Different kinds of GAlAXIES

Prepared by: CHRISALYN L. RUBIO

Galaxygalaxy- one of the very large groups of stars and other matter that are found throughout the universe

Galaxies are sprawling space systems composed of dust, gas, and countless stars.

The number of galaxies cannot be counted—the observable universe alone may contain 100 billion. Some of these distant systems are similar to our own Milky Way galaxy, while others are quite different.

Milky Way Galaxy - Our HomeMilky Way galaxy is the spiral galaxy we call home, as do roughly 100 billion other stars.

Sun is far from the center of the Galaxy, halfway to the edge of the Galaxy along the Orion spiral arm.

The Sun is revolving around the center of the Galaxy at a speed of half a million miles per hour, yet it will still take 200 million years for it to go around once.

MILKY WAY

The Andromeda Galaxy

Andromeda is the nearest major galaxy to our own Milky Way Galaxy

MILKY way Galaxy is thought to look much like Andromeda.

these two galaxies dominate the Local Group of galaxies.

diffuse light from Andromeda is caused by the hundreds of billions of stars that compose it

Andromeda is frequently referred to as M31 since it is the 31st object on Messier's list of diffuse sky objects

M31 is so distant it takes about two million years for light to reach us from there.

It remains unknown, including why the center contains two nuclei.

ANDROMEDA GALAXY

Spiral GalaxyResembling festive lights on a holiday wreath, this NASA/ESA Hubble Space Telescope image of the nearby spiral galaxy M74 is an iconic reminder of the impending season.

Bright knots of glowing gas light up the spiral arms, indicating a rich environment of star formation.

Messier 74, also called NGC 628, is a stunning example of a grand-design spiral galaxy that is viewed by Earth observers nearly face-on.

Spiral Galaxy

Its perfectly symmetrical spiral arms emanate from the central nucleus and are dotted with clusters of young blue stars and glowing pink regions of ionized hydrogen (hydrogen atoms that have lost their electrons).

These regions of star formation show an excess of light at ultraviolet wavelengths.

M74 is located roughly 32 million light-years away in the direction of the constellation Pisces, the Fish.

M74 is estimated home to about 100 billion stars, making it slightly smaller than our Milky Way.

M81 Galaxy is Pretty in Pinkgalaxy known as Messier 81, or M81

M81 is a "grand design" spiral galaxy, which means its elegant arms curl all the way down into its center

It is located about 12 million light-years away in the Ursa Major constellation and is one of the brightest galaxies that can be seen from Earth through telescopes.

The colors in this picture represent a trio of light wavelengths: blue is ultraviolet light captured by the Galaxy Evolution Explorer; yellowish white is visible light seen by Hubble; and red is infrared light detected by Spitzer.

The blue areas show the hottest, youngest stars, while the reddish-pink denotes lanes of dust that line the spiral arms. The orange center is made up of older stars.

The Sombrero Galaxy Sombrero Galaxy (also known as M104 or NGC 4594) is an unbarred spiral galaxy in the constellation Virgo.

It has a bright nucleus, an unusually large central bulge, and a prominent dust lane in its inclined disk.

The dark dust lane and the bulge give this galaxy the appearance of a sombrero.

The galaxy has an apparent magnitude of +9.0, making it easily visible with amateur telescopes.

The large bulge, the central supermassive black hole, and the dust lane all attract the attention of professional astronomers.

Sombrero Galaxy

Black Eye Galaxy

A spiral galaxy in the Coma Berenices constellation, Messier 64, the famous "Black Eye" galaxy or the "Sleeping Beauty galaxy," has a spectacular dark band of absorbing dust in front of the galaxy's bright nucleus.

It is well known among amateur astronomers because of its appearance in small telescopes.

Black Eye Galaxy

2MASX J00482185-2507365 occulting pair

The 2MASX J00482185-2507365 occulting pair is a pair of overlapping spiral galaxies found in the vicinity of NGC 253, the Sculptor Galaxy.

This pair of galaxies illuminates the distribution of galactic dust beyond the visible arms of a spiral galaxy.

The heretofore unexpected extent of dust beyond the starry limits of the arms, shows new areas for extragalactic astronomical study.The dusty arms extend 6 times the radii of the starry arms of the galaxy, and is shown silhouetted in HST images against the central and core sections of the background galaxy.

2MASX J00482185-2507365 occulting pair

Also known as NGC 123, this fascinating galaxy is dominated by millions of bright stars and dark dust, caught up in a gravitational swirl of spiral arms rotating about the center.Open clusters containing bright blue stars can be seen sprinkled along these spiral arms, while dark lanes of dense interstellar dust can be seen sprinkled between them.

