Question

December 21, 2012: Are we all going to die? Section: ____________ Written by: Jeremy Jones

Over the past few years, websites, books, and even a big blockbuster movie have popped up concerning the ancient Mayan "prediction" that the world will end on December 21, 2012. It is true that the 13th bak'tun of the Mayan calendar will end on December 21, 2012. So what?, the 12th month of the modern calendar ends on December 31 every year. However, the end of the 13th bak'tun is supposed to be a special occasion (similar to the year 2000 was for us, or the last year of a decade).

If that was the end of the claims proposed by these websites, books, and movies, then we could just leave it up to the historians, anthropologists and archaeologists to deal with the myths. Unfortunately, the 2012ers (all conspiracy theorists need an "ers" behind their collective name) decided they'd make a few claims pertaining to how the world is going to end. These claims delve heavily in the pseudo-science astrology (the study of how the stars and planets affect our daily life). We will take a look at a couple of these claims, namely the claim that a planetary alignment will destroy the Earth and the claim that a previously unseen planet will destroy the Earth.

Forces of Planetary Alignment

For centuries, astrologers have "known" that planetary alignments are times of great stress and disaster, so it's no surprise that it's put forward by 2012ers as one of the ways the world will end. However, no astrologer has ever come up with a scientific theory or any evidence concerning why planetary alignments are such an issue, but let's take a look at it anyway. There are four different ways that matter can interact: gravitationally, electromagnetically, and through the weak and strong nuclear forces. The two nuclear forces only work for nuclear distances, so we can drop those from consideration. The planets have no net electric charge, but some of them (including Earth) have magnetic fields. Could they be interacting? Well, no. The magnetic fields of the planets are incredibly weak, and the distances between the planets so large that they have no effect. The Sun's magnetic field interacts with the Earth's, but that won't change if you have planetary alignment.

This leaves one force to analyze, gravity. Keep this question in mind as you do this part of the lab exercise: can the gravity distribution in a planetary alignment change the Earth's orbit?

Given in the table below is the mass of 8 bodies in the solar system (the Sun and the planets that aren't Earth). Also given is the distance from Earth to these different bodies when the planets are all aligned.

Body	Mass (g)	Distance (cm)	Distance2 (cm2)	Force (dynes)
Sun	1.99x1033	1.50x1013
Mercury	3.30x1026	9.12x1012
Venus	4.87x1027	4.14x1012
Mars	6.40x1026	7.84x1012
Jupiter	1.90x1030	6.29x1013
Saturn	5.69x1029	1.28x1014
Uranus	8.70x1028	2.72x1014
Neptune	1.03x1029	4.35x1014

In the table above, calculate R2 and F for each body. The force of gravity between a body of mass M and the

Earth is Fgrav=(3.98x10^20) (M/R^2) (R is the distance from the Earth to that body when the planets are aligned) R2

Answer 1