Shadowing Practice: Introduction to Astronomy: Crash Course Astronomy #1 - Learn English Speaking with Video
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Hello, and welcome to Crash Course Astronomy.
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I'm your host, Phil Plait, and I'll be taking you on a guided tour of the entire universe.
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You might want to pack a lunch.
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Over the course of this series, we'll explore planets, stars, black holes, galaxies, subatomic particles, and even the eventual fate of the universe itself.
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But before we step into space, let's take a step back.
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I want to talk to you about science.
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There are lots of definitions of science, but I'll say that it's a body of knowledge and a method of how we learned that knowledge.
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Science tells us that stuff we think we know may not be perfectly known.
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It may be partly or entirely wrong.
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We need to watch the universe, see how it behaves, make guesses about why it's doing what it's doing,
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and then try to think of ways to support or disprove those ideas.
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That last part is important.
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Science must be, above all else, honest if we really want to get to the bottom of things.
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Understanding that our understanding might be wrong is essential, and trying to figure out the ways we may be mistaken is the only way
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that science can help us find our way to the truth .
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Science learns.
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We meander a bit as we use it, but in the long run we get closer and closer to understanding reality,
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and that That is the strength of science, and it's all around us.
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Whether you know it or not, you're soaking in science.
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You're a primate, you have mass, mitochondria in your cells are generating energy, presumably you're breathing oxygen.
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But astronomy is different.
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It's still science, of course, but astronomy puts you in your place.
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Because of astronomy, I know we're standing on a sphere of mostly molten rock and metal 13 ,000 kilometers across,
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with a fuzzy atmosphere about 100 kilometers high,
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surrounded by a magnetic field that protects us from the onslaught of subatomic particles from the Sun 150 million kilometers away.
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Which is also flooding space with light that reaches across space to illuminate the planets, asteroids, dust, and comets, racing out past the Kuiper Belt,
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through the Oort Cloud, into interstellar space, past the nearest stars, which orbit along with gas clouds and dust lanes,
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in a gigantic spiral galaxy we call the Milky Way, that has a supermassive black hole in its center,
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and is surrounded by 150 globular clusters and a halo of dark matter and dwarf galaxies, some of which it's eating,
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all of which can be seen by other galaxies in our local group, like Andromeda and Triangulum.
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And our group is on the outskirts of the Virgo Galaxy Cluster, which is part of the Virgo Super Cluster,
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which is just one of many other gigantic structures that stretch most of the way across the visible universe,
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which is 90 billion light -years across and expanding every day, even faster today than yesterday, day due to mysterious dark energy,
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and even all that might be part of an infinitely larger multiverse that extends forever both in time and space.
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See?
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Astronomy puts you in your place.
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But what exactly is astronomy?
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This isn't necessarily an obvious thing to ask.
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When I was a kid, it was easy.
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Astronomy is the study of things in the sky — the Sun, Moon, stars, galaxies, and stuff like that.
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But it's not so easy to pigeonhole these days.
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Take, for example, Mars.
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When I haul my scope out to the end of my driveway and look at Mars, that's astronomy, right? Of course!
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But what about the rovers there?
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Those machines aren't doing astronomy, surely.
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They're doing chemistry, geology, hydrology, petrology.
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Everything but astronomy.
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So nowadays, what's astronomy?
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I'd say it's still studying stuff in the sky, but it's branched out quite a bit from there.
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Borders between it and other fields of science are fuzzy, a theme I'll be hitting on several times over this series.
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Humans might like firm, delineated boundaries between things, but nature isn't so picky.
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And that brings us to our first edition of Focus On.
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This week's topic, astronomers.
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Who are we?
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What do we do?
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I used to look through telescopes for a living, or at least study the data that came from detectors strapped onto them.
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But now I talk and write about astronomy, and relegate my viewing to my personal backyard telescope.
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But I still consider myself an astronomer.
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So that should give you an idea that there's a lot of wiggle room in the profession.
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In fact, when I worked on Hubble Space Telescope, I was actually hired as a programmer.
