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Internet Search Results
What is a light-year and how is it used?? - NASA
A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More p recisely, one light-year is equal to 9,500,000,000,000 kilometers.
StarChild: The Milky Way - NASA
Our Galaxy is a spiral galaxy that formed approximately 14 billion years ago. Contained in the Milky Way are stars, clouds of dust and gas called nebulae, planets, and asteroids. Stars, dust, and gas fan out from the center of the Galaxy in long spiraling arms. The Milky Way is approximately 100,000 light-years in diameter.
StarChild: Galaxies - NASA
Galaxies A light-year is the distance light travels in one year. It is 9.5 trillion (9,500,000,000,000) kilometers. The size of a galaxy may be as little as a thousand light-years across or as much as a million light-years across.
Does the Sun move around the Milky Way?? - NASA
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 would look like "face-on" and the direction in which it would spin as viewed from that vantage point.
StarChild: The Milky Way - NASA
The Milky Way is over 100,000 light-years wide. It is called a spiral galaxy because it has long arms which spin around like a giant pinwheel. Our Sun is a star in one of the arms. When you look up at the night sky, most of the stars you see are in one of the Milky Way arms. Before we had telescopes, people could not see many of the stars very ...
Just How Big is this Place - NASA
How many light years is that? 4.21 light years If we hopped aboard our jet, how long would it take us to get to Alpha Centauri C? 40,000,000,000 hours How many years would that take? 4,566,210.0 years Are you packed yet? As an extra challenge, calculate the time it would take to reach Betelgeuse, a red giant located 600 light years away.
Redshift and Hubble's Law - NASA
Redshift and Hubble's Law For very far objects (beyond about 1 billion light-years) none of the above methods work. Scientists must move from direct observation to using observations in conjunction with a theory. The theory used to determine these very great distances in the universe is based on the discovery by Edwin Hubble that the universe is expanding.
Supernovae - NASA
Supernovae At large distances (up to about 1 billion light-years), astronomers can no longer use methods such as parallax or Cepheid variables. At such large distances, the parallax shift becomes too small and we can no longer even see individual stars in galaxies. Astronomers then turn to a series of methods that use "standard candles", that is, objects whose absolute magnitude is thought to ...
StarChild: Glossary - NASA
P PARSEC One parsec equals 3.26 light-years. PAYLOAD BAY The main body of the Space Shuttle where the payload, or cargo, is stored. PHOTOSYNTHESIS The process by which plants use carbon dioxide, nutrients, and sunlight to produce food. PHYSICIST A person who studies physics.
Parallax - NASA
Astronomers derive distances to the nearest stars (closer than about 100 light-years) by a method called stellar parallax. This method that relies on no assumptions other than the geometry of the Earth's orbit around the Sun. You are probably familiar with the phenomenon known as parallax. Try this. Hold out your thumb at arm's length, close one of your eyes, and examine the relative position ...
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