Subglacial lakes on Mars

Last updated
The square indicates color-coded results superimposed on the location of the reported subglacial lake at 193degE, 81degS. Blue represents the area with the brightest radar reflection. Mars-SubglacialWater-SouthPoleRegion-20180725.jpg
The square indicates color-coded results superimposed on the location of the reported subglacial lake at 193°E, 81°S. Blue represents the area with the brightest radar reflection.

Salty subglacial lakes are controversially inferred from radar measurements to exist below the South Polar Layered Deposits (SPLD) in Ultimi Scopuli of Mars' southern ice cap. [1] [2] [3] The idea of subglacial lakes due to basal melting at the polar ice caps on Mars was first hypothesized in the 1980s. [4] [5] [6] For liquid water to persist below the SPLD, researchers propose that perchlorate is dissolved in the water, which lowers the freezing temperature, [1] [2] but other explanations such as saline ice or hydrous minerals have been offered. Challenges for explaining sufficiently warm conditions for liquid water to exist below the southern ice cap include low amounts of geothermal heating from the subsurface and overlying pressure from the ice. [7] As a result, it is disputed whether radar detections of bright reflectors were instead caused by other materials such as saline ice [8] or deposits of minerals such as clays. [8] [9] While lakes with salt concentrations 20 times that of the ocean pose challenges for life, [10] potential subglacial lakes on Mars are of high interest for astrobiology because microbial ecosystems have been found in deep subglacial lakes on Earth, such as in Lake Whillans in Antarctica below 800 m of ice. [11] [12] [13] [14] [15]

Contents

Features

The proposed subglacial lake at the base of the South Polar Layered Deposits on Mars has a stronger radar reflection than ice or rock. Analyses are based on radar profiles (such as in the middle panel) taken by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) and was first interpreted as a subglacial lake. (Image credit: This corresponds to Figure 1 from Schroeder & Steinbrugge 2021 obtained with permission from D. Shroeder using the Creative Commons Attribution-Share Alike 4.0 copyright license.) Schematic of bright radar reflections suggesting a subglacial lake on Mars.png
The proposed subglacial lake at the base of the South Polar Layered Deposits on Mars has a stronger radar reflection than ice or rock. Analyses are based on radar profiles (such as in the middle panel) taken by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) and was first interpreted as a subglacial lake. (Image credit: This corresponds to Figure 1 from Schroeder & Steinbrugge 2021 obtained with permission from D. Shroeder using the Creative Commons Attribution-Share Alike 4.0 copyright license.)

A study from 2018 first reported radar observations of a potential 20-km wide subglacial lake centered at 193°E, 81°S at the base of the SPLD [1] using data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on the European Space Agency’s Mars Express spacecraft. The team noticed radar echoes stronger than what ice or rock would reflect coming from 1.5 km below the surface at the base of the SPLD. [16] They interpreted the bright radar reflections to indicate high permittivity (the ability of a material to become polarized and store energy in response to an electric field), consistent with liquid water. [3] Three additional subglacial lakes on the km-wide scale next to the original lake were also proposed from a more detailed study, [10] [17] though the study also indicates the possibility that the three locations could contain wet sediment instead of lakes. [2] [18]

Though the SHAllow RADar (SHARAD) on the Mars Reconnaissance Orbiter operates at higher frequencies, a subglacial lake should be detectable but bright radar reflectors are absent. [19] However, with the discovery of many widespread occurrences of the radar features in the SPLD area, [20] corroboration between the two instruments might become possible. [21]

