Summary of physical laws for astronomy
Use of scientific notation.
Units of measurement.
Important numbers:
- Speed of light: 3 x 108 m/s.
- Astronomical unit: 150 x 106 km.
- Temperature of Sun at photosphere: 6000 K.
Laws:
Here are some laws in .html format. A better version in .pdf format is also available.
- Distance d an object goes if it moves for time
t at speed v.
- Wavelength and frequency of light.
- Energy radiated by a blackbody per unit surface area per
unit time
- Energy radiated by a whole star per unit time, given the radius
and surface temperature of the star.
- Wavelength of peak intensity of blackbody radiation.
- Energy of a single photon
- Energy conservation
- Relation between luminosity of a star and its apparent brightness
when viewed at a distance d from the star.
- Mass, gravity, and motion. The total mass of a two star system as
determined from the size of the star's orbits (the semimajor axis
a) in AU and the orbital period P in years.
- Distance and parallax. The distance to a star in pc as determined
from its parallax angle in arc seconds.
ASTR 122 course home page
Updated 4 December 2007
Davison E. Soper, Institute of Theoretical Science,
University of Oregon, Eugene OR 97403 USA