Tag Archives: Odds

Harvard astrophysicist backs the Rare Earth hypothesis

What is the Rare Earth hypothesis?

It’s the thesis of a recent book written by two scientists at the University of Washington.

Here’s the blurb:

What determines whether complex life will arise on a planet? How frequent is life in the Universe?

In this exciting new book, distinguished paleontologist Peter D. Ward and noted astronomer Donald Brownlee team up to give us a fascinating synthesis of what’s now known about the rise of life on Earth and how it sheds light on possibilities for organic life forms elsewhere in the Universe.

Life, Ward and Brownlee assert, is paradoxically both very common and almost nowhere. The conditions that foster the beginnings of life in our galaxy are plentiful. But contrary to the usual assumption that if alien life exists, it’s bound to be intelligent, the authors contend that the kind of complex life we find on Earth is unlikely to exist anywhere else; indeed it is probably unique to our planet.

With broad expertise and wonderful descriptive imagery, the authors give us a compelling argument, a splendid introduction to the emerging field of astrobiology, and a lively discussion of the remarkable findings that are being generated by new research. We learn not only about the extraordinary creatures living in conditions once though inimical to life and the latest evidence of early life on Earth, but also about the discoveries of extrasolar planets, the parts Jupiter and the Moon have played in our survival, and even the crucial role of continental drift in our existence.

Insightful, well-written, and at the cutting edge of modern scientific investigation, Rare Earth should interest anyone who wants to know about life elsewhere and gain a fresh perspective on life at home which, if the authors are right, is even more precious than we may ever have imagined.

And here’s a review by Library Journal:

“Renowned paleontologist Ward (Univ. of Washington), who has authored numerous books and articles, and Brownlee, a noted astronomer who has also researched extraterrestrial materials, combine their interests, research, and collaborative thoughts to present a startling new hypothesis: bacterial life forms may be in many galaxies, but complex life forms, like those that have evolved on Earth, are rare in the universe. Ward and Brownlee attribute Earth’s evolutionary achievements to the following critical factors: our optimal distance from the sun, the positive effects of the moon’s gravity on our climate, plate tectonics and continental drift, the right types of metals and elements, ample liquid water, maintainance of the correct amount of internal heat to keep surface temperatures within a habitable range, and a gaseous planet the size of Jupiter to shield Earth from catastrophic meteoric bombardment. Arguing that complex life is a rare event in the universe, this compelling book magnifies the significance — and tragedy — of species extinction. Highly recommended for all public and academic libraries.”

Note that Peter Ward is a militant atheist (he has debated against Stephen C. Meyer), and Donald Brownlee is an agnostic. These are not Christians, nor are they even theists. However, I have the book, I have read the book, and I recommend the book. I usually have this book on my shelf at work for show-and-tell.

Now for the latest news about the hypothesis of the book. (H/T Brian Auten of Apologetics 315)

There are always going to be optimistic predictions by scientists who need to attract research funding, but those are hopes and speculations. The data we have today says Earth is rare. The number of conditions required for complex life of any kind is too high for us to be optimistic about alien life in this galaxy, at least. And as the number of requirements for life roll in, the odds of finding alien life that can contact us get slimmer and slimmer.

From the UK Daily Mail. (H/T Peter S. Williams)

Excerpt:

Dr Howard Smith, a senior astrophysicist at Harvard University, believes there is very little hope of discovering aliens and, even if we did, it would be almost impossible to make contact.

So far astronomers have discovered a total of 500 planets in distant solar systems – known as extrasolar systems – although they believe billions of others exist.

But Dr Smith points out that many of these planets are either too close to their sun or too far away, meaning their surface temperatures are so extreme they could not support life.

Others have unusual orbits which cause vast temperature variations making it impossible for water to exist as a liquid – an essential element for life.

Dr Smith said: ‘We have found that most other planets and solar systems are wildly different from our own.

‘They are very hostile to life as we know it.’

‘The new information we are getting suggests we could effectively be alone in the universe.

‘There are very few solar systems or planets like ours. It means it is highly unlikely there are any planets with intelligent life close enough for us to make contact.’ But his controversial suggestions contradict other leading scientists – who have claimed aliens almost certainly exist.

These arguments are actually quite useful, and I include them in my standard list of scientific arguments for theism. (See below) You have to know this stuff cold. Most people believe in aliens because they watched movies made by artists. As a result, they think that humans are nothing special and that God is not interested in us in particular. Which is very convenient for them, because it means they can do whatever they want and not care what God thinks about what they are doing. If you want to defend against the idea that humans are nothing special, and that we were not placed here for a purpose, and that we are not accountable and obligated to seek and know the Creator/Designer, then you’ll need more than feelings. You’ll need science. You’ll need the best science available.

Related posts

How long will it take to sort a deck of cards by trial and error?

Inside the cell, things like proteins and DNA are formed by sequencing parts together in just the right way so that the sequence will have biological function. If the sequence is wrong, because some component of the sequence is the wrong piece or is in the wrong place, the sequence has no function. It’s just like writing English or computer instructions.

To calculate the probabilities, you have to use a rule called “The Product Rule”, because the order of the parts in the sequence (“permutation”) is important. For example, the odds of getting the sequence “ABC” just by choosing three random letters is 1/26 x 1/26 x 1/26 = 1/17576. Things get very unlikely quite quickly, don’t they?

So, take a look at Neil Simpson’s latest post, where he uses cards instead of letters or amino acids, but the principle is exactly the same. His calculation is a little different because the odds actually go down a little each time you choose a card. So, for the first card, it’s 1/52, but the second card is only 1/51, and so on…

Excerpt:

This is by no means a definitive argument against evolution, but I offer it to put the “time, chance and random mutation” theory in perspective.

Everyone knows that micro-evolution occurs, such as dog breeding and bacteria becoming resistant to antibiotics.  But macro-evolutionists believe that with enough time an amazingly complex single cell of unknown origin could make lots and lots of small changes, develop reproductive capacities and eventually become humans, elephants, caterpillar/butterflies, chameleons and so much more.

Let’s consider something very simple.  Imagine that you shuffle a deck of cards.  If you shuffled it one time per second, how often would all the cards go back into their original order? (Ace of spades, King of spades, etc.)  The math is simply 1/52 (the odds of the Ace of spades being on top) times 1/51 times 1/50, etc. I left out the Jokers to make it easier.

Guess how many years it takes?

Click through to see his calculations, or do them yourself! It’s easy and fun! Neil has a pretty fun discussion going on with the angry atheists who frequent his site, too.

This is everyone should learn probabilities in school, because then we can really talk about these things with our neighbor. Shalini can even do biochemistry, so she can actually explain it even better than I can!

Remember, we are looking for a specific sequence of cards – the sequence that the cards originally came in. In this example, it’s that sequence and that sequence alone that has biological function. The other sequences are just junk – they have no biological function. And most importantly, you don’t get to save any of the cards that are in the right spots because the sequence as a whole has no present function that would allow it to be “saved” for later. You have to re-select all 52 cards each time at random!

A typical protein isn’t made of 52 parts, it’s made of around 200, and there are 80 possible amino acids, not just 26! And in the case of proteins,the vast majority of the possible sequences that you can make won’t have any biological function at all! (And there are many more problems besides, such as chirality, cross reactions, and bonding type). Even if you filled the whole universe with reactants and reacted it all at Planck time, for the entire history of the universe, you still wouldn’t be likely to get even one protein!

You can read more about the origin of life in this post.