The semimajor axis of Pluto's orbit is almost 40 AU.The smallest parallax angle we can measure from orbiting observatories is about 0.001 arcsec.Suppose we use this technique to measure parallax from Pluto's orbit (over the course of half a Pluto "year").What is the maximum distance we could measure?
A) 40 pc
B) 1000 pc
C) 40,000 pc
D) 80,000 pc

Question

Quizplus · Accepted Answer

Using the formula for parallax, we can calculate the maximum distance that can be measured as follows:

maximum distance = (semimajor axis) / (parallax angle)
maximum distance = (40 AU) / (0.001 arcsec)
maximum distance = 40,000 pc

Therefore, the maximum distance we could measure from Pluto's orbit is 40,000 pc, which corresponds to choice C.

The Semimajor Axis of Pluto's Orbit Is Almost 40 AU