# How big is our Solar System?

We have all heard how big the Sun is, and how big Jupiter & Saturn are, and how small Earth is compared to them. But are you really able to comprehend the immenseness of all this? Honestly, I wasn’t. When I researched more, I found myself off by a factor of 50-100 in most cases. That’s like assuming the width of USA is 30 miles (instead of it’s approximate 3000 miles).

Earth

Let us start of with our own planet. How big is that really? Easy, and most of you will have almost the right picture of its size. Most of you.

Look at the following image (click to view full size in a new window). Hurts your eyes, huh?

Earth size comparison

Imagine all the red lines (28 lines in all) being stacked end-to-end, and that being the earth’s diameter (for the academically challenged : diameter of Earth = its height or width). In the same comparison, what would be that little dot right below the lines? A man? A car? A truck? A house? That in fact, would be a comparative Empire State building! If you answered ‘man’, note that the Empire State is 264 times taller than an average human. So there, you were just off by a factor of 264!(In other words, you thought USA was 11 miles across :D)

Stats : Diameter of earth : 12,756.2 km (28,410 pixels), Height of Empire State building : 449 m (1 pixel)

Moon & Earth

Okay, let’s go a little farther off into space. How about the moon? This you must know, that the moon is 4 times smaller than the earth. Not quite hard to imagine. But can you really imagine the distance between the earth and the moon? Look at the following image of the moon revolving around earth. Notice anything wrong with that?

Moon Earth size & distance comparison

No, nothing wrong, except you are again off by a factor of 10! Now click on the image to open it in a new window. That is the relative distance between the moon and earth! Doesn’t the moon appear to be much closer than that?

Stats : Distance from moon to earth = 384,400 km (1200 pixels) compared to size of earth = 12,756 km (40 pixels) and size of moon = 3474 km (11 pixels)

Sun & Earth

What about the distance of the Sun from Earth? Any guesses on that one? Here, have a look.

Sun Earth size & distance comparison

From experience, you shall now guess correctly that this distance is too small. But by what factor? Should the Earth have been at twice the distance it’s shown in the image? Will the Sun provide enough heat then as it does? Well, cut it short and click on the above image. That’s the relative distance of the sun from earth. That one took me by surprise too! It’s amazing how much heat/light/energy the sun can provide even at this distance.

Stats : Distance from Sun to earth = 149,597,888 km (1200 pixels) compared to size of earth = 12,756 km (0.1 pixels) and size of Sun= 1,391,000 km (11 pixels)

Planet sizes

Now, let’s have a look at our solar system. How big do you think all the planets are compared to earth? How big do you think the Sun is compared to the planets? Let’s look at this next image of the relative sizes of the Sun and the planets. Click on the image for a larger view in a new window.

Solar system objects' relative sizes

This shouldn’t really be any surprise. All of us, since our school days, have looked at relative sizes of the planets and the Sun. Although, the difference in size of Jupiter and Mercury still makes me smile. But the next image will surely take you by surprise.

Planet Distances

This following image shows the relative distances of all planets from the Sun. Click on it to view it in full size in a new window.

Planets' relative distances from sun

Remember that image above showing the distance of earth from the Sun? Look at how far away Neptune is from the Sun. It is 30 times as far from the Sun as earth is!

Stats : Size of sun = 1,391,000 km (0.3 pixel), distance of sun from Neptune = 4,503,443,661 km (1200 pixels)

It’s a pity that well educated people don’t comprehend how big these solar bodies are, and how far away they are from each other.

Not surprising though – google up ‘solar system’ images and this is what comes up! Google ‘solar system orbits’ and this is what you get! Even school textbooks (at least the one’s my school used) had pretty similar pictures of our solar system. Obviously, everyone starts assuming that this is how our solar system looks like, while it is so far from the truth.

Hope this helped you get the ‘right’ idea!

'As you can see, we've had our eye on you for some time now, Mr. Jokhi. It seems that you've been living two lives. In one life, you're Firoz Jokhi, program writer for a respectable software company. You have a Social Security number, you pay your taxes, and... you help your wife carry out her garbage. The other life is lived in computers, where you go by the hacker alias Filya, and are guilty of virtually every computer crime we have a law for. One of these lives has a future, and one of them does not.' - The Matrix

Posted on April 25th, 2009, in Analysis and tagged , , , , , , , , , , , . Bookmark the permalink. 12 Comments.

1. Jason

I love this! I’m taking Astrophysics and I’m always trying to explain to my friends the distances between Earth and everything else. It blows their mind when you explain to them that our fastest jets (not rockets) would make the Earth to Sun trip in about 20ish years one way!

