constellations

declination

used in astronomy to measure a celestial object's distance north or south of the celestial equator

right ascension

the celestial equivalent of longitude, measuring an object's position eastward along the celestial equator from the vernal equinox

sextant

a navigational instrument used to measure the angle between the horizon and a celestial body (sun, moon, or star) to determine a ship or aircraft's latitude and longitude

parallax

the apparent shift in an object's position when viewed from two different locations

Cepheid variable

a highly luminous, pulsating yellow supergiant star that expands and contracts regularly, causing its brightness to vary in a predictable cycle

luminosity

the total amount of light or energy an object emits per second

apparent magnitude

the magnitude of a celestial object as it is actually measured from the earth

Big Bang

the idea that the universe began as just a single point, then expanded and stretched to grow as large as it is right now

Polaris

the official name of the North Star or Pole Star

precession

the slow, wobbly, cone-shaped motion of a spinning object's axis

ecliptic

the imaginary plane containing the Earth's orbit around the Sun

Ptolemy

a Greco-Roman astronomer who developed the geocentric model of the universe, where Earth is stationary at the center

space-based telescopes

astronomical instruments placed in orbit above Earth’s atmosphere to observe the universe without interference from air distortion, light pollution, or absorption

Southern Cross

the smallest yet most prominent constellation in the southern sky, used as a key astronomical marker for finding the South Celestial Pole

stellar evolution

the process by which a star changes over its lifetime, spanning from its birth in a nebula to its final, dead state

red supergiant

an evolved, massive star (roughly 10–25+ solar masses) in the final stages of its life, characterized by a massive radius, low surface temperature (~3,500–4,500 K), and high luminosity

black hole

a region in space where gravity is so incredibly intense that nothing, not even light, can escape

galaxy

a massive, gravitationally bound system consisting of stars, stellar remnants, interstellar gas, dust, and dark matter

supernova

a colossal, luminous explosion marking the final, violent death stage of a massive star or the detonation of a white dwarf