So the history of the Earth has been discussed in a previous post, but what was not discussed was the mind blowing stuff that preceded it.
Before the sun existed, there was another star, a big one, that one day just up and exploded into a nebula. This cloud of dead star bits expanded out into the area that would eventually become our solar system, though that was still several million years away. Eventually, this cloud began to spin (due to conservation of angular momentum) and slowly collapse in upon itself into a huge disk. At its center a baby sun. However this baby is not like any toddler that you have ever met. It is not the cute, slightly chubby adorableness that we appreciate in human babies. No, this is a rapidly expanding fiery baby of death to all those within as certain proximity. It absorbs anything that gets to close only adding to its mass, until, eventually, it stabilizes, matures, and stops eating for a change. around it, smaller variations of this event take place, forming what would eventually be the eight planets. But this process of planetary creation was detailed in an earlier post. This process, if you the reader so choose to learn more about it, is called The Solar Nebula Theory.
But what caused this, well, scientists believe that they have found the answer in someone who has been dead for nearly 300 years, Sir Isaac Newton. Newton is the creator of the three primary laws that govern the way that we understand Gravity. These laws are creatively named, Newtons Laws of Motion, who would have guessed. Anyway, these three laws are...
1. An object at rest tends to stay at rest, and an object in motion will remain in motion with the same speed and direction unless acted upon by an unbalanced force.
A. Loosely Translated this means that in general, objects will remain in a state of motion unless acted upon by an "unbalanced" force, like friction. (this is the reason why eventually things that are moving do stop.
2. Force equals Mass Multiplied by Acceleration(F=MA)
A. This one is pretty self explanatory.
3. Every action has an Equal and opposite reaction.
A. This means that when I push on an object, it "pushes" back. This should not be taken literally, but more figuratively as in when you push, it gives back the same.
How does this tie into the aforementioned solar nebula theory, you may ask? Well you see, these laws show the way the objects interact with one another in regard to gravity. Without them, there would have been no gravitational pull to keep everything in check and bring the cloud together. But it is more then just that, these properties are the withstanding reason how gravity, inertia and matter interact.
Now, fast forward a few million years to our now formed solar system. Why is it, that the planets, in their motion around the sun, do not stay in perfect circles. There is one center, right...Right? Wrong. The planets travel in elliptical orbits because their are infact, 2 foci, the sun and a random point in space. This is the first of Kepler's Laws of Planetary Motion. These laws explain why the planets move in the way they do.
The second law details, that if a line were to be drawn from a given planet and have an small arc representing a period of time from that line. The area of the shape created by the arc and the line, will remain a constant throughout the entire orbital cycle.
Finally the ratio of the squares of the periods(orbital times) of two planets, is equal the ratio of their distances from the sun cubed.
The Fist of Science
Bids You Adieu
