Milankovisyklusene

Milankovisyklusene, or Milankovitch cycles, are long-term variations in Earth's orbit around the Sun that are believed to influence the planet's climate. These cycles are named after Serbian astronomer Milutin Milankovitch, who extensively studied their potential impact on ice ages. There are three primary Milankovitch cycles: eccentricity, axial tilt (obliquity), and precession.

Eccentricity refers to the changing shape of Earth's orbit, which oscillates between being nearly circular and slightly elliptical over a period of approximately 100,000 years. When the orbit is more elliptical, the difference in solar radiation received by Earth between its closest and farthest points from the Sun is greater, potentially leading to more extreme temperature variations.

Axial tilt, or obliquity, describes the wobble of Earth's rotational axis. This tilt varies between approximately 22.1 and 24.5 degrees over a cycle of about 41,000 years. A greater axial tilt leads to more pronounced seasonal differences, with hotter summers and colder winters at higher latitudes.

Precession involves the slow, conical motion of Earth's axis, similar to a spinning top. This cycle, occurring over approximately 23,000 years, causes the timing of the seasons to shift relative to Earth's position in its orbit. For instance, it can influence whether summer occurs when Earth is closest to the Sun or farthest away.

These orbital variations alter the distribution and intensity of solar radiation reaching Earth's surface, particularly at different latitudes. While not solely responsible for all climate change, Milankovitch cycles are considered a significant driving factor for long-term climate shifts, including the alternation between glacial and interglacial periods over geological timescales.