Big numbers

[cultureofdoubt]

I walked to work today, and got a bit wet in the process. As I was walking I wondered just how many raindrops were falling around me. Now, people are notoriously bad at guessing big numbers, and raindrops fall rather too fast to count and then multiply out an estimate, so I got to work without having much idea

Comments

[chrisvenus]

I underestimated how much rain we get here. Though I guess not by a factor of 10,000 so I'd still have been wrong. Its also nice to prove that not all your friends are smart asses. :)

[cultureofdoubt]

Well there's a lot of factors of ten to lose. I doubt many people can accurately guess the number of stars in an average galaxy to within that (heck, I wouldn't expect an astronomer to get that right to within a factor of ten). I doubt many people can guess the distance to the CMB using an appropriate distance measure to within a factor of ten*, which means their volume estimate could be out by a factor of a thousand or more. And what with other uncertainties I'm not sure this question is half as easy as the results of the poll might suggest.

*I'd expect some number of people to know that the CMB is 13.7 billion years old, convert that into light years and use that as the radius of a sphere. And they'd get an answer for the volume that was wrong by a factor of about thirty due to using the wrong sort of distance.

[chrisvenus]

Wrong sort of distance? Is this a relativity thing?

[cultureofdoubt]

Not really a relativity thing, although it is a bit. Basically, because you can't actually put down a tape measure in astronomy you need to find some other way of measuring, all of which are a bit different thanks to the universe not wanting to stay still

[cultureofdoubt]

You'll probably have noted from IRC that I got the raindrops wrong, so you were only out by a hundred. Which is a thoroughly reasonable amount to be out by, not least as it's not inconceivable that there are in fact more raindrops than stars.... just.