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Bookmark or Share- What is the biggest star we know? - NASAThe star is 25,000 light-years away from Earth. Despite this great distance, the star would be visible to the naked eye if it were not for all the dust between it and the Earth. UPDATE! As of January 2009, we now know about some other really big stars. One is called Eta Carinae.
- Does the Sun move around the Milky Way? - NASAThe Sun (and, of course, the rest of our solar system) is located near the Orion arm, between two major arms (Perseus and Sagittarius). The diameter of the Milky Way is about 100,000 light-years and the Sun is located about 28,000 light-years from the Galactic Center. You can see a drawing of the Milky Way below which shows what our Galaxy ...
- What is a light-year and how is it used?? - NASAThe light-year we have already defined. The parsec is equal to 3.3 light-years. Using the light-year, we can say that : The Crab supernova remnant is about 4,000 light-years away. The Milky Way Galaxy is about 150,000 light-years across. The Andromeda Galaxy is 2.3 million light-years away.
- Redshift and Hubble's Law - NASAThe exact value of the Hubble constant is still somewhat uncertain, but is generally believed to be around 65 kilometers per second for every megaparsec in distance. (A megaparsec is given by 1 Mpc = 3 x 10 6 light-years). This means that a galaxy 1 megaparsec away will be moving away from us at a speed of 65 km/sec, while another galaxy 100 ...
- Parallax - NASAFrom the image above, you can see that by knowing the size of Earth's orbit and measuring the angles of the light from the star at two points in the orbit, the distance to the star can be derived. The farther the star is, the smaller the angles. For stars more than about 100 light-years from Earth, we cannot measure any shift and the method fails.
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