Less visible, but detectable, are billions of dim normal stars and vast tracts of interstellar gas, together wielding such high mass that they dominate the dynamics of the inner galaxy.

Invisible are even greater amounts of matter in a form we don't yet know - pervasive dark matter needed to explain the motions of the visible in the outer galaxy.

Grand spiral galaxy

Grand spiral galaxy

Supernova 1987ATwo decades ago, astronomers spotted one of the brightest exploding stars in more than 400 years: a doomed star, called Supernova 1987A. A shock wave of material unleashed by the stellar blast is slamming into regions along the ring's inner regions, heating them up, and causing them to glow.

The ring, about a light-year across, was probably shed by the star about 20,000 years before it exploded.

The glowing ring is expected to become bright enough to illuminate the star's surroundings, providing astronomers with new information on how the star expelled material before the explosion

The most prominent feature in the image is a ring with dozens of bright spots.

The image was taken in December 2006 with Hubble's Advanced Camera for Surveys

The Whirlpool Galaxy

Also known as Messier 51a, M51a, or NGC 5194, the Whirlpool Galaxy is an interacting grand-design spiral galaxy located at a distance of approximately 23 million light-years in the constellation Canes Venatici.It is one of the most famous spiral galaxies in the sky.

The galaxy and its companion (NGC 5195) are easily observed by amateur astronomers, and the two galaxiesmay even be seen with binoculars. The Whirlpool Galaxy is also a popular target for professional astronomers, who study it to further understanding of galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions.

Whirlpool Galaxy

M81The big and beautiful spiral galaxy M81, in the northern constellation Ursa Major, is one of the brightest galaxies visible in the skies of planet Earth.

This superbly detailed view reveals its bright nucleus, grand spiral arms and sweeping cosmic dust lanes with a scale comparable to the Milky Way.

Hinting at a disorderly past, a remarkable dust lane runs straight through the disk, below and right of the galactic center, contrary to M81's other prominent spiral features.

The errant dust lane may be the lingering result of a close encounter between M81 and its smaller companion galaxy, M82.

Scrutiny of variable stars in M81 (aka NGC 3031) has yielded one of the best determined distances for an external galaxy -- 11.8 million light-years.

M81

Hoag's ObjectA non-typical galaxy of the type known as a ring galaxy, the appearance of Hoag's Object has interested amateur astronomers as much as its uncommon structure has fascinated professionals. Hoag's Object formed remains unknown, although similar objects have now been identified and collectively labeled as a form of ring galaxy. Genesis hypotheses include a galaxy collision billions of years ago and perturbative gravitational interactions involving an unusually shaped core.Hoag's Object spans about 100,000 light years and lies about 600 million light years away toward the constellation of Serpens.

On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older

Between the two is a gap that appears almost completely dark.

. The above photo taken by the Hubble Space Telescope in July 2001 reveals unprecedented details of Hoag's Object and may yield a better understanding

The astronomers had classified the galaxiesin the universe according to their:

1.shape

2.appearance

There are different galaxies that exist:

1. Elliptical galaxies 2.Spiralgalaxies 3.irregulargalaxies

Elliptical galaxy is considered as the most common type of galaxy. This type of galaxy ranges from a shape of almost spherical shape to a flattened disk shape.

which are almost spherical are designated as E0 galaxies. are less spherical are designated as E3 galaxies. This galaxy varies from small to very large galaxies.

Spiral galaxies are those which have bulge or nucleus from which there are several arms that may come out.

These arms are composed of dust and stars. Spiral galaxies that have no arms are designated as S0 galaxies.

how open the arms are;it is classified as S2, Sb and Sc.

Spiralgalaxies classified as SBa, SBb and SBc are those that have arms that extend from a bar a bar of stars in the nucleus

they are called as barred spirals. Irregular galaxies are those galaxies that are not elliptical or spiral in shapes.

Galaxies varies from their sizes:

1.dwarf galaxies 2.giant galaxies. smallest galaxy measured about 6600 light-years in diameter -less than a billion stars largest galaxy has a diameter of about 192000 light years in diameter.

REFERENCE:

http://hubblesite.org/newscenter/archive/releases/galaxy/http://inspiringthealtruisticmoment.com/http://www.nasa.govhttp://www.oddee.comhttp://expertscolumn.comhttp://science.nationalgeographic.com/http://www.astr.ua.eduhttp://imagine.gsfc.nasa.gov

THTHE ENDGOD BLESS <3