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Speaker 1: Welcome to tech Stuff, a production from I Heart Radio.

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Speaker 1: Hey there, and welcome to tech Stuff. I'm your host,

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Speaker 1: Jonathan Strickland. I'm an executive producer with I Heart Radio.

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Speaker 1: And how the tech are you? You know? Ever since

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Speaker 1: the then Soviet Union sent ups foot Nick way back

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Speaker 1: in nineteen fifties, seven man made satellites have played a

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Speaker 1: really important role in our world in multiple contexts. You know,

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Speaker 1: in the early days, at least from a political standpoint,

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Speaker 1: it was a lot about demonstrating scientific and engineering superiority.

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Speaker 1: That was kind of what was driving the space race,

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Speaker 1: at least from a financial and political standpoint, back when

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Speaker 1: the US and USS are we're racing to achieve first

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Speaker 1: in space. But I mean, obviously they're also important to

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Speaker 1: further our scientific under standing of our world and beyond,

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Speaker 1: and also to do stuff like layout communications infrastructure that

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Speaker 1: would allow for global communication. And of course there are

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Speaker 1: thousands of other applications and satellites are really out of

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Speaker 1: this world. And yes, I also hate me for saying that,

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Speaker 1: And I thought it could be a little beneficial to

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Speaker 1: talk about the various orbits that satellites can inhabit and

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Speaker 1: then explain the differences between those orbits and the purposes

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Speaker 1: of them. And I think that's really helpful in order

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Speaker 1: to understand stuff like why is the James Webb Space

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Speaker 1: Telescope in an orbit that's so far out that we

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Speaker 1: cannot reach it with a human crew? Right? Why is that?

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Speaker 1: Or why scientists warn us about the dangers of space chunk.

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Speaker 1: I mean, space is huge, so you would think the

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Speaker 1: odds of any two objects colliding with one another out

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Speaker 1: in space would be astronomical. Man, I'm gonna have a

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Speaker 1: lot of puns in this episode. So we're gonna go

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Speaker 1: through the various orbits and explain we would send certain

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Speaker 1: types of satellites to one orbit versus another. And first

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Speaker 1: of all, let's let's actually just talk about the word orbit.

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Speaker 1: And I'm sure everyone out there has a grasp on this,

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Speaker 1: but technically, what we're talking about is a curved path

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Speaker 1: that causes one object to move around a second object,

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Speaker 1: or two objects to move around each other due to

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Speaker 1: the poll of gravity. And gravity is one of the

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Speaker 1: fundamental forces of the universe. It's also the weakest one,

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Speaker 1: by the way, it has practically no effect once you

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Speaker 1: get down to the molecular or atomic level. Gravity is

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Speaker 1: a force of attraction that exists between stuff in our universe.

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Speaker 1: What has mass, right, anything that has mass experiences the

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Speaker 1: effects of gravity. So technically you could say there's a

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Speaker 1: gravitational attraction between every object that has mass and every

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Speaker 1: other object that has mass. However, the magnitude of that

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Speaker 1: attractive force is dependent upon two really important factors. One

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Speaker 1: is the actual mass of the objects in question. The

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Speaker 1: more mass, the greater the attraction, So to truly massive

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Speaker 1: objects will have a greater attraction to one another than

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Speaker 1: two very small objects. This is why when we get

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Speaker 1: down to the molecular and atomic levels, gravity is is negligible.

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Speaker 1: We can just ignore it. Uh. This, by the way,

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Speaker 1: is also why the gravity on the Moon is so

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Speaker 1: much less than the gravity on Earth. The acceleration due

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Speaker 1: to gravity on the Moon is a little less than

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Speaker 1: sevent of that what we'd experienced here on Earth, So

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Speaker 1: the gravitational pull between say the Moon and an astronaut

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Speaker 1: is much less than what that astronaut would experience while

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Speaker 1: walking around on Earth. Because the Moon is less massive

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Speaker 1: than the Earth, the astronaut is probably about the same.

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Speaker 1: But the other factor is the distance that's between those

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Speaker 1: two objects if they are really far apart, the gravitational

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Speaker 1: force between them, while technically still being present, will be

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Speaker 1: extremely weak. Again, if it's really really far apart, you

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Speaker 1: can ignore it because it's so weak as to be

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Speaker 1: you know, almost nothing. I should also add the Einstein's

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Speaker 1: theory of general relativity actually dismissed the idea of gravity

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Speaker 1: being an actual force. Rather, gravity is the consequence of

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Speaker 1: objects with mass bending spacetime, and that gets a little

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Speaker 1: difficult to envision, so let's simplify it. Imagine that you

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Speaker 1: have a trampoline and then you put a pretty heavy

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Speaker 1: bowling ball in the middle of that trampoline. Well, the

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Speaker 1: weight of the bowling ball will cause the trampoline's surface

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Speaker 1: to deform right, it will dip downward because the weight

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Speaker 1: of the bowling ball. And if you were to try

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Speaker 1: and roll a marble across the trampoline, then it's stead

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Speaker 1: of traveling in a straight line, the marble's path would

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Speaker 1: be affected by that bend in the trampoline. It would

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Speaker 1: actually turn towards the dip and thus towards the bowling ball. Well,

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Speaker 1: Einstein's theory stated that we're seeing that exact same effect

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Speaker 1: out in the universe, except while we could describe the

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Speaker 1: surface of a trampoline effectively as a two dimensional object,

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Speaker 1: you know, an object that doesn't have depth to it.

