If a star's parallax is 0.1 arc seconds on Earth, what would it be if measured from an observatory on Mars?

Question

Mars is 1.524 AU away from the sun..
I have to use formula of "d=constant/p"
Please help.. and please show me your calculation.
9 hours ago - 3 days left to answer.

Answer 1

0.1524 arc seconds.

d=constant/p
where
"d" is distance to the star
"p" is the parallax (0.1 in your problem)
"constant" is the distance from the Sun to either Earth or Mars, 1AU for Earth or 1.524AU for Mars. (Pretty sneaky of them not to tell you that, but that is what it is.)

So from Earth the formula is:
d=1/0.1 which gives d=10 parsecs.
and from Mars it is:
d=1.524/p where we don't know what p should be be.

Since the stars are SOOooooo far away, the distance from Earth to one of them is pretty much the same as the distance from Mars to the same one, so we can safely say that d is the same from either Earth or Mars. Filling in 10 for d in the Mars equation gives:
10=1.524/p
Then solve for p
10p=1.524
p=1.524/10
p=0.1524

But you don't really need math if you picture the situation. It is a triangulation on a distant star. A right triangle with the Earth, Sun and star at the corners, with the Sun at the corner with the right angle, the Earth (or Mars) at the corner with an angle just barely less than 90 degreres at the other end of the shortest side of the triangle, and the hypotenuse the distance from planet to the star. The parallax is the really small angle at the star end of the triangle. The triangle is SOOOoooo long and skinny that if you double the small side, you pretty much double that small angle. (For fatter triangles this is not ture, but for ones as long and skinny as this one, it is true.) Or if you multiply the short side by some not too large number like 1.524, then you multiply the small angle by the same number.

Answer 2

I THINK it would be the same. The difference between viewing it from Earth and viewing it from Mars is negligible. What's a few AUs compared with a star light years away?

Sounds like your teacher is trying a trick question.

Answer 3

if the speed of light is a constant [d?] then it should be exactly the same..no matter where you measure it from