New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Milky Way

The Milky Way is a barred spiral galaxy which forms part of the Local Group. Although the Milky Way is but one of billions of galaxies in the universe, the Galaxy has special significance to humanity as it is the home of the solar system. The term "milky" originates from the hazy band of white light appearing across the celestial sphere visible from Earth, which comprises stars and other material lying within the galactic plane. The galaxy appears brightest in the direction of Sagittarius, towards the galactic center. Relative to the celestial equator, the Milky Way passes as far north as the constellation of Cassiopeia and as far south as the constellation of Crux, indicating the high inclination of Earth's equatorial plane and the plane of the ecliptic relative to the galactic plane. The fact that the Milky Way divides the night sky into two roughly equal hemispheres indicates that the solar system lies close to the galactic plane. The main disk of the Milky Way Galaxy is about 80,000 to 100,000 light-years in diameter, about 250,000 to 300,000 light-years in circumference, and outside the Galactic core, about 1,000 light-years in thickness. It is composed of 200 to 400 billion stars.

Related Stories
 


Space & Time News

June 9, 2025

Supermassive black holes might naturally replicate the colossal energies of man-made particle colliders possibly even revealing dark matter offering a cosmic shortcut to discoveries that would ...
Astronomers have revealed new research showing that millions of new solar system objects are likely to be detected by a brand-new facility, which is expected to come online later this ...
Scientists have identified a new source of energetic particles near the Sun. These definitive observations were made by instruments aboard NASA's Parker Solar Probe, which detected the powerful phenomena as the spacecraft dipped in and out of the ...
Tracing the origin of an ultra-hot exoplanet: The chemical composition of WASP-121b suggests that it formed in a cool zone of its natal disc, comparable to the region of gas and ice giants in our Solar System. Methane indicates unexpected ...
Researchers have engineered a laser device smaller than a penny that they say could power everything from the LiDAR systems used in self-driving vehicles to gravitational wave detection, one of the most delicate experiments in existence to observe ...
A series of studies sheds light on the origins and characteristics of intermediate-mass black ...
The process of necrosis, a form of cell death, may represent one of the most promising ways to change the course of human aging, disease and even space travel, according to a new ...
A multi-sensor detection of an intense gamma-ray flash, which occurs when two lightning leaders collided, has been observed. Observations across a wide radiation spectrum enabled precise measurement of the electric current produced during this ...
Astronomers have explained how a galaxy cluster maintains its heat, despite emitting X-rays that cool the hot gas at its center. The group discovered the existence of a fast-moving, high-temperature ...
A team of international astronomers have discovered a new cosmic object emitting both radio waves and ...
A series of experiments support spectral data recently collected by the James Webb Space Telescope that found evidence that the icy surface of Jupiter's moon Europa is constantly changing. Europa's surface ice is crystallizing at different rates in ...
Scientists have observed anyons -- quasiparticles that differ from the familiar fermions and bosons -- in a one-dimensional quantum system for the first time. The results may contribute to a better ...

Latest Headlines

updated 12:56 pm ET