hello it's scott manley here so when i
made that video about the energy
required to destroy a planet i made a
fatal miscalculation you see somehow
that video got way more popular than i
was expecting i was very happy for that
but it ended up getting seen by an
audience who were perhaps less familiar
with physics than many of my viewers and
they were wondering what i was saying
every time i used the word joule I
wasn't talking about diamonds or rubies
or female singer-songwriters no I was
talking about the unit of energy you see
when you're reeling out really big
numbers a lot of people have no idea how
these kind of fit into reality when I
said 200 trillion trillion joules I
might as well been using the term pirate
ninjas at least that would have some
pop-culture reference for people to fall
back on but there are units of energy
that are used in everyday life even
though though most people don't
recognize them calories calories are on
every food label telling you how much
energy is in the food a calorie actually
comes from the amount of energy required
to heat up water and one calorie is
about 4.2 joules although if you look at
the fine print on food labels what
you'll see is they use kilocalories so
roughly speaking one kilo calorie on
whatever food you're eating is 4.2
kilojoules
anyway this is great because it means I
can invoke Ghostbusters and Egan's model
of Twinkie energy visualization the
modern Twinkie is about 40 grams of
sugar and fat coming in at 135 calories
that's about 560 kilojoules now if I
were to cross the memes and immediately
go to back to the future the energy in a
lightning bolt is about 1.1 Giga joules
and that is the equivalent of a Twinkie
that weighs about the same as me that
may seem big but for Twinkies 50th
anniversary they actually made a Twinkie
that was over a ton and if you figure
out the energy content that's about 20
Giga joules or about the same energy as
a large airliner
cruising speed okay this might seem a
little incongruent to non physicists but
energy can come in many forms you can
have the chemical energy in the Twinkie
you can have the electrical energy and
the lightning bolts already can have the
kinetic energy of the airliner all of
these are kind of equivalent physics
tells us how to convert one into the
other so let's try that energy scale
again the energy released any one
Megaton nuclear weapon is about 4.2
million billion joules our one trillion
dietary calories imagine a 300,000 tonne
Twinkie that was about twice the length
of a sports field no interesting thing
about this is that nuclear weapons
yields are measured in tons of TNT
equivalent
so a Megaton blast is equivalent to 1
million tons of TNT and smart people in
the audience will have realized that a
300,000 ton Twinkie contains the same
energy as 1 million tons of TNT yes
the fat and sugar and Twinkies contains
more energy than TNT the difference is
that TNT releases the energy a lot more
quickly whereas eating a Twinkie
releases it relatively slowly unless of
course you feed it to an eight-year-old
kid in which case the results can be
explosive the asteroid impact that made
the Chicxulub crater and probably helped
kill off the dinosaurs had a yield
roughly of about 500 billion trillion
joules which works out to be a 34
trillion ton Twinkie that's maybe a
hundred and five kilometers long and so
we come to the death star laser with its
ability to destroy a planet it would
have to be fueled by a 68 billion
trillion tonne Twinkie that would be
about a hundred thousand miles long yes
that is indeed bigger than a small moon
but the ability to destroy a planet is
insignificant next to the power of some
really big astronomical events supernova
generates something like 10 to the 44
joules of energy that is to fuel that
you would require a Twinkie that was
about 3 million solar masses and 4 au
long
is four times the distance from the
earth to the Sun now of course it's very
hard to imagine a Twinkie that big
especially if you're not an American and
don't live in a country where Twinkies
are in store shells everywhere but you
know the good news is that a Twinkie
that large and that massive would
probably collapse into a black hole very
very quickly so you just have to imagine
a supermassive black hole which is a lot
easier because as Stephen Hawking
pointed out black holes have no hair
I'm Scott Manley fly safe
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