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I coded in the language used by the folks helping to build
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and calibrate a camera that was due to launch into space and be installed onto Hubble by an astronaut.
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Once the data from that camera are taken and analyzed, you have to know what to do with them.
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Do the observations fit the physical model of how stars blow up, or how galaxies form, or the way gas flows through space?
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Well, you better know your math and physics, because that's how we test our hypotheses.
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And someone who does that is generally called an astrophysicist.
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Of course, those telescopes and detectors don't create themselves.
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We need engineers to design and build them, and technicians to use them.
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Most astronomers don't actually use the telescopes themselves anymore.
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Someone who's trained in their specific use does that for them.
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Some of those instruments go into space, and some go to other worlds like the Moon and Mars.
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We need astronomers and engineers and software programmers who can build those, too.
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And then, at the end of all this, we need people to tell you all about it — teachers, professors, writers, video makers, even artists.
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So I'll tell you what.
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If you have an interest in the universe, if you love to look up at the stars,
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if you crave to understand what's going on literally over your head, then who am I to say you're not an astronomer?
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However you define astronomy, humans have been looking up at the sky for as long as we've been human.
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Certainly, ancient people noticed the big, glowy ball in the sky, and how it lit everything up while it was up,
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and how it got dark when it was gone.
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The other, fainter, glowy thing tried, but wasn't quite as good at lighting up the night.
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They probably took that sort of thing pretty seriously.
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They probably also noticed that when certain stars appeared in the sky, the weather started getting warmer and the days longer,
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and when other stars were seen, the weather would get colder and daytime shortened.
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And when humans settled down, discovered agriculture, and started farming, noticing those patterns in the sky would have had an even greater impact.
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It told them when to plant seeds and when to harvest.
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The cycles in the sky became pretty important.
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So important that it wasn't hard to imagine gods up there looking down on us weak
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and ridiculous humans interfering with our lives.
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Surely if the stars tell us when to plant and control the weather, seasons, and the length of the day, they control our lives, too.
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And astrology was born.
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Astrology literally means study of the stars.
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As a word, it's been used before science became a formal method of studying nature.
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It irks me a bit, since it got the good name and now we're stuck with astronomy, which means law or culture of the stars,
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and that's not really what we do.
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But what the heck?
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Words change meaning over time, and now it's pretty well understood that astronomy is science and astrology.. isn't.
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Millennia ago, astrology was as close to science as you got.
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It had some of the flavors of science.
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Astrologers observed the skies, made predictions about how it would affect people,
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and then those people would provide evidence for it by swearing up and down it worked.
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The thing is, it really didn't.
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The fault of astrology lies in ourselves and not our stars.
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People tend to remember the hits and forget the misses when predictions are made, which is why they sometimes sit in casinos pumping nickels into machines
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that are proven to be nothing more than a method for reducing the number of nickels you have.
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But astrology led people to really study the sky and find the patterns there,
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which led to a more rigorous understanding of how things really worked in the heavenly vault.
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It wasn't overnight, of course.
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This took centuries.
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Before the invention of the telescope, keen observers built all sorts of odd and wonderful devices to measure the heavens.
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And in fact, it was before the telescope was first turned to the sky that a huge revolution in astronomy took place.
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It is patently obvious that the ground you stand on is fixed, rooted if you will, and the skies turn above us.
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The sun rises, the sun sets.
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The moon rises and sets.
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The stars themselves wheel around the sky at night.
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Clearly the Earth is motionless and the sky is what is actually moving.
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In fact, if you think about it, geocentrism makes perfect sense, that all the objects in the sky revolve about the Earth
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and are fixed to a series of nested spheres, some of which are transparent, maybe made of crystal, which spin once per day.
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The stars may just be holes in otherwise opaque spheres letting sunlight through.
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Sounds silly to you, doesn't it?
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Well, here's the thing.
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If you don't have today's modern understanding of how the cosmos works, this whole multiple shells of things in the sky thing actually does make sense.
