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Earth's rotational velocity also varies in a phenomenon known as length-of-day variation. [170] Earth's annual orbit is elliptical rather than circular, and its closest approach to the Sun is called perihelion. In modern times, Earth's perihelion occurs around 3 January, and its aphelion around 4 July.
At latitudes nearer the Equator, the outward centrifugal force produced by Earth's rotation is larger than at polar latitudes. This counteracts the Earth's gravity to a small degree – up to a maximum of 0.3% at the Equator – and reduces the apparent downward acceleration of falling objects.
The magnitude of Earth's magnetic field at its surface ranges from 25 to 65 μT (0.25 to 0.65 G). [3] As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11° with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of Earth.
Thus, the Sun occupies 0.00001% (1 part in 10 7) of the volume of a sphere with a radius the size of Earth's orbit, whereas Earth's volume is roughly 1 millionth (10 −6) that of the Sun. Jupiter, the largest planet, is 5.2 AU from the Sun and has a radius of 71,000 km (0.00047 AU; 44,000 mi), whereas the most distant planet, Neptune, is 30 AU ...
Global net primary production – the total mass of carbon fixed in organic compounds by photosynthesis each year on Earth [121] 7.2 × 10 14 kg Total carbon stored in Earth's atmosphere [122] 10 15 exagram (Eg) 2.0 × 10 15 kg Total carbon stored in the terrestrial biosphere [123] 3.5 × 10 15 kg Total carbon stored in coal deposits worldwide ...
Many trans-Neptunian objects (TNOs) have been discovered; in many cases their positions in this list are approximate, as there is frequently a large uncertainty in their estimated diameters due to their distance from Earth. Solar System objects more massive than 10 21 kilograms are known or expected to be approximately spherical.
It divides the Earth into the Northern Hemisphere and the Southern Hemisphere. Of the parallels or circles of latitude, it is the longest, and the only 'great circle' (a circle on the surface of the Earth, centered on Earth's center). All the other parallels are smaller and centered only on Earth's axis.
Polar motion of the Earth is the motion of the Earth's rotational axis relative to its crust. [2]: 1 This is measured with respect to a reference frame in which the solid Earth is fixed (a so-called Earth-centered, Earth-fixed or ECEF reference frame). This variation is a few meters on the surface of the Earth.