7/22/2023 0 Comments Earths orbit![]() Graphical examples of variations in orbital eccentricity (the shape of Earth’s orbit), axial obliquity (the degree that Earth’s axis tilts away from vertical), and polar precession (the slow conical ‘wobble’ of Earth’s axis). If the Earth sat straight up and down and had no tilt, then there would be no seasons because light would strike the land at every latitude equally for the entire year. That’s why the seasons are reversed across the hemispheres… while the south bathes in summer light, the north experiences winter. As Earth orbits to the other side of the Sun, more of the other hemisphere is exposed to solar radiance while the first hemisphere experiences less sunlight. The tilted planet exposes more of one hemisphere to the Sun’s rays. We experience seasons because Earth sits at an angle. Luckily, the expansive oceans of the southern hemisphere help moderate the more extreme temperature trends. On the flip side of the coin is the southern hemisphere: near to the sun during southern summer, far from the sun during southern winter. In contrast Earth reaches its furthest point from the Sun in July, making for less sweltering summer temperatures in the northern hemisphere. Currently, we reach perihelion in January when the large landmasses of the northern hemisphere are tilted away from the sun, making for more moderate winter temperatures. When Earth’s orbital path is nearest to the sun, that point is known as perihelion. The Sun does not sit at the center of the elliptical orbit, so the Earth sometimes travels extra-close or extra-far from its energy source. The path Earth travels around the Sun is important because it dictates how much solar radiation reaches the surface, and where. Currently, our planet travels a fairly circular orbit (e = 0.017). Earth’s orbit fluctuates between the two extreme values roughly every 100.000 years. An elongated elliptical orbit has a slightly higher eccentricity (maximum e = 0.0607). A nearly circular orbit has an eccentricity approaching zero (minimum e = 0.0005). ![]() A complex gravitational balance dictates that path the location and mass of other planets and celelestial bodies in the solar system can inflict gravitational forces on our planet.Įccentricity measures how elliptical an orbit is. Sometimes the path the Earth travels around the Sun is a nearly perfect circle other times, it travels an elliptical, or oval, path. How –and how much– have the Earths’ orbital parameters (including eccentricity, obliquity, and precession) influenced global climate in the past?Įccentricity describes the shape of Earth’s orbit around the Sun. The Earth has experienced a string of ice ages in the past, interrupted by shorter, warmer, interglacial periods. ![]() In the 1930s, Serbian mathematician Milutin Milankovitch theorized that slow changes in the way the Earth moves through space about the Sun could have influenced our planet’s climate past. Indeed, long-term variations of the Earth’s orbit may help explain the waxing and waning of global climate in the last several million years. The Earth’s orbital geometry, however, is not fixed over time. These changes in the pattern of radiation reaching earth’s surface cause the succession of the seasons. Over the course of a year the orientation of the axis remains fixed in space, producing changes in the distribution of solar radiation. The tilted earth revolves around the Sun on an elliptical path.
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