On The New York Times, Adam Frank says that for the longest time we questioned whether or not there were aliens out there; however, now that we know that "every star in the sky likely hosts at least one planet," even the worse case scenario still shows that "a trillion civilizations still would have appeared over the course of cosmic history." In other words, we may not know if there are aliens right now, but there's a good change that they definitely existed.
Or consider the average lifetime of a civilization. Humans have been using radio technology for only about 100 years. How much longer will our civilization last? A thousand more years? A hundred thousand more? Ten million more? If the average lifetime for a civilization is short, the galaxy is likely to be unpopulated most of the time. Once again, however, with only one example to draw from, it’s back to a battle between pessimists and optimists.
But our new planetary knowledge has removed some of the uncertainty from this debate. Three of the seven terms in Drake’s equation are now known. We know the number of stars born each year. We know that the percentage of stars hosting planets is about 100. And we also know that about 20 to 25 percent of those planets are in the right place for life to form. This puts us in a position, for the first time, to say something definitive about extraterrestrial civilizations — if we ask the right question.
|Escape the Earth|
|The Known Universe|
|View of the turbulent heart of our Milky Way galaxy|
|Zeppelins and Cloud Cities to Colonize Venus|
|"Psyche [...] may be the exposed metal core of an early planet, the soul of a celestial body."|
|“Eliminating the time needed to stop and re-charge a conventional electric car’s battery.”|
|“Nobody is forcing the participants to stay, of course, but if they leave, they won’t be paid.”|
|“That science fiction future where robots can do what people and animals do may be closer than you think.”|
|Making a Movie Inside a Video Game|
|“This 160-step biochemical process is very well studied, and surprisingly inefficient.”|
|Google Map Shows You the Most Photographed Areas of the World|
|“During this phase of decline, the US was likely to go through a phase of reactionary 'fascism'.”|
|“We’re going to start to see chip implants get the same realm of acceptance as piercings and tattoos.”|
|“The shift from fuel and pistons to batteries and electric motors is unlikely to take that long.”|
|“Our Internet handlers, not government, are using operant conditioning to modify our behaviour today.”|
|“Within 30 years, half of humanity won't have a job. It could get ugly — there could be a revolution.”|
|“After 78 years, the helicopter has been reinvented.”|