Astronomy Glossary

Stellar Objects

RR Lyrae stars are older, less luminous pulsating variables with periods 0.2-1 day, found in globular clusters and galactic halos.

Astronomy Concepts

Radiation pressure is the force exerted by electromagnetic radiation on matter, important for understanding stellar structure and astrophysical dynami...

Stellar Objects

A red giant is an evolved star that has exhausted core hydrogen and expanded dramatically while cooling, fusing hydrogen in a shell around an inert he...

Stellar Objects

Red supergiants are the largest stars by volume, evolved massive stars (>8 solar masses) with radii up to 1,000-1,500 times the Sun.

Units Distance

Redshift quantifies how much light has been stretched to longer (redder) wavelengths, serving as both a velocity and distance indicator.

Telescopes Equipment

Reflector telescopes use curved mirrors to collect and focus light, offering the most aperture per dollar.

Telescopes Equipment

Refractor telescopes use lenses to bend (refract) light to a focus, the classic "spyglass" design.

Astronomy Concepts

Right Ascension (RA, α) is celestial longitude—angular distance eastward along celestial equator from the vernal equinox, analogous to longitude on Ea...