John Pazmino
 NYSkies Astronomy Inc 
 2017 Novermber 15

    i with several NYSkiers joined a full house at Simons Foundation 
on 15 November 2017 for 'Search for water and life on Mars' by Dr James 
wray, Georgia Institute of Technology and Geological society of 
America. He is on several teams working with Mars spacecraft.  The 
lecture was a review of our present understanding of Mars water. He 
explained he early clues, later confirmation, and present mystery of 
water -- and possibly life -- on the Red Planet.
    The quick summary is that Mars had mass water, open surface water 
like seas and lakes and flowing water like rivers. Today Mars has at 
least within observable reach only a minuscule amount of water, with 
almost none in liquid form. As yet we found nothing of any past life, 
like organic byproducts or fossils. The prospect remains open that 
microbes can survive in subsurface habitats. 
    Any presentation about Mars, water, life, attracts heavy attention 
from home astronomers, and also scientists in related fields. This one 
was no exception; the auditorium was filled to capacity. 
    The talk began at 5:00 PM EST, preceded by a coffee-&-cookie snack  
at 4:15 for the attendees. The lecture, like other Simons talks, was 
free but advance registration is needed to ensure seating. When I 
registered a few days earlier, I signed out a couple hours from my 
    On a mild day Simons is a brisk kilometer walk from my office 
along Fifth Avenue. On the 15th it was a bit chilly, teasing me to do 
a downtown 5th Av bus. I arrived at Simons at about 4:20 PM  to face a 
packed floor of scholars and scientists, all bantering about Mars.  
    I scooped up some grub from the snack counter and took a seat 
among other guests. I looked around for other NYSkiers, catching a 
few. We gathered together and noshed until the call rang out for the 

Simons foundation 
    Simons (SIGH-monz) Foundation supports many physical and medical 
sciences,  For one example, it partially funds the national Museum of 
mathematics, a couple blocks away near madison Square. Among Simons 
offerings is a weekly lecture on one of its disciplines. About eight 
per year are valuable for home astronomers. NYC Events posts them upon 
sufficient advance notice. Else they are noted in the NYSkies 
yahoogroup. The audience for these talks is sprinkled with NYSkiers. 
    Simons Foundation is housed in a plain office building at 160 
Fifth Av,  Chelsea MH. It is common on Manhattan for buildings to take 
yp an avenue address but have their entrances around the corner on the 
cross street. In Simons's case, the entry is on 21st St thru a 
curiously bland lobby fitted with only a service desk. In the yearend 
holiday season this lobby sprouts a  tall  festive illuminated tree 
and large wall-mounted wreath. 
     Simons is on the second floor, as only one of the building's many 
other unrelated tenants, reached by stair or elevator. The floor's 
public area has a central auditorium, peripheral snack alcove, and 
restrooms. Before each lecture the guests enjoy a ha'hour of coffee-&-
    Altho the auditorium  seats about 150 people, Simons asks for 
advance registration by web or phone. Sometimes the hall is full with 
registered audience. Standby arrivals wait outside for seats left 
vacant by no-shows or cancellations. 
    The auditorium is modern, well appointed and furnished, with a 
clever audience microphone system. In the back of the forward seat is 
a panel for tuning on/off an embedded mike engage in the Q&A in an 
audible voice. The very front row of seats have this feature in the 
arm rest, where elbows can accidently turn it on. 
    Like for virtually all other lecture halls, no food or drink is 
allowed. This is specially true at Simons since the audience enters 
from the snack alcove with last bites of cookies. A short introductory 
film about the auditorium is played before the talk that includes the 
no-eat/drink warning.

Liquid water on Mars?
    Water as a chemical compound can exist in almost any place in the 
solar system. The molecule, H2O, is extremely stable under ambient 
conditions on all planets. We think certain satellites of Jupiter and 
Saturn may have deep reserves of liquid water. We know of solid water 
on other satellites and in comets.
    On Mars, we are the presence of liquid water is marginal. We can 
appreciate this from the phase diagram for water. A phase diagram 
plots the physical state of a substance on a temperature-pressure 
graph. The graph for water is crudely sketched in ASCII but a properly 
rendered one is freely to hand from science webs. 

