Science

A global selfie

Earth photographed by Voyager 1 spacecraft from a distance of 6 billion kilometers. Earth is the tiny bright dot in the center of the circle. The vertical streaks are sunlight scattering off Voyager’s camera.

Earth photographed by Voyager 1 spacecraft from a distance of 6 billion kilometers. Earth is the tiny bright dot in the center of the circle. The vertical streaks are sunlight scattering off Voyager’s camera.   | Photo Credit: NASA

On February 14, 1990, the camera on-board Voyager I clicked a photo of planet Earth that depicted our home as a ‘pale blue dot’

On this day, exactly 30 years ago, a photograph clicked from the cold distant reaches of space changed forever the way we humans looked at ourselves and our true place in the universe.

In 1977, the American space agency launched the twin robotic spacecraft Voyager 1 and 2. Their combined mission was to explore the outer planets of the solar system – Jupiter, Saturn, Uranus and Neptune.

Voyagers were unmanned fly-by missions, destined to never return back to Earth. The spacecrafts were programmed to fly past the outer planets of the solar system and their myriad moons, gather as much data as they can, beam it back to Earth, and continue their one-way voyage into whatever lay beyond.

The twin missions gave many startling insights on the giant planets and their tiny moons. At the completion of its 13-year expedition, Voyager 1 was beckoned to do something incredible. On February 14, 1990, the camera on-board the spacecraft was oriented to look back into the solar system to take a series of photographs of the Sun and the planets. Voyager by then had cruised to the fringes of the solar system, to a distance of more than 6,000,000,000 km from us. From those far reaches, Voyager’s camera snapped several images.

One of those photographs had Earth in it, visible as a tiny bright pixel set against the vast emptiness of outer space. The photograph gathered instant fame for the stark reality it conveyed – that the universe is truly large, and we, truly small. Described as Voyager’s greatest gift to human kind, it was the last that the spacecraft “saw” before its cameras went into perpetual hibernation.

In his 1994 best-selling book Pale Blue Dot: A Vision of the Human Future in Space, the late astronomer Carl Sagan wrote these poignant words, as a slogan to that photograph.

Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species lived there - on a mote of dust suspended in a sunbeam.”

In my opinion this is one of the most incredible things we have done as a species. We sent a probe on an endless journey into outer space, made it look back at us for one last time from a distance farther than ever before, and snapped a selfie that includes all of us. The pale blue dot image is a powerful reminder that the universe isn’t about us or the deeply polarised worlds we weave around us.

Voyagers are continuing their journey, with the heat generated from radioactive material on-board meeting the basic power requirements. Currently the spacecrafts are at a distance of 18 billion kilometers from us, the farthest that any human made object has ever reached.

In an act of far-fetched imagination, a team chaired by Carl Sagan, placed a golden phonograph record on the Voyager. Named the ‘Murmurs of Earth’, the record contains sights, sounds, and music from all over Earth. Like the proverbial “message in a bottle” flung into the cosmic ocean – to borrow Carl Sagan’s words - the phonograph record was put in with the hope that perhaps in the far distant future the spacecraft will be picked up by some intelligent being elsewhere in the universe with a destiny similar to ours – to observe, explore and understand the cosmos and our true place in it.

(Anand Narayanan is an astrophysicist with the Indian Institute of Space Science & Technology in Thiruvananthapuram)

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Printable version | Feb 17, 2020 7:16:18 AM | https://www.thehindu.com/sci-tech/science/a-global-selfie/article30808013.ece

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