An Astrophysicist reacts to THE EXPANSE

[geektalk]

Is Amazon’s sci-fi show “The Expanse” as scientifically accurate as people claim? 

Dr. Becky

---

that is such attention to detail

and i love it this is this is why

you’ve got the physicist on your side

because this level of attention to

detail is ridiculous

hello and welcome to this episode of

astrophysicist reacts with me

dr becky smith this is the show where we

have some fun watching some sci-fi but

we also see what we might learn about

the laws of physics

along the way either from you know

things that the show creators got right

or usually for plot reasons

when they decided to ignore some of the

laws of physics and we chat about how

things

would have been different if that wasn’t

the case now last episode i reacted to

the movie

contact and in that episode i asked you

a lot to essentially put in the comments

what you wanted to see me react to next

and an overwhelming majority of you said

the expanse now i have to admit i did

try and get into the show a couple of

years ago i think i watched the pilot

and it just

it didn’t grip me like i fell asleep in

it to be quite honest and then i just

kind of

forgot that it existed until you all

reminded

me of it again so i just re-watched that

pilot didn’t fall asleep

and i’m about to watch season one

episode

two now i feel like i have to say this

before we begin because as a scientist

i’m very aware that i have a bias going

into this

i guess we can’t really call it an

experiment but let’s call it an

experiment because

so many of you and so many of my

colleagues as well like

katie mac for example like have all

raved about how

they think that the expanse is the most

accurate

sci-fi show currently on tv which is

some high high

stakes i’m kind of going into this with

a little bit of confirmation bias which

isn’t what you want

so i’m going to try and be as objective

as possible

while i watch and react to season one

episode two of the expanse

so you might think that like a tiny

piece of debris wouldn’t have that big

of an impact on a spacecraft but

actually the smaller the piece of the

debris the

bigger danger they usually are to some

extent anyway because

when they’re that small and they’re

traveling that fast as well it’s

essentially like a tiny bullet hitting

your spacecraft so instead of something

that’s much larger which might maybe

leave a den

glancing blow kind of thing the smaller

pieces of debris actually punch

straight through it’s a massive concern

for example for the international space

station like if there

is any uh debris that’s being tracked

that they know has had a collision and

turned into lots of smaller pieces

they tend to have evacuation procedures

in process for the international space

station because if you know a tiny piece

of debris

just completely goes through those metal

walls and you know ruins your

essentially seal that’s keeping your

astronauts alive

in there it’s not exactly a good thing

which is why debris like this can be

really bad for a spacecraft

we’re not going anywhere

that was weird so she turned the engines

off

like all the power is still on because

like you know all those computer desks

and the lights are still on but they had

to turn on like their

magnetic boots which i think like hold

them down to like the metal

surface which means that like their

artificial gravity

has now been turned off so that’s

somehow tied to the engine

and not like to the power so like you

know like in passengers like the ship

has a power

failure and they’re like you know

artificial gravity fails when she’s in

the pool and it’s like terrifying

but here the the artificial gravity is

not tied to the power it’s tied to the

engine

so like i’m really intrigued now like

what

they could have done to produce

artificial gravity that would be tied to

the

engine because the craft was you know

not any sort of special shape it was

sort of like a little command module

thing not like say in the martian where

they have that craft

sort of like a circle that spins it’s

that same feeling that you get when

you’re on a roundabout and you spin

really fast and you can feel that force

pushing you back as you’re spinning

right if you can spin your craft

then you’ll have the same thing this

force feeling like it’s pushing you

outwards and so it’s sort of like

pushing you into the floor and that’s

how they produce

artificial gravity and that would be

tied to the engine because i guess it

would be the engine that’s sort of

powering it to move in a circle but this

isn’t moving in a circle

so i’m intrigued i’m gonna i’m gonna

keep watching see if i can i can figure

it out because i couldn’t figure it out

in the pilot episode when they were on

this sort of big like

big long ship um

okay i keep watching just enjoy it just

enjoy

it becky don’t try and overthink it he’s

an opa smuggler and a terrorist

the secretary general he’s even the

secretary general has publicly disavowed

gravity torture if you want to talk to

that belter

you put him in the tank gravity torture

like that’s kind of crazy that they’ve

thought to actually use that in the

story like

yes bodies would completely grow up

differently under different strengths of

gravity so

for example like martian gravity is like

the third that of

earth’s a tiny asteroid in the asteroid

belt like series would probably

something like i don’t know top my head

like a hundredth or so of earth’s

gravity if that

so your bones would have developed

differently if you’d only ever

experienced that gravity they wouldn’t

be as strong to resist that sort of like

pull downwards all the time

people would probably be taller if you

brought them to earth they would

probably barely be able to

stand up you know even astronauts that

come down from the international space

station where okay

zero gravity for like six months they

come back and say earth gravity is crazy

to them it’s like it’s sort of like

crushing them to the ground is what it

feels like after

having been weightless for so long and

also like it’d be really difficult to

breathe as well if you weren’t used to

that strength of gravity because

you should have this air pressure this

column of air pressure just

crushing down on you that would make it

so so

difficult so i mean okay fair enough our

astronauts don’t necessarily notice

those kind of differences they’ve

probably not grown up you know for

years and years in only that sort of

lower gravity

but we do notice differences to their

bodies when they return to earth after

an extended time in space so for example

the astronaut scott kelly spent a year

in space whereas his twin

mark didn’t when he came back down to

earth we could literally have like a

control

in terms of a scientific experiment to

actually compare to so he actually got

taller in space

because you know like your spine isn’t

crushed down all the vertebrae aren’t

pushed down they sort of have space to

to stretch out and there’s loads of

differences just from spending

a year in space in in low gravity or in

zero gravity is on the

international space station so the fact

that they’ve actually thought that

through and thought to include it

is really cool like that’s nothing to do

with

technology or you know like any aliens

or anything like that you normally see

in sci-fi

it’s literally just pure physics

you know who i am i’ve heard a few yes

so they’ve put the belt to this person

that’s grown up on the astro belt with

this weak gravity into a tank of water

instead of just leaving them

out in the air essentially where they

would be fully subject to earth’s

gravity in the water instead

they’ve got the water to help take some

of their weight right you’re more

buoyant in water you’ll notice when you

get in a pool right or in

in the sea you do feel naturally lighter

and you can really tell that if it’s a

very very salty ocean like something

like

the dead sea or something like that a

salty body of water you obviously are

very very buoyant you know you can float

without

any effort so this will obviously take

away some of those crushing effects of

the earth’s gravity

for him and he’ll feel a lot a lot

lighter to me

that’s what they’re talking about in

that song that’s like i feel like an

astronaut in the ocean

anytime i get in the sea and you feel

that much lighter you do feel like you

could be sort of like in zero gravity

like in space or at least that’s kind of

what i think that lyric means anyway

oh carry on peace

[Music]

