properties of stars

Electromagnetic Spectrum

The range of all types of electromagnetic radiation ordered from shortest wavelength/highest energy (gamma rays) to longest wavelength/lowest energy (radio waves).

Inverse Square Law

A law stating that light intensity decreases with the square of the distance from the source, where doubling the distance reduces intensity to a quarter.

Light-Gathering Power

The ability of a telescope to collect light, which depends on the diameter of the objective lens or mirror.

Resolving Power

The ability of a telescope to show fine detail, where a larger diameter results in sharper images.

Magnitude System

A system to measure brightness, with apparent magnitude showing how bright a star appears from Earth.

Apparent Magnitude

The brightness of a star as seen from Earth, where a smaller or negative number indicates a brighter star.

Absolute Magnitude

The true brightness of a star, defined as its brightness when viewed from a distance of 10 parsecs.

Parallax

A method used to measure distances to nearby stars based on their apparent shift as observed from different positions of Earth.

Cepheid Variable Stars

Stars that change brightness in a periodic manner, with the period related to their luminosity, useful for measuring nearby galaxy distances.

Blackbody Radiation

Idealized physical body that absorbs all incident electromagnetic radiation, showing characteristic curves of energy emitted at different wavelengths.