Mars has Cows

Surprisingly, it seems there is a very good possibility of life existing outside the Earth, but still within our solar system.

Mars has methane, which implies the presence of volcanic or tectonic out-gassing or microbial life. We know Mars has been geologically inactive for hundreds of millions if not billions of years, so that’s leaving the methane looking decidedly like an organic by-product. This is one of the things NASA’s Curiosity Rover is going to investigate when it lands on Mars in 2012.

Methane, or CH₄ as it’s known to its friends, is simple molecule, but it cannot survive in the Martian atmosphere for any significant length of time because…

• The lack of a planetary magnetic core leaves it vulnerable to ultraviolet radiation that breaks the molecule apart
• The lack of substantial gravity and lack of protection from solar wind, means the thin Martian atmosphere gets stripped off into space quite easily

It’s interesting to note that micro-organisms, on Earth, at least, produce methane through a simple process known as methanogenesis, an anaerobic reaction (that doesn’t require oxygen). It’s a reaction that’s perfectly suited to the red planet as the principle pathway required for this chemical reaction is carbon dioxide and the result is methane and water. With all three molecular suspects and one element present on Mars, there’s a good case to go looking for bugs.

CO₂ + 8 H⁺ + 8 e^- → CH₄ + 2 H₂O

Methane has also been detected on Titan, although this may be from geological activity.

Titan, on the other hand, has its own peculiar mysteries. Hydrogen, which is abundant in the upper atmosphere, is curiously absent lower down, which implies it has probably been absorbed by something, something that just might be alive.

If this bears out under more scrutiny, it would raise the fascinating prospect that there could be lifeforms using hydrogen as we use oxygen.

If Mars and Titan both have life, and I know it’s a big ask, but if they do, then we would have the remarkable prospect of living in a solar system that has three habitable environments and two, possibly three, distinctly different types of lifeforms. If that turns out to be the case, then the prospect of finding life elsewhere in the universe, and possibility of there being intelligent extraterrestrial life, would leap up exponentially.

Now, there’s plenty of other avenues for methane production to consider before the champagne corks get popped, but what a tantalising possibility. These are exciting times in which we live.

I’m intensely curious about what Curiosity will uncover on the red planet, aren’t you?

 

Conversations with an Alien Hunter

OK, the book is actually called Confessions of an Alien Hunter: A Scientist’s Search for Extraterrestrial Intelligence by Seth Shostak, senior astronomer at the SETI institute, but it could have equally been called Conversations with an Alien Hunter…  because of its relaxed, informative, conversational style.

And this raises an interesting point about the 21st Century. Never before have so many had such direct access to the relatively few pioneering minds of our time. Today, you can follow scientists like Seth on Twitter or like them on Facebook.

Seth is one of the brave few that still has his direct contact details on the Internet and gets flooded with emails and phone calls. With hundreds of new emails every day, he’s gone from senior astronomer to chief correspondent as he juggles public demand against his professional inquiry in the search for extraterrestrial intelligence. I’m sure there are some days where he’d be glad to find terrestrial intelligence, while anything beyond that would be a bonus. And this brings us back to Confessions, as it is, in a nutshell, the opportunity to sit one-on-one with Seth and listen to what he has to say on the subject of intelligent alien life. Its soft, easy-going, conversational style makes it enjoyable to read.

In an age where communication moves at close to the speed of light, zipping around the planet through copper wires and fibre optics, bouncing off tin cans in the sky and through cables running along the sea floor there’s rarely the chance to have a sustained, in-depth conversation any more, but, ironically, books are filling that niche. Rather than superseding and replacing the written word, the advent of the Internet has ensured books have a place of even greater prominence in that they are the sole repositories of comprehensive knowledge. Catch something interesting in a tweet? Read some titbit in a news article and want to know more? Head for the books.

And Confessions delivers in style. It’s everything you wanted to ask after seeing the movie Contact, but didn’t know who to approach.

It is fascinating to have the search for extraterrestrial intelligence put in context. Yes, it’s been going for decades and they haven’t found anything, but do you realise how big space is? I mean, we all know space is big. But do you know how big it really is when you start searching for ET? Seth points out that if you were sitting in orbit around Alpha Centauri, the closest of over two hundred billion stars to our sun, looking for mankind, then spotting the Earth would be like noticing a mosquito circling a light-bulb from 10,000 miles away. The clincher, though, is the mosquito circles some 25 feet away from the light-bulb and never gets any closer. And that’s the view from our closest neighbour!

