As you know, November 14 (within a few days) will have what is called a “supermoon” and although I think I have explained (which it is), but not from the recall.
The moon, our favorite because it is the only satellite orbiting around the Earth, as I said, our Earth orbit in a standard orbit, an elliptical orbit.
Why are elliptical orbits ?, it is quite simple. Two objects actually revolve one another environment through its center of mass, ie, the orbits are circular objects unless these are “turning” in its center of mass.
As I explained in the first race, in mechanics, really, in space objects move in a straight line and constant velocity if no forces to change their path (Newton Approves this!), Let’s first law of Newton. Obviously, our satellite will influence a force that causes you to modify its trajectory, gravity. Earth, its gravity attracts the Moon towards. Ie the Moon is constantly falling on the Earth.
Then why do not we have hit the Moon ?, simple, when the moon falls on Earth, the Earth, is not there, that is, when it falls, the earth is moving and therefore “does not reach be with her. “
In fact, the Earth-Moon system passes the same with the Sun, is continually falling on the Sun only it moves. The fact is simply not see it as a matter of reference systems. Depending on where you put the reference system can “see” or not, and usually the system or this on Earth (and therefore is a moving system) or the Sun (another like), hence we have the idea closed orbit.
Turning to the orbits are ellipses, they have some properties, for example, the most “molona” is always the same area is traversed in the same time, ie, that in the same time the surface that travels through the body that orbit is always the same. This explains why the further this focus (remember, an ellipse) the object and slower the closer, faster … because the area must be constant with respect to the focus moves. Come on, things of angular momentum is constant.
Speaking of focus, as every ellipse, the orbit has two foci, we can consider the center of the circle that I was talking about earlier (the center of mass) unless, as always one of the objects is more massive than the other, the object more mass is one of the foci. So even though people do not believe it, also this Earth “orbiting” on the Moon, although it is so small that the orbit is within the radius of the Earth itself. This happens the same for the Sun and not for binary stars or planets where, when the two equal, if circularly orbit. But I’m rolling.
Returning to the issue of super moons, remember that you comment that being an elliptical orbit the Moon looks two sizes, when in the most remote area of his is when the smallest we see (at apogee) orbit and the more close this, we see it larger (perigee). There is a difference of 14% environment size, which is not much, but if it shows.
This is just what will happen on November 14, we will have a perfect full moon at perigee of it and that is a perfect supermoon because it will exactly match the full moon with perigee, not because it will be closer ever since the orbit of the Moon is constant (well, is moving away a little each year, a few centimeters, but that does not count) but because moon will exist at that time. In fact, there supermoons every 28 days (the time of the orbit).
On the issue of the orbits, is a very curious subject as you might remember, when you talk about how Mercury’s orbit was returning crazy people coming to think that Newton’s equations “lacked something” simply does not take into account the Einstein’s general relativity and like gravity, it takes time to arrive, modifying those 30 arcsec Mercury’s orbit. And it’s a very geometric theme, something fun to understand and if you are interested, I recommend you take a look. Because, remember, mathematics is very necessary to be a universal language.
Even with all that, enjoy the supermoon because it is a sight worth seeing.