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Speaker 1: In space, we have to deal with three dimensions, that

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Speaker 1: being spatial dimensions. I mean we also have time, which

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Speaker 1: is the fourth dimension. And this gets are a bit

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Speaker 1: tricky for us to visualize, or at least I find

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Speaker 1: it tricky. Maybe you can do it. I can't. But yeah,

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Speaker 1: when we often refer to gravity as a force, Einstein

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Speaker 1: would correct us on that one and say it's not

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Speaker 1: really a force. Now, with that bowling ball and marble

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Speaker 1: trampoline example, we can actually understand why satellites have to

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Speaker 1: work in the way that they do. So let's say

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Speaker 1: you roll the marble hard enough to reach the point

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Speaker 1: where the bowling ball's presence is going to cause the

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Speaker 1: marble's pathway to change, But you're not rolling it so

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Speaker 1: hard that the marble can make it out the other

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Speaker 1: side to the opposite, you know, into the trampoline. So,

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Speaker 1: in other words, the marble is unable to escape the

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Speaker 1: bowling balls gravitational pull. The marble will roll down and

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Speaker 1: hit the bowling ball and come to a stop it

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Speaker 1: at some point. Now, if you rolled the marble really hard.

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Speaker 1: It might be able to get through the deformed area

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Speaker 1: of the trampoline's surface like it might have enough momentum

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Speaker 1: too to navigate through the dip. But its path is

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Speaker 1: still going to change, right. It's not a flat surface.

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Speaker 1: It's not going to travel in a straight line. It

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Speaker 1: will have a bend in its pathway. But maybe it

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Speaker 1: will get all the way across the trampoline. Uh, it

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Speaker 1: just won't be directly across. However, if you wanted to

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Speaker 1: keep the marble so that it's constantly circling the bowling ball, well,

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Speaker 1: we would have to have some way to keep the

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Speaker 1: marble at just the right speed. It would need to

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Speaker 1: be fast enough to counteract the marble's tendency to fall

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Speaker 1: toward the bowling ball, but not be so fast as

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Speaker 1: to cause the marble to continue off the pathway and

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Speaker 1: eventually off the edge of the trampoline. If we could

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Speaker 1: add energy to the marble consistently, we would be all set,

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Speaker 1: because otherwise, the friction that the marble would encounter as

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Speaker 1: it rolled across the trampoline would be enough to slow

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Speaker 1: it down and it would fall towards the bowling ball.

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Speaker 1: So we'd have to find a way to give the

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Speaker 1: marble a little boost now and then in order for

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Speaker 1: it to maintain its circular pathway around the bowling ball.

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Speaker 1: So satellites in orbit around something else, whether it's our

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Speaker 1: planet or some other celestial body, need to move at

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Speaker 1: a speed that's fast enough to avoid falling toward whatever

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Speaker 1: it is orbiting around. So out in space there aren't

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Speaker 1: nearly as many factors that would slow down a satellite

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Speaker 1: speed as we find here on Earth. There's very little

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Speaker 1: friction or air resistance out there, So once you get

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Speaker 1: a satellite in orbit, the speed the satellite has courtesy

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Speaker 1: of the launch vehicle is sufficient to keep most satellites

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Speaker 1: in an orbit for many years. Satellites have thrusters, and

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Speaker 1: they have fuel, but those thrusters are not meant to

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Speaker 1: accelerate the satellite in order for it to maintain orbital speed.

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Speaker 1: Those thrusters are really used to maneuver the satellite so

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Speaker 1: it can either transition from one orbit to another, go

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Speaker 1: through a transfer orbit in other words, or used to

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Speaker 1: move the satellite out of the pathway of potential space

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Speaker 1: junk or other debris. Now, satellites and lower orbits can

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Speaker 1: and do experience drag from the Earth's atmosphere, so there's

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Speaker 1: actually no hard boundary for where our planet's atmosphere ends.

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Speaker 1: We do have the Carmen line, which is sort of

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Speaker 1: a convenient definite mission of the edge of space, but

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Speaker 1: it's mainly there as a way to define it for

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Speaker 1: political purposes and just to have a practical definition, because

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Speaker 1: it's so nebulous again to use another pun and so

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Speaker 1: vague that it's very difficult to say this is uh

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Speaker 1: categorically where space begins, and the common line is at

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Speaker 1: a hundred kilometers above sea level here on Earth. Now,

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Speaker 1: that does not mean that there is no atmosphere beyond

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Speaker 1: one kilometers in altitude. There is atmosphere beyond that limit,

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Speaker 1: but it's extremely thin. Individual particles can be very far

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Speaker 1: apart from each other, so it doesn't resemble the atmosphere

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Speaker 1: we have here on the surface. UH. And these few

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Speaker 1: particles are still enough to cause drag on lower altitude satellites,

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Speaker 1: so gradually those satellite speeds will slow down enough that, um,

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Speaker 1: you know, it will eventually de orbit. It will lose

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Speaker 1: enough velocity and fall back to Earth unless we were

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Speaker 1: to do something like if we were to move it

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Speaker 1: to a different orbit than that could be enough to

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Speaker 1: extend the life of the satellite, or we might even

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Speaker 1: use thrusters to push the satellite out into an orbit

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Speaker 1: where it'll just be dead out there in space. Now

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Speaker 1: we can classify Earth satellite orbits in different ways, including

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Speaker 1: their altitude. Now, we can classify Earth satellite orbits in

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Speaker 1: several different ways, and I'll explain some of those ways

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Speaker 1: when we come back from this break. Okay, before the break,

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Speaker 1: I mentioned we can classify Earth orbits in several different ways.

