Weekly Challenge 7: Spaceship Earth

 Posted by DrJeff on September 4th, 2009

 Copyright 2009  |  About this blog



Photo caption: Computer-generated image of the Milky Way galaxy based on real data.


This post is a Dr. Jeff’s Weekly Challenge. It was requested by (teacher extraordinaire) Jami Lupold and her class in the great city of Houston, Texas, USA.

If you’re a teacher and your class has an idea for a blog post, slip me a note!


You wanted to be an astronaut? Poof. Done.


You and your friends are on a spaceship called Earth—with all known life aboard. With you sitting there calmly reading this, and no obvious need to hold on to something for dear life, it might seem that the spaceship under your feet is carrying you on a nice steady trajectory through space. Uh … Nope. Right now you’re being carried along on something more akin to a cosmic-sized amusement park ride. Earth is rotating on its axis, it’s orbiting the Sun, and the whole Solar System (the Sun and its planets, dwarf planets, asteroids, comets, and Trans-Neptunian Objects) is orbiting the center of the Milky Way galaxy. The Milky Way itself is moving relative to other nearby galaxies, the local group of galaxies is moving through a greater space, and all this is set against a backdrop of an expanding fabric of space and time across the entire universe. I know!!!! (© Craig Ferguson) Dizzy?


[Pleasant Ding] The captain has just turned on the seat belt sign. There may be some conceptual turbulence up ahead. But I’ll make the ride as smooth as possible.


OK, I think a Weekly Challenge requesting that you calculate all the spinning, and revolving, and free-flying is a bit much, so let’s concentrate on three things:


Here now the Challenge—


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