Saturday, February 25, 2012

Climbing higher

If we ever to expand beyond our home planet, we need to find suitable places to colonize first. There is no lack of plans for future missions, such as return to Moon, missions to Mars, exploration of Venus or near-Earth asteroids.

However, these environments are less hospitable for humans than ice deserts of Antarctica or Everest summit and also is much harder to reach. Such remote destinations on Earth are visited only by small number of scientists and explorers with even smaller o number of permanent residents.

Other locations within Solar system appear to be no more hospitable to human beings, lacking earth-like atmosphere, gravity or radiation protection, leaving the future of space colonization uncertain.

For humans to expand beyond their home planet, they have to find satisfactory answers for the following three questions:

  • Why should humans colonize space? 
  • Which destinations should be selected for colonization programs? 
  • How exactly should colonies beyond Earth should be developed?

Saturday, February 18, 2012

Life, death and afterlife

Every now and then every one of thinks about death and what is beyond it. You may wonder if the death is truly the end to your existence, if there is any chance to avoid it and if there is such thing as afterlife. People who have various religious beliefs can please themselves with tales of heavens or possible reincarnation. However, if you consider yourself an atheist of any kind, you know that real answer is rather unpleasant and painful.

The entirety of your personality, memories and dreams is contained within your brain, in the vast network of neurons and their connections. Your brain is the only container of all the information that is you. And what happens when this container is destroyed after your body ceases functioning? Pretty much the same as happens to any other information container that is destroyed, like a CD being thrown into the document shredder. There is no more chance of your personality spontaneously reforming anywhere in the Universe, then for the above mentioned CD to reform itself from scattered shards in the landfill. When you die, you disappear from the existence forever and you are not going to ever return. There is no afterlife for you and your current life is the only one. Such is the reality of existence and dying is the worst possible things that can happen to you or your loved one.

But death is no more natural than smallpox was. People currently see death as inseparable part of reality only because there is no way to avoid it. There are no unresolvable mysteries or supernatural reasons for death that science cannot explain and even possibly prevent at some point in future. People and other life forms die when their bodies are too damaged to properly function, either from accidents or from accumulated wear from the old age. Is there any hope for death to be defeated? We can try to preserve as much as possible of ourselves by using cryonics. There is no guarantee that you’ll be ever revived but your odds for any type of afterlife life would be better than if you left your body to be cremated or decomposed. You can also hope that at some point in future, medical science will be advanced enough that at least senescence is prevented and physical immortality will become reality and there is a slight chance you may live long enough to reach this point yourself.

However, even if people ever become immortal at some future time, this doesn’t offer anything for countless billions of human beings who didn’t live long enough to see that day. Being dead may not seem so bad if you lived to hundred years and died in your sleep, having accomplished all your life goals and remembered by your children and grandchildren. But what about those less fortunate? Those who died too young, alone and in terrible pain? What about those who sacrificed their own lives to save someone else? They are all gone, their dreams, personalities and memories forever erased from existence. Don’t they deserve something better than complete oblivion?

Our present state of knowledge about the Universe is sufficiently good to understand that there are no gods or other supreme beings that are capable of providing any sort of afterlife for those who are gone. So we have to take care of our dead ourselves. What would be the desired solution? Remember, our brains are nothing but containers of information that represent our personalities. To bring dead person back to life we either need to physically retrieve person at the last moment he/she was alive in the past or recover just enough of this information (map of neurons, their connections and electrical activity down to molecular or atomic precision) that would be sufficient to recreate the person in such a way so he/she would not notice any change in himself.

Now here is the obvious first question – is there any verifiable, scientific method to achieve these capabilities (even if only in theory)? The obvious answer is no: neither the travel back in time seems possible, nor the full recovery of past information state from the certain location in space and time in present. I’ll skip the details here, but in short, general relativity doesn’t allow causality violation and therefore time travel to the past, and physical and chemical processes are generally irreversible (they do not preserve information about past states) at least until the quantum mechanical level. So our present level of science gives a definite “no” for this question. But have we reached the ultimate limit of scientific knowledge and technological powers? Hardly so, the stream of scientific discoveries and inventions is not stopping or slowing down. There might be some unknown property of space or time that can change the outcome of this question. There is nothing fundamentally prohibiting us from continuing to increase our volume of scientific knowledge and technological capabilities. We don’t know what powers human civilization can possibly harness in another thousand (or million) years of development.

Now, here is a second question. Is there a certain future level of science and technology that can be possibly reached by our descendants in this Universe, where it would be possible to reverse death for all those who died before? The answer could only be “yes” or “no” and therefore does exist, but we don’t know what that answer would be. There is nothing to lose and everything to gain for our deceased ones if we try to find the answer to this question. Here is my third and last question. What can be done here and now to improve the odds of ever finding this answer?

Two conditions have to be satisfied in order to find the answer to the second question mentioned earlier.

First, we should become able to find this answer, by reaching the peak level of science and technology possible in the Universe.

Second, our future society should be willing to find this answer. Our descendants should care enough about people deceased long ago to bother making any efforts to find out if it is possible to bring them back to life.

The last question of the previous post can be now restated as following: what can we do today to improve the odds of ever reaching these two conditions? The answer how to reach the second condition is long and complex enough for me to delay the explanation until much later. The solution to reach the first condition, however, can be explained more easily and I will show the details below.

To ensure that we can eventually reach the highest possible science and technology level following assumptions must hold true – human civilization must survive as long as the Universe will, while our scientific and technology powers have to continuously increase. Only two outcomes are possible in this scenario. We will either run out of time available in our Universe, while still climbing higher in the quest to reach the ultimate limit of knowledge and technology powers. Or we will hit the said limit before the end of Universe existence and therefore will have some time left to produce the desired answer.

Now, how to make those assumptions hold true for the foreseeable future? Our planet will remain a comfortable environment for us on geological timescales (likely, millions of years, environment problems and global warming notwithstanding). However, this state is not guaranteed to last indefinitely. A possible asteroid impact or any other natural or man-made disaster of unusual magnitude can destroy humankind. Even without catastrophic events Earth will become inhospitable when our Sun evolves into red giant phase in the far future. But our Universe will not end with the end of our planet and we should find a way to continue to exist beyond this point.

What about being able to ever increase humankind’s science and technology level? Very roughly, this level is correlated with the total available energy, matter and information processing capability (as sum of computing resources and intellectual power). We are not yet using all of the Earth’s energy and raw materials, we have not yet exhausted its capacities to support further human population growth. However our planet is finite and so there is a limit to the amount of available resources we can use and energy production planet environment can handle and how many humans (and computers) can populate it. We should find a way to go beyond this limit if we want to continue unbounded growth in these dimensions.

Limitations described above are pointing to the need of expanding beyond our home planet if we ever want to reach our goals. However, this is not an easy feat and multiple obstacles are present on this path. But this is another story altogether.