I’ve been watching videos on YT about astronomy for years now. It’s fascinating. I never really ask questions and just believe what the experts have to say. But today I have decided to ask this question… A question that I’ve often ignored before.
So yesterday, I was watching this video and it mentioned a star/some celestial body. I don’t remember exactly, sorry. It said that the astronomers have calculated that this celestial body is about *13 billion lightyears* away from us and this many billions-something-huge.
It’s just so baffling to me. How do they do it? They’re calculating masses and distances of bodies that are supposedly soo sooo huge and far away, when we haven’t even actually managed to step on mars, yet. My point is, how are we capable of determining all this accurately when on a universal scale, we’re capable of pretty much nothing. How do these calculations work?
In: Physics
For distance: Trigonometry!
They use a method called stellar parallax. The look at the position of the star at one point in the year, and then view that same stars position at a different point in the year. By comparing position, we can triangulate the distance of the star from Earth. It isn’t dissimilar to how cartographers made maps centuries ago – if you have two angles of a triangle and the distance between them, you can calculate the other two sides of the triangle.
For mass, the calculations are complicated, but since we know the mass of the Earth, and the speed/distance of our orbit, we can look at the orbital radiuses and speed of other objects and plug those into our equations to determine their mass.
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