Introduction to Cosmology and Kepler's Laws

These flashcards cover key concepts in cosmology and Kepler's laws, from definitions of fundamental terms to essential laws governing planetary motion.

Cosmology

The study of the universe from the earliest times to the present.

Observable Universe

The part of the universe that we can see, limited by how far light has traveled.

Fundamental Dimensions

The three basic dimensions in physics: mass (M), length (L), and time (T), which can be expressed in different units.

Newton's Gravitational Constant (G)

A fundamental constant that describes the strength of gravity, with a value of 6.6738×10^-11 m³ kg^-1 s^-2.

Speed of Light (c)

The speed at which light travels in vacuum, approximately 2.9979×10^8 m/s.

Planck's Constant (ħ)

A fundamental constant in quantum mechanics, valued at 1.0546×10^-34 kg m²/s.

Kepler's First Law

Planets move around the sun in elliptical orbits with the sun at one focus.

Kepler's Second Law

A line from a planet to the sun sweeps out equal areas in equal times.

Kepler's Third Law

The square of the periods of any two planets is proportional to the cube of the semi-major axis of their respective orbits.

Dimensional Analysis

A method used to deduce relationships between physical quantities without detailed calculations.

Astrophysics

A branch of astronomy that focuses on the physical properties and behavior of celestial objects.

Mass of the Earth (Mo)

A standard unit of mass equivalent to 5.974x10^24 kg often used in astrophysics.

Astronomical Unit (AU)

The average distance from the Earth to the sun, approximately 1.496×10^11 m.

Parsec

A distance measurement in astronomy equal to about 3.26 light-years.

Galactic Scale

Refers to the larger structures in the universe, such as galaxies and clusters of galaxies.

Gravity

One of the four fundamental forces of nature, governing the attraction between masses.