land here and be like huge scary machines who stamp us into the ground, just like we do with ants.â
âOr,â said Annie, her eyes shining in the light from the flashlight, âthey might be teeny-weeny, like little wriggly bacteria under a microscope. Only they donât realize how large we are and so we donât even notice when they arrive.â
âThey might have fourteen heads and dribble slime,â said George ghoulishly. âWeâd notice that!â
They heard a creaking noise, followed by footsteps on the stairs. A bleary-eyed Eric came out onto the veranda.
âWhatâs going on here?â he asked.
âGeorge couldnât sleep,â said Annie quickly. âBecause of the jet lag. So I was just, um, getting him a glass of water.â
âHmm,â said Eric, his hair sticking up all over the place. âUpstairs with you both now.â
George sneaked into the room he shared with Emmett and hopped back into bed, but not before heâd taken Annieâs flashlight from her. He was wide awake now, so he got out his copy of The Userâs Guide and turned to the chapter, âGetting in Touch with Aliens.â
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THE USERâS GUIDE TO THE UNIVERSE
GETTING IN TOUCH WITH ALIENS
If aliens are really out there, will we ever get to meet them?
The distances between the stars are staggeringly great, so we still canât be sure that a face-to-face encounter will someday take place (assuming the aliens have faces!). But even if extraterrestrials never visit our planet or receive a visit from us, we might still get to know one another. We might still be able to talk.
One way this could happen is by radio. Unlike sound, radio waves can move through the empty spaces between the stars. And they move as fast as anything can moveâat the speed of light.
Almost fifty years ago some scientists worked out what it would take to send a signal from one star system to another. It surprised them to learn that interstellar conversation wouldnât require superadvanced technology like you often see in science-fiction movies. Itâs possible to send radio signals from one solar system to another with the type of radio equipment we could build today. So the scientists stood back from their chalkboards and said to themselves: If this is so easy, then no matter what aliens might be doing, theyâd surely be using radio to communicate over large distances. The scientists realized that it would be a perfectly logical idea to turn some of our big antennae to the skies to see if we could pick up extraterrestrial signals. After all, finding an alien broadcast would instantly prove that thereâs someone out there, without the expense ofsending rockets to distant star systems in the hope of discovering a populated planet.
Unfortunately, this alien eavesdropping experiment, called SETI (the Search for Extraterrestrial Intelligence), has so far failed to find a single, sure peep from the skies. The radio bands have been discouragingly quiet wherever weâve looked, aside from the natural static caused by such objects as quasars (the churning, high-energy centers of some galaxies) or pulsars (rapidly spinning neutron stars).
Does that mean that intelligent aliens, able to build radio transmitters, donât exist? That would be an astounding discovery, because there are surely at least a million million planets in our Milky Way Galaxyâand there are one hundred thousand million other galaxies! If no one is out there, we are stupendously specialâand dreadfully alone.
Well, as SETI researchers will tell you, itâs entirely too soon to conclude that we have no company among the stars. After all, if youâre going to listen for alien radio broadcasts, not only do you have to point your antenna in the right direction, but you also need to tune to the right spot on the dial, have a sensitive enough receiver, and be listening at the right time. SETI