“This is like watching The Martian come alive before our very eyes. “
Molecular biologist and science communicator Upulie Divisekera brings infectious enthusiasm to questions surrounding the discovery of water on Mars. Read on as she first encounters the news and explains the science behind it, as well as offering a few predictions on what might come next. Edited for presentation and clarity.
Is this jumping the gun?
. . .
Water: The Universal Solvent
Kenneth Chang of the New York Times reports that the hydration of perchlorate salts indicates the presence of liquid water on Mars.
“A finding that will fuel speculation that life, if it ever arose there, could persist now”, writes Chang.
Folks, what’s happening here is this:
You have to think of a solution as a bunch of molecules. This is a really bad sketch of what water looks like.
Water is one of the most amazing substances on earth. In solution, it can be represented like this diagram. The oxygen molecule is much larger than the hydrogens. The oxygen and hydrogen atoms share electrons to make the stable molecule, H2O. But the oxygen atom being larger, pulls the electrons very slightly towards it, giving that end of the molecule an overall negative charge (hence the funny d- symbol in the diagram). The hydrogen nucleus is a single proton, so it’s a slightly positive charge overall. This slight charge around each nucleus is called a dipole.
So why should you care? Well, it’s this property that allows water to behave like such a magnificent solvent. It’s one of the best solvents on the planet. These slight charges allow water molecules to dissolve other chemicals, or solutes. The molecules arrange themselves according to their relative charges and so on.
Perchlorate Salts and Liquid Mars Water
Perchlorate molecules are a bit like this: four oxygen atoms around a chlorine.
(Sodium hypochlorite is the major component of bleach, so you’ve met chlorates before.)
Here’s a better image of what water molecules look like in solution with the accompanying dipoles and hydrogen bonds:
A hydrogen bond is this kind of “soft” bond between a hydrogen nucleus and another atom. It’s not like a covalent bond, which is very strong.
This matters to this discovery because the perchlorate salts on Mars interact with liquid water: the water hydrates the salts and forms an arrangement with the salt. This is how they worked out that the water was liquid. The other reason is that for water to be liquid at such low temperatures is to have salts in them. Only pure water freezes at 0°C. This kind of hydration is normal for salts, whether on Earth or on Mars.
Here’s a representation of the hydration of a perchlorate with correct oxygen bonds:
The Effects of Mars’ Atmosphere
Now I have a feed [to a broadcast about the discovery]. I gather they’ve talked about how the seasonal and diurnal variations in temperatures showed unique patterns in the Martian landscape that looks like streams or streaks, and that there were variations in the colour and shape of these streaks.
So they began studying them closely and then using spectroscopy — which measures the absorption of light to determine what chemical might be present. All chemicals have a unique spectroscopic fingerprint.
Crossing to the NASA Ames Research Center now. [They’ve found out the following about perchlorates]:
– perchlorates have a unique water absorption chemistry;
– perchlorates absorb atmospheric water; and
– perchlorates have a higher ability to absorb water compared to other salts.
There also seems to be some kind of process that results in the release and concentration of perchlorates in the regions where the slope liniae are; [they] swell as other salts and substances that are —
— interrupted by breaking news —
“Our results may point to more near habitable conditions on Mars than previously thought. The detections [warrant] further astrobiological investigations, plus [are] also good for future human exploration.”
— concentrating the water. The perchlorate cycle is the favoured mechanism.
Question: “How likely do you think it is on 1-10 scale that there is life on Mars?”
Answer: “..we have great opportunity to be on the right location on Mars… to thoroughly investigate the liniae.”
LIKELIHOOD OF LIFE ON MARS JUST INCREASED BY SEVERAL ORDERS OF MAGNITUDE!
“The existence of water, even if it’s super salty and briny — we have a way of describing how it might be.” A scientist [onscreen] talks about how, over time, we have developed the technology and capability to really determine/detect life on Mars where previously we might not have. Caveats: we don’t know how life began here [on Earth], so we might not know how it looks like elsewhere. But now we know what we are looking for.