Physical limits

Geothermal heating and perchlorate

The radar evidence can be difficult to understand due to scattering effects of the layers in the SPLD on radar reflections (according to an eLetter by Hecht et al. replying to the original publication [1] along with other sources [22] ). As a result, further work has focused on explaining how the freezing temperature at the base of the SPLD might be lowered due to a combination of perchlorate salt and enhanced regional geothermal flux. Following the detection of perchlorate in the northern plains of Mars by the Phoenix lander, [23] it was predicted that perchlorate could allow a brine of 1–3 meters deep to exist at the base of the northern ice cap of Mars. [24] Perchlorate is a salt now considered to be widespread on Mars [25] and is known to lower the freezing point of water. The studies in support of the subglacial lake hypothesis proposed that magnesium and calcium perchlorate at the base of the SPLD would lower the freezing point of water to temperatures as low as 204 and 198 K, thereby allowing the existence of briny liquid water. [1] [2] However, even taking into account perchlorate, computer simulations predict the temperature to still be too cold for liquid water to exist at the bottom of the southern ice cap. This is due to a small amount of pressure melting (Mars' gravity is about a third of Earth's) that would only lower the melting point by 0.3-0.5 K and an estimated low geothermal heat flux of 14-30 mW/m2. [7] A geothermal heat flux greater than 72 mW/m2 would support the subglacial lake, thus requiring a local enhancement in the heat flux, perhaps sourced by geologically recent (within hundreds of thousands of years ago) magmatism in the subsurface. [7] Similarly, another study based on the surface topography and ice thickness found that the radar detection did not coincide with their predictions of locations for subglacial lakes based on hydrological potential, and as a result, they proposed the detection was due to a localized patch of basal melting rather than a lake. [26]

Liquid brine water is proposed to be plausible at the SPLD because magnesium and calcium perchlorate solutions can be supercooled to as low as 150 K [2] [27] and the surface temperature at the south pole is approximately 160 K. [1] [2] In addition, it is expected that the temperature at depth for the ice would increase at a rate based on the undetermined geothermal flux and thermal properties of the SPLD. [2] However, a study found the bright radar reflectors to be widespread across the SPLD, rather than limited to the previously identified areas of the putative subglacial lakes. [20] Since the bright radar detections covered a wide variety of conditions at the SPLD (e.g., different temperatures, ice thicknesses), this presents challenges for all of the bright radar reflectors to be indicative of liquid water. [20]

Surface features

Additional approaches to determining the plausibility of the subglacial lakes included a study looking for surface features induced by such lakes. [28] On Earth, examples of surface features caused by a subglacial lake include fractures or ridge features like at Pine Island Glacier in Antarctica. [29] While a study on Mars only found surface features that match CO2 and wind-related processes and none corresponding to the putative subglacial lakes, the lack of surface features also do not rule out the possibility of the subglacial lake. [30] This is because while the surface of the SPLD is expected to be at least thousands of years old and possibly millions of years old, it is hard to constrain when the putative subglacial lake would have modified the surface features. [28]

Alternative hypotheses

Three leading hypotheses to explain the bright basal radar reflections below the South Polar Layered Deposits include liquid brines, saline ice, and conductive deposits such as smectites. Not included in this image is additional work on igneous sources. (Image credit: This corresponds to Figure 2 from Schroeder & Steinbrugge 2021 obtained with permission from D. Shroeder using the Creative Commons Attribution-Share Alike 4.0 copyright license.) Hypotheses for bright radar observation.png
Three leading hypotheses to explain the bright basal radar reflections below the South Polar Layered Deposits include liquid brines, saline ice, and conductive deposits such as smectites. Not included in this image is additional work on igneous sources. (Image credit: This corresponds to Figure 2 from Schroeder & Steinbrugge 2021 obtained with permission from D. Shroeder using the Creative Commons Attribution-Share Alike 4.0 copyright license.)

In contrast with the hypothesis of subglacial water at the base of the SPLD, other suggestions include materials such as saline ice, [8] a conductive mineral deposit such as clays, [8] [9] and igneous materials. [31] Future work is necessary to resolve how these alternative hypotheses hold under Mars-like conditions using instruments like MARSIS.

