Laws Used

Overview

To calculate for the existence of certain planets, we must look at and understand different rules of space. Here are a couple that are especially relevant:

Kepler's First Law

Planets do not orbit in circles, but in elliptical motions, where the star is at one focus. By recognising this elliptical pattern, we can track the pattern of different orbits.

Kepler's Second Law

Planets move over equal areas of space over equal areas of time. Essentially, the closer a planet is to its star, the faster it will move along the orbit. By using this, we can further our understanding of orbits so that we can better predict where/if planets exist.

Kepler's Third Law

T^2=D^3 where T is time it takes for one complete orbit to occur and D is a planet's semi-major axes of their orbits. We use this formula to predict an exoplanets' distance from its star and to track its orbit.

Newton's Universal Law of Gravitation

F = G(m1*m2)/r^2, where F is the gravitational force between two objects, G is the gravitational constant, represented by 6.67430*10^-11, m1 and m2 are the masses of the two objects, and r is the distance between their centres of masses. This force proves why planets (and us) actually pull on our stars as well.

Speed of a Planet

The speed of an orbiting planet can be calculated using the formula: v=sqroot(GM/r) where v is velocity, G is gravitational force, M is mass, and r is the radius of the orbit. When we know the speed of planets, we can calculate when they will be at an approximate location to try and photograph them.

Doppler Shift

If an approaching frequency is fa, the speed of sound is a, and the velocity of a source moving closer to you is u, and the frequency of the wavelength at source is f, then we can represent the Doppler effect using the equation fa = [f * a] / [a - u]. If an object is moving away, we use the formula fl = [f * a] / [a + u], where all variables are the same except fl represent the leaving frequency. This explains the change in frequency used as an indication of a wobbling star.

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