History of Mars

The history of Mars describes the development and formation stages of the fourth planet from the Sun, ranging from 4.6 billion years ago to the present day. Space exploration and features discovered on the surface have been used for the understanding of the planet's distant past. The age of Mars is an exact equivalent of Earth's, about 4.6 billion years old.
Formation of the solar system and Noachian era
Astronomers have theorized that the Solar System was formed from a cataclysmic supernova event that occurred 4.54 billion years ago (4.54 Ga) that caused the protoplanetary disk that formed the solar system to rotate and gain angular momentum. As our star became hot and massive enough to support nuclear fusion of hydrogen atoms in its core and grew in luminosity, the planetesimals and elements surrounding the newborn Sun spanned and coalesced into the young planets.
Mars became its present diameter through a process known as accretion. The earliest Martian period, the Noachian era, named for the Noachis Terra ancient uplands in Mars's southern hemisphere, found active erosion, intense volcanic activity and expanding of possible lakes and oceans. It lasted from 4,500 MY to 3,500 MY ago, or perhaps more or less than 100 MY from the end according to recent estimates, but not well substantiated. Heavy bombardment from asteroids and meteoroids marked many impact craters on the Martian surface at this era. Despite beliefs that have arisen since the 19th century about Mars, when Mariner 4 made a successful flyby of Mars in 1965 and started mapping the planet, what was expected to be cities and extraterrestrials were really impact craters on the almost, or perhaps totally, geologically dead hulk. But the fact that water ice may exist beneath the Martian polar caps has arisen the theory that Martians might truly exist today. This indicated that the remaining Martians after the planet's magnetic field was stripped away into space might have retreated underground, where there was a significant amount of water ice, and adapted to the frozen water.
If early Mars had developed metabolism (which is currently unknown) for multicellular organisms to re-produce (e.g., an embryo developing inside a female, or even male), Martians might continually re-produce to the present day under the Martian north and south poles.
The Hesperian era and loss of habitable conditions
The Hesperian period lasted from 3,500 MY to 3,000 MY ago, named for the Hesperia Planum feature in Mars's southern hemisphere and marked by the start of extensive lava flows. When the solar wind started increasing in intensity and pressure, the electrons and protons penetrated the Martian magnetic field, where interaction with air molecules might have caused aurorae at the planet's poles. (They still occur today, despite the lack of an internal magnetic field, because of patches of strong magnetic field in the crust, primarily in the southern hemisphere, although they only appear as ultraviolet light.)
In between the Hesperian period, because the planet was so small in comparison to Earth and Venus (6,792 km to 12,756 km and 12,104 km respectively in contrast), the core started cooling and the internal dynamo ceased to continue, so the protective magnetic field started stripping away into outer space, and the atmosphere started thinning. Mars was deprived of warmth and pressure, so water became unstable and either evaporated or froze. By comparison, the early Martian atmosphere was much thicker and held enough moisture for dew or even drizzle to hit the ground, hinting a possible origin for the planet's past water.

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