Frog and Ducky and the Secret Space Stuff

g o r & F Ducky and the

Secret Space Stuff

Written and Illustrated by Aparajita Rao

Book Project for PHY 312: Relativity and Cosmology Prof. Denver Whittington Syracuse University Fall 2020

This book is dedicated to kids and parents at home during the pandemic and also our PHY 312 class.

We are Frog and Ducky!

We’re surveying the galaxy and looking for secret stuff like black holes!

We want to know why they’re so hard to see!

Every single thing in the galaxy makes a dent in spacetime even if you can't see it--big things like stars and planets, and even little things like you and me!

These dents are created by mass. (if you stand on a scale, you can see how big your mass is.)

Each dent changes the way other things move. We find most stuff by seeing the light that bounces off it...

...but we can find secret stuff by looking at the way other stuff moves around it.

Look! An asteroid belt!

Hello, asteroids!

What are you doing?

Hello, Ducky! We are going around our favorite star.

We like to go around this star because of its mass.

Looks like the asteroids are in a stable orbit with their favorite star-that means they go around and around without flying away.

The star goes around and around with the asteroids, too, but it's so big, you can hardly see!

Maybe we should go closer to the star!

Goodbye, asteroids!

Thank you for the clue!

Hello star!

What are you doing?

Hello, Ducky!

I am following lots of other stars! We are orbiting a big, dark ball! It has lots and lots of mass, but it's hard to see!

Hard to see, you say?

What if it’s secret stuff?

Like a black hole!

What if it turns us into spaghetti?

Don't worry! this ship can go super fast!

Look over there--it's some kind of disc made of space dirt!

Hello disc! What are you doing?

Hello! We are going around this black hole!

Someday we might fall in and get turned into spaghetti...

I'm scared! Let's run away while we still can!

Don’t worry!

As long as you stay where you are, i’m just like anyone else you’ve met. But don’t get any closer--my mass makes a dent in spacetime unlike anyone else’s!

When you get close enough, the dent I make is so big, your ship can’t change direction and you’ll get turned into spaghetti.

Even light can only go one way once it crosses the event horizon!

So that's why you're secret! Light can't bounce off you because your dent makes it go in instead of out.

That’s so cool!

Goodbye, black hole! Thank you for the secret!

Goodbye! Be safe!

Phew! All this fast travel has made me hungry.

Let’s have some spaghetti!

The End

Educational Overview Readers will have learned the following: A basic understanding of mass How mass affects spacetime according to General Relativity An introduction to non-Newtonian models of gravity Basic anatomy and behavior of a black hole -Event horizons -Accretion discs -Gravitational Lensing -Distortion of spacetime geodesics -Spaghettification Behavior and types of bodies in space Stable orbits and Barycenters

Omissions Readers will need to learn further: Special & General Relativity Einstein’s equations and their solutions The metric and actual effects of mass on spacetime What geodesics actually are Light Wave behavior of light and redshifting Full visual effects near black holes Black Holes Distinctions between different-sized black holes Why an Event Horizon is a horizon Swapping of time and space beyond the event horizon Orbits Effective potential Types of Orbit geometry Precession and effects from GR