The Milky Way or the Milky Way is a large spiral galaxy, which includes the Solar System, where the planet Earth revolves around the sun. The sun is only one of about 200 billion to 400 billion stars that make up the Milky Way galaxy.
The view of the Milky Way Galaxy from EarthThe Milky Way is observed from various corners of the earth. From earth, the Milky Way can be seen in the clear night sky and free of light pollution as a gray-white mist that extends around the arc of the sky with a dark groove in the center. In fact, the white fog is a collection of stars much denser and denser than in the rest of the sky and the dust and gas of space trapped in the orbital disk. The Milky Way’s arc forms an angle of about 60 degrees from the ecliptic (the disk of Earth’s orbit relative to the sun)
The Milky Way’s mist extends around the arc of the sky across 29 constellations of stars. The brightest and widest part is in the direction of Sagittarius and Scorpio, and indeed in that direction lies the center of the Milky Way. Here are the constellations that the Milky Way crosses to the southwest, starting from the galactic center:
- Sagittarius
- Scorpius
- Ara
- Norma
- Triangulum Australe
- Circinus
- Centaurus
- Musca
- Crux (paling selatan)
- Carina
- Vela
- Puppis
- Canis Major
- Monoceros
- Orion
- Gemini
- Taurus
- Auriga (posisi anticenter)
- Perseus
- Andromeda
- Cassiopeia (paling utara)
- Cepheus
- Lacerta
- Cygnus
- Vulpecula
- Sagitta
- Aquila
- Ophiuchus
- Scutum (lalu kembali ke Sagittarius)
Milky way galaxy dimension
The Milky Way’s stellar disk is approximately 100,000 light years in diameter (9.5×1017 km = 950,000,000,000,000 km) is estimated to have an average thickness of 1000 light years (9.5×1015 km = 95,000,000,000,000,000 km) The Milky Way is estimated to have at least 200 billion stars and possibly up to 400 billion stars The exact number depends on the number of low-mass stars, which is very difficult to determine. Outside the stellar disk lies a thicker disk of gas. Recent observations indicate that the Milky Way’s gas disk is about 12,000 light-years thick (1.1×1017 km = 110,000,000,000,000 km), which is twelve times the previously assumed value. As a guide to the physical size of the Milky Way, it can be assumed that if the diameter were made to 100 m, the Solar System, including the Oort Cloud, would be no more than 1 mm in size.
Galactic light radiates further, but this is limited by the orbits of the Milky Way’s two satellites, the Large and Small Magellanic Clouds, which have a perigalacticon of approximately 180,000 light-years (1.7×1018 km = 1,700,000,000,000,000,000,000 km). At this distance and beyond, the orbits of the surrounding object will be disturbed by the two Magellanic Clouds and the object will most likely be blown out of the Milky Way.
Recent calculations by the Very Long Baseline Array (VLBA) telescope show that the Milky Way is larger than previously known. The size of the last Milky Way is now believed to be similar to that of its closest galactic neighbor, the Andromeda galaxy. By using VLBA to measure the shearing of distant star formation regions when the Earth is orbiting opposite the sun, the scientists were able to measure the distances of these regions with less assumptions than previous measurement attempts. The most recent and more accurate estimate of the rotational speed (which then shows the dark matter contained within the galaxy) is 914,000 km/h. This value is much higher than the previous general value of 792,000 km/h. These results suggest that the total mass of the Milky Way is about three trillion stars, or about 50% larger than previously thought.
It is estimated that there are four main spiral arms and two smaller ones that originate from the center of the galaxy. The spiral arms are as follows.
Normal Arm
Scutum-Crux Lengan Arm
Sagittarius Arms
Orion Arm or Local Arm
Perseus Arm
Cygnus Arm or Outer Arm