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Speaker 1: One of those ways is the altitude of those orbits.

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Speaker 1: Generally speaking, we can split altitudes into low Earth orbit,

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Speaker 1: mid Earth orbit, and high Earth orbit. The low orbit

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Speaker 1: range is around one to two thousand kilometers above sea level,

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Speaker 1: so these are well above the Carmen line. Obviously, remember

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Speaker 1: the carbon lines at a hundred kilometers above sea level.

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Speaker 1: These satellites move really wicked fast. Uh. These are satellites

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Speaker 1: that orbit the Earth several times each day, so they're

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Speaker 1: not orbiting the Earth in time with the Earth's rotation.

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Speaker 1: They're actually going faster than the Earth's rotation. The lowest

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Speaker 1: orbiting satellites are completing in orbit somewhere around minutes per orbit.

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Speaker 1: That means a satellite like that could orbit the Earth

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Speaker 1: around sixteen times each day. However, lower satellites are going

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Speaker 1: to encounter more drag because they're gonna be hitting the

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Speaker 1: occasional particle of atmosphere and their orbits will deteriorate faster

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Speaker 1: than those satellites that are at a higher orbit. And

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Speaker 1: these lower satellites and only be useful for a few years.

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Speaker 1: So you wouldn't want anything designed for a long term

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Speaker 1: mission to be in that orbit. Uh, it would it

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Speaker 1: would not be able to maintain that orbit for longer

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Speaker 1: than a few years. In the low Earth orbit range,

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Speaker 1: we have a lot of satellites that do Earth observations,

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Speaker 1: so satellites meant for Earth sciences often occupy this space.

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Speaker 1: In addition, satellites like space x is Starlink network, they

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Speaker 1: occupy the low Earth orbit range. There around five kilometers

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Speaker 1: above sea level, so not quite in the middle of

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Speaker 1: low Earth orbit range. They're actually on the lower end.

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Speaker 1: And part of SpaceX's strategy for Starlink is to launch

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Speaker 1: tens of thousands of satellites into that general orbit to

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Speaker 1: provide global consistent coverage for Internet service and to essentially

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Speaker 1: resupply those satellites as older ones are decommissioned, which is

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Speaker 1: kind of a fancy way of saying, they either get

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Speaker 1: e orbited as then they fall back to Earth or

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Speaker 1: they're pushed into an orbit that no one is using,

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Speaker 1: kind of a graveyard orbit. Now, the mid Earth orbit

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Speaker 1: that ranges from two thousand kilometers above sea level up

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Speaker 1: to thirty five thousand, seven hundred eighty kilometers, so a

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Speaker 1: big big range here, and a lot of navigational satellites

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Speaker 1: and spy satellites occupy this space. Um As out here,

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Speaker 1: you can put satellites in an orbit where they stay

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Speaker 1: above particular regions for a good amount of time each day.

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Speaker 1: And in fact, now we need to talk about a

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Speaker 1: special subset of orbits that are kind of between Mid

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Speaker 1: Earth and High Earth orbits. And you probably heard terms

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Speaker 1: like geosynchronous and geo stationary orbits. These orbits are just

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Speaker 1: a touch further out from the mid orbits, and sometimes

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Speaker 1: they even get grouped with High Earth orbits. It really

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Speaker 1: just depends on whom you're talking to, UH, and it's

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Speaker 1: very easy to confuse geosynchronous with geostationary. Technically, geostationary orbits

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Speaker 1: are a subset of geosynchronous orbits. So at this altitude,

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Speaker 1: this far out from the Earth, the satellites orbit is

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Speaker 1: the same as the rotational speed of the Earth. So,

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Speaker 1: in other words, the satellite maintains its relative position to

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Speaker 1: the Earth throughout the full day. The satellite remains over

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Speaker 1: the same general region of the Earth throughout the entirety

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Speaker 1: of the day. Now we have to remember that the

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Speaker 1: Earth also has a tilt to its axis, and this

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Speaker 1: means that if a satellite is at this altitude but

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Speaker 1: not directly over the equator, the satellite's position with reference

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Speaker 1: to the Earth's surface will actually move north and south

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Speaker 1: throughout the day. So it will still maintain its position

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Speaker 1: with regard to longitude, that is, east and west. It's

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Speaker 1: gonna remain in its same location east versus west, but

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Speaker 1: it's latitudinal position north versus south that'll vary throughout the day.

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Speaker 1: A geo stationary orbit is an orbit above the equator.

