Astrology Flashcards
What is the distance from Earth to the sun known as?
1AU (1 astronomical unit)
What is the value of 1AU in metres?
1.5x10^11 m
How long does it take light from the sun to reach Earth? In seconds & minutes.
500 seconds & 8 mins
What is a solar mass & its quantity?
The mass of the sun (2x10^ 30 kg)
Where is most of the mass of the solar system?
The sun, the mass of the sun is much greater than that of all the planets combined.
What word is used to describe the motion of the Sun?
Rotational
What equation is associated with the motion of the Sun?
L = Iω (L = angular momentum, I = moment of inertia & ω = angular frequency)
What word is used to describe the motion of a planet?
Orbital
What equation is associated with the motion of planets?
L = rp (L = angular momentum, r = radius of orbit & p = momentum where p=mv)
Where is most of the angular momentum of the solar system held?
The planets have a lot more angular momentum than the sun.
Why are stars so much fainter than the sun?
Due to the inverse square law.
What is the difference between luminosity & flux?
L = Luminosity ( J s^-1 ) is the light EMITTED per second
F = Flux ( J s^-1 m^-2 ) is the light RECIEVED per unit area per second
What is the definition & quantity of a light year?
Distance light travels in a vacuum in a year ~ 9.5x10^15 m
What angle does the sun subtend?
0.5 degrees
What is an arcminute?
1’ = 1/60 degree
