1 00:00:02,040 --> 00:00:06,920 Speaker 1: Welcome to brain Stuff from How Stuff Works. Hi, I'm 2 00:00:07,000 --> 00:00:10,160 Speaker 1: Christian Seger, and this is brain Stuff. If you follow 3 00:00:10,200 --> 00:00:13,120 Speaker 1: the latest in space gossip, you might have heard about 4 00:00:13,119 --> 00:00:16,560 Speaker 1: a little rendezvous between a NASA probe called Dawn and 5 00:00:16,640 --> 00:00:19,920 Speaker 1: an object in space known as the dwarf planet Series. 6 00:00:20,360 --> 00:00:23,560 Speaker 1: This meet up is exciting news for space fanatics. But 7 00:00:23,600 --> 00:00:25,800 Speaker 1: if you don't know what Series is, and at this 8 00:00:25,880 --> 00:00:29,000 Speaker 1: point you're too afraid to ask, well, we are here 9 00:00:29,080 --> 00:00:31,920 Speaker 1: to lay down the facts you need to know. Series 10 00:00:32,000 --> 00:00:35,760 Speaker 1: first came to human attention when the Italian astronomer Giuseppe 11 00:00:35,800 --> 00:00:39,560 Speaker 1: Piazzi spied a moving point of light from the Palermo 12 00:00:39,760 --> 00:00:43,839 Speaker 1: Observatory on New Year's Day in eighteen o one. Yeah, 13 00:00:43,880 --> 00:00:48,320 Speaker 1: eighteen o one. That means Series was actually discovered almost 14 00:00:48,360 --> 00:00:52,479 Speaker 1: a hundred and thirty years before the former planet and 15 00:00:52,560 --> 00:00:57,440 Speaker 1: now fellow dwarf planet, Pluto. Piazzi correctly deduced that the 16 00:00:57,480 --> 00:01:00,840 Speaker 1: object was somewhere between the orbits of Mars and Jupiter. 17 00:01:01,280 --> 00:01:04,440 Speaker 1: In reality, that zone contains the thing we now know 18 00:01:04,720 --> 00:01:08,640 Speaker 1: as the asteroid Belt, a loose ring of rocky objects, 19 00:01:08,680 --> 00:01:12,679 Speaker 1: of which Series is the largest. Piazzi named this new 20 00:01:12,800 --> 00:01:16,400 Speaker 1: space dot after the Roman deity Series the goddess of 21 00:01:16,480 --> 00:01:21,240 Speaker 1: grain and nutritious food crops. Historically, astronomers have gone back 22 00:01:21,280 --> 00:01:24,600 Speaker 1: and forth about the status of this object. Piazzi himself 23 00:01:24,760 --> 00:01:28,160 Speaker 1: initially thought it might be a comet. It has also 24 00:01:28,200 --> 00:01:31,600 Speaker 1: been known as a planet and as an asteroid, but 25 00:01:31,680 --> 00:01:36,319 Speaker 1: today astronomers classify Series as a dwarf planet. So you 26 00:01:36,400 --> 00:01:39,679 Speaker 1: might be wondering what makes a dwarf planet different from, 27 00:01:39,840 --> 00:01:43,040 Speaker 1: you know, a regular planet or a comet or an asteroid. Well, 28 00:01:43,120 --> 00:01:47,600 Speaker 1: according to the International Astronomical Union, a dwarf planet is 29 00:01:47,680 --> 00:01:52,360 Speaker 1: any object that meets the following four criteria. First, it 30 00:01:52,400 --> 00:01:55,960 Speaker 1: goes around the Sun. Okay, that's a check for Series. Two, 31 00:01:56,440 --> 00:02:00,440 Speaker 1: it's not a moon. Another check for Series. Even though 32 00:02:00,480 --> 00:02:03,800 Speaker 1: they're not moons, death stars and other space stations are 33 00:02:03,840 --> 00:02:10,800 Speaker 1: implicitly disqualified. Three, it has attained hydrostatic equilibrium. This means 34 00:02:10,840 --> 00:02:14,000 Speaker 1: the object has enough mass that over time, the force 35 00:02:14,040 --> 00:02:17,840 Speaker 1: of gravity has shaped it roughly into a sphere. This 36 00:02:17,880 --> 