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Did Mercury once have the ingredients for life?

A colorful view of Mercury produced from images taken by the MESSENGER spacecraft.
A colorful view of Mercury produced from images taken by the MESSENGER spacecraft.
(Image: © NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)

It's possible that Mercury once held the ingredients for life. 

In 1974, NASA's Mariner 10 probe flew by Mercury and observed a cracked, cratered landscape. Now, according to one new theory, Mercury's fractured "chaotic terrain" could've been formed by volatiles — elements and compounds that can easily jump from a gas to a liquid or solid — under the surface. 

Volatiles, a chemical category that includes water, are essential for sparking and supporting life as we know it here on Earth. So, their potential presence on Mercury is an intriguing development. The study, led by Alexis P. Rodriguez, a researcher at the Planetary Science Institute in Arizona, took a closer look at Mercury'schaotic terrain and the possibility that volatiles once shaped a planet with surface temperatures hot enough to melt lead, a planet that has forever been thought of as "completely inhospitable." 

Video: Ice on Mercury – How does it form?
Related: Photos of Mercury from NASA's Messenger spacecraft

Chaotic terrain (white outline) at the antipode of the Caloris basin.  (Image credit: Planetary Science Institute. )

What cracked Mercury?

For decades, scientists have studied Mercury's chaotic terrain — a landscape made up of the planet's cracked and ragged surface, complete with jagged, broken-up rocks, sharp peaks and craters. 

Mars has chaotic terrain as well, but the Red Planet features connect much more obviously to outflow channels on the Martian surface. With no such channels on Mercury, researchers instead tied the terrain to a powerful asteroid impact that left the Caloris basin, a massive crater still visible on the planet's surface. Until now, it was thought that Mercury's chaotic terrain was created by earthquakes that ravaged Mercury following the impact.

But in the new study, researchers suggest that this couldn't be possible because the timing just doesn't make sense. 

"A key to the discovery was the finding that the development of the chaotic terrains persisted until approximately 1.8 billion years ago, 2 billion years after the Caloris basin formed," co-author Daniel Berman, also of the Planetary Science Institute, said in a statement

This was the "first, kind of, smoking gun," Rodriguez told The researchers were able to date these features using data and images from NASA's MESSENGER (MErcury Surface Space ENvironment GEochemistry and Ranging) spacecraft, which studied Mercury from orbit from 2011 to 2015. The team determined the ages of surface features including the chaotic terrain and the crater formed from the asteroid impact. 

Additionally, as Rodriguez explained, the scientists noticed that there were many small features like tiny craters still intact in these terrains. With such a massive asteroid impact, "think about the worst earthquakes you could ever imagine," Rodriguez said. "Instead of bringing down buildings you're bringing down mountains … entire mountain ranges." 

The researchers reasoned that, if earthquakes following the impact caused the chaotic terrain, then those smaller features wouldn't have been preserved. These observations informed the team/s findings that this previous notion about the chaotic terrain's formation was flawed. 

Missing material

But observations have also shown that some parts of the surface features have dropped, as if something below the surface simply gave way. And, as Rodriguez put it, when earthquakes cause buildings to fall, that matter spreads out over the surface. But in this case, they found that there was a whole bunch of matter that should've been in the chaotic terrain that seemed to be missing. 

Keeping the conservation of matter in mind, the team suggests in this study that, instead of an impact and earthquakes causing the planet's surface to crack, volatiles under the surface created these features. 

"In this case, we're seeing very clear drops in elevation, very, very abrupt surface losses that indicate that the materials were removed somehow," Rodriguez said. 

They concluded that it's much more likely that volatiles underneath Mercury's surface were heated by magma even farther down. Because of this heating, the volatiles became gaseous and sublimated. 

"Maybe these materials were volatile and they were transported away, and they could've condensed in other parts of the planet, or maybe they were entirely removed from the planet by solar winds," he added. 

The sudden loss of this material is what the scientists think caused the planet's surface to crack and fall apart, creating the chaotic terrain we see today.

So how could volatiles, which are essential to life here on Earth, survive on a planet whose daytime temperatures soar to 800 degrees Fahrenheit (430 degrees Celsius) and drop to minus 290 degrees F (minus 180 C) at night? 

While the planet's surface swings wildly between temperature extremes, just below the surface, temperatures are milder, Rodriguez explained. 

Rodriguez said that it's "likely that there was some sort of water that formed" in part of Mercury's crust. But the team cannot yet tell exactly what volatiles were present when the planet's surface broke apart. 

However, not only are the researchers continuing this work to find an answer to that question, they are also working to understand a much more recent phenomenon.

The future on Mercury

While these events happened billions of years ago, "there is evidence of recent volatile removal within the chaotic terrain … maybe ongoing right now," Rodriguez said. 

He explained that, following this study, researchers will be working on "the possibility of selecting a landing site where we could potentially sample these volatile-rich materials using some type of lander." 

This work was published March 16 in the journal Scientific Reports. 

Follow Chelsea Gohd on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.

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  • rod
    Admin said:
    It's possible that Mercury once held the ingredients for life.

    Did Mercury once have the ingredients for life? : Read more

    I find the report here on Mercury very interesting in view of another report on LHB dating. I note this from the published paper on Mercury cited in the report:

    The crater dating for this basin on Mercury uses the LHB model but other reports contradict the LHB now. From the report, “Nor is it without controversies. Until recently, the solar system was thought to have acquired its present features as a result of a period of turbulence that occurred some 700 million years after its formation. However, some of the latest research suggests it took shape in the more remote past, at some stage during the first 100 million years.”
    Okay, ponder the age for crater dating on Mercury in view of the report. Basically, no LHB period apparently. Dating crates and surfaces of planets in the solar system is getting fun 😊---Rod
  • dfjchem721
    Dating craters would be fun, but looking for life's building blocks is right up there with it.