Saline ice

While the initial study assumed negligible conductivity in their calculation of the permittivity values, [1] by accounting for conductivity, conductive materials that are not liquid water may also be considered. [21] Instead of the assumption that the bright radar reflections at the base of the ice cap are due to a large contrast in dielectric permittivity, [1] another study suggested that the bright reflection is instead due to a large contrast in electric conductivity in the materials. [8] Saline ice, observed on Earth beneath the Taylor Glacier in Antarctica, [32] is one potential source for the bright basal reflections, though the electric conductivity of saline ice at martian temperatures is unknown. [8]

Hydrous minerals

The mineralogical explanation is the most favored in follow-up studies, especially with specific hydrous minerals such as jarosite (a sulfate) [8] and smectite (a clay mineral). [33] Smectites have high enough dielectric permittivity to account for the bright reflections (though at laboratory temperatures of 230 K higher than expected conditions on Mars), and they exist at the edges of the SPLD. [9] Ultimately, although the studies propose these new hypotheses, they do not completely reject the possibility of liquid water as the source of the bright radar returns. [8] [9] [20]

Igneous materials

Another study applied computer simulations to look for what other regions on Mars might cause similar bright basal reflectors if there was a 1.4-km thick ice shell covering the base material. [31] They found that 0.3%-2% of the surface of Mars could produce similar signals, most of which belong to volcanic regions. [31] While the permittivity of igneous materials requires more research, they pointed out how high density igneous content may also cause the observed bright radar reflectors. [31]

Lake Vostok in Antarctica has been covered by ice for the last 25 million years. Microbes found near the bottom of the accreted ice and in the water have interesting implications for astrobiology. (Image credit: Lamont-Doherty Earth Observatory of Columbia University/NASA.) Subglacial Lake Vostok System.jpg
Lake Vostok in Antarctica has been covered by ice for the last 25 million years. Microbes found near the bottom of the accreted ice and in the water have interesting implications for astrobiology. (Image credit: Lamont-Doherty Earth Observatory of Columbia University/NASA.)

Terrestrial analogue sites and habitability

Lake Vostok and other subglacial rivers and lakes in Antarctica. (Image credit: NASA.) Antarctic Lakes - Sub-glacial aquatic system.jpg
Lake Vostok and other subglacial rivers and lakes in Antarctica. (Image credit: NASA.)

The putative subglacial lakes are of interest for the possibility of supporting life. [34] If physical conditions allowed one location of subglacial liquid water on Mars to exist, then this might extend to other subsurface biospheres on the planet. [35] On Earth, subglacial lakes exist below hundreds of meters of ice in both the Arctic [36] and Antarctic [15] [37] and act as a planetary analog for both the potential subglacial lakes on Mars and liquid oceans below icy shells of moons like Europa. [36] To study life in subglacial lakes on Earth, ice core drilling is used to reach the water, but contamination is commonly considered to have compromised attempts to sample the water of both Lake Vostok and Lake Ellsworth. [15] However, microbes have been sampled from the accretion ice (frozen lake water) of Lake Vostok. [38] Also, Lake Whillans was a successful sampling endeavor from under 800 m of ice, where over 4000 species of chemoautotroph microbes have been identified. [11] [13] [14] [15] Whether similar microbes could survive in the putative salty subglacial lakes on Mars is still unknown, but if liquid water is present, it could preserve inactive microbial life. [22] [34] [39]

Related Research Articles

<i>Mars Express</i> European Mars orbiter

Mars Express is a space exploration mission being conducted by the European Space Agency (ESA). The Mars Express mission is exploring the planet Mars, and is the first planetary mission attempted by the agency. "Express" originally referred to the speed and efficiency with which the spacecraft was designed and built. However, "Express" also describes the spacecraft's relatively short interplanetary voyage, a result of being launched when the orbits of Earth and Mars brought them closer than they had been in about 60,000 years.

<span class="mw-page-title-main">Deep Space 2</span> NASA space probe part of the New Millennium Program

Deep Space 2 was a NASA space probe, part of the New Millennium Program. It included two highly advanced miniature space probes that were sent to Mars aboard the Mars Polar Lander in January 1999. The probes were named "Scott" and "Amundsen", in honor of Robert Falcon Scott and Roald Amundsen, the first explorers to reach the Earth's South Pole. Intended to be the first spacecraft to penetrate below the surface of another planet, after entering the Mars atmosphere DS2 was to detach from the Mars Polar Lander mother ship and plummet to the surface using only an aeroshell impactor, with no parachute. The mission was declared a failure on March 13, 2000, after all attempts to reestablish communications following the descent went unanswered.

