made by of and for teens who like cooking today we're gonna be talking about

babies babies are being born all the time in some countries they're born more

often than others this website neil dot fun slash a baby map lights up each

country on earth at the same rate that babies are born in that country so as

you can see India and China light up a lot if you watch long enough you'll get

a little UK blip that's a baby being born I mean not like we don't it's on an

exact baby but the country's light up at about the same rate as the country's

birth rate so you can really get a sense of where people are being born you know

to be honest humans are like one of my top ten favorite animals let's keep

talking about humans and how many of them there are with population

bracketology this website sets up a bracket of cities and then it's your job

to figure out who would win in a battle of who's got the largest population I'm

gonna change it from metro area to state population make a new game uh some of

these states have a by weeks but let me see here between North Dakota and

Illinois Illinois clearly is gonna win it's got big cities it's got Chicago oh

when you click Illinois there you go now between Idaho and Vermont Vermont is not

very populated but Idaho I'm gonna go with Idaho sure close one all right

between New Mexico and Massachusetts Massachusetts definitely has more people

and between Idaho and Massachusetts obviously Massachusetts does but between

Illinois and Massachusetts that Chicago versus Boston and that Boston metro area

is quite expansive but I'm gonna go with Illinois Bob Chicago is like the number

three most populated city I will keep playing this on my own time so I don't

waste yours we need to move on to outer space specifically people who have been

there travels in time and space allows you to look at astronauts from all over

the world from every country even the commercial and tourist astronauts right

now I have my axes built so that I've got the length of trip on the vertical

axis the further down we go the longer the person was in space and

the horizontal axis is when their first launch occurred so if we go to the very

furthest dot and click on it yuri gagarin first human being in space

he only spent point zero eight days in space so he's well didn't have a very

long trip if we go to more recent launches you'll see that some of these

dots have white circles around them those represent people who are currently

in space astronaut scott tingle what's up

you obviously eat little bit the astronaut ok astronauts don't just

travel through space they also travel through time like we just did my beards

longer sure it's different continuity isn't really a priority here

at Vsauce headquarters but what is a priority is learning let's take a look

at this graph and change the horizontal axis to represent time dilation there is

clearly some function that defines how you move through time when you are

moving through space and where you're moving through space check this out

the world record for longest time in orbit is held by cosmonaut padalka who

spent 878 point 48 days flying very quickly around the earth and because of

that padalka is about well more than 25 milliseconds younger than he would have

been if he'd stayed here on earth that's because of time dilation now when you're

in orbit time moves for you at a different rate because of two different

effects special relativity and general relativity if you want to learn more

about these I highly recommend these books

first of all Martin Gardner's relativity simply explained a fantastic but my

favorite book that I read in all of 2017 was Lewis Carroll Epstein's relativity

visualized just phenomenal but if you want to get even deeper you can go a lot

less wrong than getting the Taylor wheeler spacetime physics book just

unbelievable explanations we've also got videos linked down below where you can

learn more but the gist of it is this when you are orbiting around the earth

you are moving faster than people who are just still down on earth at rest

relative to you and that means that time moves more slowly for you a person at

rest down on earth if they could take a telescope and look at your watch would

literally see your watch moving more slowly you would be aging more slowly

you would be reaching your date of death slower but also the higher up you go the

weaker the gravitational field around you will be and that will cause time to

go faster for you these two effects combined into this

blue line that we see here this red line represents time dilation due to orbital

speed and as you can see the larger your orbital altitude is the less quickly you

