Then 400,000 years after the Big BanG, the universe filled with dark clouds of cold hydrogen and helium gas.

The clouds started to collapse under their own gravity growing denser and hotter…

Once upon a time, there was darkness.

until the gas was so dense and so hot that Hydrogen started to fuse into Helium…

and the first stars were born. And then there was light. And it was good.

stars live by fusing elements in their cores where the temperature and density are great enough. The energy made through fusion in the core eventually leaves the star as light. This is what we see with telescopes!

First hydrogen is fused into helium, accumulating helium ‘ash’ in the core which is surrounded by hydrogen.

If the star is massive enough, the helium core will then start to fuse into carbon, accumulating carbon ‘ash’ surrounded by helium surrounded by hydrogen.

HHe

CNe

OSi

Fe

The more massive the star, the more layers it will accumulate as it fuses heavier elements, Until the star can’t fuse anymore and it enters the last phase of its life.

Carbon

He

H

Helium

Hydrogen

If the star is massive enough, it will explode!!!

The elements will be blown out into space, into other clouds of gas, which will eventually form into new stars like our Sun, into new planets like our Earth, and into new life like you and me.

HI!

How stars live and die depends on what’s happening inside of them, or on their “internal structure.” The internal structure of a star is affected by how much of each element is made and also by how the energy and gas moves around.

In some parts of a star, the energy created in the core moves through the gas as radiation.

In other parts of a star, circulating currents of gas carry the energy with it. This process, known as convection, is a lot like what happens to water as it is heated on a stove!

But in more massive stars, astronomers predict that convection occurs inside the star near its core! The circulation could mix lighter elements back into the core to be fused, releasing more energy and extending the star’s life. But astronomers have a poor understanding of convection inside stars.

in our sun, convection happens near the surface, which we can see with telescopes as a distinct granulation pattern.

this is because astronomers can’t see inside stars. using telescopes, we can only see their surfaces. so How can we learn about the insides of stars to better understand processes like convection that affect how stars live and die?

That’s where I come in. Hi! I’m Jacqueline, and I’m a theoretical

astrophysicist. I want to help answer some of these questions.

But how do i learn about the insides of stars?

I learn about the insides of stars by studying them like

musical instruments!

let me explain with this cello.

Listen...

As i’m playing can you hear its deep sonorous notes? why does a cello

sound like it does?

When i draw a bow across the string, the string vibrates causing the wood to vibrate. the vibrations then travel through the air and to

your ear as sound waves, carrying information about the size, shape, and composition of the

cello - its structure!

But what if for some reason you couldn’t hear the cello? Is there another way you could learn about the cello’s vibrations and its structure?

why yes there is! you could look at the surface. this is exactly what people who

make cellos, called luthiers, do.

to determine that the cello has the right structure, a

luthier sprinkles sand onto its surface.

Then they use a frequency generator to vibrate the wood. this mimics what bowing

the string will do! Based on the frequency, certain parts of the wood move up and

down, bouncing the sand off. Other parts of the wood remain stationary, which is where

the sand settles. The patterns that the sand makes are called nodal patterns.

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So What does this have to do with stars? Stars also vibrate! But instead of wood vibrating, like in a cello, it’s

the gas in a star that is vibrating.

We can’t hear a star’s vibrations because there is no air in space

to carry sound.

However, just like a cello, we can learn about a star’s vibrations by

using telescopes to look at the nodal patterns on its surface - the parts of

the gas that are stationary while others parts are moving.

sO hOW CAN i USE THESE VIBRATIONS TO LEARN ABOUT THE INTERNAL STRUCTURE OF

THE STARS?

Unlike a cello, i can’t make a star here on earth and hook up a frequency generator to

look for nodal patterns.

i can however, use computers to make simulated stars and look for

nodal patterns. This is what i do for my thesis work at the university of

wisconsin - madison!

because I maKe the simulations, I know the internal structure of the stars that i make. for example, what elements there are and what parts

are convective and radiative!

based on the simulated structure i can predict the vibrations and the nodal patterns that would

form on the surface of the star.

then I CAN compare my Predicted nodal patterns against the

observed nodal patterns detected on the surfaces of real stars.

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If my predicted patterns match the observed patterns, then I know that the insides of my simulated

stars are like the insides of those real stars!!!

My work predicting the vibrations of simulated stars is helping astronomers, like myself, better describe what’s happening inside real stars. We are gaining a better understanding of how they live and die, and how they affect new stars, new planets, and maybe new life in our

evolving universe!

If my predictions don’t match the observations, that’s ok too! This still gives me crucial information i can use to

improve my simulated stars.

Well back to work!

AMAzing!!! bravo!!!

Incredible!

thank you for your attention.

i hope you enjoyed the

show!

Story Written BY: Jacqueline goldsteinillustrated by: caleb dillinghamsupported by: jk2x comics