Astronomy Cast
Astronomy Cast offers you a fact based journey through the cosmos. Each week Fraser Cain (Universe Today) and Dr. Pamela Gay (SIUE / Slacker Astronomy) take on topics ranging from the nearby planets to ubiquitous dark matter.
Copyright: Fraser Cain and Dr. Pamela Gay
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Last week we talked about galaxies in general, and hinted at the most violent and energetic ones out there: active galaxies. Quasars have been a mystery for half a century; what kind of object could throw out more radiation than an entire galaxy? A black hole, it turns out, with the mass of hundreds of millions of suns performs this feat. Let's trace back the history of quasars, how they were first discovered and puzzled astronomers for so long. And let's look at what we know today.
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This week we're going to look at some of the biggest objects in the Universe: galaxies. It was the discovery of galaxies in the early 20th century that helped astronomers realize just how big the Universe is, and how far away everything is. Let's learn how galaxies formed and how they evolve and change over time, merging with the neighbors. And what the future holds.
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Ep. 96: Humans to Mars, Part 3 - Terraforming Mars[17.2 MB]Mon, 7 Jul 2008 00:00:00 GMT
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And now we reach the third part of our trilogy on the human exploration and colonization of Mars. Humans will inevitably tire of living underground, and will want to stretch their legs, and fill their lungs with fresh air. One day, we'll contemplate the possibility of reshaping Mars to suit human life. Is it even possible? What technologies would be used, and what's the best we can hope for?
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This is our third installment in our series of student questions shows and these questions come to us from Collinsville High School.
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After astronauts make the first tentative steps onto the surface of Mars, a big goal will be colonization of the Red Planet. The first trailblazers who try to live on Mars will have their work cut out for them, being in an environment totally hostile to life. What challenges will they face, and how might they overcome them?
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We're learned about the failed missions to Mars in the past, and the current spacecraft, rovers and landers currently exploring the Red Planet. But the real prize will come when the first human sets foot on Mars. Robots are cheaper, but nothing beats having a real human being on the scene, to search for evidence of water and life.
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I know last week was a bit of a dry history lesson, but we wanted to give you some understanding of past efforts to explore Mars. Now we'll look at the missions currently in orbit, and crawling around the surface of Mars, and help you understand the science that's happening right now.
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With last month's safe arrival of the Phoenix Mars Lander, Mars enthusiasts breathed a collective sigh of relief... phew. Now it's time to search for evidence of organic molecules in the ice at Mars' north pole. But this is just the latest in a long series of missions sent to the Red Planet. Let's have a history lesson, and look back at the missions sent to Mars, successful and unsuccessful.
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With the successful touchdown of the Phoenix Lander, NASA is continuing its quest to find evidence of past and present water on Mars. This week we discuss the geologic history of Mars, and explain why NASA thinks the story of water on Mars is so important. And how this ties into the search for life on the Red Planet.
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You've heard us say it 90 times: "How we know what we know." But how do we know how we know what we know? So astronomers like all scientists use the scientific method. Without the scientific method we'd probably still think the Earth is flat, only a few thousand years old and the center of the universe. But with the scientific method everything changes. From biology, to chemistry, to physics, to astronomy it is impossible to count the number of changes that have happened to human society because of changes brought about from the scientific method. In this episode we tell you about what the scientific method is, how you can use it to improve your life, and discuss why gravity isn't just a theory.
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Since the dawn of humanity, astronomers have wished to destroy the atmosphere. Oh sure, it's what we breathe and all, but that stupid atmosphere is always getting in the way. Since destroying the atmosphere is out of the question, astronomers have figured out how to work with it. To distort the mirror of the telescope itself though the magic of adaptive optics.
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Our understanding of the cosmos has been revolutionized by the Hubble Space Telescope. The breathtaking familiar photos, like the Pillars of Creation, pale in comparison to the astounding amount of science data returned to Earth. Hubble's getting old, though, serviced several times already, and due for another mission later this year. Let's relive the historic observatory's amazing life so far, and see what the future holds.
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Ep. 87: The End of the Universe Part 2: The End of Everything[14.2 MB]Mon, 5 May 2008 00:00:00 GMT
Hopefully you've all recovered from part 1 of this set, where we make you sad about the future of the humanity, the Earth, the Sun and the Solar System. But hang on, we're really going to bring you down. Today we'll look far far forward into the distant future of the Universe, at timescales that we can barely comprehend.
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Ep. 86: The End of the Universe Part 1: The End of the Solar System[15.5 MB]Mon, 28 Apr 2008 00:00:00 GMT
This is a show we wanted to do since we started Astronomy Cast but we always thought it was too early. We wanted you to know that we're positive, happy people with enthusiasm for astronomy and the future. It's time for some sadness. It's time for a grim look to see what the future holds for the Universe. This week we stay close to home and consider the end of humanity, the Earth, the Sun, and the entire Solar System. Next week we'll extend out to the very end of the Universe.
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Our senses can only detect a fraction of the phenomena happening in the Universe. That's why scientists and engineers develop detectors, to let us see radiation and particles that we could never detect with our eyes and ears. This week we'll go through them all, so you can understand how we see what we can't see.
