Archive for the ‘Mars’ Tag

Life in the Universe V: The Influence of Carl Sagan   5 comments

The moon sets behind the Tetons as the Milky Way soars over Jackson Lake, Wyoming.

The moon sets behind the Tetons as the Milky Way soars over Jackson Lake, Wyoming.

I have neglected this series for far too long, I’m sorry to say.  Check out the previous posts for some background and for some of my best starscape images.  Part I discusses how science has tackled the biggest questions we ask about the Universe and how life fits into the picture.  Part II continues by touching on the idea of the universe having a consciousness, or even some sort of creator; it also discusses how quantum theory fits into things.  Part III goes into what we know thus far about life’s origins.  And Part IV highlights the incredible progress we’ve made in the exploration of our solar system, with the not always explicit goal of finding life on other planets.

The progress of this series has been generally outward, from our beloved Earth (which remains the only place we know that hosts life) and out to the solar system.  My goal (at least metaphorically) is to go out to the stars, our galaxy, then finally the larger Universe.  Then I’d like to come back to the original two-part question discussed in Part I: how did we come to be and why?  In this post however, I’m going to take a short detour and speak about a scientist who greatly influenced how we have tackled these questions.  He is Carl Sagan, an astronomer from the United States.  Now passed away, he was widely known as a popularizer of astronomy.  He influenced NASA policy along with millions of people who watched his Cosmos TV series.  He had a significant effect on me.

In Little Ruin Canyon the moon illuminates Square Tower, with Hovenweep Castle visible on the rim beyond.

In Little Ruin Canyon the moon illuminates Square Tower, with Hovenweep Castle visible on the rim beyond.

SAGAN 101

Carl Sagan Planetary Society.JPGWhile he was charismatic and very good at getting all sorts of people enthusiastic about space science, he was also a very good scientist.  Among the general public in the U.S., he was mostly known for going on the Johnny Carson Show and expounding on astronomy.  Of course everyone knew that Johnny would eventually get him to say the word “billions”.  In Sagan’s landmark TV series Cosmos and in lectures, he often referred to billions (of stars, years, miles) with a definite, purposeful emphasis on the b.  With his great voice, the b literally boomed.  Comedians of the day had a great time imitating it.

Sagan started out as a planetary scientist, studying under the great Gerard Kuiper at University of Chicago and going on to make important contributions.  For example, he put together observations from the early Venus probes to demonstrate that the reason our sister planet is an incredibly hot, dry place is that it suffers from a runaway greenhouse effect.  He was first to suggest that Jupiter’s moon Europa has an enormous subsurface ocean and that Saturn’s moon Titan is bathed in an organic-rich atmosphere and had liquid organics on its surface.  He was a key figure in several important NASA missions, including the Viking robotic mission to Mars.  He led a small team that designed humanity’s first (and 2nd & 3rd as well) message to the stars.

Carl Sagan and Frank Drake came up with the idea to send messages to the stars on the Pioneer space probes.  Pioneer 10 and 11 were launched in the early 1970s to pass close to Jupiter and Saturn and then head out of the solar system into outer space.  These space-ready plaques, these cosmic messages in a bottle, had very simple messages inscribed on them.  There was a map showing where our solar system was located, along with figures of male and female human beings waving a greeting.  Five years later, the Voyager probes (which are now passing into interstellar space) carried a much more involved package.  It included a gold-plated record of pictures plus sounds from Earth (music, frogs croaking, volcanic action, human greetings in many languages, etc.).  This time capsule was designed by a team led by Sagan.

Also, in 1974, Carl Sagan and Frank Drake sent for the first time in human history a deliberate radio message out to the stars.  Aimed at the enormous globular cluster in the constellation Hercules, it was a coded radio transmission sent from the huge Arecibo dish in Puerto Rico.  It was not approved or sponsored by NASA, and drew great criticism.  Some prominent astronomers complained that it was arrogant and stupid for Sagan to advertise our presence to potentially hostile aliens.  Sagan countered that we have been broadcasting into space for generations, though the messages which continue to be broadcast (radio programs, TV sitcoms, etc.) may not be putting humanity’s best foot forward.

Wandering around Monument Valley during a full moon is a special experience.