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Speaker 1: That means there's a zero degree inclination with reference to

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Speaker 1: the equator, and the satellite will remain over the same

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Speaker 1: spot on the Earth's surface. But again, this only works

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Speaker 1: if you are along the equator. This can get pretty

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Speaker 1: congested like there's a There are a lot of reasons

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Speaker 1: why you might want to put a satellite there so

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Speaker 1: that it's over the same reference point on Earth throughout

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Speaker 1: the day. But obviously there's a limited number of of

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Speaker 1: orbits that you can put satellites in above the equator

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Speaker 1: for one thing, you know, just to avoid things like

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Speaker 1: communication interference, so it gets pretty tricky. Also, you you

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Speaker 1: often will find countries that do have space programs getting

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Speaker 1: treaties and agreement with countries that don't but are equatorial

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Speaker 1: countries so that they can essentially get the rights to

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Speaker 1: place a satellite above those countries. This is one of

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Speaker 1: those cases where it's not just science and technology but

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Speaker 1: politics that become important. And then you also have high

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Speaker 1: Earth orbit was where we start to go beyond the

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Speaker 1: geo stationary and geosynchronous orbits. We're talking about altitudes greater

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Speaker 1: than thirty five thousand seven kilometers now way out here,

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Speaker 1: you typically are talking about things like communications, satellites, um

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Speaker 1: it can be other things too, but you know, you

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Speaker 1: start to get limited in what useful stuff you can

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Speaker 1: put out in this orbit. Oddly enough, when you go

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Speaker 1: much further out you can find uh other really interesting

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Speaker 1: uses like the James Webb Space Telescope. But we'll get

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Speaker 1: there now. I mentioned geo stationary orbits, which requires the

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Speaker 1: satellite to not only be above the mid Earth orbital age,

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Speaker 1: but also over the equator ak zero inclination with reference

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Speaker 1: to the equatorial plane. But we can classify other orbits

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Speaker 1: by referencing inclination. For example, a polar orbit is one

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Speaker 1: that passes over the North and South Pole over the

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Speaker 1: course of its orbit, and this requires an inclination of

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Speaker 1: ninety degrees. That is, it needs to be at a

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Speaker 1: right angle with reference to the equator. And then you

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Speaker 1: have sun synchronous orbits. Okay, so this gets really complicated,

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Speaker 1: but I'll try and give you a very very high

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Speaker 1: level view. Again. Another pun and you might want a

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Speaker 1: satellite in a sun synchronous orbit to observe certain regions

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Speaker 1: of the Earth, and you want the lighting of those

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Speaker 1: regions to be consistent from one day to the next. Well,

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Speaker 1: if you want to do that, you put a satellite

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Speaker 1: in a polar sun synchronous orbit. This is an glinnation

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Speaker 1: of about ninety eight degrees, so it's a little bit

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Speaker 1: further out from a right angle, and a satellite in

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Speaker 1: this orbit will orbit north south or depending upon your

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Speaker 1: point of reference, south north around the Earth, and meanwhile

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Speaker 1: the Earth is continuing to rotate east west below the satellite. Now, interestingly,

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Speaker 1: the satellite's orbital path will also begin to rotate. In fact,

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Speaker 1: that's actually crucial because if the orbital path did not rotate,

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Speaker 1: you know, you can think of it like a hula

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Speaker 1: hoop around a globe, where the hula hoop is going

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Speaker 1: over the north and south pole, so it's vertical with

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Speaker 1: respect to the globe. Then imagine that you would slowly

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Speaker 1: twist the hula hoops so that it is actually orbiting

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Speaker 1: the Earth that way as well. It's important because you

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Speaker 1: have to remember the Earth is an orbit around the Sun.

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Speaker 1: So in order for you to have a consistent satellite

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Speaker 1: view with the same lighting over the same region each day,

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Speaker 1: the orbit has to rotate, right, because the Earth is

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Speaker 1: going around a circular path of the Sun. If the

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Speaker 1: orbit didn't rotate, then you wouldn't have that effect of

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Speaker 1: passing over the same region um at the same time

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Speaker 1: of day each day. Now, the rotation of the orbit

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Speaker 1: happens because the Earth is not a perfect sphere. It's

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Speaker 1: a bit bigger around the equator and holy cats, I

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Speaker 1: can totally relate to that. And so the equator region

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Speaker 1: exerts the gravitational pull on the satellite that if no

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Speaker 1: other physics were involved, would ultimately cause the satellite's orbit

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Speaker 1: to drift into one that's over the equator. But due

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Speaker 1: to the satellite's angular momentum, the satellites orbit doesn't tilt

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Speaker 1: down to become equatorial. Instead, the whole orbit rotates. If

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Speaker 1: you if you were to ever use a coin, and

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Speaker 1: you've seen a coin start to do that that cool

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Speaker 1: rotate thing on a table, like it's it's starting to fall,

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Speaker 1: but it hasn't actually clattered flat on the table, but

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Speaker 1: it's doing that thing where it's kind of rotating around,

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Speaker 1: almost like a top. That's kind of what the orbit

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Speaker 1: is doing. And the rotational speed of the Earth, the

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Speaker 1: rotational speed of the orbit, and the period of the

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Speaker 1: orbit line up so that the satellite will always pass

