# What are key formulas to remember in Astronomy?

What are key formulas to remember in Astronomy?

The formula for the average distance from Earth to the Sun is 1 astronomical unit (AU) = 93 million miles.

The formula for the force of gravity between two objects is F = G _ (m1 _ m2) / r2, where G is the gravitational constant, m1 and m2 are the masses of the two objects, and r is the distance between them.

The formula for the escape velocity of an object is v = sqrt(2GM/r), where G is the gravitational constant, M is the mass of the object, and r is the distance from the object's center of mass.

The formula for the wavelength of light is λ = c/f, where c is the speed of light and f is the frequency of the light.

The formula for the angular size of an object is θ = 2*arctan(d/2D), where d is the diameter of the object and D is the distance from the observer to the object.

The formula for the magnitude of an object is m = -2.5 * log(L/L0), where L is the luminosity of the object and L

Nebula: a cloud of gas and dust in outer space.