<span class="mw-page-title-main">Life on Mars</span> Scientific assessments on the microbial habitability of Mars

The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ancient Noachian time period, the surface environment of Mars had liquid water and may have been habitable for microorganisms, but habitable conditions do not necessarily indicate life.

<span class="mw-page-title-main">Ganges Chasma</span> Chasma on Mars

Ganges Chasma is a deep canyon at the eastern end of the vast Valles Marineris system on Mars, an offshoot of Capri Chasma, and is in the Coprates quadrangle. It is named after the River Ganges in South Asia. Ganges Chasma is thought to have formed through a series of catastrophic discharges of water and CO2 from chaos terrains such as that preserved in Ganges Chaos at its southern margin. Most of the evidence for these discharges and the ensuing collapses is believed to have been washed away. Prior to developing an outlet that joined it to Capri Chasma and the connected outflow channels to its east, Ganges Chasma may at some point in the Noachian period have contained a lake which drained northward through partially subsurface pathways into Shalbatana Vallis.

<span class="mw-page-title-main">MARSIS</span>

MARSIS is a low frequency, pulse-limited radar sounder and altimeter developed by the University of Rome La Sapienza and Alenia Spazio. The Italian MARSIS instrument, which is operated by the European Space Agency, is operational and orbits Mars as an instrument for the ESA's Mars Express exploration mission.

<span class="mw-page-title-main">Subglacial lake</span> Lake under a glacier

A subglacial lake is a lake that is found under a glacier, typically beneath an ice cap or ice sheet. Subglacial lakes form at the boundary between ice and the underlying bedrock, where gravitational pressure decreases the pressure melting point of ice. Over time, the overlying ice gradually melts at a rate of a few millimeters per year. Meltwater flows from regions of high to low hydraulic pressure under the ice and pools, creating a body of liquid water that can be isolated from the external environment for millions of years.

<span class="mw-page-title-main">Compact Reconnaissance Imaging Spectrometer for Mars</span> Visible-infrared spectrometer

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) was a visible-infrared spectrometer aboard the Mars Reconnaissance Orbiter searching for mineralogic indications of past and present water on Mars. The CRISM instrument team comprised scientists from over ten universities and was led by principal investigator Scott Murchie. CRISM was designed, built, and tested by the Johns Hopkins University Applied Physics Laboratory.

Radioglaciology is the study of glaciers, ice sheets, ice caps and icy moons using ice penetrating radar. It employs a geophysical method similar to ground-penetrating radar and typically operates at frequencies in the MF, HF, VHF and UHF portions of the radio spectrum. This technique is also commonly referred to as "Ice Penetrating Radar (IPR)" or "Radio Echo Sounding (RES)".

<span class="mw-page-title-main">Planum Australe</span> Planum on Mars

Planum Australe is the southern polar plain on Mars. It extends southward of roughly 75°S and is centered at 83.9°S 160.0°E. The geology of this region was to be explored by the failed NASA mission Mars Polar Lander, which lost contact on entry into the Martian atmosphere.

<span class="mw-page-title-main">SHARAD</span>

SHARAD is a subsurface sounding radar embarked on the Mars Reconnaissance Orbiter (MRO) probe. It complements the MARSIS radar on Mars Express orbiter, providing lower penetration capabilities but much finer resolution.

Extraterrestrial liquid water is water in its liquid state that naturally occurs outside Earth. It is a subject of wide interest because it is recognized as one of the key prerequisites for life as we know it and thus surmised as essential for extraterrestrial life.

The presence of water on the terrestrial planets of the Solar System varies with each planetary body, with the exact origins remaining unclear. Additionally, the terrestrial dwarf planet Ceres is known to have water ice on its surface.

<span class="mw-page-title-main">Mars</span> Fourth planet from the Sun

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.

<span class="mw-page-title-main">Medusae Fossae Formation</span> Large geological unit of uncertain origin on Mars

The Medusae Fossae Formation is a large geological formation of probable volcanic origin on the planet Mars. It is named for the Medusa of Greek mythology. "Fossae" is Latin for "trenches". The formation is a collection of soft, easily eroded deposits that extends discontinuously for more than 5,000 km along the equator of Mars. Its roughly-shaped regions extend from just south of Olympus Mons to Apollinaris Patera, with a smaller additional region closer to Gale Crater.

