1 00:00:00,631 --> 00:00:04,133 Before we start going off into things outside of our solar system 2 00:00:04,133 --> 00:00:08,200 I wanna take a few steps back because I found this neat picture of 3 00:00:08,200 --> 00:00:11,933 the sun over here, and the reason why at least in my mind it's kinda 4 00:00:11,933 --> 00:00:16,800 mindblowing it's because at this scale the sun is obviously still a huge object 5 00:00:16,800 --> 00:00:21,800 at this scale, the Earth would be roughly, and this is an approximation, 6 00:00:21,800 --> 00:00:28,467 roughly that big, so for me at least, this is mindblowing because this idea 7 00:00:28,467 --> 00:00:33,460 that our whole planet, everything we could fit into one of these kind of plasma flares 8 00:00:33,460 --> 00:00:37,039 coming off of the sun, and you can only imagine, we can't realistically 9 00:00:37,054 --> 00:00:40,333 be there but if you were in some type of protective capsule what it would be like 10 00:00:40,333 --> 00:00:43,047 to be in this type of an enviroment 11 00:00:43,047 --> 00:00:46,600 so I just thought this was kind of a fascinating concept, but anyway, 12 00:00:46,600 --> 00:00:50,000 with that out of the way, let's just think about what it means to be 13 00:00:50,028 --> 00:00:53,225 at the boundary of the Solar System, in the last video we explored the 14 00:00:53,225 --> 00:00:59,133 Oort Belt which was about, it started a little under 1 light year away from the Sun 15 00:00:59,133 --> 00:01:03,133 but depending on what you view as a boundary it could be something way 16 00:01:03,133 --> 00:01:07,779 further in or as far out as something like the Oort Cloud 17 00:01:07,779 --> 00:01:13,533 So if the Sun, well we see this things being ejected, but even in unseen ways 18 00:01:13,533 --> 00:01:21,533 unseen particles, super high energy electrons and protons are also 19 00:01:21,533 --> 00:01:29,032 being ejected from the Sun at super high velocities, 400 km/s, let me write that down 20 00:01:29,047 --> 00:01:33,372 400 km/s 21 00:01:33,403 --> 00:01:36,667 and on Earth we're protected from this highly energetic particles 22 00:01:36,667 --> 00:01:42,721 because of Earth's magnetic field, but if you're on the surface of the Moon 23 00:01:42,736 --> 00:01:47,892 when the Sun is on top of the Moon, and you're in the dark side of the Moon 24 00:01:47,892 --> 00:01:51,897 you'll have direct contact with this, and you can imagine, not the best thing 25 00:01:51,897 --> 00:01:56,600 to hang around in too long, but the whole reason why I'm talking about this, 26 00:01:56,600 --> 00:02:00,028 this charged particles that are coming out at huge velocities 27 00:02:00,059 --> 00:02:02,533 from the surface of the Sun, these are considered the Solar Wind 28 00:02:02,533 --> 00:02:08,848 these are the Solar Wind, and I'll put the "Wind" in quotes 29 00:02:08,848 --> 00:02:12,702 'cause it's really very different that out tradicional asociation of a nice breeze 30 00:02:12,702 --> 00:02:17,903 these are just charged particles that are going out at super high velocities from the Sun 31 00:02:17,903 --> 00:02:21,930 and I'm even going into the idea of the Solar Wind because to some degree 32 00:02:21,930 --> 00:02:26,933 they can help us with one definition of maybe the limits of the Solar System 33 00:02:26,933 --> 00:02:31,400 and that's the limits of how far the Solar Wind is getting before 34 00:02:31,400 --> 00:02:36,129 it kinda comes in confrontation with the interstellar medium 35 00:02:36,129 --> 00:02:40,400 and this right here shows a depiction of that, so the Oort Cloud is way 36 00:02:40,400 --> 00:02:44,175 at least the edges of the dense part is way 37 00:02:44,175 --> 00:02:47,950 outside of this, as we saw this is just where Voyager I and Voyager II, 38 00:02:47,950 --> 00:02:55,385 if we wanted the orbit of Sedna, it would be something like, the close part would 39 00:02:55,431 --> 00:02:58,743 be something over here and then it would go out but the Oort Cloud is 40 00:02:58,743 --> 00:03:03,498 much much further out, so if you look at this kind of view of the Solar System as the 41 00:03:03,498 --> 00:03:07,007 extent of the Solar Wind it's much smaller than the Oort Cloud but it's still 42 00:03:07,007 --> 00:03:12,359 farely large, so this is right here this heliopause right here, and I got this from 43 00:03:12,359 --> 00:03:19,508 Wikipedia, this is essentially where the velocity and the forces of the Solar Wind are 44 00:03:19,508 --> 00:03:26,048 counteracted, the preassure is so diluted at this point that it's counteracted 45 00:03:26,064 --> 00:03:32,046 by mainly the hydrogen and the helium that's in the interstellar kind of 46 00:03:32,046 --> 00:03:38,000 'medium', that's just kind of out there, after this point it's not being ejected out anymore 47 00:03:38,000 --> 00:03:42,421 it's just kind of, there's this kind of 'pause' there, I guess you could say 48 00:03:42,421 --> 00:03:46,298 and Voyager I and Voyager II have essentially gotten pretty close to 49 00:03:46,298 --> 00:03:51,348 people believe, that 'pause' over there, and that's one view of the edges of the Solar System 50 00:03:51,348 --> 00:03:55,462 there's