North Polar Basin (Mars)

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Not to be confused with Vastitas Borealis.
North Polar Basin
Mars topography (MOLA dataset) with poles HiRes.jpg
The North Polar Basin is the large blue low-lying area at the northern end of this topographical map of Mars. Its elliptical shape is partially obscured by volcanic eruptions (red, center left).
Coordinates 67°N 208°E / 67°N 208°E / 67; 208Coordinates: 67°N 208°E / 67°N 208°E / 67; 208

The North Polar Basin, or Borealis basin, is a large basin in the northern hemisphere of Mars that covers 40% of the planet. Chryse Planitia, the landing site of the Viking 1 lander, is a bay that opens into this basin.

One possible explanation for the basin's low, flat and relatively crater-free topography is that the basin was formed by a single large impact. Two simulations of a possible impact sketched a profile for the collision: low velocity—6 to 10 km (3.7 to 6.2 mi) per second—oblique angle and a diameter of 1,600–2,700 km (990–1,680 mi).[1][2] Topographical data from Mars Global Surveyor are consistent with the models and also suggest that the elliptical crater has axes of length 10,600 km (6,600 mi) and 8,500 km (5,300 mi), centered on 67°N 208°E / 67°N 208°E / 67; 208, though this has been partially obscured by later volcanic eruptions that created the Tharsis bulge along its rim. There is evidence for a secondary rim as well.[3][4] This would make the North Polar Basin by far the largest impact crater in the Solar System, approximately four times the diameter of the next largest craters: Utopia Planitia, which is imbedded inside the North Polar Basin, the South Pole–Aitken basin on the Moon, and Hellas Planitia on Mars's southern hemisphere.[5]

See also[edit]


  1. ^ Marinova; et al. (2008). "Mega-impact formation of the Mars hemispheric dichotomy". Nature. 453 (7199): 1216–1219. Bibcode:2008Natur.453.1216M. doi:10.1038/nature07070. PMID 18580945. 
  2. ^ Nimmo; et al. (2008). "Implications of an impact origin for the Martian hemispheric dichotomy". Nature. 453 (7199): 1220–1223. Bibcode:2008Natur.453.1220N. doi:10.1038/nature07025. PMID 18580946. 
  3. ^ Andrews-Hanna; et al. (2008). "The Borealis basin and the origin of the Martian crustal dichotomy". Nature. 453 (7199): 1212–1215. Bibcode:2008Natur.453.1212A. doi:10.1038/nature07011. PMID 18580944. 
  4. ^ "Huge Impact Created Mars' Split Personality". Retrieved 2008-07-01. 
  5. ^ Chandler, David (2008-06-25). "Solar system's biggest impact scar discovered: MIT scientists solve riddle of Mars' two-faced nature". MIT News. Retrieved 2015-01-01.