<span class="mw-page-title-main">Water on Mars</span> Study of past and present water on Mars

Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of flowing sand and dust slipping downhill to make dark streaks. While most water ice is buried, it is exposed at the surface across several locations on Mars. In the mid-latitudes, it is exposed by impact craters, steep scarps and gullies. Additionally, water ice is also visible at the surface at the north polar ice cap. Abundant water ice is also present beneath the permanent carbon dioxide ice cap at the Martian south pole. More than 5 million km3 of ice have been detected at or near the surface of Mars, enough to cover the whole planet to a depth of 35 meters (115 ft). Even more ice might be locked away in the deep subsurface.

<span class="mw-page-title-main">Martian polar ice caps</span> Polar water ice deposits on Mars

The planet Mars has two permanent polar ice caps. During a pole's winter, it lies in continuous darkness, chilling the surface and causing the deposition of 25–30% of the atmosphere into slabs of CO2 ice (dry ice). When the poles are again exposed to sunlight, the frozen CO2 sublimes. These seasonal actions transport large amounts of dust and water vapor, giving rise to Earth-like frost and large cirrus clouds.

<span class="mw-page-title-main">Dorsa Argentea Formation</span>

The Dorsa Argentea Formation (DAF) is thought to be a large system of eskers that were under an ancient ice cap in the south polar region of Mars. The ancient ice cap was at least twice the size of the present ice cap and may have been 1500–2000 meters thick. Later research suggests that the area of this polar ice sheet is believed to have covered about 1.5 million square kilometers, roughly twice the size of France or the American state of Texas. This group of ridges extends from 270–100 E and 70–90 S, around the south pole of Mars. It sits under the Late Amazonian South Polar Layered Deposits (SPLD), in the Mare Australe quadrangle.

Mars habitability analogue environments on Earth are environments that share potentially relevant astrobiological conditions with Mars. These include sites that are analogues of potential subsurface habitats, and deep subsurface habitats.

Rebecca Woodgate is a professor at the University of Washington known for her work on ocean circulation in polar regions.

