Wish I May, Wish I Might
One day many years ago in a valley not far away, Geoff Marcy’s parents gave him a used 4-inch telescope. At night he would unlatch his bedroom screen and climb onto the patio roof with his new toy. There, for countless hours, the boy toured the solar system and Milky Way. Marcy recalls feeling very small but strangely connected to something much larger and grander as he studied Saturn’s rings, monitored the movements of Jupiter’s moons and wondered whether anyone or anything was out there looking back at Granada Hills.
Marcy grew up and defected to Northern California, to a planet called Berkeley. He’s taller now but still feels small as he scans the skies with UC Berkeley computers, $5-million spectrometers and telescopes with 33-foot mirrors. Marcy leads one of several global teams quietly collecting intriguing evidence of earthlike planets orbiting stars. While we obsess about really important things such as budgets, secession and soccer and a few things of somewhat less galactic import like songs and thongs, these isolated bands of men and women spend their nights atop mountains imagining what might be in places far away.
Because their work does not involve blowing anything up, these astronomers get little attention. Until the other day, when they announced the discovery of a solar system, 55 Cancri, with planets possibly positioned like ours. This could create the conditions for evolutionary life “just” 41 light-years away.
It took years to find the first such planet. Now, seven years later, Marcy and others have plotted more than 90 planets orbiting stars like our sun; most are like Goldilocks’ porridge--too hot, too cold or too hot and then too cold. Because the host stars are so bright, Marcy doesn’t actually see these planets; that awaits a new generation of telescopes. He can, however, infer a planet’s presence by the minute wobble of its star, as the unseen planet’s gravity tugs during orbits. Big tugs equal big planets. Star movements appear as shifting colors in a spectrum as starlight passes through telescopes.
If you think your house is big or your commute long, here on this summer solstice weekend are some numbers the 47-year-old Marcy confronts daily: In 15 years, they’ve examined 1,200 nearby stars. In our Milky Way, there are about 200 billion stars like our sun. Probably half of those stars harbor orbiting planets. And there are an estimated hundreds of billions of other galaxies like ours. Today’s rockets travel 20,000 miles an hour. But light travels 186,000 miles a second. Which means the telltale wobbling starlight recently transiting Marcy’s huge telescope left 55 Cancri right about the time the young boy with the little telescope was peering up from that patio roof in Granada Hills.
