Stars & Galaxies
How are stars are born in nebulae and how do they end their lives? What do we see in the sky? Galaxies are made up of vast numbers of the stars, but what are they like and how do they evolve?
Andromeda the Chained Princess
Andromeda stands in the northern sky eternally chained to her rock. She is one of the five constellations that Ptolemy described in the second century, all part of one particular ancient Greek myth. In the constellation is a quadruple star, a blue snowball, exoplanets and spiral galaxies.
Constellation or Asterism & Other Posers
Constellations, asterisms, galaxies and star clusters are all groups of stars. So how are they different? Why isnít the Big Dipper a constellation? Where are the globular clusters? And if Saturn is in Virgo, has it left the Solar System?
We no longer see the heavens as perfect and the stars as eternal and unchanging. Even the Universe had a beginning, and everything that we observe changes and evolves. Many of these changes involve cosmic collisions.
Galaxy Facts for Kids
The Milky Way used to be the only galaxy people knew. Big telescopes changed that. Now we know there are billions of them. They come in different sizes and shapes and have some surprises for us.
Milky Way - Facts for Kids
We live in the Milky Way galaxy. When we look up at the sky all the stars we see are part of the Milky Way. But did you know that most of the Galaxy is made of mysterious, invisible dark matter and that thereís an even darker secret at its heart?
Milky Way - Our Galaxy
The Milky Way is a giant spiral galaxy. Along with our neighboring giant Andromeda Galaxy, it dominates the Local Group of galaxies. But where are we in the Galaxy? Why do astronomers think that 95% of the Galaxy is mysterious dark matter? And what is lurking at the heart of the Milky Way?
Stars are born, we see their light in the sky, and they die. Find out about the patterns of stars we see, about the stars themselves and the galaxies they inhabit.
Top Astronomy Stories 2012
What were the big astronomy stories of the year 2012? Here is my choice of the top ten plus a non-story. What do you think?
What Is a Galaxy Astronomy Homepage | Editor's Picks Articles | Top Ten Articles | Astronomy Site Map
What is a galaxy? A great star system held together by gravity, with stars, gas and dust, black holes and dark matter. Astronomers used to think our Galaxy was the whole universe. But now that we know of billions of galaxies, they're considered to be the building blocks of the universe.
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