image credit: Wikimedia Commons; image source; larger image
3C273 - Quasar in Virgo
In a telescope, object 3C273 will look like an ordinary star to you--it looked like an ordinary star to astronomers until the 1950s, too. In fact it is a quasar, or quasi-stellar radio source. These objects might look like stars, but they emit radio noise and are very distant--in the case of 3C273 above, nearly 2.5 billion light years away.
3C273 is bright enough to be seen with a very good backyard telescope. If you can find it, you can look back billions of years in time. Read 3C273 - Quasar in Virgo to learn how to find it in the night sky.
Login to Comment on this Item
Balloon Analogy in Cosmology
Quasars are the most distant objects we can see from Earth. Their light reaches us from billions of years in the past. Astronomers know how far they really are from us because the light we see is dramatically redshifted, meaning they are moving away from us astonishingly fast. See the Balloon Analogy in Cosmology to learn more about the expansion of the universe and how astronomers use redshift to measure distances in space. Find out how you can paste galaxies on a balloon and make a model of how the universe expands.