[3] The crater was named after Walter Frederick Gale, an amateur astronomer from Sydney, Australia, who observed Mars in the late 19th century.
[5][6] Peace Vallis,[7] a nearby outflow channel, 'flows' down from the hills to the Aeolis Palus below and seems to have been carved by flowing water.
Gale, named for Walter F. Gale (1865–1945), an amateur astronomer from Australia, spans 154 km (96 mi) in diameter and holds a mountain, Aeolis Mons (informally named "Mount Sharp" to pay tribute to geologist Robert P. Sharp) rising 18,000 ft (5,500 m) from the crater floor, higher than Mount Rainier rises above Seattle.
The crater formed when an asteroid or comet hit Mars in its early history, about 3.5 to 3.8 billion years ago.
The expected near-surface atmospheric temperatures at the landing site during Curiosity's primary mission (1 Martian year or 687 Earth days) are from −90 to 0 °C (−130 to 32 °F).
Scientists chose Gale as the landing site for Curiosity because it has many signs that water was present over its history.
The crater's geology is notable for containing both clays and sulfate minerals, which form in water under different conditions and may also preserve signs of past life.
The history of water at Gale, as recorded in its rocks, is giving Curiosity many clues to study as it pieces together whether Mars ever could have been a habitat for microbes.
The Stimson formation represents the preserved expression of a dry aeolian dune field, where sediment was transported towards the north, or northeast by palaeowinds within the crater.
[34] In February 2019, NASA scientists reported that the Mars Curiosity rover had determined, for the first time, the density of Mount Sharp in Gale, thereby establishing a clearer understanding of how the mountain was formed.
On September 26, 2013, NASA scientists reported that Curiosity detected "abundant, easily accessible" water (1.5 to 3 weight percent) in soil samples at the Rocknest region of Aeolis Palus in Gale.
[55] On December 9, 2013, NASA reported that, based on evidence from Curiosity studying Aeolis Palus, Gale contained an ancient freshwater lake which could have been a hospitable environment for microbial life.
[58][59][60] On October 8, 2015, NASA confirmed that lakes and streams existed in Gale 3.3 to 3.8 billion years ago delivering sediments to build up the lower layers of Mount Sharp.
[63][64][65] On August 5, 2017, NASA celebrated the fifth anniversary of the Curiosity rover mission landing, and related exploratory accomplishments, on the planet Mars.
Organic molecules preserved in 3.5 billion-year-old bedrock and seasonal variations in the level of methane in the atmosphere further support the theory that past conditions may have been conducive to life.
This new result shows that low levels of methane within Gale repeatedly peak in warm, summer months and drop in the winter every year.
This is close to the amount observed in Martian meteorites and about 100 times greater than prior analysis of organic carbon on Mars' surface.
[68] On November 4, 2018, geologists presented evidence, based on studies in Gale by the Curiosity rover, that there was plenty of water on early Mars.
[79] Research published in August, 2023 found evidence that liquid water may have existed for a long time and not just when an impact or volcano erupted.
Much evidence exists to show that impacts and volcanic activity could melt ground ice to make liquid water.