Medellín, September 2009
What is a galaxy
A galaxy is a massive system of star gas clouds, planets, dust, and gravitationally bound dark matter. The number of stars forming a galaxy varies from dwarfs, with 10 7 , to the giant, with 10 12 stars. Within a galaxy as there are substructures nebulae, star clusters and the star systems.
Historically, galaxies have been classified according to their apparent shape (morphology visual, as it has been appointed). A common form is the elliptical galaxy, as the name implies, has the light profile of an ellipse. Spiral galaxies are circular, but with curved arms wrapped structure powder. Galaxies with irregular or unusual shapes are called irregular galaxies, and are typically the result of disruptions caused by the gravitational pull of neighboring galaxies.
CH TMLXC What is the Milky Way
The Milky Way is the galaxy where is the Solar System. According to the observations, has a mass of 10 12 solar masses and has a spiral shape, with an average diameter of 100,000 light years is estimated to contain between 200 and 400 billion stars The distance from the Sun to the center of the gaLaxia is around of 27,700 light years. The Milky Way is part of a group of about forty galaxies called the Local Group and is the second biggest and brightest after Andromeda galaxy.
name Milky Way comes from Greek mythology and Latin means way milk. That is, in fact, the appearance of the band of light around the sky, and so claims to Greek mythology, explaining that it is spilled milk from the breast of GodHera, Zeus's wife, who refused to nurse the little Hercules, having been the result of an affair.
Note. Astronomical distances.
1AU is the distance from Earth to the Sun and amounts to 149'600, 000 km.
1 light year = 9.46x10 = 1 to 12 63241 km = 0.3066 AU = Parsec
1 parsec = 206265 AU
; On a cloudless night land sand seen as a blurred band of white light around the entire celestial sphere . The visual phenomenon of the Milky Way is due to stars and other materials that are on the plane of the galaxy.
The Milky Way appears brightest in the direction of the constellation Sagittarius, toward the center of the galaxy. Air pollution on our planet has led to the Milky Way is almost not visible. However, in the field on a starry night, the Milky Way looks like a ring around the night.
Figure 1
Who was Edwin Hubble
Edwin Powell Hubble (Born in Missouri on 28/11/1889 and died in Pasadena, California on 9/28/1953) , was one of the scientists with a greater contribution in past to expand our vision of the universe. Indeed, in the early twentieth century, most astr & oacutee; nomos thought the Milky Way Galaxy was the universe, with an area of only a few hundred light years. At the beginning of the second decade of last century, Harlow Shapley showed that the galaxy had an area of about 100,000 light years, and Henrietta Leavitt was established that large and small clouds Magellan (two companion galaxies to our own, visible from the southern hemisphere) were outside the borders of the Milky Way. However it was still important about the nature of objects known as nebulae emitting a diffuse light. CH TMLXC
Between 1923 and 1924, Hubble used the largest telescope then existing in the world, the 100-inch Hooker, Mont. Wilson, to examine the Andromeda nebula. As a fledgling Galileo telescope, more than three centuries earlier, had managed to turn the diffuse light of the Milky Way into stars, Hubble discovered and photographed with the powerful astrograph of the telescope, the stars that made an arm of the Andromeda spiral nebula outside our galaxy. Were the first pictures of objects outside our galaxy.
CAmong the stars HTMLXC spiral arm of Andromeda, Hubble found some Cepheids, and applying the law of Henrietta Leavitt, calculated the distance of the nebula at 800,000 light years. Too far, almost beyond our imagination. This will confirm what some astronomers had suspected: the milky spots of the distant nebula was revealed as a galaxy similar to ours. However, the Andromeda Nebula is one of the most distant galaxies near the limits of our Milky Way.
If weather conditions permit and if the light from the towns and cities not hinder, the Milky Way is observable each night of the year, anywhere on Earth. It's like a milky cloud, forming a ring on the celestial sphere. Figure two (2) shows us how to see the Milky Way. Who does not know about this subject you can imagine that spot are clouds of water vapor, dimly lit in the darkness of night. In memory of this scientist built the Hubble Space Telescope.
