Why do we keep coming back to Mars?



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Humanity has been looking at Mars for centuries, dreaming of what might be on its orange surface. As our telescopes have improved, our image of the Red Planet has also improved, although the interpretation of this growing detail has not always been accurate (see: Mars channels). The first mission to see Mars up close, the Mariner 4, took home a handful of blurred views of the crater, but the missions that followed – those that succeeded; the overall failure rate is 50 percent for the spacecraft bound for Mars – painted a clearer picture of the planet's dusty present.

More recently, scientists have found evidence of a warmer, more humid ancient past for the planet that could have sedimented Earth-like life, and so the quest for life continues, though it now extends into the past. And the planet has less mixing of tectonic movement material than Earth, so its composition can tell scientists about the formation of the solar system.

NASA's InSight Mars mission, scheduled for Monday (Nov. 26), will delve deeper beneath the surface of the planet than any mission before it, learning about the interior of the planet. InSight is a smaller mission than many of the rovers and orbiters that precede it, but it is the latest in a long line of robotic emissaries to explore our planetary neighbor. [Missions to Mars: A Robot Red Planet Invasion History (Infographic)]

"Mars is an incredible natural laboratory on the side of the Earth," said Lori Glaze, interim director of NASA's planetary science division, during an InSight press conference on Nov. 21. "We really want to understand how we create this diversity of rocky planets in our solar system – they are all very different, each of them is unique in its own way, and trying to understand how they ended up so differently is a really important issue."

In addition – despite the failure rate – the planet is comparatively easy to land and is less likely to melt our equipment than Venus or Mercury.

Artist's illustration of NASA's InSight landing module, scheduled to land on Mars on November 26, 2018.

Artist's illustration of NASA's InSight landing module, scheduled to land on Mars on November 26, 2018.

Credit: NASA / JPL-Caltech

The geology of Mars presents many evidences of past waters, added Glaze, so that "it could have been potentially a place where life might have formed very early in the history of Mars." Of course, trying to understand how life is or has been distributed system is one of the main issues we have. "

Earth, Mars and the other rocky planets in our solar system clustered on a dusty disk around the young sun, getting warmer as the material was added and fused into bodies with distinct mantles and cores. However, we do not know much about this primitive time in the history of the planets.

"On Mars, this structure has been preserved for the last 4.5 billion years, while on Earth, where we can actually study it easily, this structure was all shuffled by plate tectonics, convection of the mantle, and then the evidence of the earliest processes have been eliminated on Earth, "said Bruce Banerdt, chief investigator of the InSight mission and researcher at the NASA Jet Propulsion Laboratory in California during the briefing.

So, as well as studying comets – the remnants of this training process – it tells researchers about the early days of the solar system, probing the Mars structure by measuring the temperature of the planet and marsquakes can inform scientists about the next step in planetary evolution.

And knowing more about Mars' current conditions can also help researchers understand how it might have been in the past. [Why We’re Obsessed with Mars]

"Mars is a very unique place in our solar system, because it is one of the few planets that, in our view, were really similar to Earth," said Briony Horgan, a planetary scientist at Purdue University, who focuses on the geological history of moon. and Mars, Space.com said. "Today, it is this cold, inhospitable place with a very fine atmosphere … low pressure, all the radiation that is bathing the surface. But when you look at the geological record of Mars, you see a huge amount of things like dry river channels , dry lakes and lake sediments, we see minerals all over the planet that can only form in the presence of water. " [Water on Mars: Curiosity Rover Uncovers a Flood of Evidence]

Mars, 3 or 4 billion years ago, may have looked much like primitive Earth, Horgan said, and as the erosion of our planet, plate tectonics and other processes swept rocks of the time, Mars offers another chance to see them.

"The geology of Mars has been much less active in the kind of scale than the Earth is that rocks 4 billion years ago are only on the surface," Horgan said. "They were not subducted, they were not buried, they were not eroded – they are just sitting there, basically waiting for us to go look at them and try to understand what these old, 4 billion years old may have looked like, and they supported life ".

Horgan is a scientist for NASA's next Mars 2020 space mission, whose landing site the agency announced on November 19. The Mars 2020 rover follows in the footsteps of the 1976 Viking sleepplanes, which landed on the Red Planet to seek life according to scientists. Better understanding of the planet's conditions, and the Curiosity rover, which landed in 2012 to investigate the habitability of Mars's past.

As our visions of the planet evolve, our life-search tools also said Horgan – after the explorers of Spirit and Opportunity presented evidence of water in the past, Curiosity brought a vast array of scientific instruments to try to find organic or other evidence of habitability. near those ancient water beds. Mars 2020 will build on Curiosity's ongoing work, bringing even more refined analytical tools to, for example, organic images on rocks, looking for microfossils or textures that suggest ancient biology. Scientists still do not know whether the flowing water was often on the surface, or whether it could have been mostly frozen with occasional melts due to volcanic activity.

"Some of the instruments by 2020 are really focused on the finer details of rocks, the kind of things we can not see with the instruments we currently have, and cache samples that eventually get returned to Earth could provide us with key information in the long run, "said John Grant, a geologist at the Smithsonian Institution who was on the science teams for the Spirit and Opportunity vehicles, Curiosity and Mars Reconnaissance Orbiter. He also led the Mars 2020 landing site selection process.

"InSight is a very important part of this, because none of the [NASA’s previous missions] really – pun intended – scrape beneath the surface in terms of planetary evolution and understand how the planet has evolved over time, "added Grant.

"If we know something about their internal structure and evolution, we can say something about the time that has been active, whether active or not, and they all have implications for changing conditions … related to things like habitability and whether there was past life "he told Space.com. So while InSight is not directly related to the life of Mars, "everything is intertwined," he added.

And, of course, with NASA's evolving plans to send humans to Mars, everything we learn will help us prepare for that moment.

"Yes, we are returning to the moon, but we are also on our way to Mars and science [helps] Make sure we understand the features and exploit that we understand the living conditions and understand what needs to be searched there, "said Thomas Zurbuchen, associate administrator of the board of NASA's scientific mission, during the announcement of Mars landing site 2020.

"That is, I would say, an additional argument about why Mars is so exciting to us," he added. "We will not go anywhere else so soon, from our terrestrial planets, for all the obvious Mars is really the obvious place after the moon to come back and expand our presence into an ever deeper space. "

So why are we still going to Mars? Learn about our solar system, learn about the primitive earth, search for life and simply learn about our neighbor before visiting it.

"Science boosts our understanding and allows us to take humans to a place like Mars," Glaze said during the briefing. "The more exploration we have, the better we will understand this environment, the better prepared we will be to send humans to Mars in the future."

Email Sarah Lewin at [email protected] or follow her SarahExplains. Follow us on Twitter @Spacedotcom and in Facebook. Original article on Space.com.

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