Free Form: Creationism?

First off, I understand this post could potentially be seen as controversial.  In order to avoid that, I'm going to do my best to do nothing but present the two sides of an argument.  You, the reader, can choose for yourself what to believe.

I was scrolling through my facebook newsfeed when I saw pictures of a high school acquaintance at the Creation Museum in Petersburg, KY.  (This isn't actually as surprising or uncommon as you might think since I come from a town in Pennsylvania where confederate flags are still flown and I've actually heard people say they "don't believe in science.")  A couple weeks ago, I would have kept on scrolling, but the recent discovery of what most of the science community believes to be proof the Inflationary Theory made me stop.  I wanted to see what their argument was, so I decided to look up the creation Museum's exhibits.  And this is what I found.


The museum recently added an exhibit dedicated to the comet ISON, called Fires in the Sky.

Museum's trailer for the 23-minute long video shown in its Stargazer's Planetarium as proof of a young universe

The museum's exhibit explains that ISON is a sun-grazer, which means its orbit takes it really close to the sun.  Every time it reaches the part of its orbit that's closest to the sun*, it loses some of its mass.  Last December, ISON completed its last orbit as it passed the sun and lost too much of its mass to continue.

This is not the only way comets get destroyed, though, according to the exhibit.  They can also get shot out of the solar system if they hit an object's gravitational field in the right way, or they can get pulled in by an object's gravity and crash.

By itself, this information isn't enough to prove that the universe is only a few thousand years old, but we also have to consider that there's no source of new comets.  Astronomers claim that most of the comets we see orbiting through our solar system come from sources called the Oort Cloud and Kuiper Belt, located far beyond Pluto and just past Neptune, respectively.  We've never seen the Oort Cloud, though, we we likely never will, so we can't know that it exists.  These two facts together--that all comets will die or be shot out of our solar system and that there's no way for us to get new ones-- prove that the universe can't possibly be more than a few thousand years old.  If it were, we wouldn't still comets orbiting through our solar system.

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Astronomers have several facts supporting their theory that the universe is, without a doubt, older than  three to four thousand years old.

1) They're pretty sure the Oort Cloud does exist.  Even if we've never seen it, a collection of comets so far away that they aren't too strongly bound by the sun's gravity and are therefore easily influenced by other objects is the most plausible explanation for long-period comets.  Long-period comets are seen relatively infrequently and have more erratic orbits (presumably due to the influence of other objects), like Halley's Comet.

Space.com

2) That little discovery (mentioned above) of gravitational waves, which were predicted to be visible 380,000 years after the Big Bang.  No matter how long ago the Big Bang happened, if something happened 380,000 years after it, the universe is at least that old.

3) This is a (relatively) simple exercise we did in class (WS 7, Problem 5) that shows a ballpark age of our solar system.  

The Virial Theorem states that half of a gravitationally-bound system's potential energy goes into kinetic energy. It turns out that for a cloud of gas, the other half of U goes into thermal radiation. We know that the Sun started from the gravitational collapse of a giant cloud of gas. Let's hypothesize that the Sun is powered solely by this gravitational contraction, as was once posited by astronomers long ago. As it shrinks, its internal thermal energy increases, increasing its temperature and thereby causing it to radiate. How long would the Sun last if it was thermally radiating its current power output, $L_\odot =4\times 10^{33}erg/s$? This is known as the Kelvin-Helmholtz timescale. How does this timescale compare to the age of the oldest Moon rocks (about 4.5 billion years, also known as Gyr)?

The first two sentences of the problem can be interpreted as 

$KE=-\frac{1}{2}U=TE$

In the previous problem on the worksheet, we figured out that potential energy, U, can be found using this equation:

$U=-\frac{3}{5}\frac{GM^2}{R}$

By combining these equations, we get:

$KE_\odot=TE_\odot=\frac{1}{10}\frac{GM_\odot^2}{R_\odot}$

If, as stated in the problem, we're assuming that the only source of the sun's energy is gravitational contraction, we can take the thermal energy of the sun (found using the equation above) and divide it by the sun's luminosity to find its age.  When we did this, we found that the sun, and therefore the solar system is about 16 million years old.

This is far from accurate because gravitational contraction contributes very little to the sun's total source of energy--most of its power is nuclear fusion.  But still, even with so little energy, the sun is at least several million years old.  

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I've given you the different arguments.  Now its up to you to decide what to believe.


*I know that there's a word for this--perihelion--but that word is not used in the Creation Museum's explanation, and I wanted to keep my representation of their argument as authentic as possible.