From today's featured article Mars is the fourth planet from the Sun. It was formed approximately 4.5 billion years ago, is a terrestrial planet and is the second smallest of the Solar System's planets with a diameter of 6,779 km (4,212 mi). A Martian solar day (sol) is 24.5 hours and a Martian solar year is 1.88 Earth years (687 Earth days). Mars has two small and irregular natural satellites: Phobos and Deimos. Carbon dioxide is substantially present in Mars's polar ice caps and thin atmosphere. It has the highest mountain in the solar system, Olympus Mons, and the largest canyon, Valles Marineris. There are large annual temperature swings on the surface, between −78.5 °C (−109.3 °F) and 5.7 °C (42.3 °F) – similar to Earth's seasons. Due to its geological history, the possibility of past or present life on Mars remains of great scientific interest. Mars has been explored by uncrewed spacecraft and rovers, and is an attractive target for future human exploration missions. (This article is part of a featured topic: Solar System.)
Recently featured:
Did you know....jpg) Li Zhaoxing
|
In the news Aurora australis seen from Melbourne, Australia
On this day...May 14: Feast day of Saint Matthias (Catholicism); Independence Day in Israel (2024)  Monument to the Battle of Lewes
|
Today's featured picture
|
The Tarantula Nebula, also known as 30 Doradus, is a large H II region in the Large Magellanic Cloud (LMC). It is one of the largest H II regions in the Local Group, with an estimated diameter around 650 to 1860 light years. It is around 160,000 light-years from Earth and has apparent magnitude of 8. The Tarantula Nebula was first observed by Nicolas-Louis de Lacaille during an expedition to the Cape of Good Hope between 1751 and 1753. This high-resolution photograph was taken by the Hubble Space Telescope and shows the star-forming region of Tarantula Nebula with the R136 super star cluster at its center. Photograph credit: NASA, ESA, Space Telescope Science Institute
Recently featured:
|
Other areas of Wikipedia
- Community portal – The central hub for editors, with resources, links, tasks, and announcements.
- Village pump – Forum for discussions about Wikipedia itself, including policies and technical issues.
- Site news – Sources of news about Wikipedia and the broader Wikimedia movement.
- Teahouse – Ask basic questions about using or editing Wikipedia.
- Help desk – Ask questions about using or editing Wikipedia.
- Reference desk – Ask research questions about encyclopedic topics.
- Content portals – A unique way to navigate the encyclopedia.
Wikipedia's sister projects
Wikipedia is written by volunteer editors and hosted by the Wikimedia Foundation, a non-profit organization that also hosts a range of other volunteer projects:
-
Commons
Free media repository -
MediaWiki
Wiki software development -
Meta-Wiki
Wikimedia project coordination -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikispecies
Directory of species -
Wikiversity
Free learning tools -
Wikivoyage
Free travel guide -
Wiktionary
Dictionary and thesaurus
Wikipedia languages
This Wikipedia is written in English. Many other Wikipedias are available; some of the largest are listed below.
-
1,000,000+ articles
-
250,000+ articles
-
50,000+ articles