Searching for extraterrestrial intelligence is, then, perhaps the most adventurous undertaking in the history of science.

The Arecibo telescope, made famous by the movie Contact, is located in Puerto Rico with a dish measuring 1,000 feet across. It’s capable of holding 373 tennis courts and is so sensitive that the dish can detect signals one-trillionth the energy of an ant taking a single step. These guys may not have found ET yet, but it’s not for lack of trying. The reality is, our galaxy is astonishingly big. Shostak points out that if the largest, most comprehensive SETI search to date had been conducted on a haystack, we would have made a particularly thorough search through roughly a tablespoon’s worth of hay and determined there were no needles…yet…

So patience is the order of the day, but, as Shostak points out, Moore’s Law not only ensures ever faster computers for our home office/study, it means our ability to trawl through millions of frequencies is growing exponentially. Within the next couple of decades we’ll have gone through a sizeable portion of our haystack and, as we suspect there are thousands of needles buried within it, we should end up pricking our finger.

There’s a whole bunch of extraordinary insights throughout the book, but I won’t spoil it for you, suffice to say, Hollywood gets it all spectacularly wrong. If you enjoyed Contact, you’ll love Confessions.

 

Life on Mars

It’s somewhat ironic that, with all our efforts to find life on Mars, if there is life it may have originated from Earth.

There are currently 50,000+ catalogued meteorites, with roughly just a hundred thought to originated from Mars because of their composition, the ratio of trapped gases matching the Martian atmosphere, etc.

Some have even proposed that the Allan Hills meteorite contains fossilised Martian nanobacteria. As tantalising as that prospect is, and as convincing as the scanning electron microscopic images are, nanobacteria, itself, is controversial and unproven here on Earth (let alone Mars). To me, the images are quite convincing, as they really do appear organic in nature, but the beauty of peer-reviewed science is that it is not for me, a neophyte, to guess when there are peers equal to the task, already pouring over this subject.

But now, another alternative has emerged, and it’s one I considered as the subject of a novel a few years back (and should have jumped on it at the time), and that is that life may have been spread from Earth through out the solar system, being thrown up by large impacts like the Chicxulub impact.

Remarkably, computer models have been developed that show that…

• 0.02 per cent would reach the Moon
• 0.17 per cent would reach Venus
• 0.01 per cent would reach Mars
• 0.06 per cent would reach Jupiter
• 0.19 per cent would fall into the Sun
• and a staggering 6.75 per cent would reach the orbit of Pluto.

Now, you may wonder how so much can reach Pluto when so little reaches Mars and Jupiter, by comparison. The answer lies in understanding the gravity wells spread throughout the solar system (planets), with their complex paths following various Lagrange points and gravity-assisted boosts that run, like a highway, throughout space.

Achieving panspermia, with life reaching out from the Earth to other worlds, is actually quite probable, given how hardy bacteria are in a vacuum.

When Apollo 12 brought back a camera from Surveyor 3, the intention was to examine the prolonged effect of space vacuum and solar radiation on equipment. Little did they realise that, three years previous, a technician had inadvertently contaminated the camera casing with Streptococcus mitis. Much to everyone’s surprise, the bacteria could be revived.

So could bacteria from Earth, spread as the debris of a massive impact, survive for thousands or millions of years in space and be naturally revived on contact with liquids on Mars or Europa? Yes. In fact, we’ve already successfully revived yeast from the Eocene period, some 45 million years ago and made Jurassic beer (you’ve got to love science). So, as a concept, all the elements have been individually shown to be plausible.

If there is life on Mars, it may well have originated from Earth.

How would we tell? Actually, that would be quite easy. We’d recognise the DNA quite quickly and, by comparisons with the phylogenetic tree of life, would even be able to tell roughly when it split off and started an independent evolutionary branch, so we’d know roughly when it departed the Earth.

Ah… the mind boggles with possibilities…

 

Calculating the probability of life in outer space

Probability is a mathematical expression of the likelihood of a given scenario occurring. It is normally expressed as a number between zero and one. Zero, meaning there’s no probability of it occurring, and one, meaning it is an absolute certainty. The probability of a coin toss coming up heads, as an example, is 0.5.

So what is the probability of life existing in outer space? Well, you’re probably thinking we’re going to need something like the Drake equation and take into account the number of stars being formed within our galaxy, the fraction of those stars with planets and then the sub-category of those planets that are capable of supporting life (as we know it), etc.

But we need not go to all this effort because we already know the answer. The probability of life existing in outer space is one. It is beyond doubt. It is an absolute certainty. We know space can support life because we’re alive. We are in outer space (or, at least, our planet is).

