First of all, let’s start by reminding a fact again; The earth is not flat, you can even see it with your own eyes. However, our Earth is not round either, as we have learned since our early education years, the Earth is an ellipse that is flattened from the poles and bulging from the equator. Due to this cute shape, it has been determined that it draws a slightly inclined orbit both around itself and around the Sun. This is what scientists call axial tilt.
Axis tilt is not only a concern of astronomers, it directly affects us living on this planet, because this tilt gives rise to seasons and thus we can survive. In other words, Leyla, who turns our summer into winter and our winter into summer, is actually a tilted axis. Let’s take a closer look at the details such as what is axial tilt, who invented it, and see some of the effects of this situation on our planet.
What is axial tilt?
The angle between the Earth’s axis of rotation and its orbital axis as it revolves around the Sun is called the axis tilt. Our Earth’s axial tilt is exactly 23.439281 degrees. However, this degree has changed over the years.
Measuring axial tilt may surprise many people because, as we know, space has no direction. When calculating axis tilt, the Earth’s equatorial line aligns with its fixed rotational trajectory. The slope resulting from the alignment is accepted as the axis tilt.
Who discovered axial tilt?
Hold on tight, we’re going way back in time. The axial tilt of the Earth was measured for the first time in China and India in 1100 BC, since humanity has been curious about exploring space and understanding the movements of the Earth since its existence. A Greek philosopher named Piteas made a very effective measurement around 350 BC.
The axial tilt that the astronomers of Baghdad had measured by the Caliph al-Mamun in 830 was used for many years in the Arab world. The first person to sign one of the real measurements was the Muslim scholar Ibn al-Shatir, who lived in the 14th century. The most accurate and modern oblique observation was made by Danish astronomer Tycho Brahe in 1584.
Consequences of axial tilt:
- Seasons forming
- Day and night times
- Sunbathing times
- Seasonal changes and temperature changes
- Climate zones
Of course, none of us feel a slight dizziness because of gravity, but much more importantly, we experience the seasons. The biggest impact of axial tilt, which has numerous consequences for astronomers, is the seasons, which is seen and felt by everyone. Especially since we are a country that lives all four seasons to the fullest, we know the axial tilt best.
Due to this inclined rotation of our Earth, six months of day and night are experienced at the South and North Pole, respectively. Summer begins on the side of our world facing the Sun, the weather gets warmer, the sunshine duration increases and we see the Sun much higher. On the other hand, the opposite happens and the winter months begin.
Day and night durations, sunshine durations, seasonal changes, temperature changes and the climatic zones formed due to all these are the results of axial tilt. In other words, as much as we are talking about sunrise, sunset, hour, season and similar concepts, all these are the result of axial tilt.
Axis tilt changes:
Even though our Earth’s axial tilt is mostly constant, it changes in certain cycles. The biggest reason for this is that our planet moves like a spinning top. In other words, the Earth does not always rotate in a definite and fixed orbit, its axis tilt also changes as it is shaken with an irregular movement called nutation during rotation.
When we examined within the geological time cycle, it was determined that the axial tilt changed between 22 and 24.5 degrees during a period of 42 thousand years. When we think about this process, we see many terrible droughts and ice ages. So even a few degrees of axial tilt can change a lot.
This axial tilt change process spanning thousands of years actually consists of smaller, approximately 18.6-year cycles. It is seen that conditions such as day and night duration, seasonal normals and sunshine duration change in each cycle. Even if there are no major changes, it is possible to say that in a few thousand years, everything will be completely reversed.
What would happen if there was no axial tilt?
You might be thinking that even if the axis was not inclined, wouldn’t these still happen, no it wouldn’t. The sun’s rays would always come straight, the annual temperature differences would remain constant, the seasons would not occur because the temperature was constant, there would be no poles, the day and night would always be equal, and as a result of all this, life as we know it today would never occur, let alone continue.
It is much more important than we think that the axial tilt creates the seasons that allow us to maintain our existing life. Because we know that even small changes that will occur regionally are strong enough to destroy the vitality of that region. Also, if we consider that it differs globally, the probability of not starting life is quite high.
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