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Speaker 1: over a specific spot on the Equator at the same

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Speaker 1: time of day each day. So let's say it passes

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Speaker 1: over Bogatam at three pm. Well that's gonna happen from

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Speaker 1: there on out, So tomorrow it'll be overhead of Bogata

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Speaker 1: at three pm, and the next day, and the next

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Speaker 1: day and so on. Subsequent orbits throughout the day will

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Speaker 1: have the satellite pass over different equatorial cities, like say

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Speaker 1: Singapore or Nairobi, and it will always pass over those

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Speaker 1: respective cities at the same time of day each day

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Speaker 1: for that city. I'm not saying it will pass over Bogata,

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Speaker 1: Singapore and Nairobi at three pm. That would be impossible,

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Speaker 1: but that they will pass over uh those respective cities

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Speaker 1: at the same time per day. And I realized that

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Speaker 1: this gets really tricky to imagine. It's hard to explain

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Speaker 1: without visual aids. So if you're having trouble getting a

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Speaker 1: handle on polar Sun synchronous orbits, I recommend searching for

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Speaker 1: videos that illustrate how they work. Also, I'm not even

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Speaker 1: scratching the surface here as far as how complicated these get.

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Speaker 1: If you really want to learn more, I recommend a

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Speaker 1: paper by Ronald J. Bowaine, and it's titled A B

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Speaker 1: C's of Sun Synchronous Orbit Mission Design. It is a

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Speaker 1: really good paper that goes into the technical details. Anyway,

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Speaker 1: you might wonder why we would even worry about getting

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Speaker 1: that kind of information in the first place, Like what's

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Speaker 1: the big deal. Why do we even care about getting

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Speaker 1: a satellite out there to pass over the same part

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Speaker 1: of the Earth at the same time of day each day. Well,

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Speaker 1: one reason is that it helps us track changes in

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Speaker 1: a region over time. This is particularly important as we

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Speaker 1: examine the effects of climate change in that region. So

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Speaker 1: you want as many factors to be the same in

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Speaker 1: your observation so that any differences you see you can say, well,

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Speaker 1: this clearly didn't show up because the satellite is passing

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Speaker 1: over at a different time of day, so the lightings

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Speaker 1: at a different angle instead, Uh, really reflective of actual

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Speaker 1: changes that are happening on the ground. So keeping as

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Speaker 1: much of your other factors consistent as possible is really important.

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Speaker 1: Keeping in mind that obviously, like angles of light are

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Speaker 1: going to change as the seasons change, but you know

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Speaker 1: that's something you can you can factor in. Whereas like

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Speaker 1: you want to be able to say, like, from one

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Speaker 1: summer to the next, Oh, we've seen that, say the

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Speaker 1: coastline of this region has changed dramatically, and potentially that's

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Speaker 1: due to climate change. That's why you would need to

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Speaker 1: have something like this so that you could draw those

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Speaker 1: kind of conclusions. All Right, we've got more to say

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Speaker 1: about orbits. I know it's just gonna keep on going

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Speaker 1: around and around, because that's what orbits do. But before

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Speaker 1: we get to that, let's take another quick break. Okay,

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Speaker 1: so far, what I've described are you could essentially call

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Speaker 1: them circular orbits. They don't have to be, but that's

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Speaker 1: the way we typically imagine orbits, or at least the

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Speaker 1: way I typically imagine an orbit is kind of like

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Speaker 1: a circle around whatever body it's orbiting, so they more

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Speaker 1: or less keep a a consistent distance from the the

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Speaker 1: orbiting uh center, so Earth. In other words, like they

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Speaker 1: would just keep a pretty consistent distance from the Earth.

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Speaker 1: But orbits do not have to be perfectly circular, or

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Speaker 1: even circular at all. You can have elliptical orbits, and

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Speaker 1: an elliptical orbit is oval in shape, and this means

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Speaker 1: that the satellite's distance from the Earth varies throughout its

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Speaker 1: orbital path. That also means that the satellite's velocity will

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Speaker 1: change as it orbits the Earth. So as the satellite

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Speaker 1: is moving toward the Earth, its velocity will start to

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Speaker 1: increase due to the Earth's gravitational pull, and as it

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Speaker 1: moves away from the Earth, its velocity begins to slow

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Speaker 1: down again because the Earth's gravity is pulling back on it.

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Speaker 1: Now the low point of the orbit, so the part

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Speaker 1: where the satellite is closest to the Earth is called

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Speaker 1: the parage, the furthest point from the Earth is the apogee.

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Speaker 1: That's the high point of the orbit. And a lot

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Speaker 1: of communication satellites have an elliptical orbit. And you might

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Speaker 1: wonder why, Well, because an elliptical orbit means that a

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Speaker 1: satellite is going to travel over a specific region for

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Speaker 1: a really long time as it moves through its apogee, right,

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Speaker 1: because it's slow, and this is the part where it's

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Speaker 1: for this from the Earth, So you can provide a

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Speaker 1: long period of coverage UH using this kind of orbit.

