Meanwhile, 40 miles away, also in New Jersey, two researchers with Bell Labs named Arno Penzias and Robert Wilson were in pursuit of more mundane signals. Using the 50-foot-long Holmdel Horn Antenna, they were trying to measure the radio waves emanating from galaxies beyond our own Milky Way. Even 50 years ago, our local radio waves were busy, and Penzias and Wilson spent time sifting out the chatter of broadcast radio and military radar, not to mention the constant roar of the sun, in order to make out the fainter extragalactic signals.But even after removing the obvious interference, a noisy hum remained.They pointed their telescope toward New York City, and then away again, but the signal was unchanged. So it wasn’t the Big Apple.They considered the Milky Way, since they were after all looking for signals from galaxies. But the noise didn’t change no matter where they looked in the sky – at the Milky Way’s heart or into the darkness beyond.But instrumentation itself can be noisy, they thought, since all machinery vibrates, gives off heat, or otherwise creates signals just by existing and doing its job. So Penzias and Wilson cooled their receiver with liquid hydrogen to soothe away these signals, yet their hum persisted.Finally, acknowledging even more worldly flaws, they took a look at the radio antenna itself. Unlike telescopes that look at optical light, using mirrors carefully shielded from the elements and kept free of any imperfections, radio telescopes are usually robust instruments kept out in the open.In the case of the Holmdel Horn Antenna, a group of pigeons had taken to roosting in and around the instrument. Apparently lacking graduate students or other lackeys, Penzias and Wilson rolled up their sleeves and applied their expertise to rooting out pigeons. The metal cage they used to trap the winged trespassers is now in residency at the National Air and Space Museum . Once the pigeons were ousted, the researchers had to remove their nests and droppings, which certainly muddied the look of the experiment.It’s easy to imagine their frustration when they saw the signal still humming along in their observations. Perhaps they threw something, and then poured a stiff drink. The official record doesn’t specify, so imagine what you like.