never going to be any hard edge to it, another view would be something like 51 00:03:55,508 --> 00:04:01,323 the Oort Cloud, you know, the area where you have the still objects out there 52 00:04:01,323 --> 00:04:05,477 and this is all, actually we haven't directly observed objects in the Oort Cloud, 53 00:04:05,477 --> 00:04:11,031 we think they're out there, and then maybe the most abstract definition would be 54 00:04:11,031 --> 00:04:16,569 the significant influence from the Sun's gravitational pull, so all of those ways 55 00:04:16,569 --> 00:04:21,431 are to imagine the extent of the Solar System, but they all kinda leave a gray area 56 00:04:21,431 --> 00:04:25,456 for what is and what is not in the Solar System, but my whole point here, 57 00:04:25,456 --> 00:04:28,329 what I wanna do is start explaining a little bit outside of the Solar System 58 00:04:28,329 --> 00:04:33,579 and just give you a sense of the scale as we just go to the closest start 59 00:04:33,595 --> 00:04:38,575 so if we go right over here, this shows our local neighbourhood 60 00:04:38,575 --> 00:04:42,320 from a stellar point of view, and even though this stars look pretty big, if you 61 00:04:42,320 --> 00:04:48,369 actually were to draw, this is our Solar System right here, but clearly, 62 00:04:48,369 --> 00:04:51,267 oh and you might be saying 'oh that's the Sun', no, the Sun 63 00:04:51,267 --> 00:04:54,034 if you were to draw it here, it wouldn't even make up one pixel, in fact 64 00:04:54,034 --> 00:04:59,654 the entire orbit of Pluto, everything inside it still wouldn't make up 65 00:04:59,654 --> 00:05:05,933 one pixel on the screen right here, what we see right here, which is a radius 66 00:05:05,933 --> 00:05:12,867 it's roughly a radius of about, give or take, a light year, this is roughly 67 00:05:12,867 --> 00:05:19,298 maybe the radius of the Oort Cloud, and we saw in the last video how huge that was 68 00:05:19,298 --> 00:05:28,267 especially relative to the radius of, say, Pluto's orbit, which is roughly 69 00:05:28,267 --> 00:05:37,595 like that, and that itself it's a huge, huge diameter, a huge distance away from the Sun 70 00:05:37,595 --> 00:05:44,255 and that wouldn't even make a pixel on this diagram right over here. 71 00:05:44,255 --> 00:05:52,246 But just to give you an idea of how far we are, we're a speck of a speck of a speck inside here, 72 00:05:52,246 --> 00:05:59,236 a pixel of a pixel in the center here, to make it from our Solar System, or in particular from Earth maybe 73 00:05:59,236 --> 00:06:04,205 to the nearest star, or maybe the nearest cluster of stars, the Alpha Centauri 74 00:06:04,205 --> 00:06:09,375 they're the nearest cluster of stars, there's 3 stars, Alpha Centauri A, which is 75 00:06:09,375 --> 00:06:13,029 the largest, Alpha Centauri B, and then there's one that you can't 76 00:06:13,029 --> 00:06:18,333 observe with the naked eye, Alpha Proximus, or I think Proximus Centauri I think it's called, 77 00:06:18,333 --> 00:06:22,642 not Alpha Proximus, Proximus Centauri, so that's a much smaller star, 78 00:06:22,642 --> 00:06:30,629 but that's the closest star, and this whole cluster of stars, and they're the closest, 79 00:06:30,629 --> 00:06:40,000 is about 4.2 lightyears away, or another way to think about it, if someone were to shine a light 80 00:06:40,000 --> 00:06:44,224 on one of these planets and assuming that light could get to us it would take 4.2 years 81 00:06:44,224 --> 00:06:49,704 to get to us, or if this guys were to dissapear or blew up we wouldn't know it for 4.2 years 82 00:06:49,704 --> 00:06:54,053 and you might say 'hey, that's not too bad, we should take a trip over there and check them out 83 00:06:54,053 --> 00:06:58,354 and see if there are any other people there that we can meet, and exchange technologies 84 00:06:58,354 --> 00:07:06,331 with or whatnot', but this is a huge distance, just this 4.2 lightyears is an unbelievably ridiculous 85 00:07:06,331 --> 00:07:11,134 distance, and just to give you a sense, the Voyager I and II, we talked about them 86 00:07:11,134 --> 00:07:13,684 in the last video and we an even see how far they've gotten, they've gotten 87 00:07:13,684 --> 00:07:25,529 pretty much to the heliopause, this guys are traveling at 60,000km/h 88 00:07:25,529 --> 00:07:34,044 which is the same thing as 17km/s, if we were able to get up to those type of velocities, 89 00:07:34,044 --> 00:07:38,990 and this guys got up to this type of velocities by leveraging the gravitational 90 00:07:38,990 --> 00:07:42,698 pull of some of the larger planets to keep accelerating, so this is 91 00:07:42,698 --> 00:07:48,579 a pretty hard velocity to actually reach, but if you were able to reach that velocity 92 00:07:48,579 --> 00:07:57,913 and go straight to the direction of the Alpha Centauri system, the closest starts to Earth, 93 00:07:57,913 --> 00:08:09,200 it would take you 80,000 years travelling at the same velocity as Voyager I, which is the fastest of 94 00:08:09,200 --> 00:08:14,918 the Voyagers, so it's a ridiculously long time, so we're gonna have to figure out some better way to 95 00:08:14,918 --> 99:59:59,999 do that.