Today's lesson: What does 1 year means? What are its origins?

To understand this, imagine that we have one of those clocks that have hands, and that we have it lying on the floor looking up. Now in the center of the clock we will put an apple (which will be the equivalent of our Sun), and at the ends of the hands we will put the head of a pin, which will be the equivalent of our planet Earth.

Imagine now that the hand points to 12. Well we can imagine that this means that we are at the end of month 12 (December), or beginning of month 1 (January).

The planet's movement around its star is what determine what a year is. It varies from planet to planet

Just as the hand of the clock revolves around its center (the Sun), in the same we all know that the Earth revolves around the Sun, but what interests us is the fact that every time the hand passes through the same place (In this case, let's say that each time you pass by the number 12), that means that 1 year has passed.

Or in other words, every year the Earth is in exactly the same place as it was last year in relation to the Sun. And to make it fun, the same applies for our birthdays: it is guaranteed that the stars we will see on our birthday will be basically the same, in exactly the same place, year after year.

I know that this might be obvious to a lot of people, but for those who don’t realize it, this is wonderful and a beautiful thought to have, because it tells us that in a certain way each of us has a special particularity in relation to others, another example each of us can indeed be unique in someway.

Note that this knowledge comes from possibly prehistoric times, when our ancestors realized that every so often something curious happened: It got cold, or it got hot, or it rained a lot. Every year, even without they knowing the exact duration of 1 year, they invented sort of a symbolic day to start each year. That day in some place was perhaps called "the first harvest day", or in another place it could have been called "the first day of winter", but in the end, on average it was more or less the same day each year, or at least the same week.

Eventually we understood better what happened, and we were able to calculate with great accuracy the duration of 1 year (which is not exactly 365 days, that's why leap years exists). Even, the reason why we have the horoscope and the 12 months of the year is precisely because we realized in ancient times that the stars seemed to move from place to place every so often, although eventually the scientists realized that the stars did not move, but that it was us who moved around the Sun.

Eventually we realized there were certain times in which it was easier to get food

Something important to understand, is that time measurement is relative, in our case the concept of 1 year was invented by us to measure the time it took our planet to go around the Sun, it is relative to us, and we need to remember this because it has huge implications when talking about other celestial bodies and places in the space-time of the universe.

And by the way, the Sun is actually also moving across galaxy, the Milky Way, which in turn is part of a local cluster that also moves, and all this huge mass moves in all directions as the universe expands.

For example, when we talk about a certain planet different from Earth having a 300-day orbit, we are talking about 300 Earth days, which means that in 300 days according to us, that planet will go around its star 1 time, so if this planet had intelligent beings in it, these beings would perhaps have years consisting in 300 days, not 365.25 days like us, and of course, their days could be longer or shorter in duration.

This tell us, that all of our science innovations and discoveries, in which numerical calculations were involved and there is talks about time measurement (1 light year for example), are all relative to us, and could not be understood by possible intelligent beings from other corners of the Universe, and this is the reason scientist try to figure out more universal ways to share information when thinking about strategies to eventually contact other extraterrestrial civilizations.

Why if the stars are moving at an incredible high speed, they seem still in the night sky?

Actually all this has a very simple explanation: The distances are so colossally large, and the spaces of times so colossally small, that we do not notice any difference in practice (except with very precise instruments but this is another subject).

It happens that although these stars move so quickly through space, the distances are so large in relation to their sizes, that their movements are imperceptible. Likewise, if we make a comparison between what we see today in the night sky and what was seen 2,000 years ago, it would be almost the same, because 2,000 years is very little on universal scales, where events tend to last for millions and even billions of years.

The further we are from an object, the slower we perceive its movements, that is why objects in space seems to be still when they are not

Imagine, for example, recording a movie from the sky, but at a rate of 1 trillion frames per second, and then try to see the difference between one picture and another: It would be essentially impossible, since the change is practically zero between one picture and another, and the difference could only be seen after the film has advanced a lot.

Another way to understand this is with airplanes. If a plane passes you close to your head, you will think that a racing car is going much faster than any Formula 1 car, but if you see the same plane at a very high altitude above the clouds, you will notice that it appears to be very slow, like having the speed of an ant, and the same goes for objects that are far away, always with relation to their sizes.

As a final note, the speed in which the Earth moves around the sun is about “30 kilometers per second, or 67,000 miles per hour. In addition, our solar system--Earth and all--whirls around the center of our galaxy at some 220 kilometers per second, or 490,000 miles per hour” | Source

Or in other words, even if you are sitting at a desk, or lying on a sofa or a bed while reading good articles on steemit, the reality is that you are moving at that incredible speed through space.

So the next time someone tells you to get out of bed and move, answer that you are already moving at 490,000 miles per hour...

What do you think of today’s lesson? Were you able to learn something new?

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