at this scale would be like trying to see a quarter from space. Actually, it would be even harder because at this scale, the sun would be the size of a single red blood cell. You simply wouldn’t see it until you zoom way, way, way down.

Now, our sun is just one of hundreds of billions of stars in our Milky Way. So, imagine all of North America covered with billions of quarters (the quarters representing star systems like ours). At the center of each quarter is a tiny speck, smaller than a speck of dust, that represents a star. At this scale, our nearest star, Proxima Centauri is (as mentioned earlier) 350’ feet away. Imagine if you will, quarters scattered all over the place, every few hundred feet, all over North America. That’s pretty incredible!!

Here you can see the orbit of our sun around the galaxy.

Even though the sun is traveling around the galaxy at over half a million miles per hour, it still takes 225 million years to complete one revolution (we’ve made about 20 rotations so far). Interestingly, our solar system is moving in a clockwise motion at about 60 degrees from the galactic plane.

Here’s another one that will blow your mind. How many of the Milky Way’s stars are you actually seeing at night with the naked eye? 3,000 – 5,000. That’s it! Out of 100s of billions of stars, the human eye can only see about 3,000 – 5,000 stars (and a couple galaxies like Andromeda, LMC, and SMC).

If you’re still not impressed with the sheer magnitude of space let’s move past our galaxy. Let’s get serious!

Here is our local galactic group. It is just a few satellite galaxies and Andromeda (which is about twice the size of the milky way). The Andromeda galaxy is 2.5 million light years away. That means that it has taken light from this galaxy 2.5 million years to reach us. So when looking up in the night sky, we are seeing Andromeda as it was 2.5 million years ago.  

Zooming out even further we see the Virgo super cluster. There are thousands of galaxies here, similar to ours, with 100’s of billions of stars and planets. If this alone were the size of the universe I would be amazed, but there are an estimated 10 million more super clusters like this one.

More and more super clusters as we move out further and further away.

The entire observable universe – 93 billion light years across.

We may never know what’s beyond the part of the universe that we can see, but due to the acceleration of space, it is believed that the universe itself is at least 250 times bigger than the observable universe.

Wow, a lot of information… but what’s the point… What can we learn from all of this?

First, can we all just be honest with ourselves for a minute? The truth is, we know nothing. Pretending we have all the answers limits our open mindedness to what’s really there. Look at us, floating around on a little dirt rock ball in the middle of nowhere. It’s great that we are able to see as deep and far as we can into the universe, but ultimately, we know nothing. We don’t know why things happen the way they do. More than likely, whatever it is that is happening is happening for reasons that our little brains simply can’t comprehend. So, the next time something happens that doesn’t go your way, just go with the flow man. Do you really think there is any point in resisting the universe?

Also, we don’t have to know everything. Accept that we don’t have all the answers and enjoy life. Live the moment you’re in, do things you’re passionate about, and just have a good time while you’re here.

Second, you are the universe. Eckhart Tolle stated, “You are not IN the universe, you ARE the universe, an intrinsic part of it. Ultimately, you are not a person, but a focal point where the universe is becoming conscious of itself. What an amazing miracle.”

Obviously from our limited perspective at this moment, being in our heads, we feel quite separate from the universe, but think about this:

Every atom inside your body was once in a star.

When a star explodes, it sends new materials and elements all over the place and that’s where carbon, metals, and everything else comes from. That in turn forms other stars and planets and the planets ultimately create you. That’s how you were made. Literally from star stuff! It took billions of years for the universe to evolve and change and to create us. We are tiny but we are also exceptionally special, as is everything in the cosmos.

Here is my belief – the universe is intelligent. It’s not just a bunch of dumb matter floating around colliding haphazardly. One universal intelligence or one consciousness is what’s guiding this whole thing… including you. We just feel like separate selves because that’s how our limited minds work.

You didn’t come into the universe as some separate thing, you came out of the universe. You were born from it. Ultimately, you are not some separate thing, you’re the whole thing. Which means, we’re all in this together.

As Neil Degrasse Tyson put it, “we are all connected. To each other, biologically, to the earth chemically, to the rest of the universe atomically. Not only are we in the universe, the universe is in us.”  

Do your best to treat everyone with love, respect, and dignity. We need to stick together as a species and a planet if we’re going to survive and I think we will. 

I’ll leave you with one final quote:

“The cosmos is within us. We are made of star stuff. We are a way for the universe to know itself.” Carl Sagan