References

  1. 1 2 3 4 5 6 7 8 9 10 Orosei, R.; Lauro, S. E.; Pettinelli, E.; Cicchetti, A.; Coradini, M.; Cosciotti, B.; Di Paolo, F.; Flamini, E.; Mattei, E.; Pajola, M.; Soldovieri, F. (2018-08-03). "Radar evidence of subglacial liquid water on Mars". Science. 361 (6401): 490–493. arXiv: 2004.04587 . Bibcode:2018Sci...361..490O. doi:10.1126/science.aar7268. ISSN   0036-8075. PMID   30045881. S2CID   206666385.
  2. 1 2 3 4 5 6 7 Lauro, Sebastian Emanuel; Pettinelli, Elena; Caprarelli, Graziella; Guallini, Luca; Rossi, Angelo Pio; Mattei, Elisabetta; Cosciotti, Barbara; Cicchetti, Andrea; Soldovieri, Francesco; Cartacci, Marco; Di Paolo, Federico (January 2021). "Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data". Nature Astronomy. 5 (1): 63–70. arXiv: 2010.00870 . Bibcode:2021NatAs...5...63L. doi:10.1038/s41550-020-1200-6. ISSN   2397-3366. S2CID   222125007.
  3. 1 2 "Liquid water spied deep below polar ice cap on Mars". www.science.org. Retrieved 2022-05-30.
  4. ↑ fischer (2018-07-27). "Evidence of Subsurface Martian Liquid Water Bolstered". Planetary Science Institute. Retrieved 2022-06-03.
  5. ↑ Witze, Alexandra (2018-07-25). "There's water on Mars! Signs of buried lake tantalize scientists". Nature. 560 (7716): 13–14. Bibcode:2018Natur.560...13W. doi: 10.1038/d41586-018-05795-6 . PMID   30065323. S2CID   51887407.
  6. ↑ Clifford, Stephen M. (1987). "Polar basal melting on Mars". Journal of Geophysical Research. 92 (B9): 9135–9152. Bibcode:1987JGR....92.9135C. doi:10.1029/JB092iB09p09135. ISSN   0148-0227.
  7. 1 2 3 Sori, Michael M.; Bramson, Ali M. (2019-02-16). "Water on Mars, With a Grain of Salt: Local Heat Anomalies Are Required for Basal Melting of Ice at the South Pole Today". Geophysical Research Letters. 46 (3): 1222–1231. Bibcode:2019GeoRL..46.1222S. doi:10.1029/2018GL080985. hdl: 10150/633584 . ISSN   0094-8276. S2CID   134166238.
  8. 1 2 3 4 5 6 7 8 Bierson, C. J.; Tulaczyk, S.; Courville, S. W.; Putzig, N. E. (2021-07-16). "Strong MARSIS Radar Reflections From the Base of Martian South Polar Cap May Be Due to Conductive Ice or Minerals". Geophysical Research Letters. 48 (13). Bibcode:2021GeoRL..4893880B. doi:10.1029/2021GL093880. ISSN   0094-8276. S2CID   237755186.
  9. 1 2 3 4 Smith, I. B.; Lalich, D. E.; Rezza, C.; Horgan, B. H. N.; Whitten, J. L.; Nerozzi, S.; Holt, J. W. (August 2021). "A Solid Interpretation of Bright Radar Reflectors Under the Mars South Polar Ice". Geophysical Research Letters. 48 (15). Bibcode:2021GeoRL..4893618S. doi:10.1029/2021GL093618. ISSN   0094-8276. S2CID   237654444.
  10. 1 2 O'Callaghan, Jonathan (2020-09-28). "Water on Mars: discovery of three buried lakes intrigues scientists". Nature. doi:10.1038/d41586-020-02751-1. PMID   32989309. S2CID   222155190.
  11. 1 2 "Microbes Discovered in Subglacial Antarctic Lake May Hint at Life in Space". Animals. 2014-08-20. Archived from the original on August 2, 2021. Retrieved 2022-05-31.
  12. ↑ Magazine, Smithsonian; Thompson, Helen. "Thousands of Microbe Species Live in This Buried Antarctic Lake". Smithsonian Magazine. Retrieved 2022-05-30.
  13. 1 2 Christner, Brent C.; Priscu, John C.; Achberger, Amanda M.; Barbante, Carlo; Carter, Sasha P.; Christianson, Knut; Michaud, Alexander B.; Mikucki, Jill A.; Mitchell, Andrew C.; Skidmore, Mark L.; Vick-Majors, Trista J. (August 2014). "A microbial ecosystem beneath the West Antarctic ice sheet". Nature. 512 (7514): 310–313. Bibcode:2014Natur.512..310.. doi:10.1038/nature13667. hdl: 2160/30202 . ISSN   1476-4687. PMID   25143114. S2CID   4470332.
