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In the local (primarily thin) disk of the Milky Way, there appears to be no evidence of a strong AMR. [12] A sample of 229 nearby "thick" disk stars has been used to investigate the existence of an age-metallicity relation in the Galactic thick disk and indicates that there is an age-metallicity relation present in the thick disk.
In some cases where the orbit is eccentric and the tidal effect is relatively weak, the smaller body may end up in a so-called spin–orbit resonance, rather than being tidally locked. Here, the ratio of the rotation period of a body to its own orbital period is some simple fraction different from 1:1.
The orbit of a planet is an ellipse with the Sun at one of the two foci. A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. The square of a planet's orbital period is proportional to the cube of the length of the semi-major axis of its orbit.
All eight planets in the Solar System orbit the Sun in the direction of the Sun's rotation, which is counterclockwise when viewed from above the Sun's north pole. Six of the planets also rotate about their axis in this same direction. The exceptions – the planets with retrograde rotation – are Venus and Uranus.
This plot shows the distribution of rotation periods for 15,000 minor planets, plotted against their diameters. Most bodies have a period between 2 and 20 hours. [1] [a] This is a list of slow rotators—minor planets that have an exceptionally long rotation period.
A solar wind event squashed the protective bubble around Uranus just before Voyager 2 flew by the planet in 1986, shifting how astronomers understood the mysterious world.
This plot shows the distribution of rotation periods for 15,000 minor planets as of September 2016, plotted against their diameters. Most bodies have a period between 2 and 20 hours. [1] [a] This is a list of fast rotators—"minor planets" (which includes asteroids) that have an exceptionally short rotation period, i
Earth’s inner core, a red-hot ball of iron 1,800 miles below our feet, stopped spinning recently, and it may now be reversing directions, according to an analysis of seismic activity.