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Have you ever wondered what it takes to get a spacecraft off the Earth and into space. And how managers at NASA can actually navigate a spacecraft to another planet? And how does a gravity assist work? And how do they get them into orbit? And how do they land? So many questions...
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Have you ever heard that photons behave like both a particle and a wave and wondered what that meant? It's true. Sometimes light acts like a wave, and other times it behaves like a little particle. It's both. This week we discuss the experiments that demonstrate this, explain how scientists figured it all out in the first place. What does wave/particle duality have to do with astronomy? Well, everything, since light is the only way astronomers can see out into the Universe.
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We're polluting every corner of our own planet, so it only makes sense that we'll take our trashy habits out into space with us. This week we look at the myriad of ways we're messing up space, from the trash orbiting the planet to the radiation we're leaking out into space.
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Ep. 81: Questions on the Shape Size and Centre of the Universe[14.0 MB]Mon, 24 Mar 2008 00:00:00 GMT
As predicted we got a lot of questions from people about our trilogy of shows on the size, shape and centre of the universe. Today we'll do our best to clear them all up.As always, if you're still confused drop us an email to info at astronomycast dot com.
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Pamela's attending the 39th Lunar and Planetary Sciences Conference, and you know what that means: the Moon... and planets! When you think of the Moon, you think of craters. In fact, that's a big theme this week at the conference, so Pamela took it as inspiration. Here you go, the week we drove the show into a crater. Wait... there's got to be a better way to describe this.
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We´re ready to complete our trilogy of discovery about the universe. We´ve learned that it has no center; rather everywhere is its center and nowhere. We discovered that the universe seems to be flat. It not open, it is not closed, it is flat. If that doesn´t make any sense, you need to listen to the previous show because there´s no way I could give that an explanation. So now we want to know: How big is it? Does it go on forever or is it finite in scale? How much of it can we see?
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Some of the biggest questions in the universe depend on its shape. Is it curved? Is it flat? Is it open? Those may not make that much sense to you, but in fact it´s very important for astronomers. So which is it? How do we know? How did we figure it out? Why does it matter?
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There are some people I´m not naming names who think the universe revolves around them. In fact, for most of humankind, everybody thought that. It´s only been in the last few hundred years that scientists finally puzzled out that the Earth isn´t the centre of the universe at all. That begs the question: where is the centre?
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Gravity is always pulling you down, but there are places in the solar system where gravity balances out. These are called Lagrange points and space agencies use them as stable places to put spacecraft. Nature is on to them and has already been using them for billions of years.
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This is our second installment in our series of student questions shows and these questions come to us from Curtis High School.
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After the big bang, all we had was hydrogen, a little bit of helium, and a few other trace elements. Today, we´ve a whole periodic table of elements to enjoy, from oxygen we breathe to the aluminium cans we drink from to the uranium that powers some people´s homes. How did we get from plain old hydrogen to our current diversity? It came from stars, in fact successive generations of stars.
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Sometimes, we don´t get to decide what our show´s about. So many threads come together at the same time driving the decision for us. This is one of those situations. We´ve gotten so many questions from listeners in just the last week about antimatter that our show had just been chosen for it. You command, we obey. Let´s talk about antimatter.
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We´ve been so crazy following our own whims through the universe that we´ve neglected your questions. That ends today. It´s time to dig deep into our overflowing email box to retrieve the puzzling questions our listeners have sent in.
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We´re going to return back to a long series of episodes we like to call: Radiation that Will Turn You Into a Superhero. This time we´re going to look at cosmic rays, which everyone knows made the Fantastic Four. These high-energy particles are streaming from the Sun and even intergalactic space, and do a wonderful job of destroying our DNA, giving us radiation sickness, and maybe (hopefully!) turning us into superheroes.
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When he put together his theories of relativity, Einstein made a series of predictions. Some were confirmed just a few years later, but scientists are still working to confirm others. And one of the most fascinating is the concept of gravitational waves. As massive objects move in space, they send out ripples across the Universe that actually distort the shape of matter. Experiments are in place and in the works to detect these gravitational waves as they sweep past the Earth.
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Just a couple of shows ago, we showed you how to get a career in astronomy. Now that you've got your career in astronomy, obviously the next goal is to win a Nobel prize. We're here at the American Astronomical Society meeting in Austin, which is just one tiny step that a person has to take before you get that Nobel prize. Before you get that call in the middle of the night from Sweden, you're going to need to come with an idea, do some experiments, write a paper, get published and a bunch of other stuff. This week, we'll tell you all about it.
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Thanks to GLAST, Astronomy Cast is now able to provide equipment to send to high school teachers who want to Pamela and Fraser to do a special questions show just for their class. We will be making this shows available on the feed on days other than Monday (that's still reserved for your regularly scheduled Astronomy Cast). This is the first one available and comes with questions from Farmersburg School.
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Episode 69: The Large Hadron Collider and the Search for the Higgs-Boson[19.0 MB]Mon, 31 Dec 2007 00:00:00 GMT
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