What is the shape of the Milky Way galaxy?

Question

and can someone please describe any motion that it may have, and its age?

Answer 1

CHEESE!!!!!!]] 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. Democritus (450 BC–370 BC) was the first known person to claim that the Milky Way consists of distant stars.

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 [1]. 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 in) in width. The Galactic Halo extends out to 250,000 to 400,000 light-years in diameter. As detailed in the Structure section below, new discoveries indicate that the disk extends much farther than previously thought.

The Milky Way's absolute magnitude, which cannot be measured directly, is assumed by astronomical convention to be −20.5, although other authors give an absolute magnitude of -21.3.

Structure
As of 2005, the Milky Way is thought to comprise a large barred spiral galaxy of Hubble type SBbc (loosely wound barred spiral).[2][3] As of 2006, the Milky Way's mass is thought to be about 5.8×1011 M☉[4] comprising 200 to 400 billion stars. Its integrated absolute visual magnitude has been estimated to be -21.3.[citation needed]

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.[5]

The galactic disk, which bulges outward at the galactic center, has an estimated diameter of about 100,000 light-years. The distance from the Sun to the galactic center is now estimated at 26,000 ± 1400 light-years while older estimates could put our parent star as far as 35000 light-years from the central bulge.

The galactic center harbors a compact object of very large mass (named Sagittarius A*), strongly suspected to be a supermassive black hole. Most galaxies are believed to have a supermassive black hole at their center.

As is typical for many galaxies, the distribution of mass in the Milky Way is such that the orbital speed of most stars in the galaxy does not depend strongly on its distance from the center. Away from the central bulge or outer rim, the typical stellar velocity is between 210 and 240 km/s.[6] Hence the orbital period of the typical star is directly proportional only to the length of the path traveled. This is unlike in the solar system where different orbits are also expected to have significantly different velocities associated with them, and is one of the major pieces of evidence for the existence of dark matter.

The galaxy's bar is thought to be about 27,000 light-years long, running through the center of the galaxy at a 44 ± 10 degree angle to the line between our sun and the center of the galaxy. It is composed primarily of red stars, believed to be ancient. The bar is surrounded by a ring called the "5-kpc ring" that contains a large fraction of the molecular hydrogen present in the galaxy and most of the Milky Way's star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way[7]

Each spiral arm describes a logarithmic spiral (as do the arms of all spiral galaxies) with a pitch of approximately 12 degrees. There are believed to be four major spiral arms which all start at the Galaxy's center. These are named as follows, according to the image at right:

* 2 and 8 - 3kpc and Perseus Arm
* 3 and 7 - Norma and Cygnus Arm (Along with a newly discovered extension - 6)
* 4 and 10 - Crux and Scutum Arm
* 5 and 9 - Carina and Sagittarius Arm

There are at least two smaller arms or spurs, including:
* 11 - Orion Arm (which contains the solar system and the Sun - 12)

Outside of the major spiral arms is the Outer Ring or Monoceros Ring, a ring of stars around the Milky Way proposed by astronomers Brian Yanny and Heidi Jo Newberg, which consists of gas and stars torn from other galaxies billions of years ago.

The galactic disk is surrounded by a spheroid halo of old stars and globular clusters approximately 250,000 to 400,000 light-years in diameter[8]. While the disk contains gas and dust obscuring the view in some wavelengths, the spheroid component does not. Active star formation takes place in the disk (especially in the spiral arms, which represent areas of high density), but not in the halo. Open clusters also occur primarily in the disk.

Most of the mass of the Milky Way is thought to be dark matter, forming a dark matter halo of an estimated 600-3000 billion solar masses (M☉) which is concentrated towards the Galactic Center.[3]

Recent discoveries have given added dimension to our knowledge of the structure of the Milky Way. With the discovery that the disc of the Andromeda Galaxy (M31) extends much further than previously thought,[9] the possibility of the disk of the Milky Way extending further is apparent, and this is supported by evidence of the newly discovered Outer Arm extension of the Cygnus Arm.[10] With the discovery of the Sagittarius Dwarf Elliptical Galaxy came the discovery of a ribbon of galactic debris as the polar orbit of Sagittarius and its interaction with the Milky Way tears it apart. Similarly, with the discovery of the Canis Major Dwarf Galaxy, a ring of galactic debris from its interaction with the Milky Way encircles the galactic disk.

On January 9, 2006 Mario Juric and others of Princeton University announced that the Sloan Digital Sky Survey of the northern sky has found a huge and diffuse structure (spread out across an area around 5,000 times the size of a full moon) within the Milky Way that does not seem to fit within our current models. The collection of stars rises close to perpendicular to the plane of the spiral arms of the Milky Way. The proposed likely interpretation is that a dwarf galaxy is merging with the Milky Way. This galaxy is tentatively named the Virgo Stellar Stream and is found in the direction of Virgo about 30,000 light-years away.

You could get more information from the link below...

Answer 2

It's believed that the Milky Way is a barred galaxy (shaped something like the letter "S" with a bulge in the middle). Until recently it was thought to have more arms, giving it a pinwheel appearance. Thus older books and sources will picture it as a spiral galaxy, and newer sources will depict it as a barred galaxy.

Answer 3

the milkyway is a spiral galaxy. The closest full size galaxy, andromeda, gives us an idea of how it would look if we were outside of our galaxy looking at it. As a whole, it moves away from most other galaxies as the universe expands. Also the stars that make up the galaxy are orbiting around the center of our galaxy so it is spinning as it flys through space as well

Answer 4

No it isn't. There are other spiral galaxies in the Universe, and in fact, the galaxy of Andromeda is another example of a spiral galaxy. There are numerous spiral galaxies in the Universe.

Answer 5

Only namowal had it right. Recent analysis of the Sloan survey data showed that the Milky Way isn't a regular spiral galaxy like Andromeda, but a barred spiral.
Check out http://www.space.com/php/multimedia/imagedisplay/img_display.php?pic=050816_milky_way_02.jpg&cap=An+artist%27s+rendering+of+the+Milky+Way+and+its+central+bar+structure%2C+with+the+Sun%27s+position+noted.+NASA%2FJPL-Caltech%2FR.+Hurt+%28SSC%2FCaltech%29
for a rendition.

Answer 6

the milky way is a spiral galaxy and is not too old (by science standards) it is constantly moving through out the universe because of the big band and Hubble's law.

Answer 7

Spiral

Answer 8

i think that the it is shaped like a spiral, or a pinwheel. im not sure about the motion or age.

Answer 9

milkyway galaxy is a spiral galaxy

Answer 10

milky way is different and galaxy is different.\dont be lazy google it