The Moon is a ball of left-over debris from a cosmic collision that took place more than four billion years ago. A Mars-sized asteroid - one of the countless planetesimals that were frantically churning our solar system into existence - hit the infant Earth, bequeathing it a very large natural satellite.

Seth Shostak

Art Years Ago Years

Plate tectonics is not all havoc and destruction. The slow movement of continents and ocean floors recycles carbon dioxide dissolved in the oceans back into the atmosphere. Without this slow speed carbon cycle, Earth's temperatures would cool dozens of degrees below your comfort zone.

Seth Shostak

Men Cool Car

Jupiter, a world far larger than Earth, is so warm that it currently radiates more internal heat than it receives from the Sun.

Seth Shostak

War Art World

Today's voguish threats, including climate change, population growth, massive war, and resource depletion, are all amenable to a fix if we act prudently. And even if we don't, these problems are incapable of obliterating all of humanity, let alone destroying the Earth. No, the real End of Days will happen slowly, as the Sun ages.

Seth Shostak

War Men Change

Forecasting Armageddon has become trendy of late, with a great deal of attention being given to an interpretation of the Mayan Calendar suggesting that Mother Earth is destined for doom in December of 2012.

Seth Shostak

Great Art Age

The mission of NASA's Kepler telescope is to lift the scales from our eyes and reveal to us just how typical our home world is. Kepler operates by measuring the dimming of stars as planets pass ('transit') in front of them. It has found thousands of previously unknown worlds.

Seth Shostak

Home Yes Worlds

It will be the mother of all telescopes, and you can bet it will do for astronomy what genome sequencing is doing for biology. The clumsy, if utilitarian, name of this mirrored monster is Large Synoptic Survey Telescope, or LSST. You can't use it yet, but a peak in the Chilean Andes has been decapitated to provide a level spot for placement.

Seth Shostak

Men You Will

Despite the impression you may have from watching too much TV, movies are not about reproducing reality. They're about telling stories.

Seth Shostak

Movies You Watching

Data from orbiting telescopes like NASA's Kepler Mission hint that the tally of habitable planets in our galaxy is many billion. If E.T.'s not out there, then Earth is more than merely special - it's some sort of miracle.

Seth Shostak

Art Tin Then

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.

Seth Shostak

Work Space Art

The bottom line is that the position of the Sun relative to the stars slowly changes for any given date, and over the course of 26,000 years, it can easily slide between constellations. So you may think you're a Pisces, but you're actually an Aquarius.

Seth Shostak

Change You Years

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.

Seth Shostak

Power Us UN

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.

Seth Shostak

War Music Good

Certainly the history of astronomy shows that every time we thought we were special, we were wrong.

Seth Shostak

Time History Wrong

Typically, only about 2 percent of the American populace tunes in to PBS's 'Nova' series - the most successful science show on the tube. 'Survivor' and 'X Factor' get twice the ratings.

Seth Shostak

Success Science X Factor

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.

Seth Shostak

Men Age Well

Judging by informal observation, most young Americans burn up their spare time buffing their emotional IQ and self-esteem with social media and non-stop texting. That's great for eye-thumb coordination, but what about the satisfaction of actually making something?

Seth Shostak

Time Great Young

The strongest signals leaking off our planet are radar transmissions, not television or radio. The most powerful radars, such as the one mounted on the Arecibo telescope (used to study the ionosphere and map asteroids) could be detected with a similarly sized antenna at a distance of nearly 1,000 light-years.

Seth Shostak

Power Years Year

Our brains are continuing to evolve, and perhaps a few tens of thousands of years from now, our descendants will walk around with five pound brains, allowing them insights that we can't imagine.

Seth Shostak

Years Year Wit

Admittedly, it would take industrial-grade chutzpah and a massive dose of malevolence for anyone to bulldoze the spot where Neil Armstrong stepped off the Eagle lander. But even innocent visits could be damaging.

Seth Shostak

Would Where Visit

The Moon is a ball of left-over debris from a cosmic collision that took place more than four billion years ago. A Mars-sized asteroid - one of the countless planetesimals that were frantically churning our solar system into existence - hit the infant Earth, bequeathing it a very large natural satellite.

Seth Shostak

Art Years Ago Years

Neil Armstrong was no Christopher Columbus. In most respects, he was better. Unlike the famous fifteenth century seafarer, Armstrong knew where he landed. He also spent his time in public service, not in jail, and his passing was marked by world-wide encomiums. He ended his days as a celebrated explorer rather than a royal inconvenience.

Seth Shostak

Three-fourths of the universe is hydrogen, and oxygen is incredibly abundant, too. So H2O is something you can find nearly everywhere.

Seth Shostak

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.