The Hubble Space Telescope (HST for short) is a robotic telescope located at the outer edges of the atmosphere in orbit circulate around the Earth at 593 km. above sea level, with an orbital period between 96 and 97 min. It was launched on April 24, 1990 in mission STS-31 and as a joint project of NASA and ESA .
http://www.todoelsistemasolar.com.ar/_vlacte. jpg
Figure 2
How the Milky Way consists
As indicated, consists ofstars, planets, comets, rocks, space dust, gases, perhaps
matter and dark energy, although this level is a plausible hypothesis. As shown in Figure 1, the Milky Way has three major arms: Orion, Perseus and Sagittarius, lower arm, several globular clusters and a nucleus or bulge main in which the density of stars is maximum and is presumed to be at least one black hole superrmasivo.
Our solar system is in the arm Orióny estimated the distance to the center of the galaxia is of 28000 al.
sizing To address this distance, remember that 28000 to = 1.8 x 10 9
AU. The Sun's diameter is 1'392, 000 km = 0.0093 AU.
The distance from Earth to the Sun is 1 AU.
The diameter of the Earth SS12, 713 km = 0.000085 AU
Therefore, in the distance Sun - Galactic Center
fit
1.8 x 10 9
/ 0.0093 = 1,935 10 ^ 11 diaeters solar. representásemos If the Sun as a soccer ball from 0.3 m in diameter, located in the Alpujarra (center of Medellin), the center of the galaxy, drawn estaríaa scale
11 1,935 x 10 x 0.3 m
= 0.58 x 10 11 m, ie 0.58 x 10 ^ 8 km = 58,000,000 miles. But far from Earth to Mars. is talk of a possible alignment Earth, Sun, Galaxy Center for the December 21, 2012. It is said that ancient cultures as the Mayans had predicted. This would have to prove it, because the knowledgents that are on the Milky Way are too recent to accept that ancient societies that left no one truly scientific legacy may have to make such prediction. Actually, using an astronomical program, such as World Wide Telescope, this alignment is not going to take that Diaye probably will not ever. However, considering that the bulge of the galaxy is too great, if you may have an alignment, Earth-Sun - galactic bulge, although the alignment does not aim at the center of it.
Finally, all the stars and objects that can be observedar to clean eye from Earth belong to the Milky Way, except for some objects found in the constellation of Orion.
The
Andromeda Galaxy, also known as Messier Object 31, Messier 31 or NGC 224 is a galaxy and giant spiral, one that is in the neighborhood of lthe Milky Way. It is the object visible to the naked eye further from the Earth (although some claim to see with the naked eye M · 33 is a bit further away)
deep Universe
Our galaxy is located in a group called the Local Group. is called Local Group the group of galaxies in that is ours, Milky Way. is dominated by two giant spiral galaxies,
Andromeda and the Milky Way. The rest of galaxies, about 30, are smaller, many of which are satellite galaxies of a major. free galaxies revolve around the center of mass
the group, between Andromeda and the Milky Way. In addition, our Local Group is contained within the Virgo supercluster, into whose center of gravity addresses Loc Groupal. Within the Local Group, there are three known systems dominated by massive galaxies that act as centers of gravity, and several galaxies acting as satellites:
The solar system is at the VI a galaxy. The Milky Way in the Local Group
. The Local Group is contained in the Virgo Supercluster and still not over the universe. Everything beyond the Milky Way and Local Group, is called the deep space.
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"The
Virgo Supercluster or Local Supercluster is the supercluster of galaxies containing the Local Group and é l, our galaxy, theMilky . It's shaped like a flat disk with a diameter of 200 million of light years. The supercluster contains about 100 groups and clusters of galaxies and is dominated by the CHTMLX C Virgo cluster, located near its center. The Local Group is located near the edge of the Virgo cluster, which is drawn "(1).
Earth, knowledge center is a tiny particle in a universe, we can not understand and whose concept can be likened to the mathematical concept of infinity.
(1) http://es.wikipedia.org/wiki/Supercúmulo_de_Virgo
Juan Fernando Sanin E