Wandering around Monument Valley during a full moon is a special experience.

SAGAN & ET

Carl Sagan believed deeply in both the existence of extraterrestrial intelligence and in the many benefits that contact with them would provide humanity.  Do not misunderstand, however.  He was not a believer in ancient aliens or even that UFOs were evidence that we are being visited in recent times.  He simply believed that life had not only gotten started in many many places throughout the galaxy, but that it had progressed far beyond our level in a significant number of star systems.  He believed that if we made contact with any aliens, it would be near certain that their technology and culture would be far more sophisticated than ours.

This makes perfect sense if you believe that the Drake Equation (which estimates the chances of extraterrestrial intelligence) strongly suggests there are very many instances of intelligent civilizations in our galaxy.  Sagan combined that conclusion with the Fermi Paradox.  In 1950, Enrico Fermi famously asked of his colleagues (including Edward Teller, the father of the hydrogen bomb) “where are they?”  If there are so many potentially life-friendly star systems and literally billions of years to play with, why haven’t we seen any evidence of aliens, present or past?  Sagan took these two factors, plus the fact that we are in the infancy of space exploration ourselves, and concluded that any civilizations which do exist have somehow avoided having destroyed themselves, and are thus greatly advanced both technologically and culturally.

The Lamar River Valley in Yellowstone National Park is a peaceful place at dusk.

The Lamar River Valley in Yellowstone National Park is a peaceful place at dusk.

He had faith that we would eventually make contact with an advanced intelligence.  He also believed that their success in handling increasingly sophisticated, potentially destructive technology meant that they would be peaceful and non-aggressive.  Further, he thought they could teach us how to avoid destroying ourselves through technology, wars or ecological collapse, and that this would be the greatest discovery in the history of humanity.  This is why in the latter part of his career he focused intensively on making contact with extraterrestrial intelligence, and on convincing the general public that this was a worthwhile endeavor.

Some criticized this belief as not only quasi-religious, but as out-of-date and quasi-colonial.  They thought Sagan’s beliefs smacked of the justification for imperial powers of the west conquering primitive peoples in order to provide them with the benefits of the modern world (all the while stealing their resources and infecting them with disease).  In this cosmic case, those backward beings would be us Earthlings, and the “benevolent” conquerors would be extraterrestrials.  Many people who think about this stuff believe that contact with aliens would bring a similar fate:  exotic disease, theft of the Earth’s resources, and similar bad outcomes.  I think this criticism of Sagan is unfair.

A full moon illuminates Ship Rock in New Mexico.

A full moon illuminates Ship Rock in New Mexico.

SAGAN & SETI

The movie Contact is based on Sagan’s book of the same name, where SETI’s Jill Tarter (played by Jodi Foster) makes first contact with aliens.  SETI (Search for Extraterrestrial Intelligence), the effort that Frank Drake, Guiseppe Cocconi and Philip Morrison started is now a very mature organization.  Basically an effort to detect alien transmissions, SETI was kept alive during the 1960s by the Russians.  Carl Sagan, during the Cold War, collaborated with the Russians on SETI.  Now an American organization run by Seth Shostak, with both Frank Drake and Jill Tarter still involved, SETI is carried out by an international cast of scientists.  They conduct highly sophisticated monitoring of our galactic neighborhood.  Still looking primarily for alien radio transmissions, SETI incorporates sophisticated computer-assisted arrays of telescopes and also looks for optical signals (such as messages carried on laser beams).

SAGAN & MARS

Carl Sagan has been criticized for his almost religious zeal and optimism surrounding the existence of life on other planets.  He was very adamant that cameras on the Viking Lander be capable of sweeping the area in case any intelligent creatures show up to check out the intruder.  He endorsed a theory by the Russian Iosof Shklovsky which proposed that Phobos and Deimos (the two small moons of Mars) were artificial satellites created by Martians to escape a deteriorating climate on the planet’s surface.  Regarding the controversial “face” on Mars, Sagan parted ways with mainstream astronomers when he supported further study of it.  But he believed it was probably natural, a fact that was confirmed during subsequent flybys.

