Are We Alone?

When I was small, my wildest fantasy would be sighting a UFO. Honestly, I was very passionate about the possibility that there are some aliens out there, technologically more advanced and more superior to us, the feeble earthlings. I eagerly grabbed any books about this extraterrestrial life or read testimonials of people abducted by aliens. I could spend hours just looking up at the sky, who knows I might catch their spacecrafts there. Some people got some sights, some took pictures of them, so I could be lucky too. I even read a book telling a story about advanced civilization underneath the earth, wow. I admit that there was a time I prayed to God, hoping that I could be given the chance to see them hahahaha. Well, such mystery is truly captivating millions of people like me.

That was me before I read this book, Rare Earth. This book is jointly written by Peter Ward, a geologist, and Donald Brownlee, an astrobiologist. Their mixed expertise certainly gave a fresh review on the contemporary notion held by scientific community and people at large, that advanced extraterrestrial life is possible out there. This book, however, is proposing a contrasting argument. While extraterrestrial life may be abundant (or even more much more abundant than what we might predict now), their presence would be limited to singular organisms, microbes, or just simple creatures. Complex plants and animals are exceedingly rare, and technologically advanced creatures would be impossible to exist. They argued that our presence on earth was the results of series of increasingly improbable events, and in no way it could be reproduced outside the earth. I found that their arguments are so strong and convincing, such that I don’t believe in ET-stuff anymore.

So what are their arguments? The authors managed to compile some arguments that our earth is truly unique and our evolution to intelligence is highly coincidental. I grouped their arguments into three main topics:

1. Critical location of our earth
The galaxy must be not too young or too old, otherwise it will lack sufficient metals to produce planets or it will have such intense radiation that will kill off any organisms. The location of our solar system at the edge of galaxy is just right, other wise large meteors, asteroids or planets may fall upon us. Thus large parts of our universe and most area in our galaxy are truly inhabitable. Big brother Jupiter and big moon are there for us, to protect us from intermittent space missiles. Our sun is very very stable and in the just right size, thus our solar system is quite unique in this sense.

2. Special characters of our earth
The presence of magnetic field in our earth is due to unusually stable iron core, which is also the result of long-life radioactive elements, and such elements will not be present in younger galaxies than our milky way. Plate tectonic is also necessary characteristic, since it will, among other things, regulate atmospheric temperature. The atmosphere must also contain right amount of green house gasses, not too much or too little, with right degree of protection against harmful radiation. All of these are special attributes of our earth.

3. Series of improbable events in our evolution
Our earth was 4.6 billion years old, and the life of singular cell appeared a billion years later. It remains simple microbes for the next 3 billion years until pre-Cambrian explosion. Why did it take so long to evolve? Pre-Cambrian explosion was initiated with sudden increase of oxygen, in highly special circumstances; will it occur in other planets too? Our planet was dominated by dinosaurs until 60 millions year ago, until a meteor crashed to the earth. Yet our ancestor mammals survived. How often does doomsday like this occur in other planets? How would the proto-intelligent beings survived in other planets? Long stable periods of time is needed for survival and, if necessary, evolution. Yet, evaluation does not always lead to complex creatures, let alone the evolution to intelligent beings. (It is primarily believed that the evolution of our vocal cords, not the brain size, that leads to our intelligence)

There are so much more important arguments in the book, which is impossible to discuss each one of them here. Each argument is accompanied with fine details, which I skipped in this book summary. Needless to say, this is truly a revolutionary book. Mainstream scientists rejected their ideas, but they could not find any satisfactory rebuttals since their arguments are mostly solid. And most importantly, we have not confirmed the presence of ET scientifically (oh, emotionally yes, we even have a cult here hehehe)

If I may add, I also read in other book that our planet is the noisiest (in term of radio frequency) in our galaxy. So any advanced creatures with knowledge of radio communication in other galaxies could easily detect our presence. Yet until know we hear no answer to our SETI (Search for Extra-Terrestrial Intelligence) radio-signaling efforts. Or at least we should pick up their radio signals too. But what do we hear now? Total silence.

[By the way, Jared Diamond made a funny joke about this SETI project in his book, Collapse. Sending radio signals to the universe is like assuming that animals or plants there evolved to pick up radio frequency, with ears (or equivalent audio-receiving organs) specifically took radio signals and were able to interpret them. We are looking for radio-telecommunicating species hahaha]

As far as I know, this is the only book that refutes the notion (and long-held tradition) that we are not alone in this universe. So read the book yourself and make your own judgment. As for me, I stop pondering at the skies anymore