Scale of earth, sun, galaxy and universe
Scale of Solar System Scale of Solar System
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- Where we left off on the last video,
- I think we're getting a reasonably good appreciation
- for how huge the Sun is especially relative to the Earth
- and how far the Earth is away from the Sun.
- And most of these diagrams that we see in science textbooks,
- they don't give justice...
- In fact, when I showed this Sun over here
- that was about 5 or 6 inches across,
- I said that the Earth would be this little speck,
- about 40 feet to the left or the right,
- or its orbit would have a radius of about 40 feet.
- So you wouldn't even notice it,
- if you were looking at this thing over here.
- It would be this little speck orbiting at this huge, huge distance.
- If you look at this Sun over here
- --if I were to draw the whole Sun--
- it would have a diameter of about 20 inches.
- So in this situation, this Earth right here
- --this is drawn to scale--
- this Earth would not be anywhere near this close,
- it would be about 200 feet that way,
- or about 60 or 70 meters.
- So if you could imagine, if the Sun was this size
- sitting on something like a football field,
- this little speck of an Earth, this little thing right here,
- would be sitting on the other 40 yard line,
- 60 meters away.
- So huge, you wouldn't even notice it.
- You might notice this from a distance.
- But you wouldn't even see this thing over here.
- And the other planets are even further,
- well not all the other planets.
- Obviously you have Mercury,
- you have Mercury here.
- I think most of us are familiar with these,
- but I'll just list them in case.
- That's Mercury. This is Venus.
- Mercury is the smallest of the planets
- that is not debated whether it is a planet.
- Pluto is the smallest, but some people debate
- whether it's really a planet or kind of a large solar body
- or dwarf planet or one of those kind of things
- And then you have Venus,
- which is probably the closest in size to the Earth
- or it is the closest in size to the Earth
- and then you have Mars and then you have Jupiter.
- And just to give you a sense of
- once again how far these things are.
- If I were to go back to the analogy of
- this being the size of the Sun,
- then Jupiter is five times further than Earth.
- So this would be,
- if I were to actually do this scale distance,
- this would be 300 meters away.
- So if I had a nice big medicine-ball-sized Sun,
- or maybe a basketball-sized Sun--
- a little bit bigger than a basketball
- as it looks on my screen.
- Then I would put this little thing
- that's smaller than a ping-pong ball,
- I would put this three football fields away.
- That's how far Jupiter is.
- And then Saturn's about twice as far as that.
- Saturn is about nine times the distance.
- Let me make that clear,
- the Earth is one astronomical unit away from the Sun, roughly.
- Its distance changes. It's not a perfectly circular orbit.
- Jupiter is approximately a little bit 5+ astronomical units,
- so a little bit more than
- 5x the distance from the Sun to the Earth.
- And Saturn is approximately 9 astronomical units
- or 9x the distance from the Sun to the Earth.
- So once again this would be 9 football fields away.
- Or another way to think of it is
- that it's essentially a kilometer away,
- if we had kind of a medicine-ball-sized Sun.
- This little, smaller-than-a-ping-pong-ball Saturn
- would be a kilometer away.
- And I just want to really reiterate that,
- because you never kind of visuallize it that way.
- Just for the sake of being able to draw it on a page,
- you see diagrams that look like this
- and they really don't give you a sense of
- how small these planets are relative to the Sun
- and especially relative to their distances from the Sun.
- And after Saturn you have Uranus and then Neptune.
- And obviously these guys are even further.
- Just to give you a sense, you know, it's very easy
- to start talking about galaxies and the universe.
- But what I really just want to get, you konw,
- already we're talking about huge distances, huge scale.
- We already talk about that it would take a jet plane
- 17 years to travel from the Earth to the Sun.
- Multiply that by five,
- that's about 100 years to go from Jupiter to the Sun.
- 200 years to go from Saturn to the Sun.
- So you could have had Abraham Lincoln get into a jet plane,
- and he still wouldn't have got (if he left from Saturn),
- he still would not have got to the Sun.
- So these are huge, huge distances.
- But we're not done, with the solar system there.
- Just to give a sense of scale.
- So this is, this right here, that's the Sun
- and each of these planets is narrower than these orbits.
- So they just draw these orbits,
- but you wouldn't actually even see
- the actual planets here at this type of scale.
- but this is one astronomical unit right over here,
- the distance from the Sun to the Earth.
- Then you have Mars. Then you have the asteroid belt.
- There you have the asteroid belt,
- which also has some pretty big things in itself.
- It has these things
- that are kind of considered almost dwarf planets.
- Things like Ceres, you could look those kind of things up.
- And then you have Jupiter out here,
- and once again we said it would take about 100 years
- or roughly 100 years
- for a jet plane to get from Jupiter to the Sun.
- But even if you take this whole box here,
- which is a huge amount of distance,
- roughly about five astronomical units,
- It would take about 40 minutes
- for light to get from the Sun to Jupiter,
- So this is a huge, huge distance.
- Even this huge distance,
- we could put it into this little box right over here.
- So this whole box, this whole box, right over there,
- can be fit into this box,
- and you need to do that
- in order to appreciate the orbits of the outer planets.
- And so on this scale,
- the Earth and Venus and Mercury and Mars,
- their orbits look pretty much,
- You can't even differentiate them from the Sun.
- They look so close.
- They almost look like that they're part of the Sun,
- when you look at it on this scale.
- And then you have Nepp..
- you have the outer planets Saturn, Uranus, Neptune
- and then you have a Kuiper belt.