Sagan has been likened to that controversial icon of early 20th century Mars exploration, Percival Lowell.  Lowell was the dogmatic scientist who was convinced up to his death that Mars was laced with canals.  Sagan criticized Lowell for his refusal to accept evidence against the canal theory, but it is said secretly admired him for his belief in intelligent Martians.  Lowell was a tireless promoter of the theory for an advanced Martian society and, at least in part, so was Carl Sagan.  I think it’s a stretch, however, to label Sagan as Percival Lowell’s successor.

The full moon as viewed through a translucent veil formed by geothermal steam at Firehole Lake in Yellowstone National Park.

The full moon as viewed through a translucent veil formed by geothermal steam at Firehole Lake in Yellowstone National Park.

SAGAN THE SCIENTIST & AUTHOR

While it’s true that Carl Sagan had a strong belief in alien intelligence, possibly nearby, I regard him as a very good scientist, a straight thinker who could never ignore evidence that contradicted his beliefs.  He famously said “Extraordinary claims require extraordinary evidence.”  Although he though the study of UFOs was a legitimate effort, he debunked the famous alien abduction of d considered the chances of alien visitation to be extremely small.  For years he taught a course at Cornell on critical thinking.  But there’s no getting around the fact that Sagan’s interest in astronomy was stoked at an early age by the science fiction of H.G. Wells and Edgar Rice Burroughs.

Sagan was a well-trained astronomer who had a huge diversity of scientific interest and knowledge.  I have read quite a few of his books, and they are diverse.  Cosmos, The Pale Blue Dot, Cosmic Connection, Comet and Intelligent Life in the Universe are all great astronomy reads.  But he also wrote The Dragons of Eden, which explores the evolution of human intelligence.  Shadows of Forgotten Ancestors, about human evolution, is a fascinating book.  He worked for some years with famous biologists and geneticists, including Harold Urey and H.J. Muller.  He also worked with famous physicist George Gamow.  In a book called Demon-Haunted World, he defends science as a way to counter the chaos and misery of totalitarianism and war, along with ignorance.

The starry sky on a clear evening is reflected in the aptly-named Reflection Lakes at Mount Rainier National Park in Washington.

The starry sky on a clear evening is reflected in the aptly-named Reflection Lakes at Mount Rainier National Park in Washington.

SAGAN & FAITH

Sagan claimed that he was agnostic.  Based on some of his statements (“The idea that God is an oversized white male with a flowing white beard is ludicrous.”) many considered him an atheist.  But others thought he brought a religious bias into his science.  He believed that “Not only is Science compatible with pirituality, it is a profound source of spirituality.”   I believe he was somebody who welcomed that soaring elation that comes with scientific discovery, and that he regarded this as a deep spiritual experience with the nature of the universe, a sort of God.  I don’t think he was an atheist.  In fact, he once said:

An atheist is someone who is certain that God does not exist, someone who has compelling evidence against the existence of God. I know of no such compelling evidence. Because God can be relegated to remote times and places and to ultimate causes, we would have to know a great deal more about the universe than we do now to be sure that no such God exists. To be certain of the existence of God and to be certain of the nonexistence of God seem to me to be the confident extremes in a subject so riddled with doubt and uncertainty as to inspire very little confidence indeed.

In eastern Washington state stands a replica of Stonehenge, here viewed just before complete darkness descends with the stars coming out.

In eastern Washington state stands a replica of Stonehenge, here viewed just before complete darkness descends with the stars coming out.

Sagan was in some ways a child of the 1960s.  He was strictly anti-war, a staunch environmentalist, a believer in a woman’s right to equality and access to birth control (including abortion).   He smoked marijuana, and did little to hide the fact.  He married three very talented, intelligent and strong women throughout his life.  I believe Sagan’s most important legacy is what he did to make astronomy (and science in general) understandable and exciting to the public.  Sagan really believed science was a spiritual quest, but not in the strictly religious sense in which the word spirituality is often used.  Many people think his belief in extraterrestrial intelligence had strong religious elements.  But I think that he simply wasn’t conflicted about his science, and that he really was agnostic.  I believe that many of his critics mistook his spiritual-like enthusiasm (especially evident when he talked to the public about science) for some sort of religiosity.

