Astronomy Flashcards
(16 cards)
1
Q
What is the Universe?
A
- Collection of billions of galaxies
2
Q
What is a Galaxy?
A
- Collection of billions of stars
3
Q
What is the Milky Way?
A
- The galaxy our solar system is in
4
Q
What is the shape of orbits?
A
- Elliptical
5
Q
What are natural satellites and what are the shapes of their orbits
A
- Moons, planets: near circular orbit at constant speed
- Comets: very elliptical orbit, faster nearer the sun
6
Q
How are stars classified?
A
- OBAFGKM (oh be a fine guy kiss me)
- Hot to cold, Blue to Red
- Temperature determined by peak colour of star
7
Q
What is the evolution of sun-like stars?
A
- Nebula, main sequence star, red giant, white dwarf, black dwarf
8
Q
What is the evolution of heavy stars?
A
- Nebula, main sequence star, red supergiant, supernova, neutron star or black hole
9
Q
What is absolute magnitude?
A
- How bright a star would appear on earth if it were 10 parsecs away
10
Q
What is apparent magnitude?
A
- How bright a star appears on earth
11
Q
What is luminosity?
A
- Power irradiated by the surface of a star
12
Q
What are the arguments for the Big Bang?
A
- Increasing Red-shift and velocity of galaxies further away implies universe is expanding
- Cosmic Microwave Background is the remnants of the big bang
13
Q
What is Doppler shift?
A
- The apparent change in frequency of a wave caused by the relative motion between a source of the wave and the observer
- Due to the doppler effect
14
Q
What is red shift?
A
- Doppler shift to lower frequency (higher wavelength)
15
Q
What is blue shift?
A
- Doppler shift to higher frequency (lower wavelength)
16
Q
How is orbital speed calculated?
A
- 2π x orbital radius/orbital period
