Why Life on Mars May Be Impossible

Mars is a lousy place to try to live—what with the paralyzing cold, the blistering radiation and the thin carbon dioxide atmosphere. That hasn’t stopped us from looking for life on Mars or from hoping to to live there ourselves once day. The Red Planet was once a watery world like ours, after all, with oceans and seas and rushing river valleys. Microbial life that got started in those days could, scientists theorize, still be holding on in pockets today. That theory may well be a good one, but the odds just got a lot slimmer. According to a new study in Scientific Reports, the Martian soil itself may be toxic to bacteria. Any microorganisms that could have emerged in the past would be poisoned to death today. When the Viking 1 and 2 spacecraft landed on Mars in 1976, they detected what appeared to be perchlorates in the Martian soil, and three subsequent spacecraft, including the Curiosity rover, which is still hard at work on the Red Planet, confirmed that finding. A highly oxidized form of chlorine, perchlorates can serve as an energy source for bacteria—a simple food that helps them live off the land. What’s more, like common salts, perchlorates lower the melting point of water, allowing it to exist in life-friendly liquid form. The problem is, perchlorates can also be toxic to bacteria, depending on the presence of ultraviolet radiation—which, unfortunately, bathes Mars continuously. To determine whether the compound is a good thing or a bad...
Source: TIME: Top Science and Health Stories - Category: Science Authors: Tags: Uncategorized Bacteria Curiosity Rover exobiology is there life on mars microbes NASA onetime perchlorate red planet soil space toxins Source Type: news