The Silence of the Universe is Significant

Geoff Marcy, the University of California at Berkeley astronomer who has found scores of exoplanets, and who has diligently searched for signs of anything artificial in the data, says the silence is significant: “If our Milky Way Galaxy were teeming with thousands of advanced civilizations, as depicted in science-fiction books and movies, we would already know about them. They would be sending probes to thousands of nearby stars. They would have a galactic Internet composed of laser beams a...

 The Parallax Method

It is possible to measure how far away from us each galaxy is. How? How, for that matter, do we know how far away anything in the universe is? For nearby stars the best method uses something called 'parallax'. Hold your finger up in front of your face and look at it with your left eye closed. Now open your left eye and close your right. Keep switching eyes, and you'll notice that the apparent position of your finger hops from side to side. That is because of the difference between the viewpoi...

 Carl Sagan's Vision of the Human Race's Future

We were hunters and foragers. The frontier was everywhere. We were bounded only by the Earth and the ocean and the sky. The open road still softly calls. Our little terraqueous globe as the madhouse of those hundred thousand millions of worlds. We who cannot even put our own planetary home in order, riven with rivalries and hatreds, are we to venture out into space? By the time we're ready to settle even the nearest other planetary systems, we will have changed. The simple passage of so many...