The Size of Space

I’m starting with a fact today; two actually.


According to astronomer Dr Peter Edwards, if our solar system was a grain of sand, then The Milky Way (our Galaxy) would be 1,000 times the size of Durham Cathedral.

Durham Cathedral from the South

Durham Cathedral


According to NASA there are hundreds of billions of galaxies in our universe.

Need a more visual representation of that? Well luckily for you, the American Museum of Natural History have spent quite a long time developing a digital universe.

Somewhat mind boggling, isn’t it. Dr Edwards doesn’t think the human mind is really built to understand the enormity of the universe. I think I probably agree with him.

In 2012 the Hubble Space Telescope zoomed in on a seemingly empty area of space. This area of space could be covered up with just a single grain of sand if you were looking at it from Earth. Astronomers didn’t think they would discover much, but if you have a super duper space telescope, why not see what it can find?

This is what that seemingly empty bit of space actually looked like when Hubble zoomed in.

A Hubble Space Telescope picture of millions of galaxy clustersEvery single speck of light you can see is a galaxy. Yes the 100 or so huge ones in the foreground, but also the millions in the background.

Each of those galaxies contains billions of stars. Yes many of them look insignificantly small, but they are very very far away. So the well used fact that there are more stars in the universe than there are grains of sand on Earth is actually true. In fact there are many billions more stars in space than there are grains of sand on the Earth. Each star is in solar systems filled with matter – from specs of dust to moons and planets.

The title of this article suggests that I will try to quantify the size of space. This isn’t really possible, so all we can currently do is describe its size relative to other things. If I had to use one word to describe space, I think it would have to be enormous.

A key question surrounding space is: is it infinite?

That is an existential question which I doubt we will ever know the answer to, but never the less it is still an interesting question, which is worth considering.

The theory that the universe is a sphere – like the Earth – is a popular one, and I can understand the logic in this, if you keep going, eventually the universe will loop you back around to where you started. But then my problem with this theory is we can go beyond the Earth. We can travel around the Earth, but space travel proves that we can move in 3 dimensions, straight and sideways on Earth and then upwards into space. If you got to the very edge of the universe, what would happen if you went upwards? If there isn’t an upwards, what is there?

New Scientist states that from all current data, it seems that the known universe has a diameter of about 93 billion light years. That’s pretty big, but by no means infinite. So if this estimate is correct – which is ridiculously unlikely – what comes after that? A big wall with a no entry sign? Just empty space? Another universe? Who knows…

That’s Your Lot

See you next week for the next in the series.

Discover a New Planet


The days of discovering planets by pointing a telescope at the skies are long gone. If you are interested in discovery you can join the Galaxy Zoo project.

The Galaxy Zoo project has been running for several years, and involves hundreds of thousands of people. One of the problems for scientists today is the analysis of the enormous amounts of scientific data generated. This example is that of The Hubble telescope. It captures such a large amount of images that they risk never being studied, but one way of getting round this problem is to invite non scientists to view the pictures online and classify what they see. The tutorial on their website is simple to follow and in a few minutes you are away and participating in scientific discovery.
There is always the possibility of finding something new too, as in the example of the dutch primary school teacher Hanny Van Arkel who now has an object known as “Hanny’s Voorwerp” named after her, an object that would probably never have been noted had it not been for Ms Arkel’s lay interest in star gazing.

When looking for planets and other objects scientists rely on mathematics to determine where they may be located. Incredibly enough they have been doing it for many years too, and Neptune was in fact discovered after its position was mathematically predicted.

The planet Neptune was mathematically predicted by Urbain Le Verrier, with telescopic observations confirming the existence of a major planet made on the night of September 23–24, 1846, working from Le Verrier’s calculations. It was a sensational moment of 19th century science and dramatic confirmation of Newtonian gravitational theory.
By 1846 the planet Uranus had completed nearly one full orbit since its discovery by William Herschel in 1781, and astronomers had detected a series of irregularities in its path which could not be entirely explained by Newton’s law of gravitation. These irregularities could, however, be resolved if the gravity of a farther, unknown planet were disturbing its path around the Sun.

So nowadays there is an algorithm that helps us of course, and an educational game, and you can play with it if you like. It is fantastically titled Super planet crash. The site that hosts this game is a portal to an entire series of worlds. Planet exploration worlds.

But back to the game. Using Newton’s laws of gravity the game allows you to place planets in orbit around a sun. Each planet has its correct gravitational pull (they are different sizes of course) and this pull effects the orbits of the other planets. The objective is to build a solar system that functions for 500 years without the planets crashing into each other or falling out of orbit.

Once you get involved in putting large planets into orbit the game gets quite difficult. It’s fun for kids and adults and educational, and might lead you into becoming a discoverer yourself.