Extra Exam Knowledge Flashcards
What is the Photosphere?
Surface of a star.
What is the Rock Line?
The snow line.
What is a Standard Ruler?
Physical size is known.
What Happens to the Energy in the Sun’s Core?
Radiation then convective.
What is the Temperature of the Sun’s Core?
16 million degrees Kelvin.
What is the Temperature of the Sun’s Corona?
1 - 2 million degrees Kelvin.
How did we Discover that the Milky Way wasn’t Alone?
Cepheid variables.
Which Celestial Bodies have Crescent Phases?
All planets and the moon.
What Effect does the Greenhouse Effect have on Earth?
Raises temperature by 34 degrees celsius.
How do we use Cepheid Variables to Measure Distance?
Measure period and use it to determine luminosity, use distance modulus equation to compare absolute and apparent magnitude and get a distance.
What is the Significance of a Cepheid Period?
Longer period = larger absolute luminosity.
What are the 4 Steps of Solar System Formation?
1) Large gas cloud collapses into disc
2) Material accumulates at centre
3) Planetesimals are formed
4) Sun begins fusion
What is a Dynamical Family of Asteroids?
Population of asteroid with similar properties, eccentricity, orbital inclination etc.
What Evidence is there that Comets are Loosely Held Together?
They are very small, so don’t have enough gravity to hold a spherical shape.
Who Invented Stellar Classification?
Annie Jump Cannon.
Who showed that Stars are Made of He and H?
Cecilia Payne-Gaposchkin.
What are 3 things Stellar Spectra can tell us?
Composition, magnetic field, temperature.
How do Supernova show that Expansion of the Universe is Speeding up?
Find distance and redshift of galaxies using supernova, create an expansion history of the universe, shows that the rate of universe expansion is increasing.
Where did Dark Energy Evidence come from?
Supernovae.
How did the Orbits of Mercury and Uranus Lead to Dark Matter Suggestions?
Uranus’ orbit doesn’t fit Newton solar system, Mercury precesses too much, could be missing matter or modified gravity - occurrences all over universe.
