Flying back

Those of us originating on the right side of the atlantic ocean are familiar with a little quirk of international flights: the flights home are shorter. Specifically, going from Tel Aviv to New York takes about one hour longer than going the other way around.

This is an oddity, and the very first explanation that comes to mind the rotation of the Earth. After all, our naive image of a plane going up in the air might be something a little like a rock being thrown up from a moving cart, and we would imagine the plane to pick up some relative speed by not rotating as fast as the Earth. Is this a factor in the plane's movement?

Earth Day - Earth Units

In honor of Earth day, I thought I would take a look at what it would mean to do physics in 'Earth' units. What do I mean by that? Well lets be anti-Copernican here, in fact lets assume the opposite of the
Copernican principle, and state that the Earth is privileged in the universe and define all of our units around the Earth.

So, I will put a little subscript earth on all of the 'earth' units. They are to be read as 'earth meters' or 'earth amps', etc. We will take as our starting point the mass, radius and day of the earth, normalizing all of our standards to that. This gives us our initial conversion factors
\[ 1 g_{\oplus} = M_{\oplus} = 5.9742 \times 10^{34} \text{ kg} \]
\[ 1 m_{\oplus} = R_{\oplus} = 6378.1 \text{ km} \]
\[ 1 s_{\oplus} = T_{\oplus} = 86,400 \text{ s} \]

From this, we can figure out what all of the other 'earth' units would be.