The shining little star is definitely not little, but it is really far. In fact, the stars are so far that the astronomers cannot measure them in the conventional units of measurement like Kilometers. How do they measure these distances then? They took the fastest moving thing in the universe which is light. These distances are measured in light-years which is how far light travels in an year. One light-year is 9.46 billion kms or 5.86 billion miles.
When the astronomers felt that light-years was not large enough they started using parsecs which is equal to 3.26 light-years.
Now that you know how to measure large distances in space, let us measure some of the nearest stars and galaxies.
- Moon sits really close at 356,410 kms away.
- The nearest planet is Earth’s twin sister Venus which is 40 million Kms ( 24 million miles away).
- Sun is 147 million km or 91 million miles away.
- The nearest star Proxima Centauri is 4.3 light-years away or 40 trillion km away.
- Andromeda, the nearest galaxy outside our own is 2.5 million light-years away.
- The furthest galaxy is 13 billion light-years away.
While it is interesting to know how far outer space is, have you wondered how scientists measure the distance? The method varies depending on how far the planet or the star is. For example, Moon is the nearest, so the distance to the moon is measured to within a few meters by bouncing laser beams off the mirrors left on the moon by astronauts. The Sun and the planets are measured by using radar beams. The nearby stars are observed for their brightness and distances are approximately estimated.
Distance from the galaxies is measured by looking for the nearest stars within that galaxy and estimate the distance by looking at the star’s brightness. The distance are not exact and usually off by a few billion light-years.
Did you know?
The most distant bright galaxies called quasars – are over 13 billion light-years away, that means if it takes light over 13 billion years to reach us, astronomers are looking at them as they were 13 billion years old and not as they look now. Wow!
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