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It explains a lot of what's going on over your head.
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And if it was good enough for Plato, Aristotle and Ptolemy, then by God it was good enough for you.
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And speaking of which, it was endorsed by the major religions of the time,
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so maybe it's better if you just nod and agree and don't think about it too hard.
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But a few centuries ago, things changed.
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Although he wasn't the first, the Polish mathematician and astronomer Copernicus came up with the idea that the Sun was the center of the solar system,
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not the Earth.
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His idea had problems, which we'll get to in a later episode, but but it did an incrementally better job than geocentrism.
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And then along came Tycho Brahe and Johannes Kepler, who modified that system, making it even better.
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Then, Isaac Newton.
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Oh, Newton.
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He invented calculus, partly to help him understand the way objects moved in space.
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Over time, our math got better, our physics got better, and our understanding grew.
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Applied math was a revolution in astronomy, and then the use of telescopes was another.
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Galileo didn't invent the telescope, by the way, but made them better.
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Newton invented a new kind that was even better than that, and we've run with the idea from there.
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Then, about a century ago, came another revolution—photography.
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We could capture much fainter objects on glass plates sprayed with light -sensitive chemicals, which revealed stars otherwise invisible to us.
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Details in galaxies, beautiful clouds of gas and dust in space.
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And then, in the latter half of the last century, Digital detectors were invented, which were even more sensitive than film.
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We could use computers to directly analyze observations, and our knowledge leaped again.
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When these were coupled with telescopes sent into orbit around the Earth, where our roiling and boiling atmosphere doesn't blur out observations,
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we began yet another revolution.
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And where are we now?
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We've come such a long way.
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What questions can we routinely ask that our ancestors would not have dared?
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What statements made with a pretty good degree of certainty?
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Think on this.
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The lights in the sky are stars.
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There are other worlds.
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We take the idea of looking for life on alien planets seriously and spend billions of dollars doing it.
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Our galaxy is one of a hundred billion others.
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We can only directly see 4 % of the universe.
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Stars explode.
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And when they do, they create the stuff of life.
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The iron in our blood, the calcium in our bones, the phosphorus that is the backbone of our DNA.
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The most common kind of star in the universe is so faint you can't even see it without a telescope.
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Our solar system is filled to overflowing, with worlds more bizarre than we could have dreamed.
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Nature has more imagination than we do.
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It comes up with some nutty stuff.
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We're clever too, we big -brained apes.
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We've learned a lot.
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But there's still a long way to go.
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So with that, I think we're ready.
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Let's explore the universe.
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Today, you learned what astronomy is, and that astronomers aren't just people who operate telescopes, but include mathematicians, engineers, technicians, programmers, and even artists.
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We also wrapped up with a quick history of the origins and development of astronomy, from ancient observers to the Hubble Space Telescope.
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Crash Course is produced in association with PBS Digital Studios.
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This episode was written by me, Phil Plait.
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The script was edited by Blake DePastino, and our consultant is Dr. Michelle Thaller.
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It was co -directed by Nicholas Jenkins and Michael Aranda, and the graphics is Thought Cafe.
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Vocabulary and speaking notes for this lesson
This speaking lesson is built on the video “Introduction to Astronomy: Crash Course Astronomy”. The speaker keeps coming back to these words: astronomy, star, sky, science, telescope. This video has 53 sentences and 2244 words to shadow. The speech runs for 11:59. The speaker talks fast, about 187 words per minute, so expect linked and reduced sounds. Only 80% of the words are among the 3,000 most common in English, so the vocabulary is demanding. 12 of its 53 sentences are questions, so it is good practice for question intonation and short answers.