Ok, there’s groans from the cheap seats, but this is a perfectly valid point. Without realising it, we tend to think of the Earth as the centre of the universe. We think of the Earth as being somehow special and unique, and from our perspective, it is. It’s the pride of ownership, the pride of tribalism applied to “our” planet. But Copernicus demonstrated long ago that the Earth has no special place of importance in the universe. It’s special to us, but both the Earth and the Sun are rather ordinary and average in a dull kind of way. That life exists here, in an unassuming, less-than-remarkable neighbourhood, is strong grounds for considering that it could occur elsewhere.

Ok, so what about any other life in outer space?

This is where things get particularly interesting. NASA has observed Glycolaldehyde and over 120 other simple molecules in vast gas clouds in space spanning three light years in size (which is huge. Voyager is currently on the edge of our solar system and it’s only 13 light hours away, less than one light day as compared to three light years).

Glycolaldehyde is a basic sugar that is found in both Ribose and Glucose sugars. Ribose is the building block of DNA, the basis of all life of Earth, while Glucose provides the metabolic energy for cellular life. So space is brimming with the basic building blocks for creating and sustaining life.

Another recent discovery has found 140 trillion times as much water in one small region of space than in all the oceans on Earth!

Numbers like this are meaningless until you put them in context. You probably read that last sentence in roughly a second. So if we think of seconds as a point of comparison, being the equivalent of all the water on Earth for the purpose of our analogy, then how long is a trillion seconds? Well, you’ll hit a million seconds after 11 days, but it will take you 32 years to pass a billion, while a trillion will take a whopping 32,000 years. So when we say there is an abundance of stuff out there essential for life, it’s a gross understatement. The components for life exist in such overwhelming quantities it is unfathomable.

And this brings up an interesting point. When scientists talk about the prospect of life in outer space, they talk almost exclusively in terms of probabilities. Creationists, determined to downplay any rational thinking about the universe, will often liken these probabilities to things like a 747 being randomly constructed as the result of a tornado hitting a junk yard. But this misses a crucial point, and that is the context in which things occur changes the on-going probability.

The probability of tossing five heads in a row might be slim, but after four heads, the probability of making it five in a row is actually quite good, at 0.5. In the same way, the probability of life accumulates and increases as each component required for life compounds and builds upon the previous.

150 years ago, Charles Darwin demonstrated that evolution works through Natural Selection, the gradual accumulation of inherited traits according to natural laws. Natural selection applies to living, organic creatures because of the compounding effect of numerous small changes adding up over time.

Could a similar principle apply to inorganic substances?

At first, it’s tempting to say, no. But this is not necessarily the case. Remember, the only reason Natural Selection works is because there is a mechanism in place for traits to accumulate and pile up from one generation to the next (which we call DNA). Inorganic selection is possible if there is a similar mechanism causing a compound effect.

Stay with me here.

There’s no cosmic DNA but there is the accumulation of compounds, the slow clumping of “stuff” that makes climbing mount improbable no arduous task, and that is a galaxy, accumulating into solar systems, accumulating into stars and planets. Together, they have a compounding effect, like interest in your bank.

With such an abundance of mater (metals, gases, water and pre-organic molecules like glycolaldehyde) being drawn together by gravity to form planets and moons around stars, we have, in effect, the same accumulation of the fundamental components required for life occurring all throughout the universe.

So why don’t we see ET staring back at us?

SETI are struggling with that question right now, and it seems there are a variety of possibilities. Firstly, there are a phenomenal number of stars within the Milky Way, some 200 to 400 billion of them, and it takes considerable time and effort to examine each of them. Also, we cannot see all of them. Radio astronomy can see through dust clouds, but if life existed in abundance, directly opposite us, on the other side of the galactic core at roughly the same point on a similar spiral arm, we would never be able to see it directly with a regular telescope, determine what planets there were in each system, etc. So there are limits to how well we can search.

Also, it may be that not every solar system is conducive for life. It seems our Sun is a third generation Population I heavy-element rich star. So our solar system may well be one of the early occurrences of compounding accumulation that allows life to thrive.

And the sheer distances involved mean the other several hundred billion galaxies (minimum) in our universe are just too distant for us to observe life. It would be like being stranded on a island off the coast of Africa and doubting there was any life on the distant desert shores when, in fact, the continent is teeming with the most remarkable diversity of life.

So… is there life in outer space?

Yes.

At the very least there is us, but, more than likely, the universe is teeming with life because it is teeming with the building blocks for life.