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Speaker 1: And then when it moves out of sight, when it's

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Speaker 1: out of the line of sight, it's actually starting to

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Speaker 1: approach its parage, so it speeds up, so it zips

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Speaker 1: around the back of the Earth. So this way you

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Speaker 1: have UH limited interruptions of coverage. And if you have

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Speaker 1: just a few set communication satellites that have these kind

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Speaker 1: of elliptical orbits over a region, you can have consistent

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Speaker 1: communications coverage over that region and you don't have to

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Speaker 1: use as many satellites. UH. You just have to have

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Speaker 1: enough so that there's one to cover. When you know,

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Speaker 1: when satellite A is moving out of site, you have

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Speaker 1: a satellite B that you can switch to that will

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Speaker 1: continue coverage. So these are really important orbits specifically for

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Speaker 1: communications uh satellites, not just them, but that's a big

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Speaker 1: reason to to use an elliptical orbit. And sometimes we

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Speaker 1: describe these satellites with these orbits as having highly elliptical

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Speaker 1: orbits or h e O s. And then let's wrap

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Speaker 1: this up with lagrange orbits or lagrange points. Okay, so

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Speaker 1: there are a few positions in space in our Solar

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Speaker 1: System where if you place an object there, it tends

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Speaker 1: to stay there relatively speaking. I mean, you do have

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Speaker 1: to remember that all of us, our Solar System included,

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Speaker 1: we're all whizzing through space. So really when we say

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Speaker 1: it stays there, we we mean relative to Earth or

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Speaker 1: in it doesn't have to be Earth. You can have

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Speaker 1: lagrange points around any orbiting objects, but we primarily concern

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Speaker 1: ourselves with the Earth lagrange points. So at these points

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Speaker 1: in space, the gravitational pull of two large masses on

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Speaker 1: an object precisely matched this in tripetal force needed for

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Speaker 1: that object to move with them, so that that's complicated,

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Speaker 1: but it's kind of like saying, imagine you've got a

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Speaker 1: tug of war game and both sides of the game

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Speaker 1: are of perfectly equal strength. So the middle of the

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Speaker 1: rope that's being used in the tug of war isn't

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Speaker 1: going anywhere because the forces that are acting on it

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Speaker 1: on either side are equal. Well, there are five lagrange

432
00:27:24,840 --> 00:27:29,840
Speaker 1: points in our Earth and Sun relationship Earth Sun Moon.

433
00:27:29,920 --> 00:27:33,320
Speaker 1: Really one is on the opposite side of the Earth

434
00:27:33,600 --> 00:27:36,760
Speaker 1: from the Sun, so it's always on the night side

435
00:27:37,080 --> 00:27:39,520
Speaker 1: because it's always going to be on the opposite side

436
00:27:40,160 --> 00:27:42,919
Speaker 1: of the Earth from where the Sun is. This is

437
00:27:42,920 --> 00:27:45,840
Speaker 1: at a point that's actually beyond our moon, so it's

438
00:27:45,880 --> 00:27:50,359
Speaker 1: it's beyond lunar orbit. This is the L two lagrange point.

439
00:27:50,440 --> 00:27:53,480
Speaker 1: This is where the James Web Space Telescope is, along

440
00:27:53,480 --> 00:27:57,600
Speaker 1: with a few other space observation satellites, and it's useful

441
00:27:57,640 --> 00:28:01,760
Speaker 1: because when you put satellites out in this point, they

442
00:28:01,800 --> 00:28:06,440
Speaker 1: are protected from the radiation of the Sun. So if

443
00:28:06,480 --> 00:28:11,360
Speaker 1: you're trying to detect very faint sources of radiation out

444
00:28:11,520 --> 00:28:15,080
Speaker 1: in the in the in the universe, then you don't

445
00:28:15,119 --> 00:28:19,800
Speaker 1: have to worry about the radiation from the Sun interfering um.

446
00:28:19,840 --> 00:28:21,960
Speaker 1: You also only need a heat shield on one side

447
00:28:21,960 --> 00:28:24,480
Speaker 1: of the satellite because it's going to be the heat

448
00:28:24,520 --> 00:28:27,840
Speaker 1: that's radiated from the Sun and the Earth which will

449
00:28:27,880 --> 00:28:33,680
Speaker 1: be behind that satellite. Well it's facing out towards you know, space.

450
00:28:34,720 --> 00:28:38,440
Speaker 1: The L one lagrange point is between the Earth and

451
00:28:38,480 --> 00:28:41,200
Speaker 1: the Sun. It's actually much closer to the Earth than

452
00:28:41,240 --> 00:28:45,040
Speaker 1: the Sun. But that makes sense because remember gravitational force

453
00:28:46,040 --> 00:28:50,200
Speaker 1: sorry Einstein, is dependent upon not just mass but distance.

454
00:28:50,680 --> 00:28:54,160
Speaker 1: So you have, since the Earth is far less massive

455
00:28:54,240 --> 00:28:58,080
Speaker 1: than the Sun, you have to have the satellite at

456
00:28:58,120 --> 00:28:59,920
Speaker 1: a position that's much closer to the Earth than it

457
00:29:00,160 --> 00:29:01,560
Speaker 1: is to the Sun. But once you get to that

458
00:29:01,640 --> 00:29:05,880
Speaker 1: sweet spot, it'll pretty much stay there. And we've got

459
00:29:05,880 --> 00:29:09,640
Speaker 1: satellites in that orbit that are designed to observe the Sun.