oh my god it’s like have you try and

turn it off and turn it back on again

god people are dying here

i love how the the door for the airlock

is like an

old window crank on a car

someone hurt us someone hurt us yeah

are they coming just waiting for the

mouse back

i like that they’ve included that that

there is actual light travel time so any

message you send

you know you’re gonna have to wait for

that to get there and then for the light

to travel back to you to actually

receive a reply

as well and in the solar system you know

that’s not going to be

years or anything like that like with

sort of like interstellar light signals

but it will be

you know minutes to hours for example

like earth to mars travel time

depending on where earth and mars are if

they’re like their closest approach it’s

five minutes or so or if they’re at

their furthest possible distance apart

in their orbits it’s more like about

half an hour ish or so so that gives you

some idea in terms of you know light

travel

distance in the solar system so i guess

they’re hoping it’s someone close by

that let’s heard this message

they can actually come and rescue them

so they should only be a couple of light

minutes away hopefully and so they

shouldn’t have to wait too long for this

message to come back

ship how far

it’s almost 80 000 clicks it keeps using

clicks as a distance measure and i

have not heard of clicks

the term click is derived from the word

kilometer oh okay

so one click equals one kilometer so

they’re 80 000 kilometers away

that is quite the distance

so just for context like the earth and

the moon are like about

300 000 kilometers away on average

or so i think anything back you’ll tell

me if i’m right if i’ve remembered that

number right

what just happened to that like he

poured that water and it didn’t

pour straight out of it so yeah okay so

that must mean

that they’re spinning

to get the artificial gravity on

this station so i think they’re the

series

station so they must be spinning in

which case the the point where you start

spinning the water you know it’s not

gonna fall straight down it’s gonna fall

with the spin

so you you’re gonna have to like

re-learn where to pour from in the same

way that like

you learn say for example when you’re

playing tennis or something like that

you learn where to put your racket

because you know where roughly the ball

is going to be once it’s bounced

you’re almost going to have to like

relearn where to pour your water from

to to account for the fact that it won’t

fall straight down

because your force of gravity is not

coming from straight down it’s coming

from the fact that this whole

thing is spinning that is

such attention to detail

and i love it this is this is why you’ve

got the physicist on your side because

this

level of attention to detail is

ridiculous

so that massive ship that just took them

aboard like that didn’t appear to be

spinning at all and yet there’s still

artificial gravity aboard it so

like i’m still confused like if it’s not

spinning like clearly some of them are

spinning to get their artificial gravity

like the series station

but then the and some of the smaller

craft but these larger craft aren’t

oh that’s bugging me that i can’t figure

it out

you are prisoners of the mars

congressional republic move and you die

yeah i mean i really enjoyed that like i

can see why people like it so much just

because there’s so much attention to

physics detail which obviously is a nerd

i appreciate

it’s amazing to think about how they’ve

built this story around

resources essentially like gravity

almost as a resource but then

like water and air things you take for

granted on earth you know not

necessarily being readily available and

it actually reminded me of something

that happened last week which was the

perseverance mission

which is currently on mars made oxygen

out of the carbon dioxide that makes up

the majority of the martian

atmosphere they made about like five

grams of oxygen which is enough to keep

your personal life for about

10 minutes or something but somewhere

like mars

you know with that you know natural

resource if you want to call it the

carbon dioxide would be able to sustain

themselves to make their own

oxygen on mars as long as you put it you

know inside some sort of tent

or i think they were kind of like little

domes like the eden project in carmel i

guess is how i saw them in the pilot

if you could fill those then you know

you you would have

your own way of producing oxygen from

the natural resources and that is kind

of like the first step

to humans actually putting a base that

we could live on on mars and so that’s

why everyone got excited last week when

perseverance actually did this because

it was that

first step but you can imagine like out

in the asteroid belt and beyond

like those natural resources aren’t

necessarily there for you they were even

mining ice from around the the rings of

saturn

to melt into water for drinking out on

series so

it’s amazing you know how many wars have

been started over fighting basically

over resources so it’s amazing to think

how they’ve sort of taken