        |\    PHASE DIAGRAM FOR WATER, H2O          | 
        |\                                          | 
        | \                                         | 
    /|\ | \                            +            | 
     |  |  \                         /  CPP         | 
     P  |  \                       /               | 
        |   \      liquid        /                 | 
     |  |    \                 /     gas           | 
        |     \              /                     |
        |      \ 0C        /                       | 
       1|=======\========/=== Earth                | 
        |        \ 3C  / 100C                      | 
    0.01|=========\===/====== Mars                 | 
        |          \ / 15C                         | 
        |           +TP                            | 
        |  solid  /                                | 
        |     /                                    |

    Each chemical substance is unique with its own phase diagram. 
Altho the diagram probably can be generated thru physical chemistry or 
chemical physics, the traditional method is brute force experiment. 
    For a given pressure P and temperature T water takes on one of its 
three  phases or states: solid, liquid, gas. In the specific case of 
H2O there is a T-P point where all three states can coexist, the 
Triple Point, TP in the diagram. There is also a point CP, the 
Critical Point, where liquid and gas are no longer distinct phases. 
     The scales differ among authors. Temperature is in either Celsius 
or Kelvin, C = K+273. The size of the degree is the same but K starts 
at absolute zero while C is plus/minus from the freezing point of 
water on Earth.
    The pressure is one of several. it can be atmospheres, with 
Earth's surface pressure being one. It can be in the physical units of 
in bar or pascal. And it can be in units of some barometers, mm of 
    It so happens that one atmosphere is very nearly one bar or 100 
kiloPascal. It is also, more clumsy, 760mm. Home astronomers must be 
conversant in all of these pressure schemes to follow news about 
planetary explorations. 
    For Earth, 1 atmosphere, the double line across the graph cuts the 
solid-liquid border at T = 0C or 273K. It cuts the liquid-gas border 
at 100C or 373K. 
    On Mars, whose atmosphere pressure is 1/100 Earth's, the double 
line passes a little above the Triple Point. It crosses a narrow zone 
of liquid. Liquid water could exist between about 3C and 15C. A ground 
temperature less than 3C freezes water into ice. hotter ground than 
15C boils water into gas, Martian steam. 
    A typical maximum ground temperature on Mars in the equatorial 
summer is 25C, falling to a typical night value of -75C. Even if there 
was a pond of water, it would boil away by day or freeze at night. 
Liquid water can only survive intermittently and momentarily. 
    At the poles in winter the temperature is insanely cold, around -
160C, freezing out just about all water, even from the mars 
atmosphere, to form the polar caps.  This degree of cold also 
condenses carbon dioxide from the air, mixing with the ice in the 
polar caps. 

Properties of Mars 
    Mars is the only planet whose surface can be studied from Earth. 
From the 1600s thru the mid 20th century we saw what could be an other 
'earth'. Mars had dark regions for seas, bright ones for land, ice 
caps at the poles, clouds, shifting 'vegetation', winds. We in the 
late 1800s discovered what could be channels or canals, suggesting 
that people on Mars built conduits to circulate water from the poles 
and, OK, enable water-based navigation. 
    Astronomers and the public more or less assumed Mars was inhabited 
with people, altho no one agreed what they were like. The Martians  
ranged from friendly tribes ready for trade and business with Earth 
all the way to hideous monsters coming after Earth to wipe out 
humanknd.  In fact, the Earth-like conditions on mars, derived from 
our crude knowledge in the turn of the 20th century, convinced many 
engineers and scientist to agitate for human space travel! 
    With no open water, Mars is entirely dry land. Mars is about 1/2 
Earth diameter with about 1/4 Earth's surface area. Earth's surface is 
about 1/4 land and 3/4 water. This ratio  makes the total surface of 
Mars about equal to the entire land area of Earth! 
    Mars shows no evidence of tectonics or ground quakes. On the other 
hand Mars has several large extinct volcanos. 
 The surface has strong relief from deep valleys to tall mountains, 
often exceding the extremes for these features on Earth. All 
topography seems to be completed in the distant past, with no 
evidence of significant modification in recent times. 
    The Martian craters a nd much of the overall topography seem 
weathered like by bulk water and by aeolian forces. 
    The ground on Mars is almost globally reddish, like some deserts 
on Earth. This tint comes from the content of iron oxide. We don't 
know how this occurred. 
    There are hints that the axial tilt of Mars, now about 25 degrees, 
was drasticly altered in the past. If correct, the modelling                 
of Mars's seasonal history could be severely complicated. 
     Water ice and dry ice sit on land in the polar regions.  The ice 
alternates poles for the winter/summer seasonal shift. From the early 
20th century we figured out that the polar caps contain almost all of 
any surface water on mars. This casually explained the need for the 
network of canals to distribute this water thruout the planet. 
    Mars air is almost entirely carbon dioxide with a little water 
vapor and traces of other gases. The water can condense into ice in 
high elevation cirrus-like clouds. The water is far too scarce to 
precipitate as rain or mist or fog. 
    The ground-level air  pressure is 1/100 Earth's, yet it's enough 
to loft up massive dust storms that at times blanket the whole planet. 
In fact, these storms are the only physical action on an other planet 
that can be observed by bare eye from Earth! Mars under a global storm 
turns pale yellow, from its normal reddish hue. These color shifts 
were noticed since antiquity without any clue for its cause. 
Astrologers sometimes blended the Mars coloration in their fortune-
telling as a mysterious cosmic omen. 
    The thin air lets in solar radiation lethal to Earth-like life. 
Ultraviolet ionizing radiation, plus cosmic rain of energetic nuclei, 
sterilize the top layer of the Mars surface. The soil absorbs the 
radiations, perhaps letting some life survive a meter or so below the 
surface. The Scarce water in the air can not capture infrared 
radiation to hold hear for the night or circulate around the planet. 
    Carbon dioxide, a;most the whole atmosphere, does not capture and 
hold infrared waves; it is not really the 'greenhouse gas' on mars. 
The result is that ground temperature at a given place under day/night 
cycle swings thru about 100C. This, if not already killed by incident 
radiation, would remove life from the surface that works on liquid 
water. In the polar winter ground temperatures are incredibly low, 
around -150C until the spring season. 

