Every once in a while, a clever screenwriter reminds us that when we peer up at some distant star or planet, we are actually looking into the past because the light thrown off by the celestial body takes so long to travel to us here on Earth.
On public-television stations around the country tonight, would-be astronomers and insomniacs alike can spend the wee hours looking at close-up photographs of Neptune's recent past as Voyager 2 zips past the planet and its moons at 38,000 m.p.h., snapping pictures like a shutter-happy tourist.
Traveling at the speed of light, the signals that make up those photographs will take four hours and six minutes to traverse the 2.7 billion miles separating Neptune and Earth. And just as soon as the signals are received by the National Aeronautics and Space Administration's deep space tracking antennas in California, Spain and Australia and then turned into photographs by scientists at the Jet Propulsion Laboratory in Pasadena, viewers will be able to see them on their television screens.
The cosmic slide show begins at 11:30 p.m. on KCET Channel 28, at 11 p.m. on KVCR Channel 24 and at 12:25 a.m. on KPBS Channel 15, and will continue until at least 4 a.m. Friday. Anyone willing to stay up will get the first look at these pictures from deep space just hours after the 1-ton Voyager spacecraft makes its closest pass over the clouds of Neptune, turns 45 degrees with the help of the planet's gravity and then flies past Neptune's quirky moon, Triton. Voyager is scheduled to buzz within 3,000 miles of Neptune's wispy cloud tops tonight at 9.
Reports on Voyager's close encounter with Neptune, the pale-blue eighth planet from the sun that was discovered in 1846, will also be carried throughout the night on Cable News Network and C-SPAN. CNN will have extended live coverage of the mission beginning at 1 a.m.
During its 4.4-billion mile, circuitous journey through the solar system, Voyager 2 has already photographed Jupiter, Saturn and Uranus. Tonight's meeting with Neptune, which is four times the size of Earth, will be Voyager's final visit to a planetary system before it darts off into the infinity of space. Scientists hope that Voyager will provide the first direct measurements of the environment outside the solar system sometime in the next century.
PBS' "Neptune All Night" will feature 20-minute updates each hour from NASA and JPL scientists as they examine and interpret the most recent photographs. The remaining 40 minutes each hour will originate live from WHYY-TV in Philadelphia and will include a panel of experts on the East Coast and at JPL analyzing the new data, live viewer calls on a nationwide toll-free hot line, reaction to the Neptune voyage from science-fiction writers and celebrities, a recap of Voyager's previous planetary encounters and a frivolous look at space travel in movies and science-fiction literature.
"We are staying on the air all night to present this program because there really has been a rebirth in public interest in the space program," said Don Leifer, program director at KVCR in San Bernardino. "We literally had a block party on my street with all the people watching the lunar eclipse (last week). This show is a once-in-a-lifetime kind of thing. It's the first time anyone will have seen such close-up pictures of Neptune, and we felt this falls exactly into where public television should go."
Earlier this week, Edward Stone, Voyager's chief project scientist, called the meeting with Neptune "the final movement in the Voyager symphony of the outer planets, and like a symphony, its tempo is accelerating as it nears the end."
Already Voyager has discovered four previously unknown Neptunian moons, a complete ring and several partial rings circling the planet, a huge storm system the size of the Earth that may pack winds up to 400 m.p.h. and a strong magnetic field. JPL scientists expect further discoveries today as the spacecraft sails through the upper reaches of Neptune's atmosphere and then within 2,500 miles of Triton, the moon that revolves the "wrong" way and appears to have a transparent atmosphere and a pinkish, iced surface.
"It may snow from time to time in places, there may be heavy frost laid down," astronomer Bradford Smith said of the eccentric satellite. "What we would really like to do is to get some idea of what Triton's geological history has been. It's a strange satellite, it's in the wrong orbit, it's going backward around Neptune, and something truly catastrophic must have happened at some time in its past."
Voyager's snapshots of Neptune can also be seen on the NASA-Select satellite feed by anyone with their own satellite dish, on some cable-access channels and at various locations around the Southland. The NASA-Select feed will contain fresh images from space as well as NASA and JPL press conferences and discussions of the mission and the spacecraft's discoveries. The NASA feed will begin at 9 a.m. today and continue through the night, and also will be broadcast from 9 a.m. to 11 p.m. every day through Tuesday.
The NASA-Select feed can be seen at the California Museum of Science and Industry, the Griffith Park Observatory, Reuben H. Fleet Space Theater in San Diego, the Santa Barbara Museum of Natural History, Cal State Long Beach, El Camino College, San Diego State, Santa Monica College, UCLA, USC, Ambassador College, Southwestern College and on some cable systems. Interested viewers should call their cable operators for details.
The Learning Channel will also offer a one-hour progress report on Voyager today at 5 p.m. CNN will air a special report, "Voyager: Rendezvous With Neptune," Saturday at 5 a.m. And TBS will carry its own special on Voyager at 7 p.m. Sunday, hosted by Carl Sagan and Sidney Poitier.