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I canali di Marte non sarebbero stati scavati dall'acqua, bensì dallo "scongelamento" del ghiaccio secco fatto di anidride carbonica solida. A sostenere questa nuova ipotesi, che potrebbe portare a una revisione delle teorie sul passato del Pianeta Rosso, sono due ricercatori del Consiglio nazionale delle ricerche francese (Cnrs), che nei giorni scorsi hanno pubblicato uno studio su "Nature Geoscience".
A prima vista, le numerose similitudini tra i canali marziani e i corsi d'acqua terrestri avevano fatto pensare che i due fenomeni avessero la stessa origine. I canali di Marte, però, sono relativamente giovani e l'ambiente attualmente presente sulla superficie del pianeta è troppo freddo a quelle latitudini per consentire lo scorrere di grandi volumi di acqua.
Questi indizi hanno spinto i ricercatori a ipotizzare che il vero motore della formazione dei canali fosse il processo di sublimazione del ghiaccio secco, ovvero il suo passaggio dallo stato solido a quello gassoso.
ATS/Reuters/EnCa
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