  14. 1 2 Mikucki, J. A.; Lee, P. A.; Ghosh, D.; Purcell, A. M.; Mitchell, A. C.; Mankoff, K. D.; Fisher, A. T.; Tulaczyk, S.; Carter, S.; Siegfried, M. R.; Fricker, H. A. (2016-01-28). "Subglacial Lake Whillans microbial biogeochemistry: a synthesis of current knowledge". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 374 (2059): 20140290. Bibcode:2016RSPTA.37440290M. doi: 10.1098/rsta.2014.0290 . hdl: 2160/42715 . PMID   26667908. S2CID   15307967.
  15. 1 2 3 4 Siegert, Martin J.; Priscu, John C.; Alekhina, Irina A.; Wadham, Jemma L.; Lyons, W. Berry (2016-01-28). "Antarctic subglacial lake exploration: first results and future plans". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 374 (2059): 20140466. Bibcode:2016RSPTA.37440466S. doi:10.1098/rsta.2014.0466. PMC   4685969 . PMID   26667917.
  16. 1 2 Kaufman, Marc (2018-07-25). "Large Reservoir of Liquid Water Found Deep Below the Surface of Mars". Astrobiology at NASA Life in the Universe.
  17. ↑ Reid, Tim (2020-10-19). "New evidence for subglacial lakes on Mars". Nature Italy. doi:10.1038/d43978-020-00008-z (inactive 31 January 2024).{{cite journal}}: CS1 maint: DOI inactive as of January 2024 (link)
  18. ↑ "Mars may be hiding tantalizing lakes beneath its glaciers". Science. 2020-09-28. Archived from the original on February 20, 2021. Retrieved 2022-05-31.
  19. ↑ "Underground Lake Found on Mars? Get the Facts". Science. 2018-07-25. Archived from the original on April 18, 2021. Retrieved 2022-05-31.
  20. 1 2 3 4 Khuller, Aditya R.; Plaut, Jeffrey J. (2021-07-16). "Characteristics of the Basal Interface of the Martian South Polar Layered Deposits". Geophysical Research Letters. 48 (13). Bibcode:2021GeoRL..4893631K. doi:10.1029/2021GL093631. ISSN   0094-8276. S2CID   232045163.
  21. 1 2 3 Schroeder, Dustin M.; Steinbrügge, Gregor (2021-09-27). "Alternatives to Liquid Water Beneath the South Polar Ice Cap of Mars". Geophysical Research Letters. 48 (19). Bibcode:2021GeoRL..4895912S. doi: 10.1029/2021gl095912 . ISSN   0094-8276. S2CID   239389853.
  22. 1 2 Chang, Kenneth; Overbye, Dennis (2018-07-25). "A Large Body of Water on Mars Is Detected, Raising the Potential for Alien Life". The New York Times. ISSN   0362-4331 . Retrieved 2022-06-03.
  23. ↑ Hecht, M. H.; Kounaves, S. P.; Quinn, R. C.; West, S. J.; Young, S. M. M.; Ming, D. W.; Catling, D. C.; Clark, B. C.; Boynton, W. V.; Hoffman, J.; DeFlores, L. P. (2009-07-03). "Detection of Perchlorate and the Soluble Chemistry of Martian Soil at the Phoenix Lander Site". Science. 325 (5936): 64–67. Bibcode:2009Sci...325...64H. doi:10.1126/science.1172466. ISSN   0036-8075. PMID   19574385. S2CID   24299495.
  24. ↑ Fisher, David A.; Hecht, Michael H.; Kounaves, Samuel P.; Catling, David C. (2010-02-16). "A perchlorate brine lubricated deformable bed facilitating flow of the north polar cap of Mars: Possible mechanism for water table recharging". Journal of Geophysical Research. 115 (E3): E00E12. Bibcode:2010JGRE..115.0E12F. doi: 10.1029/2009JE003405 . ISSN   0148-0227.
  25. ↑ Clark, Benton C.; Kounaves, Samuel P. (October 2016). "Evidence for the distribution of perchlorates on Mars". International Journal of Astrobiology. 15 (4): 311–318. Bibcode:2016IJAsB..15..311C. doi:10.1017/S1473550415000385. ISSN   1473-5504. S2CID   98012678.
  26. ↑ Arnold, N. S.; Conway, S. J.; Butcher, F. E. G.; Balme, M. R. (August 2019). "Modeled Subglacial Water Flow Routing Supports Localized Intrusive Heating as a Possible Cause of Basal Melting of Mars' South Polar Ice Cap". Journal of Geophysical Research: Planets. 124 (8): 2101–2116. Bibcode:2019JGRE..124.2101A. doi:10.1029/2019JE006061. ISSN   2169-9097. S2CID   199414406.
