Jupiter's Great Red Spot: The Solar System's Largest Storm
Jupiter's Great Red Spot is a persistent anticyclonic storm wider than Earth. It is the largest known atmospheric vortex in the solar system.
Space, Astronomy and Cosmology
38 glossary terms
Space, astronomy, and cosmology ask three overlapping questions: what is out there, how did it get there, and where is it going? The terms in this section describe stars and galaxies, the instruments that observe them, and the large-scale frameworks astronomers use to interpret what they see. You will find definitions for the everyday (heliocentric model, absolute magnitude) alongside ideas still under active debate, including dark matter and the cosmic expansion. Taken together, these terms give you the footing to read a modern observatory paper or follow a mission update without losing the thread.
Yellow Dwarf Stars: Traits, Lifespan, and Habitability
Yellow dwarf stars are G-type main-sequence stars with surface temperatures of 5,200 to 6,000 K. The Sun is the best-known example.
Gravitational Lensing: How Gravity Bends Light in Space
Gravitational lensing is the bending of light by gravity, turning massive objects into natural telescopes that reveal the hidden structure of the universe.
Hubble's Law: The Equation Behind Cosmic Expansion
Hubble's law is the observation that distant galaxies move away from Earth at speeds proportional to their distance.
Interstellar Medium: Gas, Dust, and the Raw Stuff of Stars
The interstellar medium is the gas, dust, and energetic particles filling the space between stars, supplying raw material for new stars and planets.
Geostationary Orbit: Why Satellites Appear to Stand Still
A geostationary orbit is a circular path 35,786 km above Earth's equator where satellites match the planet's rotation, appearing motionless from the ground.
Heliocentric Model: How the Sun Replaced Earth at the Center
The heliocentric model places the Sun at the center of the solar system. First proposed in ancient Greece, it took 1,800 years to prove.
Gravitational Wave Detection: How LIGO Reads Ripples in Spacetime
Gravitational wave detection uses laser interferometry to measure spacetime ripples from merging black holes and neutron stars.
Dark Matter Detection: How Physicists Hunt the Invisible
Dark matter detection techniques are the experimental methods physicists use to search for dark matter, a form of matter invisible to all instruments except through its gravitational pull.
Exoplanet Transit Method: Finding Worlds by Starlight
The exoplanet transit method detects planets beyond our solar system by measuring the small, periodic dip in starlight when a planet crosses in front of its host star.