Clearly, unless thinking beings inevitably wipe themselves out soon after developing technology, extraterrestrial intelligence could often be millions or billions of years in advance of us. We're the galaxy's noodling newbies.
— Seth Shostak
As far as I can tell, the only unambiguous consequence of the claimed invasion of Earth by beings from another star system has been a nonstop torrent of TV specials. So if you're one of the many who believe the aliens are here, you really do have to admit this: They're the best houseguests ever.
Each year, thousands of UFOs are sighted and reported, which is an impressive tally of unidentified aerial phenomena. Surveys show that roughly one-third of the populace believes that at least some of this sky show is due to extraterrestrial spacecraft, here to probe our airspace and, when that proves boring, our bodies.
It's hard to imagine anything more interesting than learning how we're woven into the enormous tapestry of existence. Where did our universe come from? How special is our world, and how special are we? We allocate tens of billions of dollars annually to NASA, NSF and academia in search of the answers.
If aliens are really hanging out in our 'hood, it's hard to imagine any other fact more worthy of study. If not, then why does such a large fraction of the populace insist on believing they're here?
'E.T.' was far-fetched. 'E.T.' was this wimpy-looking kid that came to Earth to pick some plants, but he came from the Andromeda Galaxy to do that.
This plucky NASA telescope is able to find planets en masse. If you compare planet hunting to prospecting for gold, then Kepler is equivalent to trading in your trusty pan for a diesel-powered sluice box.
Disasters happen. We still have no way to eliminate earthquakes, wildfires, hurricanes, floods or droughts. We cope as best we can by fortifying ourselves against danger with building codes and levees, and by setting aside money to clean up afterwards.
Just knowing that there's somebody else out there - that what's happened on this planet has also happened in many other places - that might change our lives in a very subtle way, but it's interesting to know and worth looking for.
The bottom line is, like, one in five stars has at least one planet where life might spring up. That's a fantastically large percentage. That means in our galaxy, there's on the order of tens of billions of Earth-like worlds.
Heads are a good deal, and I think they would be a common feature. It's hard to think of species that don't have heads, although there are some. It's good to have a head because it puts some of the sensory organs - eyes, ears, whiskers or whatever - next to the CPU, the brain.
It bears mentioning that the Milky Way is only one of 150 billion galaxies visible to our telescopes - and each of these will have its own complement of planets.
The longtime standard for American TV was 525 lines from top to bottom of the image. As a practical matter, that was roughly equivalent to 350 thousand pixels - pretty crude, given that photos made with your iPhone boast five million pixels.
The overwhelming bulk of the cosmos is deathly quiet. But here and there - on worlds where matter is thick and conditions are right - noises are commonplace. And in some cases, these noisy worlds may ring with the sounds of life - the bleats and bellows of creatures we have never seen, but may someday discover.
On Mars, where the air is spare - a hundred times less dense than on Earth - someone could hear you scream. But you'd have to really strain to get anyone's attention. On the Red Planet, where the wind is high-pitched and faint, even a symphony orchestra will sound as thin as cheap gruel.
The planets and moons of our solar system are blatantly visible because they reflect sunlight. Without the nearby Sun, these planets would be cryptic and dark on the sky.
Exploration is an oft-lauded human activity, and one that resonates in the same way that music and good stories do. It's hard-wired into our species (and into many others), no doubt because it has survival value. Exploration occasionally rewards those who accept its risks, usually with new resources.
Humans have existed only for the last 0.001 percent of cosmic time. All of which says that - unless the Homo sapiens brain is the one-and-only instance of cogitating machinery - nearly all the intelligence that's out there is beyond our level. And that intelligence is more than just a little bit beyond.
Any beings advanced enough to traverse interstellar distances are at least a thousand years beyond our technical level. Spending gobs of time examining our missiles is equivalent to sending the Air Force back to the Middle Ages and insisting they examine the chain mail factories.
We can never prove that we're alone in the universe. But the Allen Telescope Array could prove that we're not.
Virtually any pointed edifice is considered a candidate for alien engineering. After all, how could the Egyptians or Mayans have possibly stacked up stone blocks into pyramids?
You may not see massive UFO exhibits at your local science museum, but there's no dearth of saucer stories infesting my email. Every day, I receive several reports of alien sightings, extraterrestrial plans for Earth, and agitated screeds about the reluctance of scientists to take the whole subject seriously.
When I was a kid, which was just after Edison invented moving pictures, there were films that involved aliens coming to Earth for bad purposes.
If this is the only planet on which not only life, but intelligent life, has arisen, that would be very unusual.
In 1908, there was a persuasive demonstration of the power of high-speed, low-mass asteroids in rural Siberia. The Tunguska impactor iced millions of pine trees and about a zillion mosquitoes - and was no larger than an office building.
I studied Latin in high school, and I was reading stuff from Cicero. And that signal took a few thousand years to get to me. But I was still interested in what he had to say.
