On a sunny day next summer, in front of a crowd at the Kennedy Space Center, a rocket will launch into the sky, bearing the next, best hope of life on Mars.
Seven months later, the Rover Mars 2020 lands in size near the Jezero Crater, a dry lake in the northern hemisphere of Mars. With its six wheels and a series of high-tech instruments, it will search the surrounding rocks for evidence that alien microbes once lived on the Red Planet.
Decades of surveying of Mars with orbiting probes, lander and rovers have once hosted the planet with a thick atmosphere and water on its surface. The researchers even discovered traces of complex organic molecules – potential building blocks for living cells.
Two new studies suggest that Mars 2020 could provide even stronger evidence for the life of Mars, if it ever existed.
The rocks around Jezero indicate carbonate and hydrated silicic acid molecules that are known to help preserve microscopic fossils over billions of years.
The planetary researcher at Purdue University and principal author of a study in the journal Icarus, in which he reported on the carbonate evidence: "The Jezero Crater is an incredibly diverse mineralogical site with many ways to search for biosignatures Chances to understand exactly what happened to the story of life here. "
But what does Mars 2020 have to find so scientists can be sure that Marti once existed?
The Jezero Crater houses an ancient delta that flows into a Cratert lake.
Sludge from sediments slowly entering the lake can contain carbonates and even biological remains (if there ever was a biology)
Sludge from sediments that slowly enter the lake can be carbonates and even biological Contain remnants (if there ever was a biology).
Wind-whipped sand formations known as "waves" endanger the rover elsewhere.
Sedimentary sludge that has slowly entered the lake can contain carbonates and even biological remains (if there is ever a biology) here and elsewhere.
Sludge from sediments slowly entering the lake can contain carbonates and even biological remains (if there is ever a biology).
Wind-Whipped Sand Formation The so-called "ripples" pose a threat to the rover here and elsewhere.
Satellite imagery from NASA / JPL / University of Arizona.
JOE FOX AND BRITTANY RENEE MAYES / WASHINGTON POST
Both studies have been published This week, the Compact Reconnaissance Imaging Spectrometer (CRISM) was used, a rotating camera that can scan the surface of Mars in infrared and visible light. From a height of 400 kilometers, CRISM creates colorful maps of minerals on the Red Planet.
Everywhere in the Jezero Crater, carbonates have been found to form when carbon dioxide interacts with rocks and water. However, CRISM showed a particularly high concentration of the mineral on the inner rim of the crater, exactly where the shoreline of the lake was more than 3 billion years ago.
For Horgan, this indicates that they may have been left behind by waves of stone. She compared the deposits to the foam line that forms when water hits the sides of a bathtub (scientists have even referred to the region as a "bathtub ring").
"What makes this so exciting is that [carbonate] includes everything around it," Horgan said. "It mimics the structures of the microbes, so you get preserved textures … but it also captures the organic material in it."
If microbes had lived on Jezero's lakeshore, the carbonate would almost certainly have trapped them
Some of the world's oldest fossils were stored in carbonate. Scientists have found stromatolites – layered structures of carbonate-containing bacterial mats – that date back to 3.7 billion years.
Volcanic eruptions and edges of hot springs can form hydrated silica, better known as Opal. When formed from sediments that settle on a seabed, it can form strong, robust crystals that are particularly effective at sustaining vital signs preserve. On Earth, scientists have found samples of hydrated silica containing ancient organic matter and even fossilized cells.
Because the hydrated silica of Mars is so close to a delta, it is possible that it contains material from the river system. And if Mars rivers ever harbored life, remnants of ancient organisms could still be trapped in these crystals.
Hydrated silica "has never been found before," said Katie Stack Morgan, associate project scientist at Jet Propulsion Laboratory 2020 Mission. Morgan, who was not involved in Tarna's research, said the mineral is likely to be a major target for the rover after landing.
"It's really exciting to believe that Jezero has deposits like the ones we have on Earth," she said, "we'll think about how to get as close as possible to them."
The 2020 Rover will be equipped with a variety of tools to study these minerals, and cameras could capture images of stromatolites, if any, and lasers and molecular snoopers, known as spectrometers, become the composition of rocks at the elemental level
"They will be able to perform the kind of astrobiological research that we have been doing on Mars for decades."
The Curiosity Rover, which has been cruising the Gale Crater since 2012, can only use molecules "in "Measure large quantities," said Morgan. Although it has found organic molecules, it can not accurately localize them to specific rock strata or they can not do so with microscopic structure associate.
"By 2020 we can go there and we can say that we have an associated concentration of elements or minerals that look very special fine flake structure," said Stack. "These very subtle structural differences are exactly what people are looking for and sharpening their eyes when they speak out for biosignatures."
But also in the dream scenario of the scientists – one in which there was life on Mars and its remains were preserved and the Rover 2020 is able to find the fossils – it is unlikely that mission alone will prove if Martians ever existed.
The discovery of life beyond the earth is such an extraordinary claim, as Carl Sagan would say, it requires extraordinary evidence. Proofs that only a human can deliver.
"We're really trying to find potential biosignatures with this rover," Horgan said. But only if "we confirm it here with all of our incredible laboratory equipment," she continued, "can we turn a" potential biosignature "into a" biosignature. "
The 2020 mission is just the first step in a four-part proposal. Once the rover identifies the most intriguing rocks around the Jezero Crater, he will use a specially designed drill to collect and cache samples of the material.
One day, scientists will start follow-up missions (if everything goes according to plan) to retrieve them and take them home. Eventually, in an undeveloped, highly secure facility, they will analyze the rocks at the elemental level to finally determine if they contain any clues to life.
The whole process will take years, if not decades. It can never happen. The requisite follow-up missions have not yet been approved, let alone funded and developed. And travel to Mars is notoriously difficult : Approximately 50 percent of all attempts to reach the Red Planet have failed.
"There is this tantalizing evidence that [life] might have been there, but you will not know it until you get the samples back," Tarnas said. "And you really just have to have the patience and the strength to fight it."
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