460
00:29:09,840 --> 00:29:12,640
Speaker 1: So that's how we, you know, get something that is

461
00:29:13,280 --> 00:29:16,040
Speaker 1: in a fixed orbit between the Earth and the Sun.

462
00:29:16,680 --> 00:29:20,160
Speaker 1: It can maintain that orbit and it can have continuous

463
00:29:20,200 --> 00:29:23,880
Speaker 1: observation of the Sun, which is really useful science information

464
00:29:23,920 --> 00:29:27,760
Speaker 1: for us. There's the L four and L five lagrange points.

465
00:29:27,760 --> 00:29:30,760
Speaker 1: These are actually along the Earth's orbit around the Sun.

466
00:29:31,240 --> 00:29:35,280
Speaker 1: So there's one leading the Earth's orbit and one trailing

467
00:29:35,360 --> 00:29:38,040
Speaker 1: behind the Earth's orbit, and they're each at a sixty

468
00:29:38,120 --> 00:29:41,880
Speaker 1: degree angle out from the Earth with respect to the Sun.

469
00:29:42,640 --> 00:29:45,680
Speaker 1: These points are the only ones where an orbit can

470
00:29:45,760 --> 00:29:49,680
Speaker 1: just be stable without further adjustments orbits at the other

471
00:29:49,800 --> 00:29:54,400
Speaker 1: lagrange points are delicate. They require near constant adjustments to

472
00:29:54,520 --> 00:29:58,640
Speaker 1: maintain in place. I saw one uh analogy that suggested

473
00:29:58,720 --> 00:30:03,080
Speaker 1: it's kind of like arching a ball on the point

474
00:30:03,240 --> 00:30:05,760
Speaker 1: of a pyramid, and you have to do it just

475
00:30:06,120 --> 00:30:09,560
Speaker 1: right for it to maintain balance, and you probably are

476
00:30:09,600 --> 00:30:12,760
Speaker 1: going to have to do constant adjustments so that it

477
00:30:12,800 --> 00:30:18,080
Speaker 1: doesn't tip over. And finally, we have the L three

478
00:30:18,440 --> 00:30:21,120
Speaker 1: lagrange point. This one's on the opposite side of the

479
00:30:21,160 --> 00:30:24,320
Speaker 1: Sun from the Earth, So if you were to draw

480
00:30:24,440 --> 00:30:28,320
Speaker 1: a straight line from the Earth through the Sun to

481
00:30:28,480 --> 00:30:31,840
Speaker 1: the other side, that's where the L three point is.

482
00:30:32,800 --> 00:30:35,200
Speaker 1: We are not likely to ever use that for a

483
00:30:35,240 --> 00:30:39,280
Speaker 1: satellite for a good reason, because the Sun would always

484
00:30:39,320 --> 00:30:42,640
Speaker 1: be between us and that satellite, and the Sun would

485
00:30:42,640 --> 00:30:46,280
Speaker 1: block any communications that we could send to or from

486
00:30:46,600 --> 00:30:53,000
Speaker 1: that satellite. You could presumably have some form of space

487
00:30:53,040 --> 00:30:56,640
Speaker 1: station there, I guess, but it would be one that

488
00:30:56,680 --> 00:30:59,800
Speaker 1: would be effectively cut off from the Earth without you know,

489
00:31:00,120 --> 00:31:04,400
Speaker 1: some other network out there, because again the Sun is huge,

490
00:31:04,600 --> 00:31:09,200
Speaker 1: it's gonna block all other communication efforts. But that is

491
00:31:09,200 --> 00:31:14,400
Speaker 1: a quick rundown of satellite orbits. Obviously, it gets way

492
00:31:14,440 --> 00:31:17,280
Speaker 1: more complex than this, And again I didn't touch things

493
00:31:17,320 --> 00:31:21,280
Speaker 1: like orbits around other planets, which can get pretty complicated,

494
00:31:21,280 --> 00:31:25,080
Speaker 1: particularly with planets that have lots of moons on them. Um.

495
00:31:25,120 --> 00:31:29,440
Speaker 1: And obviously the plants also have different masses, which means

496
00:31:29,520 --> 00:31:33,000
Speaker 1: that you're taking different things into consideration as far as

497
00:31:33,040 --> 00:31:38,320
Speaker 1: the gravitational pull. So yeah, it does get really complicated,

498
00:31:38,560 --> 00:31:43,080
Speaker 1: but I wanted to make sure that we had sort

499
00:31:43,120 --> 00:31:47,800
Speaker 1: of a basic coverage of the subject to kind of

500
00:31:48,440 --> 00:31:51,760
Speaker 1: kind of get an appreciation for all how complicated this is.

