Really Big!

"Space," it says, "is big. REALLY big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the street to the chemist, but that's just peanuts to space. Listen..." and so on. 

Douglas Adams, Hitchhikers Guide to the Galaxy

In maths recently, we (um, the kids) were learning about scientific notation - how we write really, really, big or small numbers. I was trying to explain what really big or really small meant, and I thought of this quote. I mean, the thing with really big or really small stuff is that it is out of the realm of our everyday experience. We can comprehend driving down the street (a couple of hundred metres), maybe even interstate (just over 4,000km). We can comprehend a pin head (2mm) or even a speck of dust (1/10mm). But we can't comprehend really big interstellar distances or really small sub-atomic particles - it's just too hard for our puny little brains of little experience.


So I did what every good homeschooling mum does, I turned to Google and YouTube. What a treasure trove I found! We started with the Powers of Ten - a film made in 1968 by Ray Eames and her husband Charles (of chair fame) and re-released in 1977, which in turn was based on Kees Boeke's book Cosmic View. The film (and book) show the relative magnitude of scale by zooming out or in ten times every ten seconds.

And then discovered they'd updated it in high-definition:

There are also some really cool interactives on the web to try and get your head around this concept. The first I knew about when I was teaching science at school - Nikon's Universcale. Go have a play, I'll still be here waiting for you!

...welcome back! While you've got your scroll on, you have to check out Scale of the Universe (2).

This stuff just spins me out. I still can't get my head around it. Maybe we're not meant to have a mental image, just accept the amazing world for what it is.

You will note in the corner of all these, index notation being used to help describe the really big and really small numbers:

And so when you are dealing with big or small numbers, rather than write 300,000,000 m/s (the speed of light), you can use Scientific Notation to stop you from getting lost in a sea of zeros. Khan Academy has a good video explaining this:

Scientific Notation (old): Introduction to Scientific Notation

And when started our Coursera Introductory Physics course (but we never finished, because someone - that would be me! - was away from home too much to keep up), this knowledge of scientific notation really came in handy.

I love being able to explore maths (and science) in this way with my kids. It makes it interesting - we can follow the interweb, make it relevant and just really, truly be blown away by how awesome the world is.

So I leave you with one of my favourite scientists, Professor Brian (yum yum) Cox. Well - it's a spoof on the Wonders of the Universe - but it made me chuckle (warning - swear word alert!) (try to imagine a trillion trillion trillion billion gazillion times five billion hours)...