00:02:21,440 Speaker 1: would disqualify all those comets and asteroids that are shaped 37 00:02:21,520 --> 00:02:27,400 Speaker 1: like lumpy potatoes. Series is pleasantly, almost delightfully round. And 38 00:02:28,000 --> 00:02:32,080 Speaker 1: number four, it has not, as astronomers say, cleared the 39 00:02:32,120 --> 00:02:36,640 Speaker 1: neighborhood around its orbit. Over time, large bodies like planets 40 00:02:36,680 --> 00:02:40,560 Speaker 1: tend to eliminate other materials from their orbital zone. This 41 00:02:40,639 --> 00:02:44,400 Speaker 1: is why objects like Series and Pluto art planets. They 42 00:02:44,440 --> 00:02:48,000 Speaker 1: haven't cleaned for room. For Series. That room is the 43 00:02:48,040 --> 00:02:51,720 Speaker 1: asteroid belt, frankly, just about the dirtiest room in the 44 00:02:51,760 --> 00:02:54,720 Speaker 1: Solar System apart from the icy pig sty that is 45 00:02:54,720 --> 00:02:59,160 Speaker 1: the Kuiper Belt. So Series remains a dwarf planet, but 46 00:02:59,560 --> 00:03:02,560 Speaker 1: there is no means anything wrong with being a dwarf 47 00:03:02,560 --> 00:03:05,840 Speaker 1: planet because Series is fascinating. Here are a couple of 48 00:03:05,880 --> 00:03:09,919 Speaker 1: quick facts. Series is about nine hundred and fifty kilometers 49 00:03:10,000 --> 00:03:13,360 Speaker 1: or five d ninety miles in diameter, meaning if you 50 00:03:13,440 --> 00:03:16,040 Speaker 1: look at the disk head on, it is about the 51 00:03:16,120 --> 00:03:20,320 Speaker 1: size of Texas. But it's total surface area is about 52 00:03:20,360 --> 00:03:24,360 Speaker 1: two point eight million square kilometers or about one point 53 00:03:24,440 --> 00:03:28,400 Speaker 1: one million square miles. That's about as much real estate 54 00:03:28,520 --> 00:03:32,680 Speaker 1: as the country of Argentina. By itself. Series accounts for 55 00:03:32,760 --> 00:03:36,080 Speaker 1: a quarter of the mass of the entire asteroid belt. 56 00:03:36,480 --> 00:03:39,000 Speaker 1: If you were to take a cross section of Series, 57 00:03:39,040 --> 00:03:41,280 Speaker 1: you would find a rocky core at the center and 58 00:03:41,360 --> 00:03:45,720 Speaker 1: a dusty outer crust on the surface, but in between 59 00:03:45,760 --> 00:03:50,040 Speaker 1: them a subterranean mantle of water ice. This layer of 60 00:03:50,080 --> 00:03:52,880 Speaker 1: water ice has drawn a lot of attention, since anywhere 61 00:03:52,880 --> 00:03:56,560 Speaker 1: there is water, there's always the slim possibility that we 62 00:03:56,600 --> 00:04:00,480 Speaker 1: could discover life. Scientists sometimes speak of Series as a 63 00:04:00,640 --> 00:04:04,600 Speaker 1: proto planet or an embryonic planet. About four and a 64 00:04:04,640 --> 00:04:07,560 Speaker 1: half billion years ago, when the planets in our Solar 65 00:04:07,600 --> 00:04:12,080 Speaker 1: system were first forming, Jupiter's gravity prevented Series from becoming 66 00:04:12,120 --> 00:04:16,200 Speaker 1: a full fledged planet. This left it frozen in its 67 00:04:16,240 --> 00:04:19,000 Speaker 1: fetal state, so there may be a lot we can 68 00:04:19,120 --> 00:04:22,680 Speaker 1: learn from Series about how planets are born in young 69 00:04:22,760 --> 00:04:31,200 Speaker 1: solar systems. Check out the brainstuff channel on YouTube, and 70 00:04:31,240 --> 00:04:33,680 Speaker 1: for more on this and thousands of other topics, visit 71 00:04:33,680 --> 00:04:48,120 Speaker 1: how stuff works dot com.