An Introduction to Basic Astronomy Concepts Quotes

“A star that appears blue is hotter, while a star that appears red is cooler. This is because the temperature of the star is related to its wavelength through Wien’s law, which says that temperature times wavelength is a constant. Higher temperature means shorter wavelength and lower temperature means longer wavelength. Red light has a longer wavelength than blue light, so blue stars are hotter and red stars are cooler.”
― Chris McMullen, An Introduction to Basic Astronomy Concepts

“The angular momentum of a planet in its orbit around the sun is L = mvr where L is the angular momentum, m is the mass of planet, v is the instantaneous speed of planet, and r is the instantaneous distance from the sun to the planet.”
― Chris McMullen, An Introduction to Basic Astronomy Concepts

“The gravitational constant equals G = 6.67 x 10-‍11 Nm2/kg2”
― Chris McMullen, An Introduction to Basic Astronomy Concepts

“Kepler’s third law, the square of the orbital period (T) of a planet is proportional to the cube of its semi-major axis (a).”
― Chris McMullen, An Introduction to Basic Astronomy Concepts

“Kepler’s second law, a planet sweeps out equal areas in equal times during its orbit around the sun.”
― Chris McMullen, An Introduction to Basic Astronomy Concepts