Welcome to the first episode of Crash Course Astronomy. Your host for this intergalactic adventure is the Bad Astronomer himself, Phil Plait. We begin with ...
In order to understand how we study the universe, we need to talk a little bit about light. Light is a form of energy. Its wavelength tells us its energy and color.
This week we build on our naked eye observations from last week and take a look at the cyclical phenomena that we can see at work in the universe. -- Table of ...
While Jupiter is nowhere near massive enough to initiate fusion in its core, there are even more massive objects out there that fall just short of that achievement ...
As we approach the end of Crash Course Astronomy, it's time now to acknowledge that our Universe's days are numbered. Stars will die out after a few trillion ...
In this episode of Crash Course Astronomy, Phil takes you through the cause and name of the Moon's phases. -- Why the Moon Has Phases 0:36.1 Spheres in ...
Thanks to observations of galaxy redshifts, we can tell that the universe is EXPANDING! Knowing that the universe is expanding and how quickly its expanding ...
Phil takes us for a closer (eye safe!) look at the two-octillion ton star that rules our solar system. We look at the sun's core, plasma, magnetic fields, sunspots, ...
Today Phil explains how telescopes work and offers up some astronomical shopping advice. -- How Telescopes Work 1:07 Refractors vs Reflectors 2:50 ...
Today we're talking about our galactic neighborhood: The Milky Way. It's a disk galaxy, a collection of dust, gas, and hundreds of billions of stars, with the Sun ...
Here it is, folks: the end. In our final episode of Crash Course Astronomy, Phil gives the course a send off with a look at some of his favorite topics and the big ...
Today on Crash Course Astronomy, Phil invites you to head outside and take a look at all the incredible things you can see with your naked eye. -- Table of ...
In the aftermath of a 8 – 20 solar mass star's demise we find a weird little object known as a neutron star. Neutrons stars are incredibly dense, spin rapidly, and ...
The Milky Way is our neighborhood in the universe. It's a galaxy and there are many others out there. Galaxies contain gas, dust, and billions of stars or more.
Thanks to the wonders of physics, astronomers can map a timeline of the universe's history. Today, Phil's going to give you an overview of those first few minutes ...
In today's episode, Phil looks at how gravity plays out across the universe. This episode is sponsored by Squarespace: ...
The big question in the comments last week was, "BUT WHAT ABOUT ECLIPSES?" Today, Phil breaks 'em down for you. This episode is sponsored by ...
Today Phil explores the world of tides! What is the relationship between tides and gravity? How do planets and their moons become tidally locked? What would ...
Now that we're done with the planets, asteroid belt, and comets, we're heading to the outskirts of the solar system. Out past Neptune are vast reservoirs of icy ...
Active galaxies pour out lots of energy, due to their central supermassive black holes gobbling down matter. Galaxies tend not to be loners, but instead exist in ...
In today's Crash Course Astronomy, Phil takes a look at the explosive history of our cosmic backyard. We explore how we went from a giant ball of gas to the ...
Today Phil's explaining the stars and how they can be categorized using their spectra. Together with their distance, this provides a wealth of information about ...
The fourth planet from the sun and the outermost of the terrestrial planets, Mars has long been a popular spot for missions and imagination. Phil walks you ...
The majority of the universe is made up of a currently mysterious entity that pervades space: dark energy. We don't know exactly what it is, but we do know that ...
How do astronomers make sense out of the vastness of space? How do they study things so far away? Today Phil talks about distances, going back to early ...
Astronomers study a lot of gorgeous things, but nebulae might be the most breathtakingly beautiful of them all. Nebulae are clouds of gas and dust in space.
Today Phil explains that YES, there are other planets out there and astonomers have a lot of methods for detecting them. Nearly 2000 have been found so far.
Phil starts the planet-by-planet tour of the solar system right here at home, Earth. -- Table of Contents Earth is a Planet 0:03 Layers of Earth 1:25 The Magnetic ...
Join Phil for a tour of our capital-M Moon, from surface features, inside to the core, and back in time to theories about its formation. This episode is brought to you ...
Today we're taking a break for another round of "Bad Astronomy" Crash Course Astronomy posters available at DFTBA.com ...
Mercury is the closest planet to the sun. It has no atmosphere and is, as such, covered in craters. It's also incredibly hot but, surprisingly, has water ice hiding ...
Gamma-ray bursts are not only incredible to study, but their discovery has an epic story all its own. Today Phil takes you through some Cold War history and then ...
Jupiter is the biggest planet in our solar system. The gas giant is NOT a failed star, but a really successful planet! It has a dynamic atmosphere with belts and ...
Today we are talking about the life -- and death -- of stars. Low mass stars live a long time, fusing all their hydrogen into helium over a trillion years.
We've covered a lot of incredible stuff, but this week we're talking about the weirdest objects in space: BLACK HOLES. Stellar mass black holes form when a ...
Now that we've finished our tour of the planets, we're headed back to the asteroid belt. Asteroids are chunks of rock, metal, or both that were once part of ...
Saturn is the crown jewel of the solar system, beautiful and fascinating. It is a gas giant, and has a broad set of rings made of ice particles. Moons create gaps in ...
Today on Crash Course Astronomy, Phil explains comets. Comets are chunks of ice and rock that orbit the Sun. When they get near the Sun the ice turns into ...
Today we're rounding out our planetary tour with ice giants Uranus and Neptune. Both have small rocky cores, thick mantles of ammonia, water, and methane, ...
Today on Crash Course Astronomy, Phil dives into some very dark matters. The stuff we can actually observe in the universe isn't all there is. Galaxies and other ...
Today Phil follows up last week's look at the death of low mass stars with what comes next: a white dwarf. White dwarfs are incredibly hot and dense objects ...