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Before we start going off into things outside of our solar system

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I wanna take a few steps back because I found this neat picture of

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the sun over here, and the reason why at least in my mind it's kinda

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mindblowing it's because at this scale the sun is obviously still a huge object

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at this scale, the Earth would be roughly, and this is an approximation,

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roughly that big, so for me at least, this is mindblowing because this idea

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that our whole planet, everything we could fit into one of these kind of plasma flares

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coming off of the sun, and you can only imagine, we can't realistically

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be there but if you were in some type of protective capsule what it would be like

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to be in this type of an enviroment

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so I just thought this was kind of a fascinating concept, but anyway,

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with that out of the way, let's just think about what it means to be

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at the boundary of the Solar System, in the last video we explored the

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Oort Belt which was about, it started a little under 1 light year away from the Sun

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but depending on what you view as a boundary it could be something way

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further in or as far out as something like the Oort Cloud

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So if the Sun, well we see this things being ejected, but even in unseen ways

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unseen particles, super high energy electrons and protons are also

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being ejected from the Sun at super high velocities, 400 km/s, let me write that down

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400 km/s

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and on Earth we're protected from this highly energetic particles

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because of Earth's magnetic field, but if you're on the surface of the Moon

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when the Sun is on top of the Moon, and you're in the dark side of the Moon

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you'll have direct contact with this, and you can imagine, not the best thing

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to hang around in too long, but the whole reason why I'm talking about this,

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this charged particles that are coming out at huge velocities

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from the surface of the Sun, these are considered the Solar Wind

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these are the Solar Wind, and I'll put the "Wind" in quotes

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'cause it's really very different that out tradicional asociation of a nice breeze

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these are just charged particles that are going out at super high velocities from the Sun

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and I'm even going into the idea of the Solar Wind because to some degree

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they can help us with one definition of maybe the limits of the Solar System

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and that's the limits of how far the Solar Wind is getting before

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it kinda comes in confrontation with the interstellar medium

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and this right here shows a depiction of that, so the Oort Cloud is way

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at least the edges of the dense part is way

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outside of this, as we saw this is just where Voyager I and Voyager II,

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if we wanted the orbit of Sedna, it would be something like, the close part would

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be something over here and then it would go out but the Oort Cloud is

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much much further out, so if you look at this kind of view of the Solar System as the

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extent of the Solar Wind it's much smaller than the Oort Cloud but it's still

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farely large, so this is right here this heliopause right here, and I got this from

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Wikipedia, this is essentially where the velocity and the forces of the Solar Wind are

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counteracted, the preassure is so diluted at this point that it's counteracted

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by mainly the hydrogen and the helium that's in the interstellar kind of

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'medium', that's just kind of out there, after this point it's not being ejected out anymore

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it's just kind of, there's this kind of 'pause' there, I guess you could say

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and Voyager I and Voyager II have essentially gotten pretty close to

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people believe, that 'pause' over there, and that's one view of the edges of the Solar System

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there's never going to be any hard edge to it, another view would be something like

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the Oort Cloud, you know, the area where you have the still objects out there

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and this is all, actually we haven't directly observed objects in the Oort Cloud,

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we think they're out there, and then maybe the most abstract definition would be

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the significant influence from the Sun's gravitational pull, so all of those ways

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are to imagine the extent of the Solar System, but they all kinda leave a gray area

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for what is and what is not in the Solar System, but my whole point here,

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what I wanna do is start explaining a little bit outside of the Solar System

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and just give you a sense of the scale as we just go to the closest start

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so if we go right over here, this shows our local neighbourhood

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from a stellar point of view, and even though this stars look pretty big, if you

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actually were to draw, this is our Solar System right here, but clearly,

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oh and you might be saying 'oh that's the Sun', no, the Sun

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if you were to draw it here, it wouldn't even make up one pixel, in fact

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the entire orbit of Pluto, everything inside it still wouldn't make up

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one pixel on the screen right here, what we see right here, which is a radius

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it's roughly a radius of about, give or take, a light year, this is roughly

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maybe the radius of the Oort Cloud, and we saw in the last video how huge that was

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especially relative to the radius of, say, Pluto's orbit, which is roughly

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like that, and that itself it's a huge, huge diameter, a huge distance away from the Sun

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and that wouldn't even make a pixel on this diagram right over here.

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But just to give you an idea of how far we are, we're a speck of a speck of a speck inside here,

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a pixel of a pixel in the center here, to make it from our Solar System, or in particular from Earth maybe

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to the nearest star, or maybe the nearest cluster of stars, the Alpha Centauri

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they're the nearest cluster of stars, there's 3 stars, Alpha Centauri A, which is

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the largest, Alpha Centauri B, and then there's one that you can't

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observe with the naked eye, Alpha Proximus, or I think Proximus Centauri I think it's called,

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not Alpha Proximus, Proximus Centauri, so that's a much smaller star,

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but that's the closest star, and this whole cluster of stars, and they're the closest,

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is about 4.2 lightyears away, or another way to think about it, if someone were to shine a light

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on one of these planets and assuming that light could get to us it would take 4.2 years

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to get to us, or if this guys were to dissapear or blew up we wouldn't know it for 4.2 years

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and you might say 'hey, that's not too bad, we should take a trip over there and check them out

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and see if there are any other people there that we can meet, and exchange technologies

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with or whatnot', but this is a huge distance, just this 4.2 lightyears is an unbelievably ridiculous

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distance, and just to give you a sense, the Voyager I and II, we talked about them

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in the last video and we an even see how far they've gotten, they've gotten

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pretty much to the heliopause, this guys are traveling at 60,000km/h

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which is the same thing as 17km/s, if we were able to get up to those type of velocities,

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and this guys got up to this type of velocities by leveraging the gravitational

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pull of some of the larger planets to keep accelerating, so this is

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a pretty hard velocity to actually reach, but if you were able to reach that velocity

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and go straight to the direction of the Alpha Centauri system, the closest starts to Earth,

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it would take you 80,000 years travelling at the same velocity as Voyager I, which is the fastest of

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the Voyagers, so it's a ridiculously long time, so we're gonna have to figure out some better way to

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do that.