The solar system is full of brines

Ed Rivera-Valentín has been spending quite a bit of time thinking about brines recently. The particular ratio of salt to water in the marinade. The special ingredients that can kick things up a notch.

I am referring, of course, to the salt solutions found throughout our solar system, on planets, moons, and even asteroids. These wouldn’t be good on a Thanksgiving turkey, but they could be one of the most intriguing substances in the search for extraterrestrial life. Last month, Rivera-Valentín, a planetary scientist at the Lunar and Planetary Institute in Texas, and other scientists gathered for BrinesCon, the first of three brine conferences over the next few years. A little water, a pinch of salt – it’s the kind of mixture that, under the right conditions, could give life a chance to be born, Rivera-Valentín told me. “When we find life,” he said, “it will probably be associated with a brine.”

Over the years, NASA has pursued a “follow the water” strategy when searching for extraterrestrial life, sending spacecraft to search celestial bodies for traces of H2O. But “you’ll never find pure liquid water,” Rivera-Valentin said. “What you’re going to find are brines.” So when scientists look for water beyond Earth, they are actually looking for salt water. This is where interesting things can happen. Life on Earth is thought to have formed in a primordial soup seasoned with salt, and our oceans today are just giant brines – and they’re teeming with life.

Even though we haven’t yet found evidence of life outside Earth, it turns out that the rest of the solar system is pretty salty. Spacecraft have discovered frozen brines on the surface of Mars and evidence of liquids that may exist deep underground. Enceladus, Saturn’s icy moon, has a brackish ocean under its icy crust. A NASA spacecraft orbiting Saturn even sampled Enceladian brine when the material escaped from a crack in the ice and sprayed into space. In addition to salts, the passing spacecraft detected organic compounds – not proof of life, but certainly an indication that the subterranean ocean could potentially harbor some form. Europa, another icy moon around Jupiter, has a brackish ocean that sometimes spills out into space. And spacecraft data suggests that even Ceres, the largest object in the asteroid belt, may have small pockets of brine flowing deep inside.

Brines are good natural places to search for life because salt can do magical things to water. The presence of salt can prevent water from freezing in very cold temperatures. This is why people salt their driveways before a snowstorm. “Salts allow liquid water to exist further out in the solar system, which expands the Goldilocks zone in the solar system where life could exist,” Mohit Melwani Daswani, a geochemist and planetary scientist at Jet told me. NASA Propulsion Laboratory. And the longer a brine can remain unfrozen, the more stability the mixture provides for any life forms that might decide to inhabit it.

But like any good recipe, there’s a balance, Daswani said. Too little salt and water could have a hard time mixing with the other chemicals in the brine. Too much salt and there is not enough water to take part in these chemical reactions, and any cellular life forms that might exist dry up and break down. “There’s definitely a sweet spot somewhere,” he said.

This is one of the goals of the astronomy brine community: to understand the conditions under which brines could produce life – the microbial type, which we are much more likely to detect than the advanced civilization type. We know that microbial life on Earth comfortably exists in strange places. “Most of the time when we look for life somewhere, even if it’s half a mile under the Antarctic sea ice or buried in a subglacial lake or in a mine, we find life there,” said Jennifer Hanley, a planetary scientist at the Lowell Observatory in Arizona, told me. For example, in Chile’s Atacama Desert, one of the planet’s best analogues for Mars, the salt in the ground – ordinary old table salt – pulls moisture out of the air on humid days. The water turns into liquid droplets and, together with the salt, produces a tasty brine for the bacteria that live in the dry land. The process is known as deliquescence, which appears to be either a chemical reaction or a cooking technique.

Much like space brine, the perfect turkey brine also involves a bit of mystery, says Bill Nolan, supervisor of the Butterball Turkey Talk-Line, a hotline the poultry company has operated since the 1980s for the most pressing questions. Americans on Thanksgiving meals. . The process can be tricky. “I’ve had people call me and say, ‘I just realized my turkey was in brine for two and a half days,'” Nolan told me. “When something is too salty, it’s a bit difficult to get that salt out of it.” Like the planetary scientists who warn that too much salt is bad for life, Nolan says too much salt is bad for taste.

So don’t oversalt your turkey and don’t oversalt the solar system. Consider adding peppercorns to your turkey brine, as Nolan recommends, or candied ginger, as Hanley did. Perhaps nature has also made some interesting additions to the brines beyond Earth, seasoning them with just enough elements for a chunk of life to emerge.

Arline J. Mercier