Search results
Results from the WOW.Com Content Network
The objects formed by accretion are called planetesimals—they act as seeds for planet formation. Initially, planetesimals were closely packed. They coalesced into larger objects, forming clumps up to a few kilometers across in a few million years, a small time in comparison to the age of the Solar System. [3]
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 ...
On Earth, the zero elevation datum is based on sea level (the geoid). Since Mars has no oceans and hence no 'sea level', it is convenient to define an arbitrary zero-elevation level or "vertical datum" for mapping the surface, called areoid. [9] The datum for Mars was defined initially in terms of a constant atmospheric pressure.
Some of the low elevation outflow channels extend into Hellas from the volcanic Hadriacus Mons complex to the northeast, two of which Mars Orbiter Camera images show contain gullies: Dao Vallis and Reull Vallis. These gullies are also low enough for liquid water to be transient around Martian noon, if the temperature were to rise above 0 Celsius.
A terrestrial planet, tellurian planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate, rocks or metals.Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Venus, Earth and Mars.
Lowest Highest Lowest Highest Lowest Highest Star: 617.7 km/s Sun [11] 332,830 M Earth Sun [26] [27] 695,000 km Sun [27] Major planet: 4.3 k m/s Mercury [18] 59.5 km/s Jupiter [18] 0.055 M Earth Mercury [28] 318 M Earth Jupiter [26] 2500 km Mercury [29] 69911 k m Jupiter [28] Dwarf planet: ≈0.43 k m/s Orcus: 1.3 km/s Eris: 0.0000916 M Earth ...
Elements with comparatively low boiling points, such as chlorine, phosphorus, and sulfur, are much more common on Mars than on Earth; these elements were probably pushed outward by the young Sun's energetic solar wind. [24] After the formation of the planets, the inner Solar System may have been subjected to the so-called Late Heavy Bombardment.
The apsides refer to the farthest (2) and nearest (3) points reached by an orbiting planetary body (2 and 3) with respect to a primary, or host, body (1). An apsis (from Ancient Greek ἁψίς (hapsís) 'arch, vault'; pl. apsides / ˈ æ p s ɪ ˌ d iː z / AP-sih-deez) [1] [2] is the farthest or nearest point in the orbit of a planetary body about its primary body.