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Today, Mars is believed to be largely tectonically inactive. However, observational evidence and its interpretation suggests that this was not the case further back in Mars's geological history. At the scale of the whole planet, two large scale physiographic features are apparent on the surface. The first is that the northern hemisphere of the ...
For example, the size of central peaks in Martian craters is larger than comparable craters on Mercury or the Moon. [52] In addition, the central peaks of many large craters on Mars have pit craters at their summits. Central pit craters are rare on the Moon but are very common on Mars and the icy satellites of the outer Solar System.
Mars is much less tectonically active than Earth, and marsquakes are unlikely to have provided seismic waves of the required magnitude. [10] Most sizable craters on Mars date to the Late Heavy Bombardment , 4.1 to 3.8 billion years ago (the Noachian period), and are older than the landslide deposits in Valles Marineris.
Terrestrial planets have a compact, rocky surfaces, and Venus, Earth, and Mars each also has an atmosphere. Their size, radius, and density are all similar. Terrestrial planets have numerous similarities to dwarf planets (objects like Pluto), which also have a solid surface, but are primarily composed of icy materials.
Mars comes closer to Earth more than any other planet save Venus at its nearest—56 million km is the closest distance between Mars and Earth, whereas the closest Venus comes to Earth is 40 million km. Mars comes closest to Earth every other year, around the time of its opposition, when Earth is sweeping between the Sun and Mars. Extra-close ...
Mars is the fourth planet from the Sun.The surface of Mars is orange-red because it is covered in iron(III) oxide dust, giving it the nickname "the Red Planet". [22] [23] Mars is among the brightest objects in Earth's sky, and its high-contrast albedo features have made it a common subject for telescope viewing.
The orientation of Mars's axis is such that its north celestial pole is in Cygnus at R.A. 21 h 10 m 42 s Decl. +52° 53.0′ (or more precisely, 317.67669 +52.88378), near the 6th-magnitude star BD +52 2880 (also known as HR 8106, HD 201834, or SAO 33185), which in turn is at R.A. 21 h 10 m 15.6 s Decl. +53° 33′ 48″.
Many places on Mars show rocks arranged in layers. Rock can form layers in a variety of ways. Volcanoes, wind, or water can produce layers. [8] A detailed discussion of layering with many Martian examples can be found in Sedimentary Geology of Mars. [9] Layers can be hardened by the action of groundwater.