Astronomers know that if white light passes through a prism and is bent, it’s separated out into its component colors—the colors of the rainbow. Astronomers also know that when light interacts with atoms, the building blocks of the universe, the atoms absorb photons of light and reemit them—but in a different direction. Put these two … Continue reading The Atomic Spectrum
Does this look familiar? People think of rainbows as a symbol of happiness and fortune. There are even myths that leprechauns hide gold at the end of a rainbow. That’s more of a tease than good fortune, if you ask me, because it’s impossible to reach the end of a rainbow. That’s right. Impossible. Some people … Continue reading The Spectrum of Light
Paradoxically, stars begin in the galaxy’s coolest places: the dense giant molecular clouds (or GMCs). This is not quite the paradox it seems, as in the beginning, stars require little else but gravity to form. And that’s really quite lucky, because one thing they do need is regions of high density, and high density is unlikely to … Continue reading From Cold Cloud to Hot Protostar
Does this sight look familiar? If you’ve had the opportunity to observe the night sky from a dark place, far away from the light pollution of the city, on a clear night, you might have seen this before. It’s the Milky Way—our view of our galaxy from the inside. It’s kind of like if you … Continue reading Radiation from Interstellar Dust
Take a wild guess: What do you think this image is showing you? If you said it looks like a giant black hole in space, I don’t blame you. I also don’t blame you if you thought it looks like a giant outer space blob…and the funny thing is, that’s actually closer to the truth. … Continue reading Extinction and Reddening of Starlight
What you see here is the Trifid Nebula, a vast cloud of gas and dust in space. In my last post, we explored why it looks the way it does. We discovered that the pink hues of emission nebulae are caused when extremely hot nearby stars “excite” the gas of the nebula itself to emit its … Continue reading What is a Nebula Made of?
What’s a nebula? Well…you’re looking at one. Okay, okay, I know. You want to know what that actually is. You want to know why it’s there. You want to know why there are colors in space…and why you’ve never noticed such a thing in your own night sky before. Nebulae are the stuff between the … Continue reading What is a Nebula?
Consider a solar system far different from our own. A solar system governed by two suns, and consisting of planets we can only dream of. Would it surprise you to hear that, based on recent discoveries, that might actually be the norm? The surroundings we grow up in determine our outlook on the world, and … Continue reading Spectroscopic Binary Stars
By now, I’ve introduced you to a lot of different ways to classify stars. Months ago, I talked about the different spectral classes—O, B, A, F, G, K, and M. Even before that, I told you about apparent visual magnitude, our ranking system for how bright stars appear to the naked eye. More recently, we explored absolute … Continue reading Star Types Demystified
Albireo is the distinctive double star in the head of the constellation Cygnus. You can find it yourself if you look for the Summer Triangle amid the dusty trail of the Milky Way across the night sky. The brighter, orange star of Albireo is a K3-class bright giant. That means it’s just a few thousand … Continue reading What Makes a Star Blue?