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The journey of the Nasa's voyagers

Dennis Overbye remembers the scientific breakthrough that Nasa's voyagers have stood for


Nasa Voyagers
Nasa Voyagers

In the shadow, one might say, of the Great American Eclipse, a major anniversary in the history of exploration — and indeed cosmic consciousness — is being celebrated. It was 40 years ago, on August 20 and September 5, 1977, that a pair of robots named Voyager were dispatched to explore the outer solar system and the vast darkness beyond.

What resulted was nothing less than a reimagining of what a world might be and what strange cribs of geology and chemistry might give rise to life in some form or other.

It was a real-life Star Trek adventure, but the crew stayed home, communicating with their two spacecraft through a million-mile bucket brigade of data bits.

New computer programs went one way, and data — including scratchy photos of new landscapes and the whispering moans of interplanetary plasma fields — came back the other way. All of it was being carried out by a robot brain with the memory capacity of an old-fashioned digital watch.

The spacecraft had been designed to make what scientists called the Grand Tour, taking advantage of a once-every-175-year planetary alignment. Voyager 1 and Voyager 2 were to use the gravity of the outer planets to slingshot from Jupiter to Saturn, and to Uranus and Neptune, and then beyond the edge of the sun’s domain into interstellar

In the end, only half the tour — to Jupiter and Saturn — was actually approved. But the Voyager crew packed for a much longer journey. When they lifted off 40 years ago, the two spacecraft carried golden records inscribed with pictures and sounds from Earth, greetings from President Jimmy Carter and instructions on how to play it all.

The Voyagers would observe the universe, and give something back to whoever might one day find them.

The robot emissaries cruised the solar system through presidential administrations, wars and scandals, and the Challenger disaster, which happened as Voyager 2 was pulling away from Uranus.

At every planetfall, the crew members, a little older and a little grayer each time, reconvened at the Jet Propulsion Laboratory in Pasadena, Calif., for a weeklong marathon of discovery, a circus of science on the fly.

With imagery returned by probes, what had been fuzzy dots in the world’s biggest telescopes bloomed into worlds.

Back on Earth, some theoreticians claimed to be homing in on a putative theory of everything, an Einsteinian dream of an equation simple enough to be inscribed on a T-shirt. But in space, scientists were finding that such theories were no help against nature’s endless capacity to invent and surprise. Each new world revealed by the Voyagers was a head-scratcher.

Once upon a time, it was presumed that the moons of the outer planets, so far from the sun and so close to the origins of the solar system, would be boring ice balls, geologically and in every other way dead.

But then Voyager 2 spotted volcanoes spraying fountains of sulfur from the surface of Jupiter’s innermost moon, Io. On close inspection, Saturn’s rings — the jewels of the solar system — dissolved into 10,000 grooves, like a vinyl record’s, braided, kinked and patrolled by tiny moonlets.

Voyager 1 plumbed a fat, smoggy atmosphere of Titan, where nitrogen and methane rains fall on a frozen slush pile of hydrocarbons and oily lakes, and then headed off toward interstellar

Voyager 2 cruised on to Uranus, mysteriously tipped on its axis and surrounded by rings that make it look like a bull’s eye. The probe passed the restful methane blue of Neptune, besmirched by a dark spot, and its moon Triton, an ice rock flowing like soft ice cream with geysering nitrogen.

I’ve never had more fun as a science writer than during those weeklong encounters in Pasadena, when my colleagues and I — a little older and grayer ourselves, humbler but no wiser about the tricks that nature might be up to out there in the realm of dark and ice — gathered to watch the scientists watch their new worlds.

The television screens in the press room showed the latest images as they came in from the Voyager spacecraft. We had the same view as the scientists.
© 2017 The New York Times

First Published: Fri, August 25 2017. 22:04 IST