Dao Vallis is a valley on Mars

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

 that appears to have been carved by water. It runs southwestward into Hellas Planitia

Hellas Planitia

Hellas Planitia, also known as the Hellas Impact Basin, is a huge, roughly circular impact basin located in the southern hemisphere of the planet Mars. It is the second or third largest impact crater and the largest visible impact crater known in the Solar System...

, and has been identified as an outflow channel. It and its tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

, Niger Vallis

Niger Vallis

Niger Vallis is a valley on Mars that appears to have been carved by water. It has been identified as an outflow channel. It merges with Dao Vallis which runs southwestward into Hellas Planitia from the volcanic Hadriacus Mons. Like Dao, it was formed around the Late Noachian and Early Hesperian...

, extend for about 1200 km. It is named after the Thai

Thai language

Thai , also known as Central Thai and Siamese, is the national and official language of Thailand and the native language of the Thai people, Thailand's dominant ethnic group. Thai is a member of the Tai group of the Tai–Kadai language family. Historical linguists have been unable to definitively...

 word for star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

. In the fictional 2007 Canadian miniseries Race to Mars

Race to Mars

Race to Mars is a 2007 Canadian television mini-series about a fictitious mission to Mars that is based on contemporary international research. The first part aired on Discovery Channel Canada and its High Definition channel on September 23, 2007 and the second part on September 30...

, it is the landing site for Gagarin, the lander, and is the site of science for the mission.

Origin

Dao Vallis begins near a large volcano, called Hadriaca Patera, so it is thought to have received water when hot magma melted huge amounts of ice in the frozen ground. Much of this water may have been released in very large "outburst floods". The partially circular depressions on the left side of the channel in the image below suggests that groundwater sapping also contributed water more gradually.

External links

• Google Mars map centred on Dao Vallis.