When at closest approach to Earth, Planet X is observed to be 3.8 arcseconds in diameter. What is Planet X's diameter in meters?
1 Answer
Feb 13, 2016
There is no enough data. You need to know the distance to the planet.
Explanation:
You can derive an expression:
Passing arcseconds to radians_
Now, imagine the distance is 50 million km (Mars or Venus can be at that distance):
The diameter will be 920 thousand meters. (Not Mars, neither Venus).