Saturday, July 10, 2010

A different take on the PepSciBlog scandal

Much has been said of the PepSciBlog scandal, both by PepSciblings, the MSM, and the rest of the internet. I won’t repeat or comment on any of those opinions. Instead, I will try to prove that corporate shilling can be useful to basic science education, by using the Pepsi logo to explain the Rossiter-McLaughlin effect. Steinn should be ashamed that he didn’t beat me to this.

Imagine that in the days before spin, the Pepsi logo was designed by physicists, and thus was a featureless, luminous white sphere.

Figure 1. The pre-spin Pepsi logo.

This is fine for the Precambrian, but here in the 21st century, spin is very important. So we will spin the logo.

Figure 2. The spinning logo.

Spinning the sphere means that the side spinning away from us will be red shifted by the Doppler effect, while the side spinning toward us will be blue shifted. This is well illustrated by the modern logo.

This is fine, as long as the Pepsi logo spins alone, in the vastness of space. But interactions with other logos are important. Consider, for example, a transit, or partial eclipse, of the Pepsi logo by the Diabetes Australia logo.

Figure 3. Beginning of a diabetes transit of Pepsi.

If the direction of the transiting logo is the same as the direction of spin from the pepsi logo, then the light from the blue-shifted portion of the logo is blocked first. This makes the average observed Pepsi light somewhat redder. Later, as the Diabetes Australia logo moves to block the red-shifted part of Pepsi, the average light becomes bluer.

Figure 4. Late stage of a Diabetes Australia transit of Pepsi.

Like our hypothetical pre-spin Pepsi logo, stars are (approximately) luminous white spheres. So if they are rotating, the same effect can be observed when planets transit in front of them. More details of this effect can be found at the systemic blog. Thus education triumphs (until the evil lawyers shut me down).

A former Frink Tanker tells his story.


Anne Jefferson said...

Nice one.

Dr. Jerque said...

Agreed...nice one!

Schlupp said...

Yes, nice!