Seth Shostak

It's the default premise in science: If you observe something in nature only once, you assume that what you've seen is typical. That's because 'typical' is just another way of saying 'most probable.'

Seth Shostak

Ever since the infamous quiz show scandals of the 1950s, the feds had insisted that TV game shows be honest - or that at least they didn't cheat. So as a 'Dating Game' bachelor, I didn't know what I was going to be asked. The other bachelors and I were required to concoct our answers in real time.

Seth Shostak

We're not just any star stuff, most of which is humdrum hydrogen and listless helium. Our bodies include fancier ingredients like carbon, oxygen, nitrogen, phosphorous, and a few other herbs and spices.

Seth Shostak

If gravity were somewhat stronger or weaker, stars wouldn't exist, and neither would you. And the same can be said of other constants of physics. Several have to be 'just right.'

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.

Seth Shostak

I you look at the drawings of aliens made by people who believe that Earth is under saucer attack, you'll quickly note that most of these invaders fit the Tinseltown mold. But you have to admit: the grays are highly anthropomorphic.

Seth Shostak

Like prospecting in the 19th century, reconnaissance of the asteroids would of necessity take place in an arena where trouble is likely and help is distant. Heroic stories of individual triumph and failure, set on landscapes never seen by humankind, are in the cards.

Seth Shostak

While it may be disappointing, I have to confess to people who ask for my insights on the meaning of it all that astronomy doesn't provide any clearly useful data on matters of sin and souls.

Seth Shostak

Television is ephemeral, a fact that some will find reassuring. But earthlings will continue to pump the kilowatts into the ether. And eventually, when those signals have washed over a few hundred thousand star systems, someone may notice.

Seth Shostak

Our retinas and brains have been wired by a hundred million years of evolution to find outlines in a visually complex landscape. This helps us to recognize prey and predators.

Seth Shostak

Planets that don't currently sport plate tectonics, such as Venus and Mars, are scarcely habitable. Tectonics might be a requirement of any world that aspires to a rich diversity of life.

Seth Shostak

In days gone by, scientists would speak solemnly about our solar system's 'habitable zone' - a theoretical region extending from Venus to Mars, but perhaps not encompassing either, where a planet would be the right temperature to have liquid water on its surface.

Seth Shostak

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.

Seth Shostak

A factory that can turn carbon nanotubes into a sheet a yard wide and long enough to stretch one-fourth of the way to the moon is not something you'll find at your local industrial park. That's the show-stopper for the space elevator. The ribbon.

Seth Shostak

While I have always thought that the motivation for looking for E.T. was both self-evident and patently worthy, it's possible that I'm a victim of my own job description. Others don't inevitably agree. Some will opine that there are better ways to spend the money.

Seth Shostak

'Battleship' is not a film that Francois Truffaut would have made. Nor would any of those other namby-pamby European directors. Nope, this picture eschews that Continental obsession with small stories, set in quaint towns filled with pockmarked folk doing their banal things.

Seth Shostak

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.

Seth Shostak

Five centuries ago, Copernicus upset humanity's applecart with the news that the Earth is not the center of the cosmos. It could be that, before you've paid off your house, we'll learn that the universe is not the center of the universe, either!

Seth Shostak

The limitless content of our universe might be only one instance of a large (and possibly infinite) number of other universes.

Seth Shostak

The ideas of science germinate in a matrix of established knowledge gained by experiment; they are not lonesome thoughts, born in a rarified realm where no researcher has ever gone before.

Seth Shostak

Star Trek's genial premise is that the cosmos is flush with intelligent species, and our descendants will interact with them face-to-face, thanks to warp drive and some winsome space cadets.

Seth Shostak

It seems obvious that if a species has the brainpower for speech, along with the sort of appendages that can manipulate a pair of pliers, it will eventually blunder into science, technology, and radio.

Seth Shostak

Lamentably, alien audiences may be frustrated by the switch to digital television. That's because the transmitter power for DTV is fairly evenly spread across the spectrum. The spikiness is gone, and from afar, the attention-grabbing squeals of analog television's carriers have been replaced by DTV's smooth, low hiss.

Seth Shostak

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.

Seth Shostak

There's no doubt that the Moon is more than a handy night light and a hair restorer for werewolves. It's responsible for the substantial amplitude of earthly ocean tides. These are of obvious influence if you're a geoduck, a type of clam that people dig up at low tide.

Seth Shostak

Are two eyes, four appendages and an upright posture really essential for any creature that can ace the galactic SAT's? Maybe not. In fact, I'd venture that any aliens we ever detect or (less likely) encounter will look quite different than this self-referential stereotype.

Seth Shostak

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.

Seth Shostak