Science of Stargazing (FoS)

As a stargazer, you will sometimes be asked how far you can see with your telescope. The answer is “billions of light-years” if you are looking at a quasar. About a dozen of these strange, energetic objects are visible in a small telescope, and while they don’t look much different than stars, they are remarkable because they lie at distances that a...

This month you learn about Type Ia supernovae, fearsome events that call attention to themselves over millions of light years and help astronomers estimate the size of the universe. And you learn about the “cosmic distance ladder” by which we try to understand the scale of the universe from our solar system to the edge of the known universe.
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A galaxy is a massive, gravitationally bound system made up of stars, remnants of stars, agglomerations of gas and dust, along with an unknown type of “dark matter” that has mass but does not emit light or interact with “ordinary” matter. The word “galaxy” comes from the Greek work galaxias which means "milky", a reference to the whitish path of t...

Each star cluster is as distinct as a European city, each as beautiful in really dark sky as a spray of diamond dust on black velvet. Open star clusters-- sometimes called galactic star clusters-- are congregations of a few hundred young stars that have emerged from the cocoon of an emission nebula and still hang together through mutual gravitation...

While not as visually dazzling as nebulae, star clusters, or galaxies, variable stars are fascinating physical systems with enormous importance in astronomy. Variable stars are all over the sky, and you’ll visit a few of the more famous variables in the coming months. You’ve already met perhaps the most important variable star, δ Cephei, in the sky...