字幕表 動画を再生する 英語字幕をプリント Welcome to Socratica Station. We’ll be departing soon on our tour of the Solar System. Along the way, we’ll see our Star, orbited by eight planets, at least five dwarf planets, and tens of thousands of asteroids. Maybe a few comets if we get lucky. Remain seated with your safety restraints in place. To have the best view, put on your goggles and keep them on for the duration of our trip. We’ll start our tour at Sol, our Star. That means we’re going to the center of our Solar System. To get there, we’ll be making a quick jump into hyperspace to travel the 150 million kilometers. Don’t let it throw you. Ready? Steady...Go. Here we are. Our Sun. There are much larger stars out there, but this one is ours. It’s a giant ball of gas, held together by gravity. The Sun makes up 99.8% of the mass of the entire solar system. This huge mass keeps everything in its orbit, from the largest planets to the trillions of bits of space debris. The Dark Sunspots you see are areas of intense magnetic activity. Electric currents in the sun generate a HUGE magnetic field. This sets up a stream of electrically charged gas blowing out from the Sun in all directions. We call this the Solar Wind. Hold on to your boots. We’re jumping to planet number one, MERCURY. Mercury is the planet closest to the Sun - the first of the four terrestrial planets. It’s also the smallest planet, around the same size as Earth’s moon. Mercury goes around the Sun very quickly. One year on Mercury takes 88 days on Earth. But at the same time, it spins very slowly on its axis. One Mercury Day takes 59 Earth Days. So there’s a long Mercury Day, but a short Mercury year. Best of both worlds! Next stop: Venus. Named for the goddess of LOVE. Will you lose your heart to this dangerous beauty? Here she is. Venus. Bright. Beautiful. DEADLY. Venus is a hot, dangerous planet, with an atmosphere of toxic gas. I know, she’s gorgeous, but I’m telling you, we can’t get any closer or our ship will melt. You’ll have to admire her from here. Notice that the planet spins backwards - so on Venus, the Sun rises in the West and sets in the East. Okay, time to go home. Just for a moment, to cool off. We’re going to visit Earth, but this time as a space tourist. Are you a resident of Earth? I’ve never been myself, personally. But it sure looks pretty. 70% of its surface is covered with water. It’s the only planet we know of in our Solar System that supports life. We’re busy setting up more and more stations for humans to live off-world, but right here is where life began. Earth lies in a so-called Goldilocks zone, within a habitable distance from the Sun, and it has a protective atmosphere that keeps the temperature relatively stable. Next on our tour comes our best hope for life off-planet - the Red Planet MARS. Okay, Red Planet isn’t quite right - it’s more brownish/yellow - but Mars looks red from Earth, and so the nickname stuck. Do we have any prospective Martians with us here today? That’s right, plans to move in are underway. What will life be like on our new home? Light. Mars has only one-third the gravity of Earth. Also, be prepared for some excitement - Mars has giant volcanoes like Olympus Mons and massive, planet-wide dust storms. Don’t forget to pack a broom. Time for a little interlude before our next planet. This next stop might be a little ROCKY. We’re talking asteroids. Lots of them. Everyone still buckled in? Good. Here we are in the Asteroid Belt. Asteroids are rocky irregular bodies - left over from the formation of the Solar System. Most asteroids are found right here, orbiting the Sun between Mars and Jupiter. We’ve found about 800,000 of them so far. The total mass of all the asteroids here in the Asteroid Belt is less than that of Earth’s moon. As you can see, the asteroids come in a variety of shapes and sizes. The largest known asteroid is Ceres - about 950 kilometers in diameter. But most are much smaller - some are only 10 meters across. Okay, brace yourself. It’s time to visit the big guy. The Titan. The Big Kahuna. You know him better as - JUPITER. We’ve arrived at the largest planet in the Solar System. It’s a handsome planet, dressed in swirly bands of gas. Don’t let the strange beauty fool you. This is no paradise planet. It’s completely inhospitable. There’s nothing solid to land on. Just gas, gas, and more gas. And Jupiter has impressive storms that last for centuries, including the Giant Red Spot. That’s not to say we won’t move into the neighborhood one day. Jupiter has many moons that are promising candidates for colonization. I’m considering Europa myself. Moving on. Our next planet has a certain RING to it. Wink wink. Saturn coming up in 3..2..1.. Saturn is a lot like Jupiter, made mostly of hydrogen and helium. It’s funny, you know, lots of planets have rings, made up of chunks of ice and rocks. But Saturn’s rings are so impressive, it’s really the first thing we think of. We recognize Saturn by its rings, but every now and then, we get to enjoy an optical illusion where the rings disappear. Saturn’s rings are so thin that they disappear if you view them on edge. Our next planet has a way of changing your perspective on things. You’ll see what I mean when we get there. Ready or not, here it comes! See what I mean? This is Uranus. It rotates on its side. OK - I’m not really supposed to do this - but hey, who’s gonna know. Let’s turn on our side to get another look. Whooooaaahhhh! Now we’re proper “Uranians!” Uranus was the first planet discovered by telescope back in 1781. It’s remained a bit of a mystery since then. We know it’s mostly hydrogen, helium, and methane, with a small rocky center. Maybe one day we’ll figure out why it’s such a tilty world. Tilt a world! I crack myself up sometimes. Moving on to a planet named for the Roman God of the Sea. It’s quite see-worthy! Hahahaha. Worth seeing. See worthy! Get it? This blue blue world is Neptune. Did I mention it’s very blue? Maybe that’s why it reminds people of an ocean. It’s dark, icy, and windy. Down below the atmosphere is supposed to be a solid center about the size of Earth. Brrr. I’m not going down there. We’re in luck my friends. A comet is gracing us with her presence. Where’s its tail you ask? Comets are like dusty snowballs orbiting the Sun. When they get to perihelion, the closest point to the Sun, THAT’S when you see them develop their tails. The radiation from the Sun causes the comet to partly vaporize, and the dust particles stream behind, carried by the solar pressure and the solar wind. That’s why comet tails always point away from the Sun. Some comets have short orbits and some have long orbits. One example is Halley’s Comet, with a short period of about 75 years. Do you know where short period comets come from? That’s right, the Kuiper belt. We must be getting close. Hang on, let’s go take a look. We made it to the Kuiper Belt. This is a ring of icy objects circling around the Sun. We call all the interesting bodies out here Kuiper Belt Objects (KBOs) Short-period comets come from here (those with orbits around the Sun less than 200 years) Here we also find Dwarf planets, including Pluto. Remember Pluto? It’s smaller than Earth’s Moon, with Blue skies, Mountains, and red snow. Like a picture postcard, isn’t it? Love ya, little guy. Other Dwarf planets include Makemake, Haumea, and Eris. Can’t wait to explore all these little worlds. Sorry folks. We don’t have enough fuel to visit the Oort Cloud today. Let’s head back to base. We’re going to go hyper-hyper speed to get back in time for lunch. And don't forget to stop by the giftshop! Everyone here in one piece? Good, good, we take our safety record very seriously here at Socratica Space Tours. Just think about how much you saw today - practically our whole Solar System! It’s a beauty isn’t it? And imagine - our solar system is moving with an average velocity of 828,000 kilometers per hour. But even at that speed, it takes us over 200 MILLION YEARS to complete one orbit around the Milky Way. We’d better save the trip around the galaxy for our next tour. ...We’re going to need a bigger ship. Thank you for voyaging with Socratica today. We know you have a choice in space travel, and we appreciate your patronage. If you’d like to collect your frequent flier space miles, you can join our 7 billion mile club by visiting Patreon.com/socratica. So long space travelers, and come again soon.