Look for water 
    All life as we understand it requires liquid water to convey 
nutrients, effluent, heat, ions thruout the living organism. in humans 
this water is mainly in the blood, with smaller amounts in digestive 
fluids, gland secretions, lymph, body fat. A person, and other higher 
lifeforms, die when internal water freezes under ambient conditions. 
    Please know well that presence of water does NOT prove presence of 
life. It's the other way round. Absence of liquid water precludes the 
existence of life, as suggested by ultra-dry places on Earth and every 
where on the Moon. 
    The first visits to Mars by flyby spacecraft yielded no hint that 
open surface water on Mars. Only a slice of the planet was imaged with 
resolution of a couple kilometers. 
    The Viking landers applied chemical reagents on scooped up soil to 
capture indications of life. The results were inconclusive.  
    Later flights were aimed at finding water, either now or in the 
past. The evidence growed ever stronger that Mars in the remote pat 
did have large regions of surface water. The first orbiting mapping 
probes discovered what looked like rivers and lakes, all dried up now 
but likely filled with water some time in the past. 
    The first positive proof of liquid water came with the Phoenix 
lander in the mid 2-thous. Phoenix at the edge of the Mars polar cap 
found water in scooped up soil. It internally heated the sample to 
release water vapor. Phoenix also photographed aerial water condensing 
into drops on its hull and struts. 
    The newest flights are seeking conditions m more than just 
presence of water,that could ever sustain life on Mats. Possible 
future missions may bring back samples of Martian soil for study in 
labs with any number of tests and tools. 
    A false report of life on Mars came from certain meteorites 
blasted off of Mars and falling on Earth. In them are vermicular 
features that suggested fossils. After intense study these were 
replicated with chemical methods not related to biological processes. 
    In all examinations it seems that lakes, rivers, other hydrology 
prevailed on Mars several billion years ago, soon after the era of 
massive asteroid collisions in the solar system. By some unknown 
mechanism the bulk of this water vanished, leaving only minute 
intermittent spots of water. Even the water as ice in the polar 
regions is only a minuscule fraction of what likely flowed over the 
planets in the remote past. 
    Yet the open water must have lasted for many millions of years 
because we find layers of salt deposit here and there. These minerals 
would accumulate over a long timespan. 

