Percival Lowell was an American businessman, author, mathematician, and astronomer who fueled speculation that there were canals on Mars, and furthered theories of a ninth planet within the Solar System. He founded the Lowell Observatory in Flagstaff, Arizona, and formed the beginning of the effort that led to the discovery of Pluto 14 years after his death.
The Viking 2 mission was part of the American Viking program to Mars, and consisted of an orbiter and a lander essentially identical to that of the Viking 1 mission. Viking 2 was operational on Mars for 1281 sols. The Viking 2 lander operated on the surface for 1,316 days, or 1281 sols, and was turned off on April 12, 1980, when its batteries failed. The orbiter worked until July 25, 1978, returning almost 16,000 images in 706 orbits around Mars.
Mars Global Surveyor (MGS) was an American robotic space probe developed by NASA's Jet Propulsion Laboratory and launched November 1996. MGS was a global mapping mission that examined the entire planet, from the ionosphere down through the atmosphere to the surface. As part of the larger Mars Exploration Program, Mars Global Surveyor performed atmospheric monitoring for sister orbiters during aerobraking, and helped Mars rovers and lander missions by identifying potential landing sites and relaying surface telemetry.
Utopia Planitia is a large plain within Utopia, the largest recognized impact basin on Mars and in the Solar System with an estimated diameter of 3,300 km (2,100 mi). It is the Martian region where the Viking 2 lander touched down and began exploring on September 3, 1976, and the Zhurong rover touched down on May 14, 2021, as a part of the Tianwen-1 mission. It is located at the antipode of Argyre Planitia, centered at 46.7°N 117.5°E. It is also in the Casius quadrangle, Amenthes quadrangle, and the Cebrenia quadrangle of Mars.
Areography, also known as the geography of Mars, is a subfield of planetary science that entails the delineation and characterization of regions on Mars. Areography is mainly focused on what is called physical geography on Earth; that is the distribution of physical features across Mars and their cartographic representations. In April 2023, The New York Times reported an updated global map of Mars based on images from the Hope spacecraft. A related, but much more detailed, global Mars map was released by NASA on 16 April 2023.
During the late 19th and early 20th centuries, it was erroneously believed that there were "canals" on the planet Mars. These were a network of long straight lines in the equatorial regions from 60° north to 60° south latitude on Mars, observed by astronomers using early telescopes without photography.
The Memnonia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Memnonia quadrangle is also referred to as MC-16.
Galle is a crater on Mars. It is located on the eastern rim of the huge impact basin Argyre Planitia in Argyre quadrangle. It is named after the German astronomer Johann Gottfried Galle. Galle is often known as the "happy face crater" because pareidolia causes a curved mountain range in the southern part of the crater and two smaller mountain clusters further north to appear to be a smiley face. The formation was first photographed by Viking Orbiter 1.
Newton is a large crater on Mars, with a diameter close to 300 km. It is located south of the planet's equator in the heavily cratered highlands of Terra Sirenum in the Phaethontis quadrangle. The crater was named in 1973 by the International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN) in honor of British physicist Sir Isaac Newton.
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". 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. It is classified as a terrestrial planet and is the second smallest of the Solar System's planets with a diameter of 6,779 km (4,212 mi). In terms of orbital motion, a Martian solar day (sol) is equal to 24.5 hours, and a Martian solar year is equal to 1.88 Earth years. Mars has two natural satellites that are small and irregular in shape: Phobos and Deimos.
The Cebrenia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The quadrangle is located in the northeastern portion of Mars' eastern hemisphere and covers 120° to 180° east longitude and 30° to 65° north latitude. The quadrangle uses a Lambert conformal conic projection at a nominal scale of 1:5,000,000 (1:5M). The Cebrenia quadrangle is also referred to as MC-7. It includes part of Utopia Planitia and Arcadia Planitia. The southern and northern borders of the Cebrenia quadrangle are approximately 3,065 km (1,905 mi) and 1,500 km (930 mi) wide, respectively. The north to south distance is about 2,050 km (1,270 mi). The quadrangle covers an approximate area of 4.9 million square km, or a little over 3% of Mars' surface area.
The Lunae Palus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The quadrangle is also referred to as MC-10. Lunae Planum and parts of Xanthe Terra and Chryse Planitia are found in the Lunae Palus quadrangle. The Lunae Palus quadrangle contains many ancient river valleys.
The Sinus Sabaeus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. It is also referred to as MC-20 . The Sinus Sabaeus quadrangle covers the area from 315° to 360° west longitude and 0° to 30° degrees south latitude on Mars. It contains Schiaparelli, a large, easily visible crater that sits close to the equator. The Sinus Sabaeus quadrangle contains parts of Noachis Terra and Terra Sabaea.
The Margaritifer Sinus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Margaritifer Sinus quadrangle is also referred to as MC-19. The Margaritifer Sinus quadrangle covers the area from 0° to 45° west longitude and 0° to 30° south latitude on Mars. Margaritifer Sinus quadrangle contains Margaritifer Terra and parts of Xanthe Terra, Noachis Terra, Arabia Terra, and Meridiani Planum.
The Thaumasia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Thaumasia quadrangle is also referred to as MC-25 . The name comes from Thaumas, the god of the clouds and celestial apparitions.
The Mare Australe quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Mare Australe quadrangle is also referred to as MC-30. The quadrangle covers all the area of Mars south of 65°, including the South polar ice cap, and its surrounding area. The quadrangle's name derives from an older name for a feature that is now called Planum Australe, a large plain surrounding the polar cap. The Mars polar lander crash landed in this region.
Dark slope streaks are narrow, avalanche-like features common on dust-covered slopes in the equatorial regions of Mars. They form in relatively steep terrain, such as along escarpments and crater walls. Although first recognized in Viking Orbiter images from the late 1970s, dark slope streaks were not studied in detail until higher-resolution images from the Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO) spacecraft became available in the late 1990s and 2000s.
To date, interplanetary spacecraft have provided abundant evidence of water on Mars, dating back to the Mariner 9 mission, which arrived at Mars in 1971. This article provides a mission by mission breakdown of the discoveries they have made. For a more comprehensive description of evidence for water on Mars today, and the history of water on that planet, see Water on Mars.
Copernicus is a large crater on Mars, with a diameter close to 300 km. It is located south of the planet's equator in the heavily cratered highlands of Terra Sirenum in the Phaethontis quadrangle at 48.8°S and 191.2°E. Its name was approved in 1973, and it was named after Nicolaus Copernicus.
The following outline is provided as an overview of and topical guide to Mars:
Viking Orbiter 1 image from 1976
High resolution image from ESA's Mars Express
Lowell crater northeast rim, as seen by HiRISE. Crater floor is toward the bottom of picture.
Shaded relief map
Sand dunes in Lowell Crater, as seen by CTX camera (on Mars Reconnaissance Orbiter).