    Almost anyone with significant knowledge of chemistry and biochemistry will tell you that life on earth is likely the only chemical form it will take anywhere in the universe (yeah, you have all heard this before). This is due to the reactivity and variable stability of carbon-based compounds. All other scenarios are logically ruled out due to the chemical complexity and stability features required for life.

    Moving along, life requires four primary elements: Carbon, oxygen, hydrogen and nitrogen (COHN). From these four elements you can make 18 of the 20 amino acids used in proteins (sulfur is required for the other two). COHN also make up all the structures of nucleic acids with the exception of phosphorus. Carbohydrates and lipids, the last of the "Big Four" biochemical classes, are also made up largely of C, H and O, with some also using phosphorus. Of course many other elements are used on earth, mostly metallic elements for enzyme reactions, structural features (bone) etc. Elements for life other than COHN are easily found as minerals, and usually exist as such at any rate.

    All of these elements can in fact exist in a solid state (minerals - carbonates, nitrates etc.), with the exception of hydrogen. I am not a geologist but I do not think minerals can be a significant source of hydrogen (hydrates of minerals would not be stable at high temperatures). Someone please correct me if this is wrong. If this is correct, on Mercury we would need to get hydrogen from comet-derived water ice in perpetually shaded craters (assuming they exist). I believe such water has been found on the moon.

    In other words, most rocky planets should have the elements of life locked up in solids and not require volatiles, although the latter would likely make life much easier to arise and evolve. But you could theoretically start from minerals, add enough water for hydrogen and that all important aqueous milieu, and with the right temperature and stable conditions for extended periods, start cooking up some life forms.
  • rod
    Okay, Mercury may have or had the *ingredients for life* according to this report. Apparently the formula we have is add some water, find the correct temperature, give it enough time, and spontaneous combustion of life from non-living matter is inevitable. Reports like this remind me of past science reports on life on Mars. Martians Get Their Water from the Poles (1907) and Beings That Are Smarter Than Humans Inhabit the Galaxy Originally published in July 1943
    Looks like Louis Pasteur experiments failed to observe the spontaneous combustion of life from non-living matter, perhaps he did not have enough time to see this.
  • dfjchem721
    The proposal is not spontaneous combustion. It is called abiogenesis, and would likely take millions of years.

    The details provided are only the bare bones requirements on such a hostile world.

    After all, we are certain that it happened at least once already on another rocky planet!
  • rod
    dfjchem721 said:
    The proposal is not spontaneous combustion. It is called abiogenesis, and would likely take millions of years.

    The details provided are only the bare bones requirements on such a hostile world.

    After all, we are certain that it happened at least once already!

    Unfortunately, based upon the fossil record, life's last common ancestor is not documented (the first, living cell) and its ancestor as non-living matter that evolved into life's last common ancestor is not shown either. From the Precambrian, Cambrian explosion through Cenozoic, we see the law of biogenesis at work, just like Louis Pasteur experiments showed with numerous missing links, and now more than 3200 living fossils documented that go way back in the fossil record.
  • dfjchem721
    Quite right on the fossil record. None of those early forms could be preserved. Just a mess of fragile chemicals. But still, much remains to be learned in the fossil record. Sadly, none of it will provide the answers to the extraordinary complexity of abiogensis.

    Do you have knowledge of a source of hydrogen in a mineral form other than hydrates? And water was found in lunar craters, right?

    Surely this story caught some attention:
  • rod
    Yes the evolutionary worm caught much press attention but no ancestor fossil showing it evolved from non-living matter was presented in the reports, the worm still came from life so biogenesis, not abiogenesis. The entire fossil record shows the law of biogenesis at work (as Louis Pasteur experiments confirm), not abiogenesis. The big problem in the worm story, since Feb-2013, there are more than 3200 living fossils published in science going back to the Cambrian and no evolutionary transformation is shown. Some living fossils are now dated 1 billion years old, algae types. Darwin's life's last common ancestor, the first living cell is not found and neither is the ancestry from non-living matter for this first living cell documented in the fossil record. Abiogenesis is not documented in the fossil record, the law of biogenesis is seen.
  • rod
    FYI. From a source I know and use, "Evolutionary scientists announced the discovery of what they claim are the oldest green-algae fossils—which look remarkably like modern, living seaweeds. The millimeter-sized, multicellular plant fossils were found in China in rocks claimed to be over one billion years old.1"

    Yes, now some living fossils may date back one billion years and exhibit little or no evolutionary changes. The fossil record establishes the law of biogenesis, not abiogenesis at work over time.
  • dfjchem721
    Clearly the fossil record will never show abiogenesis at any point in its sequence - simply no hard parts. But unless one believe in godly interventions, it must have happened here, or we would not be debating it. I do not buy into life from outer space seeding the universe either. And even if it did, abiogenesis would have had to occur somewhere, or by the magic wand of a deity.

    (Many people believe in the "magic wand theory" )

    Yes, it appears algae fossils are the oldest. I have read about Stromatolite fossils in Australia dating to over 3 bya, but the search on Wiki is now saying "They peaked about 1.25 billion years ago."
    The living fossils you mention are truely amazing. The horseshoe crab being one of the most famous. It is astonishing how long they have survived nearly unchanged.