Galactic Center - Wikipedia
The Milky Way is the galaxy that contains our Solar System. The name describes the galaxy's The oldest stars in the Milky Way are nearly as old as the Universe itself and thus probably formed shortly after the Dark Ages of . The Milky Way consists of a bar-shaped core region surrounded by a disk of gas, dust and stars. An article that identifies the location of our Solar System in the Milky Way Galaxy. The Milky Way Galaxy is organized into spiral arms of giant stars that The International Space Station's port truss segments, solar arrays and parts of the Kibo lab's Exposed Facility are in view. Read Next Related Article.
Where is Earth in the Milky Way? - Universe Today
Artist's conception of the spiral structure of the Milky Way with two major stellar arms and a bar  Spitzer reveals what cannot be seen in visible light: The mass distribution within the Milky Way closely resembles the type Sbc in the Hubble classificationwhich represents spiral galaxies with relatively loosely wound arms.
Galactic quadrants Main article: Galactic quadrant A galactic quadrant, or quadrant of the Milky Way, refers to one of four circular sectors in the division of the Milky Way.
In actual astronomical practice, the delineation of the galactic quadrants is based upon the galactic coordinate systemwhich places the Sun as the origin of the mapping system.
This value is estimated using geometric -based methods or by measuring selected astronomical objects that serve as standard candleswith different techniques yielding various values within this approximate range.
Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way. The diameter of each of the bubbles is about 25, light-years 7. Spiral galaxy Outside the gravitational influence of the Galactic bars, the structure of the interstellar medium and stars in the disk of the Milky Way is organized into four spiral arms.
Observed normal lines and extrapolated dotted lines structure of the spiral arms of the Milky Way, viewed from "north" of the galaxy. Stars generally move clockwise in this view. The gray lines radiating from the Sun's position upper center list the three-letter abbreviations of the corresponding constellations.
Milky Way Galaxy: Facts About Our Galactic Home
Universe Today And yet, our galaxy is only a middle-weight when compared to other galaxies in the local Universe. Andromeda, the closest major galaxy to our own, is about twice as large as our own. It measureslight years in diameter, and has an estimated billion stars within it. Structure of the Milky Way: If you could travel outside the galaxy and look down on it from above, you'd see that the Milky Way is a barred spiral galaxy.
For the longest time, the Milky Way was thought to have 4 spiral arms, but newer surveys have determined that it actually seems to just have two spiral arms, called Scutum—Centaurus and Carina—Sagittarius. The spiral arms are formed from density waves that orbit around the Milky Way — i. As these density waves move through an area, they compress the gas and dust, leading to a period of active star formation for the region.
However, the existence of these arms has been determined from observing parts of the Milky Way — as well as other galaxies in our universe. In truth, all the pictures that depict our galaxy are either artist's renditions or pictures of other spiral galaxies, and not the result of direct observation of the whole.
- Galactic Center
- The Location of the Solar System in the Milky Way Galaxy
Until recently, it was very difficult for scientists to gauge what the Milky Way really looks like, mainly because we're inside it. It has only been through decades of observation, reconstruction and comparison to other galaxies that they have been to get a clear picture of what the Milky Way looks like from the outside. Universe Today From ongoing surveys of the night sky with ground-based telescopes, and more recent missions involving space telescopes, astronomers now estimate that there are between and billion stars in the Milky Way.
They also think that each star has at least one planet, which means there are likely to be hundreds of billions of planets in the Milky Way — billions of which are believed to be the size and mass of the Earth.
As noted, much of the Milky Way's arms is made up of dust and gas. Our galaxy is roughlylight years across, and we can only see about 6, light years into the disk in the visible spectrum. A Traveler's Guide ] Unlike a regular spiral, a barred spiral contains a bar across its center region, and has two major arms. The Milky Way also contains two significant minor arms, as well as two smaller spurs. One of the spurs, known as the Orion Arm, contains the sun and the solar system.
The Orion arm is located between two major arms, Perseus and Sagittarius. The Milky Way does not sit still, but is constantly rotating.
As such, the arms are moving through space. The sun and the solar system travel with them. Even at this rapid speed, the solar system would take about million years to travel all the way around the Milky Way. As material passes through the dense spiral arms, it is compressed and this triggers more star formation," said Camargo. Our galaxy is surrounded by an enormous halo of hot gas that extends for hundreds of thousands of light-years.
The gas halo is estimated to be as massive as all of the stars in the Milky Way. Like the galaxy itself, the halo is spinning rapidly. This very wide-field view of the Milky Way shows the extent of the million-star VISTA infrared image of the center of the galaxy delineated by red rectangle.
This hot gas reservoir is rotating as well, just not quite as fast as the disk.
Where is Earth in the Milky Way?
New stars are constantly formed within the arms. These arms are contained in what is called the disk of the galaxy.
It is only about 1, light-years thick. The heart of the Milky Way is crammed full of gas, dust, and stars. The bulge is the reason that you can only see a small percentage of the total stars in the galaxy. Dust and gas within it are so thick that you can't even peer into the bulge of the Milky Way, much less see out the other side.