01.15.09
Searching for Other Worlds (in 1996)
While I was home over Christmas, my mom asked me to throw out some of the magazines that had piled up in my room over the years. One of those was TIME’s February 1996 cover, “Searching for Other Worlds“. Given the imminent launch of NASA’s Kepler Telescope, it was much more timely than the other headline on the cover: “Dole Drops, Clinton Rises“.
The article is a fascinating read now, almost 13 years after it was written. It’s easy to make long-term predictions, knowing that you’ll probably never get called on them. But after 13 years, I can call every single one of the bold predictions in this article. None of them have panned out.
Here are the highlights:
Everyone wants to be the next to find a distant world. The scientists are eagerly awaiting the results from the Infrared Space Observatory (ISO), a newly orbiting European satellite that can detect the faint heat from distant planets. They’re looking forward to the 1997 installation of a new infrared camera on the Hubble Space Telescope, which could take a picture of at least one of the newly discovered worlds.
The ISO was launched successfully, but it certainly did not detect planets. In fact, it’s not even clear to me that this was ever an explicit goal. It did detect dust rings around stars, and was decommissioned on schedule after just over two years of service.
The infrared camera on the Hubble is referring to NICMOS, the “Near Infrared Camera and Multi-Object Spectrometer”. It’s hard to find much information about this on the web. Here are a few images from NICMOS. They’re pretty, but planets they ain’t.
It’s not clear to me that planet-detection was a goal of NICMOS either. The TIME writer may have been prone to exaggeration.
Most promising of all, they’re buoyed by a newly unveiled NASA initiative, known as the Origins project, that will build a generation of space telescopes to search for new worlds. Says NASA administrator Daniel Goldin: “We are restructuring the agency to focus on our customer, the American people.” And the public excitement about this field, he says, “is beyond belief.
Ah, the Origins project. It’s still on-going, and is going to have its first major launch with Kepler in March. Goldin became the longest-ever serving NASA administrator before leaving in 2001.
More than one astronomical discovery has disappeared on a closer look, though, so Marcy and Butler headed for the telescope, determined either to debunk or verify the Swiss team’s claims. Sure enough, says Marcy, after four nights at Lick and many hours of computer time, “everything they’d said about the planet was confirmed.” (Butler and Marcy did, however, show that hints the Swiss team had found a second planet around the same star [51 Pegasi] were mistaken.)
After two months, they had analyzed 60 of the 120 stars in their survey. On the morning of Dec. 30, Butler went to the office to check on the computer’s progress. “When I saw the data come up, I was completely blown away,” he says. It was the telltale signature of the object orbiting around 70 Virginis. Recalls Butler: “It knocked me off the chair.”
Geoffrey Marcy went on to discover 70 of the first 100 extrasolar planets and the first transiting exoplanet. Paul Butler is a co-discoverer of approximately 2/3 of the known exoplanets.
… Such a gigantic scope is utterly beyond current technology, and beyond anything engineers can imagine for the next century as well. But astronomers know they can simulate a huge telescope by orbiting several smaller ones, widely separated, and combining their light electronically. This multimirror device is known as an interferometer, because rather than gathering light directly, it measures interference patterns created when light waves from several mirrors overlap each other.
Unlike traditional NASA projects, which tend to be expensive and complex, this one is relatively modest. “We really don’t want to start out building the Battlestar Galactica,” says Weiler. Instead he will start with a demonstration model by the turn of the century, a device consisting of four to six mirrors a foot or two across. Even at that size, the interim interferometer should be able to spot objects the size of Neptune around nearby stars.
That must be referring to the Space Interferometry Mission (SIM). Its launch date has been pushed back five times thus far and has had its budget almost entirely slashed. Wikipedia says it will be launched “no sooner than 2015″. The scientists involved in the project have regrouped and created SIM lite, which aims to accomplish most of the science goals of the original SIM at reduced cost. Their site is careful not to speculate about any launch dates.
Finally, by about 2010, NASA hopes to launch what it calls the Planet Finder: an interferometer with five 3-ft.-to-6-ft. mirrors spread over 300 ft., orbiting out by Jupiter, where the solar-system dust begins to thin out. The Planet Finder should allow scientists to identify Earthlike planets, which should show up as pale blue dots in images beamed back to ground controllers, and analyze their atmosphere for signatures of life like ozone, oxygen or carbon dioxide.
This is referring to the Terrestrial Planet Finder (TPF), which has been abandoned entirely. It’s too bad. The knowledge we’d glean from this is much more interesting than whatever it is we’re learning on the International Space Station.
The astronomers who are looking for planets, meanwhile, are sounding downright cocky. Butler says that he and Marcy are “close, real close” to finishing the analysis of their remaining 60 stars and that they would not be surprised to find two or more additional planets popping out of the data–perhaps in a matter of weeks. The pair will soon be heading for the Keck Telescope in Hawaii, the world’s largest, to continue the search with even more powerful equipment. Mayor and Queloz, meanwhile, are back at their telescope in Europe. At the same time, dozens of other groups, using instruments ranging from the high-flying Hubble to relatively small scopes, are stepping up their activities. Predicts Marcy: “We are going to find, between us and the Swiss, 10 more planets in the next two years.” Concurs Butler: “Very shortly, there could be more planets known outside the solar system than inside.” Whether or not they are right, the human race has already moved closer to answering the most enduring question about its true place in the cosmos.
There were six planets discovered in 1996 and one more in 1997. So they weren’t off by much. The count currently stands at 335.
A few lessons to take from this experience:
- Reporters tend to exaggerate.
- When a government official makes bold predictions about a 10-15 year program, don’t believe him.
- Don’t bet on space-based astronomy. Almost all of those 335 planets were discovered from the ground.
- Interests shift over time. Everyone in this article is interested in pictures of planets. Now we’re more interested in simpler goals, like transits.