Carl Sagan died in 1996 from pneumonia (of all things).  It was related to a disease he had called MDS, a condition that destroys a person’s bone marrow.   He was only 62, with plenty more to contribute to science and society.  Among many scientists and science enthusiasts, and nearly all science educators, he is sorely missed.  The movie Contact, an adaptation of his novel, came out in 1998.  If we do make contact with intelligent aliens within what would have been his natural lifetime (to the late 2020s, say), it will be a true shame he did not live to see it.

An old abandoned schoolhouse out on the Oregon prairie is illuminated by a crescent moon.  The Milky Way glows pink in the coming dawn.

An old abandoned schoolhouse out on the Oregon prairie is illuminated by a crescent moon. The Milky Way glows pink in the coming dawn.

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Life in the Universe IV   2 comments

Wherever life is, you will most likely find water or some other liquid.

Wherever life is, you will most likely find water or some other liquid.

This is a continuation of a series of posts.  Each is designed to be understandable without reading the others; they do build off each other, however, so check them out starting with Part I.  In the last post on this topic, I hope I got across how little we know of life’s beginnings.  This planet we live on hosts the only life we know of thus far…in the whole universe!  Does that mean we are most likely alone?  Not really.  This and the next post will look at the possibilities for life elsewhere.

Water is a good thing, but energy is also necessary for life; here in the form of geothermal heat in Yellowstone National Park.

Water is a good thing for life, but energy is also necessary; here in the form of geothermal heat in Yellowstone National Park.

It must be said that our ignorance of what the universe offers in terms of life beyond our solar system is profound.  Actually, I should not be so negative, because over the past decade or so we have found out much more about our universe’s capability to host life than we knew before.  This new knowledge has come in the form of the discovery of planets orbiting other star systems, along with the discovery of microscopic life in places we never thought could host life.

There is something I should mention before going further.  Scientists who study this sort of thing, called astrobiologists, do not expect to find any living thing out there that is visible without the aid of a microscope.  That’s because the conditions that are favorable for microscopic life (bacteria, etc.) are much broader in scope than those favorable for multi-cellular (big) life.  In addition, more complex life requires a much longer period of time before it can take hold, as opposed to the shorter time required for simple one-celled life to evolve.  But one thing is for certain: once we find microscopic life anywhere outside Earth, the stage is set for discovering much more complex forms.

Symmetry in nature comes in all shapes and sizes.

Symmetry in nature comes in all shapes and sizes.

Where We’ve Been

Humans have been probing the planets we share this sun with for a number of years now.  The first exploration outside of Earth orbit happened in 1962, when Mariner 2 flew close to the thick, acid-laced cloud-tops of Venus.  Then came the Apollo era, when the United States sent astronauts to the Moon and Russia managed to land a few craft on hostile Venus.  We also probed Mercury with a later Mariner mission.

The twin Voyager probes, launched in the late 1970s, were our first foray to the outer planets.  Voyager 1 showed us incredibly detailed close-up views of the gas giants Jupiter and Saturn.  Voyager 2 flew by Uranus and Neptune as well (still the only time we’ve visited those distant planets).  I recall seeing those first images of Jupiter’s clouds and Saturn’s rings in detail.  I was in High School, and the details were was truly blown away.  And I wasn’t the only one.

I normally only use my own images in this blog, but this painting is so realistic I couldn't resist.  Click image to go to source page.

I normally only use my own images in this blog, but this painting is so realistic I couldn’t resist. Click image to go to source page.

The Voyager probes are now the furthest from home that anything made by humans has ever traveled, and they win this honor by a mile!  Both are well over 100 times as far from the Earth as we are from the Sun.  They are also traveling by far faster than anything humans have ever built.  Soon Voyager 1 will arrive at the Heliopause, which is the spherical boundary around our Sun where the solar wind ceases to be the major influence, and instead galactic forces take hold.  In other words, our little travelers are about to leave our star’s neighborhood and forge a path out to the great beyond, the Milky Way Galaxy.

