Everything in the Universe is spinning. In fact, without this rotation, life on Earth wouldn’t exist. We need the conservation of angular momentum to flatten out galaxies and solar systems, to make planets possible. Let’s find out about the physics involved with everything that spins, and finally figure out the difference between centripetal and centrifugal force.
AstronomyCast
Ep. 180: Albedo
Why are some objects in the Solar System bright while others are dim? Much of an object’s brightness is caused by its albedo, or how well it reflects radiation from the Sun. If you want to know how big a distant moon, comet, or asteroid is, you’ve got to know its albedo.
Ep. 179: Mysteries of the Universe, Part 2
Today we tackle more thrilling mysteries of the Universe. And by tackle, we mean, acknowledge their puzzling existence. Some mysteries will be solved shortly, others will likely trouble astronomers for centuries to come. Join us for part 2.
Ep. 178: Mysteries of the Universe, Part 1
All finished with the Milky Way, it’s time to move on to the biggest mysteries of all. The mysteries of the Universe. Let’s wonder about dark matter and dark energy, and the very nature of reality itself.
Ep. 177: Mysteries of the Milky Way, Part 2
We survived our first group of mysteries, so now we move onto our second set of stuff of amazing Milky Way mysteries. How many spiral arms does our galaxy have, and why does everything keep dying every 60 million years or so?
Ep. 176: Mysteries of the Milky Way, Part 1
We’ve wrapped up our Solar System mysteries and now we move onto the Milky Way mysteries, and the some of the general mysteries of galaxies. From blue stragglers to Eta Carinae… what’s going on?
Ep. 175: Mysteries of the Solar System, Part 2
Apparently this is at least a 2 part series. This week we continue examining some of the baffling mysteries of the Solar System, where we fill your head with more questions than answers. Sometimes we’ve just got to share the enjoyment of not knowing the answer.
Ep. 174: Mysteries of the Solar System, Part 1
We know a lot about our Solar System, but there’s an awful lot that’s a complete and total mystery. Today we’re going to begin a series of unknown length examining some of these mysteries, and explain the best theories astronomers have so far.
Ep. 173: Herschel Space Observatory
Last week we talked about Herschel the people – William Herschel, his sister Caroline, and his son John. This week we look at the Herschel Space Observatory, a mission launched in 2009 to reveal the coldest and dustiest regions in the Universe.
Ep. 172: William Herschel
Ancient astronomers knew of 5 planets, Mercury, Venus, Mars, Jupiter and Saturn – 6 if you count Earth. But then in 1781, William Herschel discovered an entirely new planet, boosting the number of planets to 7. Let’s learn about Herschel, his equipment, his discoveries, and his sister Caroline – an accomplished astronomer of her own.
Ep. 171: Solar System Movements and Positions
Even in ancient times, astronomers realized there was something different about the planets – they move! The movement of the planets and their moons are governed by gravity. And as we all know, gravity can do some funny things.
Ep. 170: Coordinate Systems
This is going to be one of those weeks where we tackle something you’re mentally avoiding. You know all those astronomical terms, like alt-azimuth, right ascension and declination, arc seconds and arc minutes? Of course not, your mind has blocked them out. Today we’re going explain them, so you don’t need to avoid them any more. Soon, you’ll be ready to find anything in the cosmos.
Ep. 169: The Fermi Mission
Last week we talked about Fermi the man, now we’re going to talk about Fermi the space telescope. That’s right, Enrico Fermi made such an impact in the astronomy and physics community that he got a space telescope named after him. Let’s take a look at what this mission will do, and its discoveries so far.
Ep. 168: Enrico Fermi
Today’s episode of Astronomy Cast is about another famous physicist: Enrico Fermi. We’ve already taken a look at one of Fermi’s most famous ideas, the Fermi Paradox – or, where are all the aliens? But let’s meet the man behind the ideas, the namesake for the new Fermi mission.
Ep. 167: Future Civilizations
Let’s assume that humans survive the next few hundred years without destroying ourselves, or the planet, and we actually become a space faring civilization. What kinds of challenges will we face, and what projects will we build to expand ourselves out into the Solar System and eventually the galaxy. You just need to think big.
Ep. 166: Multiverses
What if our universe was just one in an infinite number of parallel universes; a possible outcome from the specific predictions of quantum mechanics. The idea of multiple universes is common in science fiction, but is there any actual science to back this theory up?
Ep. 165: Doppler Effect
You know how a police siren changes sound when it passes by you? That’s the doppler effect. It works for sound waves and it works for light waves. Astronomers use the doppler effect to study the motion of objects across the Universe, from nearby extrasolar planets to the expansion of distant galaxies. Doppler shift is the change in length of a wave (light, sound, etc.) due to the relative motion of source and receiver. Things moving toward you have their wavelengths shortened. Things moving away have their emitted wavelengths lengthened.
Ep. 164: Inside the Atom
We’ve talked about the biggest of the big, now let’s focus in on the smallest of the small. Let’s see what’s inside that basic building block of matter: the atom. You probably know the basics, but with ever more powerful particle accelerators, physicists are revealing particles within particles, announcing new discoveries all the time.
Ep. 163: Auroras
When the Sun’s solar winds crash into the Earth’s magnetosphere, we get to enjoy an incredible light show called auroras, or the Northern and Southern Lights. Let’s learn about what causes these incredible phenomena, and the best times and places that you can see them with your own eyes.
Ep. 162: Edwin Hubble
You might know the name “Hubble” because of the Hubble Space Telescope. But this phenomenal observatory was named after one of the most influential astronomers in modern history. Hubble discovered that galaxies are speeding away from us in all directions, leading to our current understanding of an expanding Universe. Let’s learn about the man behind the telescope.
Ep. 161: Launch Facilities
Launching a rocket into space requires a big effort on the ground. Space agencies have built up huge infrastructures to store, prepare and launch rockets. Let’s take a look at what’s involved on the ground at a place like Cape Canaveral. What happens before, during and after a launch.
Ep. 160: Eclipses
Every now and then, the Moon destroys the Sun. Okay, not destroys, covers. Well, not really covers, but from here on Earth, sitting inside the shadow of the Moon, that’s what it sure looks like. These events are called eclipses, or more precisely, transits and occultations. They occur whenever one object passes in front of another from a 3rd perspective. They’re beautiful and exciting, and deliver a tremendous amount of science as well.
Ep. 159: Planet X
Astronomers have been searching for the mysterious Planet X for hundreds of years. It was the search for a theoretical planet beyond Uranus that turned up Neptune, and then again for Pluto. And even now there are some astronomers who think there’s a more distant planet out there. Oh, and there are a bunch of pseudoscience cranks trying to freak people out about the end of the world. Don’t worry, we’ll make time for them too, but first let’s start with some real science.
Ep. 158: Pulsars
Imagine an object with the mass of the Sun, crushed down to the size of Manhattan. Now set that object spinning hundreds of times a second, blasting out powerful beams of radiation like a lighthouse. That’s a pulsar, one of the most exotic objects in the Universe.
Ep. 157: Constellations
Did you know there are 88 constellations in the night sky? Let’s learn about the constellations and other star formations, their history, their connection to the zodiac, and how to find some of them.