have to move to not crash into Earth and so the smaller the effect is now this

green line represents the general relativity effects the gravity well

getting weaker and as it does you move through time faster and faster and

faster their combined effect is this blue line labeled net orbital time gain

now astronauts in the National Space Station are at about you know this

altitude a few hundred kilometers and that puts them on the blue line down

here meaning they experience less time than us down on earth

that's why padalka is about maybe 30 milliseconds younger than he would have

been had he not gone into orbit if you'd like to see how you have been moving

through time time orbit will help a lot the University of Surrey created this

app and it takes information about your altitude and motion to compare how you

have moved through time since installing the app compared to someone who has

spent that entire time motionless at sea level fun fact about 3200 kilometers

above Earth's surface a little shy of 10,000 kilometers away from Earth's

center both effects exactly cancel out and no time dilation is experienced

relative to someone at rest down on earth anywho I'm sure you have a lot of

questions for instance Michael that's cool but what I don't understand is how

long can a zucchini grow I'm glad you asked because the world record for

longest zucchini was set by giovanni battista Scozzafava of Niagara Falls he

grew Sukie knee two point five two meters in length it's just phenomenal

but it's actually not that weird zucchinis like to grow big they just

don't taste great when they're large ideally

zucchinis are picked when they're young no more than 12 inches long so if you're

taking notes don't forget that one I also go back to Lightspeed when you're

traveling really quickly all kinds of weird relativistic effects occur okay

time dilation happens obviously but also measured whips change here's a

relativistic car now I can use this slider here to make the cars velocity

slower or faster I can speed it up and notice that as I speed it up the car

appears to contract and become thinner and thinner and thinner until at the

speed of light boom it is well it doesn't have any measurable dimension in

its direction of travel we've heard this before and I've talked about it before

in episodes about whether the earth is flat or not to a particle traveling near

the speed of light the earth would be measurably flat like a disc but would it

appear to be a flat disc no because of an optical illusion known as a Tyrell

rotation here's an example from Wikipedia of what that looks like

I think this animation is brilliant so on the right we have the actual visual

appearance of a cube flying by at some proportion of the speed of light and on

the Left we have the contraction the actual width of it that we would measure

but notice that at 99% the speed of light it almost is completely rotated so

that we see the other side of it here's a way to visualize what a Torrell

rotation is and why it happens here's a cube now let's imagine that this cube is

just moving right past you at some point it's gonna be right in front of you and

then it's gonna move away now normally it would look like this it's not moving

very near light speed you can't see the back of the cube I mean you can because

this one doesn't have any opaque sides but the point is that material over here

isn't reflecting light to your eyeballs we can imagine that this green stick is

a ray of light any light coming from this back edge right towards you that's

getting blocked by the fact that the cube or the shape whatever shape it is

might be opaque but if this stick represents how far light travels in a

second and it's got to travel like this to

to your eye if the object is moving near the speed of light it might be able to

move out of the way of that beam of light and not block it so it will reach

you you'll see the back of the object as if it is actually rotated so an object

traveling near the speed of light will appear to rotate like that it's only its

appearance it won't actually be rotated and if you tried to measure it you would

find that its length had contracted let's watch a video of this effect space

time travel org has a great one and what you see is a bunch of dice and they're

all in a row but then above them a die is gonna fly by I think actually a few

died known as dice will fly by in the same orientation but they won't appear

to be in the same orientation here they come

all right not looking too weird yet but as you'll see the closer they get to us

the more rotated they are until boom right there we can actually see the back

of the cube even though the back is not facing towards us this relativistic

effect is called a Terrell rotation and I love it when it comes to relativistic

effects who can forget red shifting and blue shifting of electromagnetic

radiation not us right and also not velocity Raptor in this game the speed

of light is much much much slower so the normal speed of Velociraptor can move at

is quite close to it so relativistic effects occur now here's the level and

what I need to do is get to this yellow exit door

but wait these bullets are kind of close together I should probably be able to

fit through them let me start moving my velocity will change oh and look the

entire game level warps according to how length changes which means if I go up

the bullets get closer together I can spread them out by moving down now I've

got room great whoa whoa whoa whoa okay don't you don't to fall in the water if

you ever want to center yourself on your character I think you press C yeah okay

there you go I find this interesting but not nearly as helpful press C again to

go back also notice that my velocity it's like I'm playing asteroids if I

stop pushing the key moving at the same velocity but spacebar

will freeze yourself let's save your life many times now

let's look at these keys in order for me to open up this lock I need all of the

keys to have the same color which means I need to find the velocity that

redshifts and blueshifts them so that they match now remember velocity is a

vector so there's also a direction to it so I don't just need to have the right

speed I need to be moving at the right speed in the right direction

all right I'm able to get these two near in color but how do i okay for that one

I have to move left and right I think now I'm getting it really to purple oh

wait that looked but I want to move towards the bullets all right so moving

to the right is the opposite of what I want to do let's see what I can come on

change color yes nice and that's how you do it when you are an expert at the ways

of the universe I'm gonna leave you with well honestly a bit of motivation we've

all heard of the company Arm and Hammer right they were founded 151 years ago

the brand was in use about 31 years before the birth of a man named Armand

Hammer yeah no relation he had nothing to do with founding the company was a

named after him but as you can imagine good old mr. hammer

Armand to those who were familiar with him got constantly teased for having a