Hydrogen is the most common element in the Universe, formed at the beginning of everything in the Big Bang. It’s the raw material of stars, gathering together through mutual gravity into vast nebulae. Astronomers can learn so much looking for hydrogen in the Universe. Here’s why, and how they do it.
AstronomyCast
Ep 254: Reflection and Refraction
Light can do some pretty strange stuff, like pass through objects and bounce off them; it can be broken up and recombined. In fact, everything we “see” is actually the end result of reflection and refraction of light. Time to understand how it all works.
Ep. 253: Rayleigh Scattering (Why is the Sky Blue?)
Next time a kid asks you, why is the sky blue? Answer them: because of Rayleigh scattering. If they’re not happy with that answer, feel free to expand based on the knowledge we’re about to drop today, right into your brain.
Ep. 252: Heisenberg Uncertainty Principle
Quantum theory is plenty strange, but one of the strangest discoveries is the realization that there’s a limit to how much you can measure at any one time. This was famously described by Werner Heisenberg, with his uncertainty principle: how you can never know both the position and motion of a particle at the same time.
Ep. 251: Messier Catalog
Have you ever looked into the sky and noticed a fuzzy blob? That’s a Messier Object, carefully cataloged by Charles Messier to make it easier to find comets. We’ll learn about the history of the catalog, Messier’s criteria and some of the prominent objects you’ll see in the sky.
Ep. 250: Precision
Accuracy, precision and reproducibility. These are the foundations of science that make our progress possible. How do these play into a scientist’s daily activities? And just how precise can we get with our measurements?
Ep. 249: Schrödinger's Cat
You’ve probably all heard of Schrödinger’s Cat, that strange thought experiment designed by Erwin Schrödinger to show how the strange predictions of quantum theory could impact the real world. No cats will be harmed in the making of this episode, maybe.
Ep. 248: Carina Constellation
Time for another detailed look at a constellation; one of the most fascinating in the sky, but hidden to most of the northern hemisphere: Carina. Home to one of the most likely supernova candidates we know of: Eta Carinae. Let’s talk just about this constellation, how to find it, and what you can discover in and around it.
Ep. 247: The Ages of Things
This is going to be one of the “how we know what we know” kind of shows. How do scientist determine the age of things? How do we know the age of everything from stone tools, to the age of the Earth, to the age of the very Universe.
Ep. 246: What if Something Were Different?
The number of moons, the age of the Sun, and our placement in the Milky Way all had an impact on the formation of the Earth and the evolution of life on our planet. But what if things were different? What would be the implications?
Ep. 245: Calendars
Our lives are ruled by calendars. And calendars are ruled by astronomy. As we near the end of 2011, and get ready to ring in the new year, let’s discover the astronomy underlying the days, weeks, months and years that segment our lives.
Ep. 244: Io
If you want to see one of the strangest places in the Solar System, look no further than Io, Jupiter’s inner Galilean moon. The immense tidal forces from Jupiter keep the moon hotter than hot, with huge volcanoes blasting lava hundreds of kilometres into space.
Ep. 243: Tunguska Event
On June 30th, 1908 “something” exploded over the Tunguska region of Siberia, flattening thousands of square kilometres of forest, and unleashing a force that rivalled the most powerful nuclear weapon ever detonated. What was it? What could unleash that kind of destructive energy? And will it happen again?
Ep. 242: Torino Scale
When you hear of a looming asteroid strike, do you wonder what to do? Should you go into your underground bunker, evacuate the state, or leave the planet? Fortunately, astronomers have developed the Torino Scale – a handy measurement that incorporates both the risk of a strike with the amount of devastation.
Ep. 241: Astrophotography, Part 3: Image Processing
Time for part 3 of our tour through the hobby of astrophotography. You’ve set up your gear, taken some clear images. Now we’re going to help you turn that raw data into the kind of amazing photographs you see in books and on the web.
Ep. 240: Astrophotography, Part 2: Techniques
In the first episode, we talked about the gear you’ll need for your expensive astrophotography hobby. This week we continue our discussion, and talk about the techniques you’ll use to get those amazing photographs. Bring a hot drink, and get ready for some cold nights. But trust us, it’ll all be worth it.
Ep. 239: Astrophotography, Part 1: The Gear
No matter how good your telescope is, you’re never going to see the same detail and colours as the photographs. To take amateur astronomy to the next level, you really need to attach a camera to your telescope. Welcome to the hobby of astrophotography. Fair warning, this hobby could bankrupt you.
Ep. 238: Solar Activity
The Sun looks like a harmless burning ball of fire in the sky: warm, life-giving and forever unchanging. But we know better, don’t we. It’s really a massive ball of churning hydrogen plasma, encased in twisting magnetic field lines, speckled with sunspots, and constantly disgorging vast plumes of radiation and charged particles. The Sun is very active indeed.
Ep. 237: Spooky Sounds From Space
To help you out with your halloween parties, we’ve collected together the spooky sounds of space. Every piece of audio we’re about to play might sound like it comes from a terrifying nightmare dimension, but it’s really just a natural space phenomena.
Ep. 236: Einstein Was Right
At least once a week we get an email claiming that Einstein was wrong. Well you know what, Einstein was right. In fact, as part of his theories of Special and General Relativity, Einstein made a series of predictions about what experiments should discover. Some explained existing puzzles in science, while others made predictions that were only recently proven true.
Ep. 235: Einstein
What can we say about Einstein? Albert Einstein! Lots, actually. In this show we’re going to talk about the most revolutionary physicist… ever. He completely changed our understanding of time, and space, and energy, and gravity. He made predictions about the nature of the Universe that we’re still testing out.
Astronomy Cast at Dragon*Con 2011: Strange Stuff in Space
This is an impromptu episode of Astronomy Cast that we recorded during Dragon*Con 2011. Pamela was scheduled to speak with a panel about strange things in space, but she ended up being the only person there. So Fraser jumped in, and this was what we did. We mostly talked about unusual things in the Solar System, but a few things in the rest of the Universe.
Ep. 234: Lunar Phases
The Moon is a stark reminder that we actually live in a Universe filled with stars and planets and moons. The changing phases of the Moon show us the relative positions of the Earth, the Sun and the Moon as they interact with one another. Let’s learn about the different phases, the geometry of the whole system, and some of the interesting science wrapped up with our fascination of our only natural satellite.
Ep. 233: Radar
Radar is one of the those technologies that changed everything: it allows boats and aircraft to “see” at night and through thick fog. But it also changed astronomy and ground imaging, tracking asteroids with great accuracy, allowing spacecraft to peer through Venus’ thick clouds and revealing secrets beneath the Earth’s shifting sands.
Ep. 232: Galileo Spacecraft
In last season’s thrilling cliff hanger, we talked about astronomer superhero Galileo Galilei. Will a mission be named after him? The answer is yes! NASA’s Galileo spacecraft visited Jupiter in 1995, and spent almost 8 years orbiting, changing our understanding of the giant planet and its moons.