501
00:31:51,800 --> 00:31:54,960
Speaker 1: As for space junk, well, I mean, there are certain

502
00:31:55,040 --> 00:31:58,480
Speaker 1: orbits that are very valuable and they can only hold

503
00:31:58,520 --> 00:32:01,880
Speaker 1: a certain amount of satellites before you start to run

504
00:32:02,000 --> 00:32:08,280
Speaker 1: into the possibility of collisions in that orbit, which obviously

505
00:32:08,320 --> 00:32:11,440
Speaker 1: can cause an enormous problem. Not only are you talking

506
00:32:11,480 --> 00:32:16,760
Speaker 1: about the potential destruction of at least two satellites, you're

507
00:32:16,800 --> 00:32:21,640
Speaker 1: also talking about those satellites then creating more space junk,

508
00:32:21,760 --> 00:32:26,000
Speaker 1: like more shrapnel if you will, that can potentially put

509
00:32:26,120 --> 00:32:30,160
Speaker 1: other satellites in danger, and it can become this cascade effect. Uh,

510
00:32:30,360 --> 00:32:34,720
Speaker 1: you know, there are graveyard orbits that we've had, you know,

511
00:32:34,720 --> 00:32:37,360
Speaker 1: satellites get pushed into in order to kind of be

512
00:32:37,440 --> 00:32:41,360
Speaker 1: out of the way. But that will eventually get pretty

513
00:32:41,360 --> 00:32:45,959
Speaker 1: complicated to Also, another big issue for astronomers here on

514
00:32:46,040 --> 00:32:48,800
Speaker 1: Earth is that the more satellites we put out in space,

515
00:32:48,840 --> 00:32:53,160
Speaker 1: the more interference there is for astronomical observations, at least

516
00:32:53,240 --> 00:32:57,960
Speaker 1: using earth bound telescopes. So that's another big issue UM,

517
00:32:58,040 --> 00:33:01,440
Speaker 1: and it's complicated, Like you start looking at things like

518
00:33:01,440 --> 00:33:07,360
Speaker 1: SpaceX's plan with Starlink, and it's not the only Internet

519
00:33:07,640 --> 00:33:11,160
Speaker 1: based satellite system that's been proposed to use you know,

520
00:33:11,280 --> 00:33:14,080
Speaker 1: thousands and thousands of satellites. There are others as well,

521
00:33:15,200 --> 00:33:18,960
Speaker 1: and you start to see where the potential issues are.

522
00:33:20,480 --> 00:33:25,840
Speaker 1: And we've had people warning about the dangers of space

523
00:33:25,920 --> 00:33:28,760
Speaker 1: junk for a very long time, but I feel like

524
00:33:29,640 --> 00:33:34,280
Speaker 1: there hasn't really been a huge move on the regulations

525
00:33:34,320 --> 00:33:38,480
Speaker 1: side to kind of curb that UM. And of course

526
00:33:38,520 --> 00:33:42,320
Speaker 1: certain countries are probably a bit more gung ho about

527
00:33:42,360 --> 00:33:46,720
Speaker 1: pursuing opportunities to get satellites on in orbit than others.

528
00:33:46,760 --> 00:33:49,720
Speaker 1: So this is going to continue to be an issue

529
00:33:49,760 --> 00:33:52,440
Speaker 1: and it's just going to get worse before it gets better. Uh,

530
00:33:53,560 --> 00:33:57,040
Speaker 1: it is odd to think that for something as vast

531
00:33:57,080 --> 00:34:02,760
Speaker 1: as space, there is this ligitimate concern about the potential

532
00:34:02,840 --> 00:34:09,040
Speaker 1: for collisions in these specific orbits. But that's where we are. Okay,

533
00:34:09,080 --> 00:34:13,040
Speaker 1: that's it for our brief overview of satellite orbits. Hope

534
00:34:13,080 --> 00:34:15,480
Speaker 1: you learn something, Hope you enjoyed this. Hope you go

535
00:34:15,520 --> 00:34:19,120
Speaker 1: out and look up more information about this so that, uh,

536
00:34:19,160 --> 00:34:23,200
Speaker 1: you know, my poor explanations can become more clear. As

537
00:34:23,239 --> 00:34:27,080
Speaker 1: you see things like video representations of these orbits, you

538
00:34:27,160 --> 00:34:31,160
Speaker 1: can kind of understand why we use the orbits that

539
00:34:31,200 --> 00:34:34,720
Speaker 1: we do. And if you have suggestions for future topics

540
00:34:34,760 --> 00:34:37,279
Speaker 1: I should cover on tech stuff, whether it's a technology,

541
00:34:37,480 --> 00:34:42,240
Speaker 1: a company, a person in tech, a trend, something basic

542
00:34:42,320 --> 00:34:44,080
Speaker 1: that you would like me to explain in the tech

543
00:34:44,080 --> 00:34:46,719
Speaker 1: stuff tidbits, let me know the best way to do

544
00:34:46,760 --> 00:34:49,600
Speaker 1: that is to reach out on Twitter. The handle for

545
00:34:49,640 --> 00:34:52,680
Speaker 1: the show is tech Stuff hs W, and I'll talk

546
00:34:52,680 --> 00:35:01,040
Speaker 1: to you again really soon. Text Stuff is an I

547
00:35:01,160 --> 00:35:04,680
Speaker 1: Heart Radio production. For more podcasts from I Heart Radio,

548
00:35:05,000 --> 00:35:08,160
Speaker 1: visit the i Heart Radio app, Apple Podcasts, or wherever

549
00:35:08,239 --> 00:35:09,760
Speaker 1: you listen to your favorite shows,