News for hackers. Stuff that matters.

A comment on Caltech Researchers Find Evidence of a Planet Beyond Pluto. Parent comment

Re:Caltech Researchers Find Evidence of a Planet Beyond Pluto by antognini on Wednesday January 20, 2016 @01:35PM (#10940260)
Yes. The solid angle subtended by the planet (and hence the amount of reflected light) goes as 1/r^2, and then the apparent brightness of the reflected light to us goes as an additional 1/r^2. The total dependence is then 1/r^2 * 1/r^2 = 1/r^4.
[ Parent | on HN ]
Re:Caltech Researchers Find Evidence of a Planet Beyond Pluto by gohrt on Wednesday January 20, 2016 @02:09PM (#10940503)
This is a really good physics puzzler.

The key point is that Pluto does not reflect light like a mirror, it scatters light relatively uniformly, causing more light loss to an observer than, say, a mirror that points the reflection directly at an Earth observer.

[ Parent | on HN ]