how big is the milky way galaxy?

Answer 1

100 thousand Light Years across.

Answer 2

The Milky Way is a barred spiral galaxy of a Local Group of galaxies within the Virgo Supercluster. 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.[citation needed] The galaxy is estimated to contain 200 billion stars but this number might reach 400 billion if small-mass stars predominate. As a guide to the relative physical scale of the Milky Way, if the galaxy were reduced to 130 km (80 mi) in diameter, the solar system would be a mere 2 mm (0.08 inches) in width. The Galactic Halo extends outward, but is limited in size by the orbits of the two Milky Way satellites, the Large and the Small Magellanic Clouds, whose perigalacticon is at ~180,000 light-years. New discoveries indicate that the disk extends much farther than previously thought.

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 Milky Way's visual absolute magnitude is −20.9

Although the Milky Way is but one of billions of galaxies in the observable universe (between 1×1010 and 8×1010), the Galaxy has special significance to humanity as the home of the solar system. The Greek philosopher Democritus (450 BC–370 BC) was the first known person to claim that the Milky Way consists of distant stars.

Composition and structure:
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The overall shape of the Milky Way is believed to be a barred spiral galaxy. It consists of a bar-shaped core region surrounded by a disk of gas, dust and stars. Within the disk region are several arm structures that spiral outward in a logarithmic spiral shape. The mass distribution within the Milky Way closely resembles the Sbc Hubble classification, which is a spiral-galaxy with relatively loosely-wound arms.It was only in the 1980s that astronomers began to suspect that the Milky Way is a barred spiral rather than an ordinary spiral, which observations in 2005 with the Spitzer Space Telescope have since confirmed, showing that the galaxy's central bar is larger than previously suspected.This argues for a classification of type SBbc (loosely wound barred spiral). In 1970 Gérard de Vaucouleurs predicted that the Milky Way was of type SAB(rs)bc, where the "rs" indicates a broken ring structure around the core region.

Answer 3

The Milky Way Galaxy is in the shape of a disk, 1,500 Light Years thick, and 150,000 Light years wide. Reference Ian Ridpath, ASTRONOMY, DK Publishing, NYNY.

Answer 4

I like gee_gee's answer, with this little bit added: the Milky Way Galaxy is continually expanding.....

Answer 5

Approximately 100,000 light years in diameter, and around 20,000 light years thick at the thickest point.

Answer 6

There is debate on this among the science world but they all agree that it is 150.000-200.000 light years across from end to end

Answer 7

pretty darn big

Answer 8

100,665,887,964,321 miles

Answer 9

1 000 000 000 000 000 000 meters.