Astrophysics
Black hole
A black hole is a region of spacetime where gravity is so intense that nothing—not even light—can escape. Predicted by general relativity and supported by extensive observations, black holes span a wide range of masses from stellar remnants to supermassive objects at galactic centers. Direct imaging, stellar dynamics, X-ray observations, and gravitational-wave detections provide multiple, independent lines of evidence for their existence.
Dark energy
Dark energy is the dominant component of the universe’s energy budget and the driver of its accelerated expansion, inferred from astronomical observations in the late 1990s. In the standard ΛCDM cosmological model it contributes roughly 68–70% of the total cosmic energy density and behaves like a component with negative pressure, closely approximated by a cosmological constant with equation-of-state parameter w ≈ −1. Despite extensive observational constraints, its physical nature remains unknown.
Dark Matter
Dark matter is a form of matter that does not interact with electromagnetic radiation, making it invisible to current detection methods. Its existence is inferred from gravitational effects on visible matter, such as the rotational speeds of galaxies and gravitational lensing.
General relativity
General relativity is a 1915 theory of gravitation developed by Albert Einstein that models gravity as the curvature of spacetime produced by energy and momentum. It underpins modern astrophysics and cosmology, predicting phenomena such as black holes, gravitational waves, gravitational lensing, and the expansion of the universe, and has been repeatedly confirmed by high-precision experiments and observations.
Magnetosphere
A magnetosphere is the region of space around an astronomical body where its magnetic field dominates the motion of charged particles. Shaped by interaction with ambient plasma such as the solar wind, magnetospheres include distinct boundaries and current systems, regulate the entry of energy and particles, and play a central role in space weather and atmospheric evolution.
Quasar
A quasar is an extremely luminous active galactic nucleus powered by a supermassive black hole, emitting energy across the electromagnetic spectrum and often outshining its host galaxy.
Supernova
A supernova is a stellar explosion that briefly rivals the brightness of an entire galaxy, dispersing heavy elements and often leaving behind a compact remnant. Astronomers distinguish thermonuclear Type Ia supernovae, which explode from white dwarfs in binary systems, from massive-star core‑collapse events (Types II, Ib, and Ic). Supernovae are central to nucleosynthesis, cosmic‑ray acceleration, and cosmology.