Stalking butterflies and thinking Martians, Danny nets Hubert Badger tramping across the countryside and delivers a lecture on life in outer space; after a pause for situation identification, the ""tramp"" reappears on the doorstep of Professor Bullfinch, Danny's scientific mentor, and is introduced as a famous astronomer. (Surprise!) Seems he's come to enlist the Professor's help in an attempt to monitor sounds from distant planets; seems the Professor has just developed (and perfects, with Danny's accidental assistance) the very tool that will make the attempt practical...and Danny Dunn-ites can tell it from there. There's the usual medley of pure scientific and parascientific information leading to a pseudoscientific conclusion and a thinner than usual veneer of Joe Miller jokes--and as usual, the great discovery depends on Danny's just-informed intuition. ""Go ahead, Dan,"" the Professor says. ""Tell us."" Kind of reminds us of the old dumb cop stories... We liked Danny better when he was worrying about his homework.