Key vocabulary in this video
15 words from the video worth learning, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| astronomy noun | /əˈstɹɑ.nə.mi/ | The study of the physical universe beyond the Earth's atmosphere, including the process of mapping locations and properties of the matter and radiation in the… |
| telescope noun | /ˈtɛl.əˌskoʊp/ | A monocular optical instrument that magnifies distant objects, especially in astronomy. |
| galaxy noun | /ˈɡæl.ək.si/ | Any of the collections of many millions or billions of stars, galactic dust, black holes, etc. existing as independent and coherent systems, of which there are… |
| invent verb | /ɪnˈvɛnt/ | To design a new process or mechanism. |
| dust noun | /dʌst/ | Fine, dry particles of matter found in the air and covering the surface of objects, typically consisting of soil lifted up by the wind, pollen, hair, fiber… |
| mathematics noun | /mæθ(.ə)ˈmæt.ɪks/ | An abstract representational system studying numbers, shapes, structures, quantitative change and relationships between them. |
| observation noun | /ˌɑbzɚˈveɪʃn̩/ | The act of observing, and the fact of being observed (see observance) |
| faint adjective | /feɪnt/ | Lacking strength; weak; languid; inclined to lose consciousness |
| detector noun | /dɪˈtɛktə(ɹ)/ | A device capable of registering a specific substance or physical phenomenon, and that optionally sounds an alarm or triggers a warning. |
| programmer noun | /ˈpɹoʊɡɹæmɚ/ | One who writes computer programs. |
| atmosphere noun | /ˈætməsˌfɪɹ/ | The gases surrounding the Earth or any astronomical body. |
| cloud noun | /ˈklaʊ̯d/ | A visible mass of water droplets suspended in the air. |
| sensitive adjective | /ˈsɛn.sɪt.ɪv/ | Having the faculty of sensation; pertaining to the senses. |
| physics noun | /ˈfɪz.ɪks/ | The branch of science concerned with the study of the properties and interactions of space, time, matter and energy. |
| explore verb | /ɪkˈsploɹ/ | To examine or investigate something systematically. |
Phrasal verbs you will hear
| Word | Meaning |
|---|---|
| come up with verb | To manage to produce, deliver, or present (something) by inventing, creating, thinking of, or obtaining it. |
| blow up verb | To explode or be destroyed by explosion. |
| branch out verb | To expand in the manner of branches. |
| figure out verb | To come to understand; to discover or find a solution; to deduce. |
| light up verb | To illuminate, to bring light to something, to brighten. |
| look down on verb | To regard or treat as inferior. |
| look through verb | To take a view of the contents of; search in, either with the eyes or by hand. |
| settle down verb | To make or become quiet and calm after a period of disturbance or restlessness. |
Sentences worth repeating
Short, complete lines from the video that you can reuse in everyday conversation:
- What do we do?
- Sounds silly to you, doesn’t it?
- We’ve come such a long way!
- We’re clever too, we big-brained apes.
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Passive voice be + past participle — the focus is on what happens, not who does it | may not be perfectly known · may be mistaken · is surrounded |
| Relative clauses who / which + clause — extra information about a person or thing | Cluster, which is · someone who does · astronomy, which means |
| Present perfect have/has + past participle — a past action that still matters now | we've been · it's been · we've run |
Pronunciation to watch
The speaker uses 40 contractions and reduced forms, such as don't, I'll, wasn't. Say them the short way, as you hear them.
- The “th” sounds: mathematics /mæθ(.ə)ˈmæt.ɪks/, breathe /bɹiːð/, hypothesis /haɪˈpɒθɪsɪs/, mathematician /ˌmæθ.(ə.)məˈtɪʃ.ən/
- The “sh” and “zh” sounds: observation /ˌɑbzɚˈveɪʃn̩/, prediction /pɹɪˈdɪkʃən/, technician /tɛkˈnɪʃən/, capture /ˈkæp.(t)ʃɚ/, shell /ʃɛl/
- Long words — get the stress right: astronomy /əˈstɹɑ.nə.mi/, mathematics /mæθ(.ə)ˈmæt.ɪks/, necessarily /ˌnɛs.əˈsɛɹ.ə.li/, ridiculous /ɹɪˈdɪk.jə.ləs/, photography /fəˈtɑ.ɡɹə.fi/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like astronomy, telescope, galaxy.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.