- This is more asteroids, but these are kind of more frozen...
- You know when we think of ice,
- we always think of water ice.
- But if you are out here it's so cold,
- that it's relatively getting dark now
- because we're pretty far from the Sun,
- that things that we normally associate as gases
- are going to be in their solid form out here.
- So this isn't just rocky elements.
- This will also be things that you normally associate
- as gases like methane, frozen methane.
- But even here, we're not done.
- We're not even out of the solar system yet.
- And actually, just ot give you a sense of the scale,
- we're operating on right here.
- I have this chart right here from the voyager mission.
- So the voyager missions, Voyager 1 and 2,
- actually Voyager 2 left a little bit earlier, a month eariler,
- Voyager 1 was just travelling faster.
- They left about a year after I was born.
- And their current velocity,
- just to give you a sense of how fast Voyager 1,
- Voyager 1 right here is right now travelling at 61,000 km/hr.
- That's about 17 km/s.
- That's the size of a city every second.
- It's going that fast,
- that's at least in my mind unfathomably fast velocity.
- This thing has been travelling roughly that fast.
- Well you know it has been going around planets
- and gaining acceleration as it went around orbits.
- But for most of the time it's been going at a pretty fast speed.
- Just to translate it to people who don't relate to kilometers,
- that's about 38,000 miles/hr.
- So this huge, huge, unfathomably-fast speed,
- and it's been doing it since 1977.
- I was learning to walk, and when I was learning to walk
- it was travelling at this super fast speed
- and then when I was learning...
- I mean our whole lives when we're sleeping, everything.
- When we're eating, when I'm in elementary school,
- it's still rocketing out of the solar system at roughly the speed.
- Its velocity is changed.
- But especially once it got outside of the planets
- it has been roughly at this velocity.
- So it has just been rocketing out
- and I don't want to say only,
- but it has gotten this far.
- It has gotten about that far right there.
- It's about a 115 or 116 astronomical units.
- And to give a sense, there's 2 ways to think about this,
- one says "Like wow! That's really far."
- Because if you even know that even on this scale
- you can't even see Earth's orbit,
- so this looks like it's a pretty, pretty far distance.
- And just to give you a sense of
- how far 116 astronomical units are,
- if 2000 years ago, Jesus got on a plane.
- I actually cut and pasted a copy of Jesus
- for visualization purposes.
- But if He got on a jetliner at a 1,000 km/hr
- when straight in that direction,
- in the direction of the Voyager.
- The Voyager would only just know be catching up to Jesus.
- So this is a huge, huge, huge, huge distance
- and at the same time even though it's a huge distance,
- especially relative to the everything else we've talked about.
- Relative to just even the outer regions of the solar system.
- We are still talking in terms of a small scale.
- So that is how far Voyager is and just to give a sense on this scale,
- so this whole box over here can be contained in this box,
- and when you look at this box,
- Voyager is only gotten about that far.
- After travelling at this unbelievable velocity for over 30 years,
- for 33, for about 33 years,
- just to give you an idea of these other things,
- Sedna right here is one of the ...
- it's a reasonably large sized outer-solar-system object.
- It's one of the further-est objects
- that we know of in the solar system.
- And has this very eccentric orbit, so it gets,
- I don't want to say relatively close,
- but not unreasonably far away,
- but then it gets really far away from the Sun.
- So even Sedna's orbit,
- if I were to look at this whole box over here,
- can be contained right over here.
- So in this diagram right here, you couldn't even,
- you wouldn't even be able to see,
- it would be like a speck,
- how far Voyager has travelled in 33 years, at 38,000 miles/hr.
- You wouldn't even be able to notice, that distance.
- And even though you can't even notice that distance,
- we still have the Sun's influence.
- The gravitational pull is still attracting things to it,
- and this right here, we speculate is the Oort cloud,
- and this is where the comets originate from.
- This is just a bunch of frozen, you can almost view it
- as frozen gases and ice particles, things like that.
- But this is kind of,
- we're starting to get to outer regions of the solar system.
- This distance right here is about 50,000 astronomical units.
- And just to give you a scale,
- because you hear a lot about light years and all of that.
- Light years are about 63,000 astronomical units.
- So if you go a light year out from the Sun,
- then you will end up in the Oort cloud,
- the hypothesized Oort cloud.
- And just to give a sense of the scale,
- the Oort cloud is actually,
- you know most of the planets orbits
- are roughly in the same plane,
- but this right here is the orbits of the planets,
- and once again these lines are drawn too thick!
- They are just drawn the thinnest possible so that you can see them.
- But they are still drawn too thick.
- And this goes all the way to the Kuiper belt all of these over here,
- so all the way out to the Kuiper belt.
- All the way out to all of the major planets.
- This is Pluto's orbit right over here.
- This whole diagram is only sitting in, right over there.
- You can barely see it.
- That's this whole diagram, is just that dot in this.
- And then you can see the Oort cloud all around it.
- It's more of a spherical cloud, and we think it exists.
- Obviously it's hard to observe things at that distance.
- So hopefully that gives you
- a beginning sense of the scale of the solar system.
- And what's really going to blow your mind is that,
- if this hasn't blown your mind already is that
- this whole thing is going to start looking like a speck.
- When you even just start looking
- at the local area around our galaxy,
- Much less than the universe as a whole.
- Anyway I don't want to get ....
Be specific, and indicate a time in the video:
At 5:31, how is the moon large enough to block the sun? Isn't the sun way larger?
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