Mars rovers 
    Almost immediately after rolling off of their landing bases, the 
rovers Spirit and Opportunity found positive evidence for mass water 
in bygone eras. They imged and assayed minerals that could be formed 
only in water, such as the 'blue berry' round stones and salt 
crystals. Comparison with similar materials on the Moon, which never 
had any mass water, showed that Mars minerals required water as a 
formative agent. The lunar minerals were formed under utterly dry 
    Rover Curiosity continues to verify the past presence of water. 
Apparently water flowed on Mars after the cratering period because  
Curiosity observed and studied 'bathtub rings', high-water residua, on 
crater walls. The depressions were once filled with water. 

Water releases 
    Orbiting probes by now completely mapped Mars pole to pole to 6-
meter resolution. This is far better detail than any other planet's 
mapping so far. Selected places are imaged to 30-cm resolution as 
needed to study some important feature.
    In the images there are occasional spurts of liquid water from a 
slope that disappears on the next round or so  of the satellite over 
that location. It is plain unknown where this water comes from. Is it 
from an underground cavity or aquifer? is it black ice mixed in soil  
that melted? Is it some soil chemical  taking in aerial water vapor 
and then overflowing? Which is to say, these releases could come from 
a source that's solid, liquid, or vapor! 
    There is no sure indication for a water cycle like on Earth. Water 
apparently does not circulate from ground to air and back.
    There is no precipitation of water any where on Mars. The ice at 
the poles, mixed with frozen carbon dioxide, 'dry ice', condensed 
directly from the water vapor in the air. 

'Bathtub rings' 
    Some Mars advocates are annoyed that the rovers are not 
deliberately examining the salt deposits left in their vicinity by 
water. Surely theses residua contain crucial clues -- if not positive 
evidence -- of bygone life. Maybe they harbor vestigial microorganisms 
in a tiny habitat. In the stead the rovers stand their distance and 
use hands-off methods to explore the salts. 
    The deposits do look like similar ones on Earth that now harbor 
microbes and tiny animicula. Possibly creatures on Mars could have 
evolved to withstand the solar radiation and wide swings of daily 
    The rovers keep away because they are not thoroly sterilized 
against Earth life! They do not meet the current planetary-protection' 
standards. There is the prospect that a rover tool may drop Earth life 
into the salts and then mistake it for native Martian life. Worse, the 
Earth life could flourish and contaminate the entire vicinity of the 
salt deposit, upsetting all future explorations for Mars life. 

Off-limits for humans? 
    The frothing passion of many Mars advocates is to land humans on 
Mars to both explore temporarily and to set up permanent colonies. 
There are several companies working out paper scenarios for human 
migration to Mars. None have any means what so ever for carrying out 
their scheme, only a vague expectation that a national government will 
magicly execute the plans for them.
    Among planetary scientists the consensus is that humans should 
stay off of the Red Planet. There is no way in hell a human, however 
shielded from the Mars ecology, can avoid leaving contaminating 
microbes, even germs and viruses, on the planet. Once this happens, 
Mars is for ever trashed as a pristine world. 
    Suppose we do develop a suitable containment vessel for human 
visitors? Then what's the point of sending humans to Mars? Altho they 
will 'be on Mars' they can not in any casual way interact with it. 
They may just as well be on Earth working a remote-control vehicle, 
much as we already do now. 
    Humans could travel to Mars in an orbital or loop-around flight, 
with no chance of transferring Earth life to the planet. Such would a 
national prestige mission at first and thenafter tourist rides. 
    As a matter of practicality, given the pace of human space flight 
any where in the world, it will be many decades before a human 
expedition to Mars is fielded. The cost, even for a coalition of 
countries, would be immense and the reward would be almost entirely 
intangible, maybe at best a ticker-tape parade. 

    Dr Wray went thru a thoro update on the situation of water on mars 
and its relation to potential life,  We know for sure Mars had 
abundant open and flowing water billions of years ago. We know there 
is some water left, sometimes in liquid form. We just don't know what 
happened to the water in as much as we find no clues  for some global 
calamity to make the water vanish. 
    The question of mars as an abode of life remains open. If there is 
life now it is of an extremely low-level form in perhaps isolated 
underground pockets We so far find nothing like remains of past forms 
of life, such as fossils or bones.
    This lecture is timely for home astronomers for giving much-
welcome news for discussing Mars as it comes around to opposition in 
summer 2018. Yjis is a favorable opposition, almost as good as that of 
2003. Home astronomers with small scopes may discern the Martian 
surface details. The planet looks so much like Earth! Do people live 
there, too? Will we soon visit them? Or will they visit us?