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.
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.
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?
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.
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. Show More Summary
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.
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?
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.
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.
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. Show More Summary
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.
We think we live near an average star, but that's not the case at all. Compared to most stars in the Universe, the Sun is a giant! Let's look at the small end of the stellar spectrum, to stars with a fraction of the size and mass of our own Sun. There are many ways that a star can get small, and they lead dramatically different lives and deaths.
If you live in a city, it's possible that you've never seen the Milky Way with your own eyes. To really appreciate everything the night skies have to offer, you've got to get out of the city, away from the lights, where the skies are really dark. Show More Summary
We've explained how to get into astronomy and buy your first telescope. Now we're going to take things to the next level and get you drooling about bigger and better telescopes. If you're serious about astronomy, what kinds of telescopes will give you the best bang for big bucks?
It's been more than 40 years since humans first set foot on the Moon. But plans are in place to return humans to the surface of the Moon, and maybe even to asteroids and the planet Mars. New rockets, landers and flight technology are all under development. Show More Summary
For those non-scientists trying to get their original ideas accepted by the scientific community, you've got to have thick skin. It might seem like there's a vast conspiracy, or a general attitude that drives away original, but unorthodox ideas. Show More Summary
In science fiction it's easy to hop into your spaceship and blast off for other stars. But the true distances between stars, and the limits of relativity make interstellar travel almost impossible with our current technology. What would it really take to travel from star to star, exploring the galaxy?
If you want to travel into the Solar System, you have to get off the Earth. Traditionally, that meant blasting off in a rocket. But there's another strategy for escaping the Earth's gravity. Climb to the top of an extremely tall tower, and just jump away. Show More Summary
We know there's life in the Universe. We see it all around us here on Earth. But is there life anywhere else? By studying the extremes that life can take here on Earth, scientists are learning just how hardy and adaptable life can really be. Show More Summary
Will robots be able to avoid the heat death of the Universe? Can galaxies orbit each other like binary stars? And what are the dangers of space radiation to astronauts on the Moon? If you've got a question for the Astronomy Cast team, please email it in to email@example.com and we'll try to tackle it for a future show. Show More Summary