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

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

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

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

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

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

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

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

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

to be in this type of an enviroment

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

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

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

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

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

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

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

unseen particles, super high energy electrons and protons are also

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

400 km/s

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

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

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

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

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

this charged particles that are coming out at huge velocities

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

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

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

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

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

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

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

it kinda comes in confrontation with the interstellar medium

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

at least the edges of the dense part is way

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

do that.