The Earth's tilt arose due to a cosmic collision.
An object the size of Mars crashed into the newly formed planet Earth around 4.5 billion years ago, it knocked our planet over and left it tilted at an angle.
The Earth's axis is the red line denoted by N and S. timeanddate.com
In astronomy, an axis
refers to the imaginary line that an object, usually a planet, rotates around.
Earth's rotational axis is an imaginary straight line that runs through the North and South Pole
. In our illustrations, Earth's axis is drawn as a straight red line.
The impact around 4.5 billion years ago is described in the Giant Impact Hypothesis, which is the current prevailing theory on how the Moon was formed and how Earth got its tilt.
Ever since this impact, Earth has been orbiting the Sun at a slant. This slant is the axial tilt, also called obliquity.
This impact, in turn, also created the moon. The evidence supporting this is in part that the Moon and the Earth have very similar orientations and chemical compositions. Before this impact, the earth's axis was at a perfect 180 degrees perpendicular to that of the sun
. Due to this collision, however, it is now tilted at 23.5 degrees
Earth's obliquity angle is measured from the imaginary line that runs perpendicular to another imaginary line; Earth's ecliptic
plane or orbital plane (see illustration).
At the moment, Earth's obliquity is about 23.4 degrees and decreasing. We say 'at the moment' because the obliquity changes over time, although very, very slowly, within a
The temperature is based on how far or how close the earth is to the sun. The earth’s climate and the winds in the atmosphere continue to change every day. Every year the winds change causing different weather patterns to act on the solid earth
. The earth’s spin axis is tilted at 23.5 degrees with respect to the elliptic giving us moderate seasons and preventing temperature extremes anywhere on earth.
Today, on September 14, 2022 at noon, Earth's axial tilt, or mean obliquity was 23.43633° or 23°26'10.7".
Earth's mean obliquity today is about 0.00001°, or 0.04", less than 30 days ago.
The Arctic and Antarctic circles today are 1.2 m (4 ft) closer to the poles, and the Tropic of Cancer and Tropic of Capricorn are equally closer to the equator than 30 days ago.
Earth's axial tilt actually oscillates between 22.1 and 24.5 degrees. The reason for this changing obliquity angle is that Earth's axis also wobbles around itself. This wobble motion is called axial precession, also known as precession of the equinoxes. It is caused by the gravitational force from the Sun
, the Moon
, and other planets
Axial precession can be described as a slow gyration of Earth's axis about another line intersecting it. A complete wobble of Earth's axis takes around 26,000 years. It outlines the shape of a pair of cones or two spinning tops connected at the tips, which would be at the center of Earth.
Greek astronomer Hipparchus of Nicea, one of astronomer Carl Sagan's favorite ancient scientists, is historically credited as the man who first proposed that Earths axis gradually shifts, though very slowly. Hipparchus made his discovery around 130 BCE
, based on comparisons of astronomical observations more than a century apart.
Because Earth orbits the Sun at an angle, the solar energy reaching different parts of our planet is not constant, but varies during the course of a year
This is the reason we have different seasons
and why the seasons are opposite in the Northern and Southern Hemispheres
From the March equinox
to the September equinox
, the Northern Hemisphere tilts towards the Sun. During this time, there are more than 12 hours of daylight north of the equator
At the same time, the Southern Hemisphere tilts away from the Sun, resulting in shorter days.
From the September equinox to the next March equinox, the days are longer south of the equator and shorter north of the equator.
The core of the earth grows tilted. Growth is faster under the Banda Sea, Maluku, Indonesia
This conclusion emerged from the results of research by seismologists at the University of California, United States of America
, about the asymmetrical growth of the center of the earth some time ago. The researchers studied it through seismic waves traveling through the Earth.
The core of the earth is located about 3 thousand kilometers below the earth’s surface. To be precise, it is within the outer core of the earth’s fluid. The size is approximately three-quarters of the moon. The shape of the core is like a ball containing iron and nickel.
, the inner core of the earth is always growing. Its radius increases by a millimeter every year. As the molten iron pieces in the outer core cool and harden, they turn into iron crystals.
A study published in Nature Geoscience shows the Earth’s core in Indonesia
is losing heat more quickly. This is in contrast to the opposite side, namely under Brazil.
The Earth’s core grows tilted because one side is growing faster than the other. In the eastern part of the core, which lies beneath Indonesia
, 60% more iron crystals are formed than on the other side.
“The west side looks different from the east side to the middle,” said University of California seismologist Daniel Frost, quoted from Insider
, Saturday (12/6).
Frost studied it through seismic waves. These waves come from underground vibrations generated from the earthquake
This slanted growth can affect the earth’s magnetic field. But the researchers are confident there won’t be any defects or other risks to put it off balance.
The Earth’s core plays a key role in protecting the planet from wind and harmful solar radiation. The rotating iron in the outer core produces a magnetic field that stretches around the earth and it channels solar radiation away from the Earth.
Interestingly, scientists found the Earth’s inner core may be only 500 million years old. While the earth has existed since 4.5 billion years ago.
At present, the heat release from the inner core plays a major role in generating the magnetic field. The vortex of the magnetic field occurs because the hotter and lighter material from the outer core rises to the Earth’s mantle above it.
There, the eddies swap places with cooler, denser mantle material, which sinks to the core below. This is referred to as convection.
Convection also occurs between the inner and outer nuclei. So if the outer and inner cores cool at different rates, it can affect how much heat is exchanged at the boundary.
It may also have an impact on the engine speed that powers the earth shield. Frost said his party would soon conduct research again to discuss this further.
I felt that the information above, which provides explanations on the Earth's tilt and core, might be of interest to you.
You might also be interested in this paper: https://www.sciencedirect.com/science/article/abs/pii/S0019103512002461