Last week we talked about fusion, where atoms come together to form heavier elements. This week, everything comes apart as we talk about nuclear fission. How it occurs naturally in the Universe, and how it has been harnessed by science to produce power, and devastating weapons.
AstronomyCast
Ep. 205: Fusion
When the Universe formed after the Big Bang, all we had was hydrogen. But through the process of fusion, these hydrogen atoms were crushed into heavier and heavier elements. Fusion gives us warmth and light from the Sun, destruction with fusion bombs, and might be a source of inexpensive energy. We’ll also look into the controversy of cold fusion.
Ep. 204: Temperature
Now we’re going to answer a question that a 4-year old might ask – what is temperature? Why are things hot and why are they cold? How hot or cold can they get? And how is this all important for astronomy?
Ep. 203: Europa
Europa is the smallest of the Jovian satellites, but it might be one of the most exciting spots in the Solar System. When NASA’s Voyager spacecraft flew past the moon, they discovered huge cracks in its icy surface. Is it possible that Europa has a huge ocean of liquid water, and maybe even life? This is a world that needs more investigation.
Ep. 202: The Planets at Gliese 581
With the discovery of a planet in the habitability zone of Gliese 581, the chances of finding life on other worlds is just getting better and better. Let’s take a look at the discoveries made at Gliese 581, provide some perspective on the real chances of life, and talk about what might come next.
Ep. 201: Titan
Titan is Saturn’s largest moon, and the second largest moon in the Solar System. It’s unique in the Solar System as the only moon with an atmosphere. In fact, scientists think that Titan’s thick atmosphere – rich in hydrocarbons – is similar to the early Earth, and could give us clues about how life got started on our planet.
Ep. 200: The Mariner Program
The first interplanetary series of missions was the American Mariner program. These successful spacecraft visited Mercury, Venus, and Mars, and laid the groundwork for the US missions to the outer planets. Let’s take a look at the program and their incredible accomplishments.
Ep. 199: The Voyager Program
Launched in 1977, the twin Voyager spacecraft were sent to explore the outer planets: Jupiter, Saturn, Uranus and Neptune. Because of a unique alignment of the planets, Voyager 2 was the first spacecraft to ever make a close approach to Uranus and Neptune. Let’s take a look back at this amazing program, and see where the spacecraft are today.
Ep 198: How is a Space Mission Chosen?
Space missions are expensive to build and launch, so there’s a lot of planning that goes into choosing exactly what’s going to be shot into space. Space scientists and engineers recently went through the process of deciding on their science goals, so we thought we’d spend an episode explaining how this works, and how the next generation of spacecraft and telescopes will be selected.
Ep. 197: Astronomy Cast Live from Dragon*Con 2010
In this special live Dragon*Con 2010 episode of Astronomy Cast we welcomed special guest Les Johnson, Deputy Manager for NASA’s Advanced Concepts Office to talk about the state of human space exploration. And then we opened up the show to some amazing questions from the audience. Listen to the first live show ever done with both Fraser and Pamela in the same room.
Ep. 196: Luminosity and Magnitude
Astronomers measure the brightness of stars as magnitude. But this brightness depends on the distance to the star as well as the total amount of energy it’s pumping out into space. And from our vantage point here on Earth, appearances can be deceiving.
Ep. 195: Planetary Rings
Saturn is best known for its rings. This huge and beautiful ring system is easy to spot in even the smallest backyard telescope, so you can imagine they were a surprise when Galileo first noticed them. But astronomers have gone on to find rings around the other gas giant worlds in the Solar System – the differences are surprising.
Ep. 194: Dwarf Planets
In 2006, the International Astronomical Union demoted Pluto out of the planet club. But they also started up a whole new dwarf planet club, with Pluto, Eris and the asteroid Ceres as charter members. Let’s find out what it takes to be a dwarf planet, and discuss the current membership.
Ep. 193: Astronomy with the Unaided Eye
We talk a lot about telescopes here on Astronomy Cast, but you really don’t need any special equipment to appreciate what the night sky has to offer. Just head outside with some sky charts, maybe a planisphere, some friends and hot chocolate, and you’re good to go. Let’s talk about what kinds of things you can see with just your eyes.
Ep. 192: Chandra X-Ray Observatory
The Chandra X-Ray Observatory is the third of NASA’s Great Observatories, sent into space aboard the space shuttle to view the Universe in high energy X-ray radiation. This is the territory of supernovae, supermassive black holes and neutron stars; some of the most extreme places in the Universe.
Ep. 191: Chandrasekhar
The first half of the 20th Century was a productive time for astronomy, with theorists working out much of the science that we take for granted today. One of these astronomy stars was Subrahmanyan Chandrasekhar, who determined the maximum mass of a white dwarf star.
Ep. 190: Kepler Mission
Last week we studied Kepler the man, and this week we take a look at Kepler, the mission. Launched in March, 2009, this is a spacecraft designed to search for Earth-like planets orbiting other stars. Let’s take a look at the history this mission, the launch and the science gathered so far.
Ep. 189: Johannes Kepler and His Laws of Planetary Motion
Nicolaus Copernicus changed our understanding of the Universe when he rearranged the Solar System to put the Sun at the center, with the Earth becoming just another of the planets orbiting it. But the movement of the planets didn’t really match the theory; not until Johannes Kepler came along with his ellipses, and everything finally worked.
Ep. 188: The Future of Astronomy
We spent 5 episodes telling the story of astronomy so far, how we got from the work of the Babylonians to the modern discoveries made in the last decade. But now we want to look forward, studying the current space missions and experiments to uncover the mysteries that astronomers hope to solve.
Ep. 187: History of Astronomy, Part 5: The 20th Century
Many of the modern ideas in astronomy happened in just the 20th century: dark matter, the Big Bang, inflation, quasars, black holes. So many discoveries in one important century.
Ep. 186: History of Astronomy, Part 4: The Beginning of Modern Astronomy
With our proper place in the Universe worked out, and some powerful telescopes to probe the cosmos, astronomers started making some real progress. The next few hundred years was a time of constant refinement, with astronomers discovering new planets, new moons, and developing new theories in astronomy and physics.
Ep. 185: History of Astronomy, Part 3: The Renaissance
Now we reach time with names that many of you will be familiar: Galileo, Kepler, Copernicus. This is an age when the biggest names in astronomy used the best tools of their time to completely rearrange their understanding of the Universe, putting the Earth where it belonged – merely orbiting the Sun, and not the center of everything.
Ep. 184: History of Astronomy, Part 2:The Greeks
With the earliest astronomers out of the way, we now move to one of the most productive eras in astronomy; the ancient Greeks. Even though they didn’t have telescopes, the Greeks worked out the size and shape of the Earth, the distance to the Moon and Sun, and even had some accurate ideas about our place in the Universe.
Ep. 183: History of Astronomy, Part 1: The Ancient Astronomers
We know you love a good series. This time we’re going to walk you through the history of astronomy, starting with the ancient astronomers and leading right up to the most recent discoveries. Today we’re going to start at the beginning, with the astronomers who first tried to understand the true nature of the Earth, the planets and our place in the cosmos.
Ep. 182: Astrometry
Astronomers have been cataloging star positions for thousands of years, from the first calculations made by Hipparchus, to the more recent star catalogs made by the spacecraft named after him. This is astrometry; another way to find our place in the Universe.