that what is almost like a trope of

humanity really and just completely

transplanted it into

this sort of futuristic society that’s

conquered

the solar system and this is why it

reminds me of red rising by pierce brown

as well because they play on that as

well

in that book and yeah it’s just

so so well done the gravity thing though

is still me so i’m actually

gonna look this

up like how do they actually have

artificial gravity in the expanse like

what do they

do who knew there was like a whole page

on my computer about artificial gravity

in

fictions where’s these one so there it

is okay in the expanse series space

stations generate artificial gravity by

rotating as do

spun up hollowed out asteroids usually

around 0.3 g so

martian gravity-ish moving ships under

constant thrust also assuming that

gravity by linear

acceleration right okay that’s how they

do it so those

big long ships we saw by constantly

accelerating

they are producing a force that would

create gravity so you would have to have

all the flaws that you’re walking on on

your ship

sort of perpendicular to whatever

direction that you’re accelerating it

in so i guess it would be kind of like a

building on its side that’s

thrusting through space essentially i

guess you can kind of

recreate that feeling like if you’re in

a lift or elevator as americans call

them right when you when you feel it’s

starting to to push you up you feel that

force of acceleration as the lift goes

and you feel that sort of extra force

and when it decelerates you sort of get

that swooping in your stomach right as

you feel lighter all of a sudden

that’s the kind of force that they’re

generating there because we talk about

gravity like

historically it was described as a force

but technically gravity is not a force

like einstein described gravity as

massive objects curving space time and

then

we as all the objects traveling on that

curved space-time

essentially feel an acceleration because

of it so gravity isn’t really force it’s

more of an acceleration

so if you can generate an acceleration

then essentially you can generate

artificial gravity as well and i love

that that’s what the show has

has chosen to do and i feel like only

people who are really in the know with

physics would necessarily

get at that from the show

and would just assume that it did the

usual sci-fi thing of being like eh

we somehow managed to figure out how to

generate our own gravity in space don’t

worry about it

these they’ve actually worried about it

and that’s

that’s what makes me really

appreciative of this show is that they

went to those

lengths to do it all right that was me

reacting to

season one episode two of the expanse if

there’s

other episodes of this series that you

want me to watch if there’s other movies

or

tv films that are sci-fi based that you

want me to react to let me know

down in the comments just going to pick

up on a couple of things i noticed in

the comments from last episode

first of all the martian yes 100 have

seen that film

one of my favorite films of all time and

i probably couldn’t react to it because

instead i would just be quoting it at

you word for word i’ve seen it

that many times uh interstellar and a

rival were requested

a lot i have to be honest didn’t enjoy

those films that much it was

specifically the ending of both of them

that i didn’t enjoy i just

couldn’t turn my astrophysicist brain

off when i was watching interstellar

specifically

so i’ve seen them both once i

technically do a reaction to them but

i’d be going into it knowing that i

don’t like them so if there’s any other

films or tv series that you think of

that you want me to react to

let me know maybe something i haven’t

seen before as well would be

really really cool but until next time

enjoy some good sci-fi

and uh if you get chance head outside

and look up at those

stars because they are as always truly

spectacular

before we get to everybody’s favorite

part the bloopers i just want to say a

big thank you to this week’s video

sponsor

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after watching the expanse

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becky

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thank you so

much to brilliant and now we’re all

those bloopers

the main guy in this kind of looks like

the darkling from shadow and bone

but that might just because i’ve just

finished shadow and bone i wish i hadn’t

i’m not like breathed because it’s over

see there it kind of looks like bucky

but again it could be

just because i’m like breath

with the soldiers over as well

oh god just dribble water all over

myself

like astrophysicists like that’s just

your daily reminder that intelligent

people are just

not that smart

[Music]

oh sorry i just got so distracted by the

artificial gravity infection wikipedia

plate

it was so interesting i was like oh yeah

look at all these ways that it’s been

employed in various different films and

books

anyway one outro i need to do an outro

i actually think that was like maybe

five minutes reading my wikipedia

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