Most of the intelligence out there must be artificial intelligence. We keep looking for critters like us living on a planet like ours, where in fact the majority of the intelligence out there is not biological. That would be my argument.
Most of the things at the zoo don't look like us. We're one design that works. Our chimp pals sort of look like us, so that's a different take on the same basic design. But fish don't look like us, and giraffes don't. They look a little like us, but not too much. And insects certainly don't look like us, and they work just fine.
Estimates are that at least 70 per cent of all stars are accompanied by planets, and since the latter can occur in systems rather than as individuals (think of our own solar system), the number of planets in the Milky Way galaxy is of order one trillion.
There will be an end point to how good TV pictures can get. The boob tube has hugely benefited from the rapid advance of digital electronics. Consequently, the strategy for hardware has changed. In the old days, sets had to be as simple as Elmer Fudd to keep them inexpensive. All the technical 'smarts' were at the transmitter end.
Of course, Sol is a big ball of hot gas, but one that - thanks to its endlessly boiling innards - shakes and vibrates. By studying patterns on the Sun's surface, astronomers can learn much about Sol's internal construction.
Jupiter, a world far larger than Earth, is so warm that it currently radiates more internal heat than it receives from the Sun.
Recent results from astronomers who study the occasional gravitational lensing of unknown worlds by intervening stars suggest that orphan planets could be at least as numerous as the stars. In other words, there could be hundreds of billions of orphan worlds shuffling through our galaxy.
The total funding of SETI (the Search for Extraterrestrial Intelligence) in the U.S. is 0.0003 percent of the tax monies spent on health and human services. And it's not even tax money. The SETI Institute's hunt for signals is funded by donations.
The cosmos is three times as old as Earth. During most of creation's 14 billion year history, our solar system wasn't around. Nonetheless, the early universe still had the right stuff for life, and contained worlds that were just as suitable for spawning biology and intelligence as our own.
Some pundits have proposed that the aliens have come here to breed with us. Apparently, too much bike riding or something similar has rendered them incapable of reproducing within their own species. But do extraterrestrial infants toddle through your neighborhood?
Sure, nobody will make a fortune if we figure out why the Big Bang happened. But just about everyone would like to know.
The majority of my UFO diet consists of reports describing suspected encounters. This is not surprising, as there are thousands of sightings annually. The emailer has seen something unusual in the sky that he interprets as probable evidence of alien presence.
Charles Darwin sailed around the world for two years on the 'Beagle,' and he had quite a bit of interest in things like the iguanas of the Galapagos, even though they were primitive compared to your average Englishman.
People don't learn science in movies. You don't go to the movies thinking, 'I hope I learn some quantum mechanics this afternoon.' But on the other hand, movies are instrumental and influential in getting young people interested in science.
Buying insurance is no one's idea of fun. And it's especially easy to berate something as funky-sounding as writing checks to defend our neighborhoods against apartment-size rocks from space. But this is one insurance pitch that makes perfect sense. Ask the dinos.
Consider that the overwhelming majority of those 40,000 near-Earth asteroids are small enough to fit on the parking lot at the mall. And while these rocky runts won't cause Armageddon, they could still flatten such popular hominid hangouts as Manhattan or downtown Des Moines.
The thing to keep in mind is that we're still in the very early days when it comes to the search for extraterrestrial intelligence. Saying there's a silence is a bit like if Columbus, looking to discover a new continent, only sailed 10 miles off the coast of Spain before turning back to say, 'Nothing out there!'
By 2020, most home computers will have the computing power of a human brain. That doesn't mean that they are brains, but it means that in terms of raw processing, they can process bits as fast as a brain can. So the question is, how far behind that is the development of a machine that's as smart as we are?
The usual metric for whether a planet is habitable or not is to ascertain whether liquid water could exist on its surface. Most worlds will either be too cold, too hot or of a type (like Jupiter) that may have no solid surface and be swaddled in noxious gases.
Engineers are now experimenting with 4,096-line TV systems, suggesting that with the next generation of sets you'll be able to count the grass blades on the Superbowl field, an obvious lifestyle improvement.
Once typecast as the indispensable altarpiece of a well-appointed living room, TVs have infected every human environment. The average American household has more television sets than people.
Studying Sol's interior by looking for analogous patterns on its incandescent face is known as helioseismology, an active - if largely unpronounceable - research area that uses sound as a probe of our home star.
The bottom line is that finding orphan planets - small, faint, and located who-knows-where - is not for the faint of heart. The task is comparable to observing a match flame at the distance of Pluto. The WISE satellite, a hi-tech, space-based infrared telescope especially suited for such work, has found only a few.
Are we the only members of the Galaxy that can actually understand what a galaxy is? Could Homo sapiens really be the pinnacle of Creation - the cleverest critters in the cosmos? If we learn the answer is 'no,' that would affect our philosophies forever.