Also, I know you’ve already answered the response about ‘kick-starting’ a dying sun, but the definitive answer is no. Not only because of the vast difference in Energy production between our Nukes and the Sun like you said, but because the Sun is dying because it lacks enough Hydrogen to create nuclear fusion. We would have to give it more Hydrogen. Although that might sound simple, we could collect all the Hydrogen from every single orbiting object around the Sun and we still wouldn’t have enough Hydrogen for the Sun to burn for a second. This makes sense when you consider that if enough Hydrogen was in our Solar System for two suns, we would have two suns :)

• Filya

Thank you so much :)
Am glad this could help make your friends understand. These astronomical scales are difficult to grasp and am myself taken by surprise at times.

I didn’t quite get you though. The Sun is made up of Hydrogen and the fusion process combines the Hydrogen atoms into Helium atoms. So why do you say we would have to give it more Hydrogen?
Unless you are talking about when the Sun has used up all the Hydrogen and that is the reason it is dying?

• Jason

Yes that is what I was referring to. ‘kick-starting’ a dying Sun just can’t be done because you would need to make another Sun. This happens in binary star systems where the stars obit close enough to pass mass between themselves. However, we are not in a binary star system so once our Sun gobbles up its Hydrogen there is no amount of human interference that can help it.

• Filya

I see. Thanks for clarifying.

I haven’t watched ‘Sunshine’, only heard about the concept. So do they succeed in the movie?

Just wondering though, if the sun had converted all its H to He, would it shrink in size? I would think so since He has almost twice the density of H.

• Jason

I haven’t watched it either, although it probably did in the movie cause they wanted a happy ending.

The Sun will actually swell so that it’s visible surface is beyond Mars (Go to your solar system scale and digest that for a bit lol). Helium requires a much higher temperature and pressure to fuse than Hydrogen (in fact as you climb up the periodic table the temp/pressure goes up as well for fusion until Iron) and because of this the volume must increase or it will annihilate itself in a very large explosion. Because there is nothing to stop the sun from expanding it simply swells to accommodate its new requirements and swallows all the inner planets.

• Filya

Oh ok. That is how those dying Giants are formed. I shall have to read up on how the dying Dwarfs form and why.

Thanks again!

2. snowvil

Very Interesting. What has got me really interested is that there is such huge distance between Neptune and sun and it stills rotates around it, So the force (gravitational???) which makes this happen must be so strong. i cant get my head around how this happens. what are the chances of Neptune breaking free for the orbit.

• filya

Thank you for reading up, and a good question.
For the answer to your question : Neptune’s speed around Sun is just 5.43 Km/s, whereas Earth moves around Sun at 29.78 Km/s. So that is why Neptune does not break free off Sun’s pull.

Here’s a little experiment. Tie a short tough string to your finger and an object at the other end. Twirl the object around your finger (like you twirl a keychain). To break that thread, you would have to twirl the object really really fast! (Sun-Earth analogy)
Now if you took a much longer, thinner string with the same object, you would have to twirl really slow to not break the thread. (Sun-Neptune analogy)

if any of the planets moved faster than they do, they wouldn’t break free off the Sun. Rather they would start moving in elliptical orbits, longer and longer as they moved faster. Of course, beyond a certain speed, they would definitely break free.

3. Having just suffered through ‘Sunshine’ by Danny Boyle, and having read various comments on Amazon about the film I thought I’d better check my facts on the transit of Mercury. In the film it takes about 40 seconds to go from edge to edge, at the equator, which struck me as a little nippy, seems that you might actually see it move if you watched for long enough (well if you watched the whole transit obviously), but you’d probably get bored and make a cup of tea at some point, I stumbledupon your page, I was telling my son that a bomb the size of Manhatten (as in the film) would be a bit of a pin-prick even on the smallest sun, so the film’s premise of ‘kick-starting’ a dying sun with an atom bomb is nonsense, your site is a good illustration of relative sizes. In fact if you have a few pence I gladly turn those pixel images into animation….????

• filya

Well, there are science fiction movies, and there are science fiction movies :)
Honestly, it would be difficult for me to judge how accurate (the kick-starting a dying sun with an atom bomb) that could be, but I would bet on a ‘No’ option.

The Sun produces energy equivalent to 9 x 10^10 megaTons of TNT each second.
The biggest nuclear warhead ever (Tsar Bomba) produced about 50 megaTons of TNT a second.
So comparing the two, I don’t think a bomb can kickstart something already producing a ‘billion’ times the energy of the bomb.

4. MJ

This is quite an interesting post… dint really reflect on this until now…
You are not exaggerating when you say your thoughts are more random than random…

• filya

I too was surprised at some of these things I found while researching for this blog.
:) well, use me for your next random generation … filya.random.next()