What If The Milky Way Were Made Of Beach Sand?
There is nothing quite like drifting off to sleep in a swag, with the dull glow of a fading campfire, a light breeze on your face, the knowledge that you are so remote you really could be on another planet, and with the Milky Way above.
Whilst I love to comforts of a modern life, I do miss this simple activity and the way it connects me to millions of years of human evolution and the Universe. Sitting around the campfire contemplating the Universe – it’s heavy stuff!
So to get you ready for a swag experience in the Kimberley, here’s some facts about our Milky Way.
First some terminology
A solar system is what we call a star which has at least 1 planet orbiting around it. In the solar system that we live in, we call the star the sun, and we have 8 planets, the earth is the 3rd from the Sun.
A Galaxy is a a whole lot of stars and solar systems which are bunched up together.
The Galaxy in which we live is called the Milky Way, all up it’s estimated that there are 100 billion stars in the Milky Way.
The milky Way, like most Galaxies, is shaped like a round disk, from above it looks like a plate, from the side it looks like a plate but with a bulge in the middle where there is a higher concentration of stars.
We live about halfway from the centre of the milky way to the outer edge.
When we look at the Milky Way from the earth, we are looking at one of those spiral arms you can in the image.
At the centre of the Milky Way there is a Black Hole, just as Earth and other planets obit around the Sun, all the stars and Solar systems in the Milky Way orbit around the Black Hole at the centre, whilst we go around the Sun in 1 year, it takes about 250 million years to for the Sun to do 1 orbit of the Milky Way.
The Milky Way is big, about 1,000,000,000,000,000,000 km across.
The Universe is everything, basically a whole lot of space containing a whole lot of Galaxies floating around in it.
It is estimated that there are 100,000 billion Galaxies in the Universe.
It’s quite large, about 880,000,000,000,000,000,000,000,000 km
The photo above compares it’s shape to brain cell.
What if the Milky Way were made from beach sand?
Have you ever sat on the beach and wondered what if stars were the same size as grains of sand?
Thats exactly what these guys are doing.
So, lets imagine that the sun is a grain of sand 1mm in diameter.
What we need is 100 billion grains of sand, we can then throw all the sand in the air and spread it out in the shape of the milky may.
The first bit, gathering 100 billion grains of sand is not as hard as it sounds, assuming they are all 1mm in diameter like our Sun, we would need a cube of sand with 4.6 metre sides and height.
(We are ignoring the fact that not all the stars in the Milky Way are the same size as the sun, but lets not get too complex)
The second part of the challenge, get the grains of sand to float in the same formation is the Milky Way, for this we need magic.
Once complete, the first thing we would notice is that the earth would be an invisible speck (if you can notice invisible!) 10cm away from the sun.
Next, we could look for other grains of sand. The closest grain of sand (star) would be 30km away, this a star called Alpha Centauri, and while it looks like a single star when we look at from Earth, it’s actually 3 stars grouped together, 2 are about the size of the Sun plus a much smaller one.
It’s a long way to these other grains of sand and there is essentially nothing but silent, cold open space in between (well if you get technical there is theoretical stuff like dark energy and who knows what).
If you wanted to travel there in a tiny space shuttle, even at Shuttle top speed of 28, 300km/h, it would take you about 165,000 years to get there, by which time you’d have some serious cabin fever.
So, we have explained the location of 4 grains of sand in our sandy Milky Way, what about the other ninety-nine billion nine hundred ninety-nine million nine hundred ninety-nine thousand nine hundred ninety-six?
Well, they are out there, spread over an enormous area. The diameter of our sandy Milky Way would be 679,650km, which is roughly the distance to moon and back.
The centre of the Milky Way would be 177,371 km away.
The mind blowing thing about all this, is that the Milky Way, as vast as it is, is just your average galaxy and it’s not alone, it’s estimated that there are at least another 100 billion galaxies in the universe.
We are going to need more sand.
The best pace to contemplate all this is lying in a open air bed in a very remote part of the world with no light pollution. The Kimberley is such a place.