Tag Archives: phil plait

Saturn: Crash Course Astronomy #18

This episode of Crash Course is brought to you by Squarespace. So now we’ve come to the last of the naked eye planets in the solar system: Saturn. It’s the second largest planet, but ironically the least dense. In fact, if you could find a bathtub big enough, Saturn would float in it! But it… Read More »

Comets: Crash Course Astronomy #21

Hey, Phil Plait here and this is Crash Course Astronomy. Since humans have been human we’ve looked to the skies for portents of the future. The Sun, the Moon, the planets, the stars; they’ve all been used for prognostication. And so have comets. A fuzzy blob, moving slowly across the stars? How could soothsayers resist?… Read More »

Outtakes #5: Crash Course Astronomy

[music] The universe will be dark — dark to human eyes, at least assuming we have eyes in a trillion years or we’re even around that long. Wow, that– yeah. OFF-SCREEN: Yeah. I was trying to be a little more jocular. [intro] OFF-SCREEN: I am rolling. Are you? Are you? Are you hating? OFF-SCREEN: They… Read More »

Uranus & Neptune: Crash Course Astronomy #19

This episode of Crash Course is brought to you by Squarespace. You run us. YOU run us. You RAN us. You ran us. Ooo- Ooo ran ose. There are five planets in our solar system you can see without a telescope; well, six if you include the one you’re sitting on. But there are two… Read More »

Dark Energy, Cosmology part 2: Crash Course Astronomy #43

The previous episode of Crash Course Astronomy was a bit of a brain-stretcher. We saw that the Universe is expanding, space is expanding, and it’s carrying galaxies along with it. That means it was denser in the past, and at some point — 13.82 billion years ago, to be fairly precise — all of space,… Read More »

The Gravity of the Situation: Crash Course Astronomy #7

We live — and stop me if I’m going too fast — on a planet. I mean, sure, duh. But this isn’t the natural state of the Universe; or, at least, it’s not the way things usually are. Most of the Universe is pretty empty — that’s why we call it “space” — and if… Read More »

Asteroids: Crash Course Astronomy #20

When you look at a diagram of the solar system, you’ll see a big gap between Mars and Jupiter. A few centuries ago, that gap bugged astronomers; they really wanted there to be a planet in there. On the first day of the 19th century—January 1, 1801—they got their wish. Kinda. Italian astronomer Giuseppi Piazzi… Read More »

Introduction to the Solar System: Crash Course Astronomy #9

The Solar System is the name we give to our local cosmic backyard. A better way to think of it is all the stuff held sway by the Sun’s gravity: The Sun itself, planets, moons, asteroids, comets, dust, and very thin gas. If you took a step back — well, a few trillion steps back… Read More »

High Mass Stars: Crash Course Astronomy #31

Stars are in a constant struggle between gravity trying to collapse them and their internal heat trying to inflate them. For most of a star’s life, these two forces are at an uneasy truce. For a star like the Sun, the balance tips in its twilight years. For a brief glorious moment it expands… but… Read More »

Gamma-Ray Bursts: Crash Course Astronomy #40

Sometimes in science, the story of HOW we learned something is just as cool as what we learned. In the case of gamma-ray bursts, it’s kinda hard to beat the awesomeness of what they are. But of all the plotlines in astronomy, their origin story comes the closest. It begins, quite literally, in the grip… Read More »