YOU GUYS THIS IS MUCH EXCITE
WHAT I TELL YA
WHAT I TELL YA
OMG WHO EVEN NEEDS SLEEP
Onscreen: “Possibility of life inside Mars has always been very high. Meteorites from Earth have landed on Mars, so it’s likely that there are microbes in the planet’s crust.”
Ouestions for NASA:
– Do you have a series of experiments to determine whether there is life? Will this precede human missioNS?
– What is the time frame for these experiments?
– WOULD YOU LIKE US TO SEND MORE MONEY WE LOVE YOU
Ah, they want to bring back Mars soil to analyse on Earth!!! In the next five years.
Dr Paul Coxon, Physicist in Materials Science at Cambridge University, interjects:
“Chemistry is hard enough to do in a lab on Earth, but to do it remotely on another planet is a real achievement. I’m impressed.”
The Future of Mars Missions: Is There Life on Mars? Can We Humans Live There?
This is one scientist’s (not mine) opinion, from the French labs reporting (sorry the name didn’t go across). I can’t actually type any more.
“In principal [we] can make solid rocket fuel” because perchlorates (ammonium perchlorate) are a component of rocket fuel. “NASA’s approach to exploration is not Star Trek: it’s not ‘where no man has gone before’; it’s methodical”.
This discovery makes future trips and human missions more feasible.
This is completely delightful. This is like watching The Martian come alive before our very eyes.
Ken Chang now on the line: “Is there life on Mars? We know there is life on Mars… we tried to clean our spacecraft as well as we can but it’s possible there is contamination. The surface of Mars is very cold, the UV [ultraviolet radiation level] is very high, so we hope haven’t sent anything… so detecting actual life is tricky.”
Reiteration of how the surface of Mars is quite inhospitable to life; challenges to growing plants if you wanted to terraform. Plenty of carbon dioxide for plants, [we] may have to genetically engineer to grow them on-surface. Plants would create the oxygen [for the atmosphere to become breathable].
Still, coldness, harshness, UV makes this difficult.
Good question about planetary protection and working out how much sterilisation for Mars 2020, etc.
Theoretical physicist Dr. Chanda Prescod-Weinstein adds:
“There is going to be plenty of naysaying about today’s NASA announcement because pretty much no matter what they do, someone is unhappy.
But I think today’s announcement is an exciting opportunity for NASA to share what “significant” looks like to scientists.”
Some good points about [the question], “if there is life, will we recognise it?”
Also: “is there rain on Mars?” There seems to be an ice cycle and water cycle.
3.5 billions years ago there was an active water cycle, but not perhaps one like we see on earth. But there’s snow on the poles!
We’re not sure how much water there is on Mars – the streaks are three or four centimeters wide.
Alfred McEwen, principal investigator of HiRISE, the High Resolution Imaging Science Experiment on Mars: “Water is far saltier than Earth ocean water. 10mm thickness is enough to make it flow down slopes. It’s thin layers of wet soil rather than ponds and streams.”
McEwen continues: “NASA’s journey to Mars is very real” — and close.
What would it be like to take a walk on Mars?
Piece by piece, we’ve built and continue to build a picture of the geology and weather of another planet we can’t walk on. Yet. On a terrestrial planet, the solidity of the ground, the ridges, dried riverbeds, even the fine regolith feels vaguely familiar.
That reddish regolith is a coating on a great planet. But these features are familiar to us. There’s an atmosphere that makes familiar sunsets and horizons. But it’s not like earth. Not much at all, really. The sky is hazy, not bright blue. It’s cold. Very cold.
The salts in the soil are not that conducive to life. The air is mostly carbon dioxide. But there is a bit of water. There is some water, perhaps a warmer space within the crust. Water makes all of the difference in our perception and practicality of exploration.
It also hints at life.
Mars was always regarded as our sister planet. Now, even more so.
What’s Next For Our Sibling Planet?
I’ll call it now: life precursors, self sustaining processes, small primitive forms within the crust, novel chemical structures and precursor biomolecules and processes as a heretofore undescribed form of life.
This is speculation only.
Here’s science writer Matthew R. Francis on why the Mars water announcement is a big deal:
I bet Carl Sagan is having a bit of a grin right now, wherever he is.