Travel to Extra-solar Planets Possible? Well, Not Now But…

April 20, 2013
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So the Kepler telescope has discovered two new planets, not too much bigger than Earth, and located in the “goldilocks zone” of their stars, meaning that liquid water, and presumably life, might exist there.  The nearer planet is “only” 1200 light years from us.  The farthest, 2800 light years.

To put that into perspective, it takes light about 8 minutes and 20 seconds to travel the 93 million miles separating us from the sun.  Traveling at the speed of light, it would take a ship 1200 years to get to the nearest of these planets.  That doesn’t take into account speeding up and slowing down.  We could make 50,478,400 round trips to the sun in the time it would take to get to the farthest of the two planets. And these two planets are relatively close in terms of just galactic distances.  So why bother even thinking about the possibility of life on these two worlds, or of some day visiting them?

Well,  back in Columbus’s time nobody had conceived of steam power or the internal combustion engine either–or of being able to plot a course with a computer.  On Star Trek, the Enterprise is powered by anti-matter conversion–right now the concept that would produce the most energy per unit of fuel.  We don’t have anti-matter conversion yet.  We don’t even know how to make enough anti-matter to give it a try. But  the best “scientists” in Columbus’s time didn’t know how to produce gasoline either.  Even if anti-matter engines became real they would produce only enough energy to make travel in this solar system an everyday occurrence.  It would still take hundreds of years to get much of anywhere else in the galaxy.  So Star Trek goes one step further.  The Enterprise uses dilithium crystals powered by the anti-matter to warp space.  Its engines shorten the fabric of space ahead of it and lengthen the fabric behind it.  That shortens the actual distance the ship has to travel.  Sounds fantastic but some parts of cutting edge physics suggest that space actually has a “fabric” that might be malleable.  For example, we know that the universe is expanding.  And when cosmologists say that, they don’t mean that galaxies are rushing away from each other.  They mean the actual fabric of space is expanding in all directions.    Still pretty far out.  But so would a passenger jet be to Alexander the Great.

Each generation prefers to believe that it has discovered most of what is important about reality, and all researchers have to do is fill in some of the details. We are in that mode now.  But sooner or later, a discovery or invention occurs that changes the world and the whole way scientists look at things. Einstein’s theories would be one example.  The invention of gunpowder might be another.  Computers and the internet a third.  I would prefer to believe that there is much we still don’t know and that one of those discoveries in the future will put us on a path to the stars.  Limitations are always challenges to human beings, and the accumulation of knowledge is proceeding at a much faster pace today than it was in Columbus’s time.

The Search for Life in the Universe

April 8, 2013
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In order to find life on other worlds, we first must be sure of what it is–that is, what constitutes life as separate from non-life?  To do this, according to scientists, we must go back to life’s possible origins. 

Astronomers, who first thought that only separate atoms could exist in space,  discovered some time ago  that the universe is teeming with organic molecules.  By organic they mean that these molecules are present in large quantity in living organisms.  But these same molecules are present in other materials too that we wouldn’t identify as living. There is a bridge that must be crossed between living and non-living, and so far scientists admit, they don’t have evidence of how that bridge is crossed. But  life on Earth is carbon-based, meaning its essential molecules depend on carbon for their structure.  In the movie Alien an extraterrestrial creature is encountered whose molecular make-up is silicon-based, producing an especially hard outer shell.  The make-up of the universe seems to aruge against this possibility, however.

If you boil off the hydrogen and helium in a typical star, (not an easy task in reality), you’ll see that life has almost the same amounts of carbon, oxygen, and calcium as the star possesses.  Since other bodies in and around solar systems are made up of the remnants of dead stars and since the same rough proportions of parts of those  remnants appear in us, we can posit that life everywhere has certain “common cosmic traits” as Jacob Berkowitz puts it in his recent book The Stardust Revolution.   So other life is likely to be carbon-based just like us.  If we are star stuff, then so must they be.

To separate rocks from tadpoles, metallic ore from trees, Mexican evolutionary biologist Antonio Lazcano defines life as “self-sustaining, replicative chemical systems capable of undergoing Darwinian evolution.”  Presumably, since the same chemicals are involved, roughly the same kind of evolutionary processes would exist on any planet other than Earth on which organic chemicals somehow managed to arrange themselves in self-replicating ways.  These processes would involve the production of oxygen, carbon dioxide, and methane.  Scientists know of no other way that oxygen could be produced in the quantities present in Earth’s atmosphere other than through biological processes.

This is not to say that alien life would look pretty much like us.  Look at the diversity of structures present in the biosphere of our native planet.  But, for intelligent life,  there are obvious evolutionary advantages to standing upright, having our brains encased in a hard shell on top, possessing long fingers with opposable thumbs, and having complex voice boxes.  Had dinosaurs not been wiped out by a chance comet or asteroid, however, they might have been the ones to have evolved intelligence instead of mammals.  They might have done it sooner too, since they already had a head start.

Based on this knowledge and these fair assumptions, the search for other life in the universe will become a search for planets with easily detectable oxygen in their atmospheres.  However, Dr, Berkowitz points out that we shouldn’t be too in love with oxygen.  For most of Earth’s history, millions of species of bacteria were and are anaerobic–they breathe gases other than oxygen.  One possibility would be dimethyl sulfide, which smells sort of like cooked cabbage, or dead fish.  So the abundance of certain other gases in atmospheres might hint at the presence of some form of  life too.

Getting spectroscopic signatures of gases in exoplanet atmospheres will take a whole new generation of space-based telescopes, according to most scientists.  The Spitzer telescope or Hubble just aren’t designed for that.  Europe’s Darwin and Gaia telescope missions have been cancelled along with NASA’s terrestrial planet finder. The culture wars over evolution still go on stifling progress in these areas.   “The stardust revolution has changed our view of the cosmos, but perhaps we stand unwilling to change, and to embrace, a new view of ourselves,” says Berkowitz.