What is the Milky Way galaxy?
The Milky Way galaxy contains the solar system which is where Earth is located. Officially there are eight planets orbiting the sun as of 2006 due to Pluto being announced as a dwarf planet by the International Astronomical Union.
Astronomers have noticed that most stars have at least one planet orbiting them.
-An exoplanet is a planet which orbits a star out with the solar system; they are also called extrasolar planets.
-Irradiance is the change of radiant energy per unit area.
-Transit is the action of passing across or through a place.
– The Drake Equation is an effort to summarise all the variables that would be relevant to establishing the number of intelligent evolutions that survive in the Milky Way galaxy.
The Drake Equation is:
N= R * fp * ne * fl * fi * fc * L
N=The number of broadcasting civilisation
R=Average rate formation of suitable stars (stars per year) in the Milky Way galaxy.
fp=Fraction of stars that form planets
ne=Average number of habitable planets per star
fl=Fraction of habitable planets (ne) where life emerges
fi=Fraction of habitable planets with life where intelligence evolves
fc=Fraction of planets with intelligent life capable of interstellar communication
L=Years a civilisation remains detectable
G is Newton’s gravitational constant – 6.673 x10^-11NM^2kG^-2
P is the orbital period of the exoplanet.
M is the mass of the star.
m is the mass of the exoplanet.
a is the orbital radius.
– The brightness drop is when there is a decrease in brightness and is used to determine the radius of a planet using the formula in the image below.