tag:blogger.com,1999:blog-5376628436133716219.post5845896802031824447..comments2024-03-19T02:21:02.379-07:00Comments on Why I hate physics: What if the Moon were Made of Golfballs?Marty Greenhttp://www.blogger.com/profile/17624084719249673373noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-5376628436133716219.post-71388984374189139722013-06-02T03:25:30.676-07:002013-06-02T03:25:30.676-07:00Hi Marty, thanks for replying.
Right, before I did...Hi Marty, thanks for replying.<br />Right, before I did the computations, I had the same thinking that the half-moon would yield less than 50% of the brightness of the full moon. In fact, the real (non-Lambertian) half-moon gives only 8% of the light of full moon. Check out this interesting article:<br />http://www.asterism.org/tutorials/tut26-1.htmAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-5376628436133716219.post-81652863174738141152013-05-27T11:03:13.463-07:002013-05-27T11:03:13.463-07:00Hi Peter
I thinks that's great that you ended...Hi Peter<br /><br />I thinks that's great that you ended up working on the same problem as me, and then you found me on the internet. Yes, your 33% appears to be the same as my 50%...in Talmudic Law that's called the difference between a "shtut milguph" and a "shtut milbar". (But that's another story.)<br /><br />I'd like to try and work out your integrals for the brightness of the half-moon but right now I'm stacked up with some other obligations. But I definitely agree the half-moon should be less than 50% the brightness of the full moon, because you are seeing a greater proportion of the surface area which is only obliquely illuminated. Marty Greenhttps://www.blogger.com/profile/17624084719249673373noreply@blogger.comtag:blogger.com,1999:blog-5376628436133716219.post-39671178752832539322013-05-24T17:49:17.464-07:002013-05-24T17:49:17.464-07:00Hi Marty,
Sorry for this late comment (over a yea...Hi Marty,<br /><br />Sorry for this late comment (over a year now from your post), but I could not resist. Nice post, BTW.<br /><br />Recently I was thinking about a similar problem - visual magnitude of the ideal/Lambertian moon/planet depending on its phase. After I did some calculations, I was trying to verify their correctness on internet. To my surprise it was really hard to find anything relevant, but after googling for couple of hours I found your post.<br /><br />My result was that the spherical Lambertian full moon would provide 1/3 less reflected light than the flat drywall moon. So first I thought... 33% is different from your 50%, but after reading your post again I realized it's the same thing (I bet you know what I mean). You know, it's 2am now and it's hard to focus :). So good news for both of us - we got the same result.<br /><br />Anyway, I went further with my calculations as I was interested in the amount of reflected light from the moon in certain phase relative to the full moon. Still talking about ideal Lambertian moon. Really interesting integrals, man ;) For example, the first/third quarter moon (half-circle) gives exactly 1/pi (approx. 32%) of light compared to the full moon. As I said, I could not verify the result and I was wondering if it's correct. If you are interested and find some time to do the calculations, would you mind to confirm you get the same result? Thanks.<br /><br />Peter<br />Anonymousnoreply@blogger.com