  27. ↑ Toner, J. D.; Catling, D. C.; Light, B. (2014-05-01). "The formation of supercooled brines, viscous liquids, and low-temperature perchlorate glasses in aqueous solutions relevant to Mars". Icarus. 233: 36–47. Bibcode:2014Icar..233...36T. doi:10.1016/j.icarus.2014.01.018. ISSN   0019-1035.
  28. 1 2 Landis, M. E.; Whitten, J. L. (2022-05-28). "Geologic Context of the Bright MARSIS Reflectors in Ultimi Scopuli, South Polar Layered Deposits, Mars". Geophysical Research Letters. 49 (10). arXiv: 2205.00091 . Bibcode:2022GeoRL..4998724L. doi:10.1029/2022GL098724. ISSN   0094-8276. S2CID   248704170.
  29. ↑ Vaughan, David G.; Corr, Hugh F. J.; Bindschadler, Robert A.; Dutrieux, Pierre; Gudmundsson, G. Hilmar; Jenkins, Adrian; Newman, Thomas; Vornberger, Patricia; Wingham, Duncan J. (2012-08-03). "Subglacial melt channels and fracture in the floating part of Pine Island Glacier, Antarctica". Journal of Geophysical Research: Earth Surface. 117 (F3): n/a. Bibcode:2012JGRF..117.3012V. doi:10.1029/2012jf002360. ISSN   0148-0227. S2CID   131444235.
  30. ↑ Landis, Margaret; Whitten, Jennifer (2021). "Geologic Context of the Bright Marsis Reflector in Ultimi Scopuli, South Polar Layered Deposits, Mars". Geological Society of America Abstracts with Programs. Geological Society of America. doi:10.1130/abs/2021am-366811. S2CID   240149381.
  31. 1 2 3 4 5 Grima, C.; Mouginot, J.; Kofman, W.; Hérique, A.; Beck, P. (2022-01-24). "The Basal Detectability of an Ice-Covered Mars by MARSIS". Geophysical Research Letters. 49 (2). Bibcode:2022GeoRL..4996518G. doi:10.1029/2021gl096518. ISSN   0094-8276. S2CID   246327935.
  32. ↑ Montross, Scott; Skidmore, Mark; Christner, Brent; Samyn, Denis; Tison, Jean-Louis; Lorrain, Reginald; Doyle, Shawn; Fitzsimons, Sean (2014-01-02). "Debris-Rich Basal Ice as a Microbial Habitat, Taylor Glacier, Antarctica". Geomicrobiology Journal. 31 (1): 76–81. doi:10.1080/01490451.2013.811316. ISSN   0149-0451. S2CID   129837784.
  33. ↑ Choi, Charles (2021-07-29). "Mars' buried polar 'lakes' may just be frozen clay". Space.com. Retrieved 2022-05-31.
  34. 1 2 Rothery, David (28 September 2020). "Mars: mounting evidence for subglacial lakes, but could they really host life?". The Conversation. Retrieved 2022-05-31.
  35. ↑ Billings, Lee (July 25, 2018). "Deep within Mars, Liquid Water Offers Hope for Life". Scientific American. Retrieved 2022-05-31.
  36. 1 2 Rutishauser, Anja; Blankenship, Donald D.; Sharp, Martin; Skidmore, Mark L.; Greenbaum, Jamin S.; Grima, Cyril; Schroeder, Dustin M.; Dowdeswell, Julian A.; Young, Duncan A. (2018-04-06). "Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic". Science Advances. 4 (4): eaar4353. Bibcode:2018SciA....4.4353R. doi:10.1126/sciadv.aar4353. ISSN   2375-2548. PMC   5895444 . PMID   29651462.
  37. ↑ Wright, Andrew; Siegert, Martin (December 2012). "A fourth inventory of Antarctic subglacial lakes". Antarctic Science. 24 (6): 659–664. Bibcode:2012AntSc..24..659W. doi:10.1017/S095410201200048X. ISSN   0954-1020. S2CID   129337881.
  38. ↑ Bulat, Sergey A. (2016-01-28). "Microbiology of the subglacial Lake Vostok: first results of borehole-frozen lake water analysis and prospects for searching for lake inhabitants". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 374 (2059): 20140292. Bibcode:2016RSPTA.37440292B. doi: 10.1098/rsta.2014.0292 . PMID   26667905. S2CID   8399775.
  39. ↑ Hallsworth, John E. (6 September 2018). "What on Earth could live in a salt water lake on Mars? An expert explains". The Conversation. Retrieved 2022-05-31.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.