# Reply to post: Re: Eight times brighter than the Moon?

### Chinese biz baron wants to shove his artificial moon where the sun doesn't shine – literally

#### Re: Eight times brighter than the Moon?

Yes, the Moon reflects most of the light away, and has a poor albedo, but it is many orders of magnitude larger than this satellite will be.

I don't buy the 8 times brighter just because an article says so. I want to see the math. I found something that says the sun is 400,000 brighter than the moon. So if you assume this is eight times brighter than the moon then it must be 1/50,000th as bright as the sun. So you'd have to reflect light equal to 1/50,000th of the sun onto this city sized area. I don't know how to calculate the size of the mirror that would require, but that's a huge damn mirror. It isn't going to be some "simple" 50 meter x 50 meter unfolding mirror like the solar panels on a communications satellite.

Besides, I'm not sure 8 times brighter is going to eliminate the need for streetlights. They are a hell of a lot brighter than 8 times as bright as the full moon...

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