The U.S. has been the de facto explorer of the Moon and Mars, along with the outer planets, while the Russians picked the most hostile rocky planet on which to land a probe – Venus.  The European Space Agency has also been active more recently, designing the probe that landed on Saturn’s moon Titan.  While Mars garners the most attention, with its rovers and orbiting observatory, two U.S. probes are busy elsewhere.  Messenger is finishing up its mission at Mercury and Cassini continues to orbit Saturn and its zoo of moons.

The full moon rises on the North Rim of Grand Canyon, as Orion, Jupiter and company shine above.

The full moon rises on the North Rim of Grand Canyon, as Orion, Jupiter and company shine above.

Life on Mars?

In the 1970s we landed for the first time on Mars.  The lander was called Viking.  Along with incredible photography, the non-mobile lander dug up a small sample of soil and analyzed it for life.  Although it looked initially like the results might turn out positive, the soil was found to be completely hostile to life.  Since then, a series of Martian orbiters and rovers have found abundant evidence of water on Mars.  The only problem?  This water appears to have last flowed billions of years ago.  (Intriguingly, there is some evidence of periodic eruptions of liquid water from below ground, even recently.)  We have yet to find fossil evidence of past life on Mars, and the planet’s current condition appears to be as hostile to life as we ever thought.

An eclipse of the sun is one of the more humbling natural spectacles.

An eclipse of the sun is one of the more humbling natural spectacles.

Life Beyond Mars: It’s the Moons

Since both Venus and Mercury are much too hot to hold liquid water, even in the distant past, the next good place (beyond Mars) to look for life are the many moons of Jupiter and Saturn.  Europa, one of Jupiter’s moons, has been known for years to have a liquid ocean beneath a thick ice cap.  The moon is heated by enormous tidal forces created by the nearby gas giant, so this probably means that hot vents discharge into the sea.  On Earth, undersea hot springs host entire ecoysystems, so it stands to reason that Europa could  hide similarly-powered concentrations of life clustered around hot vents beneath its ice cap.  Also, Enceladus, a moon of Saturn that also has a subsurface ocean, represents an excellent habitat for life.

Mount Rainier and the night sky above Eunice Lake.

Mount Rainier and the night sky above Eunice Lake.

Although other moons around Jupiter and Saturn are thought to contain liquid or partly liquid interiors, arguably the most intriguing place to search for life is Titan.  Titan, orbiting Saturn, is the Solar System’s second largest moon.  It’s larger than Mercury and not much smaller than Mars.  There is a lot of methane on Titan, much of it liquid because of the frigid temperatures.  In fact, methane on Titan might serve the same role as water does on Earth.  We have observed features like river valleys and lakes on Titan, but instead of being filled with water they are filled with liquid methane.

The relative sizes of Earth, Mars and selected moons in the solar system.

The relative sizes of Earth, Mars and selected moons in the solar system.  Click on image to go to website where the author of this image, Abel Mendez, is sourced.

Why is this interesting for life?  Because prior to the emergence of oxygen, Earth was a planet rich in methane as well.  Early life on Earth relied on methane not oxygen, and in fact, these organisms are still around.  There is an enormous community of micro-organisms (methanogens) living just beneath the sea floor today.  In fact the methane they produce has been stored in ice formations that could, because of global warming, erupt and release into the atmosphere, greatly accelerating global warming.  Many scientists think Titan could be revealed to operate much as Earth did billions of years ago, with microscopic life very similar to those early Earth days.

The fact is, although we have made great strides in understanding how likely it is to find life within this solar system of ours, we are just now scratching the surface.  Life on Mars has by no means been ruled out, and the moons of the outer solar system are just now being examined.  It will take a very sophisticated effort to look for life in Europa’s subterranean ocean, or across the huge and distant moon Titan, or on Enceladus.  But even the discovery of a community of extremophiles (micro-organisms adapted to extreme environments) on one of these relatively nearby bodies would be a watershed moment.  It would tell us that we are not alone in our neighborhood, and that life has likely gotten started in countless locations across the universe.

Next up: the incredibly diverse zoo of planets orbiting other stars.

Evening falls on the Columbia River, where two explorers passed on their way to discovery.  It's now quiet, and the frontier has moved on.

Evening falls on the Columbia River, where two explorers passed on their way to discovery. It’s now quiet, and the frontier has moved on.

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