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Science. 2018 Aug 3;361(6401):490-493. doi: 10.1126/science.aar7268. Epub 2018 Jul 25.

Radar evidence of subglacial liquid water on Mars.

Author information

1
Istituto di Radioastronomia, Istituto Nazionale di Astrofisica, Via Piero Gobetti 101, 40129 Bologna, Italy. roberto.orosei@inaf.it.
2
Dipartimento di Matematica e Fisica, Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Roma, Italy.
3
Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica, Via del Fosso del Cavaliere 100, 00133 Roma, Italy.
4
Agenzia Spaziale Italiana, Via del Politecnico, 00133 Roma, Italy.
5
Istituto di Radioastronomia, Istituto Nazionale di Astrofisica, Via Piero Gobetti 101, 40129 Bologna, Italy.
6
Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica, Vicolo Osservatorio 5, 35122 Padova, Italy.
7
Consiglio Nazionale delle Ricerche, Istituto per il Rilevamento Elettromagnetico dell'Ambiente, Via Diocleziano 328, 80124 Napoli, Italy.
8
Dipartimento di Ingegneria dell'Informazione, Elettronica e Telecomunicazioni, Università degli Studi di Roma "La Sapienza," Via Eudossiana 18, 00184 Roma, Italy.
9
E.P. Elettronica Progetti, Via Traspontina 25, 00040 Ariccia (RM), Italy.
10
International Research School of Planetary Sciences, Università degli Studi "Gabriele d'Annunzio," Viale Pindaro 42, 65127 Pescara (PE), Italy.
11
Danfoss Drives, Romstrasse 2 - Via Roma 2, 39014 Burgstall - Postal (BZ), Italy.
12
Serco, c/o ESA Centre for Earth Observation, Largo Galileo Galilei 1, 00044 Frascati (RM), Italy.

Abstract

The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.

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PMID:
30045881
DOI:
10.1126/science.aar7268

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