Skip to main content

If 'E.T.' finds Voyager 1, will it phone Earth?

By Meg Urry, Special to CNN
September 23, 2013 -- Updated 1753 GMT (0153 HKT)
As NASA scientists report that Voyager 1 has left the solar system, take a look at some of the amazing images the probe has provided its earthbound audience. As NASA scientists report that Voyager 1 has left the solar system, take a look at some of the amazing images the probe has provided its earthbound audience.
HIDE CAPTION
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
What Voyager saw
<<
<
1
2
3
4
5
6
7
8
9
10
11
12
13
14
>
>>
STORY HIGHLIGHTS
  • NASA's Voyager 1 spacecraft left the solar system and entered interstellar space
  • Meg Urry: Voyager's achievement is a major milestone in human exploration
  • She says the mission, launched 36 years ago, will go forth unimpeded for millenniums
  • Urry: There are no expectations that it will encounter other civilizations, but possibility exists

Editor's note: Meg Urry is the Israel Munson professor of physics and astronomy at Yale University and director of the Yale Center for Astronomy and Astrophysics.

(CNN) -- In 1519, Portuguese explorer Ferdinand Magellan launched the expedition that completed the first circumnavigation of the globe. And so humanity learned the full extent of its world.

This week, we learned from Science magazine that NASA's Voyager 1 spacecraft -- currently the man-made object farthest from Earth -- crossed a boundary of the solar system and entered interstellar space sometime last summer.

Like Magellan's voyage, Voyager's achievement is a major milestone in human exploration. In a remarkably short time by cosmic standards (the universe being 13.7 billion years old), humans have evolved to the point of sending robotic diplomatic missions to other planets and stars.

This particular emissary from the human race carries a recording of greetings in 55 languages as well as images explaining who we are. Although the Voyager scientists had no particular expectation of encountering other civilizations, they knew the mission would go forth unimpeded for millenniums. So they prepared a message for any distant future being who might stumble across this man-made artifact.

Meg Urry
Meg Urry

If "E.T." finds Voyager 1, will it phone home? We know that planets around other stars ("exoplanets") are abundant, and that when liquid water and carbon-based compounds and an energy source are present even in the most inhospitable zones on the Earth, life arises easily. But the kind of intelligent life that can build and launch a pioneering spacecraft is surely much more rare. And if someone answers the call, it will be sufficiently far in the future that the Earth-bound world as we know it will have changed beyond recognition.

Unlike missions to nearby Mars or Venus, Voyager 1 and 2 (both spacecraft were launched in 1977) and their older siblings, Pioneer 10 and 11 (launched in 1972 and 1973, respectively) headed for outer space from the beginning. They visited Jupiter, Saturn, Uranus and Neptune, taking photographs of unprecedented clarity and making complex measurements of the particles and magnetic fields around the planets.

Voyager 1 is the fastest-moving and most distant of the four spacecraft. Data collected by its remaining instruments have been interpreted by scientists as indicating a crossing of the boundary between our solar system and interstellar ("between the stars") space. It's not a sharp boundary, and there are definitely no signposts, so there has been some debate about the exact moment of transition.

NASA: Voyager 1 has left solar system
Where no man-made object has gone before

In fact, the exact date doesn't matter. Whether it was July 2012 or August 2012 or even months earlier or later, humans have unquestionably projected their presence well beyond any previous location.

It's a bit different from Magellan's voyage, however. In those ancient days, travel was the only way to investigate the world. Today we survey our world -- and a large fraction of the observable universe -- using powerful telescopes, on the ground and in space.

Very deep exposures taken with the Hubble Space Telescope have revealed that the Milky Way galaxy is but one of a trillion galaxies in the observable universe.

There are hundreds of billions of stars in the Milky Way galaxy alone, each of which could have a system of planets orbiting around it. Some of these are likely to harbor life, albeit of a primitive form.

In terms of knowing our 21st-century world, NASA's robotic scientific satellites have made huge advances. And from the ground, telescopes study exoplanets and the SETI Institute searches for extraterrestrial intelligence using a large radio telescope array in California. In terms of receiving signals, Earth-bound and near-Earth telescopes are unsurpassed.

In terms of outward communication, TV signals created decades ago have long since announced our presence -- in fact, because such signals travel at the speed of light, they left the solar system only days after the initial broadcast.

But in terms of pieces of metal human hands have touched, Voyager 1 is unique. Now some 36 years and a few days after it was launched into space, more than 11 billion miles from the sun, traveling at 38,000 mph, Voyager 1 will doubtless travel onward for tens of thousands of years to come.

Its power source won't last nearly that long. Voyager 1 has sufficient power for remaining instruments through at least 2020, and if some are turned off to conserve power, a single instrument could last another five years afterward. But then the "little spacecraft that could" will go silent.

Forty thousand years from now, after traversing 10 trillion miles or so of interstellar space, Voyager 1 will approach the then-closest star, AC +79 3888. At that point it will be a ghost ship, representing an old civilization, gone but enshrined forever in the golden record.

As John Grunsfeld, NASA's associate administrator for science in Washington, said, "Perhaps some future deep space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their journey."

Follow us on Twitter @CNNOpinion.

Join us on Facebook/CNNOpinion.

The opinions expressed in this commentary are solely those of Meg Urry.

ADVERTISEMENT
Part of complete coverage on
July 29, 2014 -- Updated 1650 GMT (0050 HKT)
LZ Granderson says the cyber-standing ovation given to Robyn Lawley, an Australian plus-size model who posted unretouched photos, shows how crazy Americans' notions of beauty have become
July 28, 2014 -- Updated 1156 GMT (1956 HKT)
A crisis like the Gaza conflict or the surge of immigrants can be an opportunity for a lame duck president, writes Julian Zelizer
July 26, 2014 -- Updated 1822 GMT (0222 HKT)
Carol Costello says the league's light punishment sent the message that it didn't consider domestic violence a serious offense
July 28, 2014 -- Updated 1251 GMT (2051 HKT)
Danny Cevallos says saggy pants aren't the kind of fashion statement protected by the First Amendment.
July 28, 2014 -- Updated 1852 GMT (0252 HKT)
Margaret Hoover says some GOP legislators support a state's right to allow same-sex marriage and the right of churches, synagogues and mosques not to perform the sacrament
July 28, 2014 -- Updated 1831 GMT (0231 HKT)
Megan McCracken and Jennifer Moreno say it's unacceptable for states to experiment with new execution procedures without full disclosure
July 28, 2014 -- Updated 1850 GMT (0250 HKT)
Priya Satia says today's drones for bombardment and surveillance have their roots in the deadly history of Western aerial control of the Middle East that began in World War One
July 28, 2014 -- Updated 1635 GMT (0035 HKT)
Jeff Yang says it's great to see the comics make an effort at diversifying the halls of justice
July 26, 2014 -- Updated 1555 GMT (2355 HKT)
Rick Francona says the reported artillery firing from Russian territory is a sign Vladimir Putin has escalated the Ukraine battle
July 27, 2014 -- Updated 1822 GMT (0222 HKT)
Paul Callan says the fact that appeals delay the death penalty doesn't make it an unconstitutional punishment, as one judge ruled
July 24, 2014 -- Updated 2225 GMT (0625 HKT)
Pilot Robert Mark says it's been tough for the airline industry after the plane crashes in Ukraine and Taiwan.
July 25, 2014 -- Updated 1510 GMT (2310 HKT)
Jennifer DeVoe laments efforts to end subsidies that allow working Americans to finally afford health insurance.
July 26, 2014 -- Updated 1533 GMT (2333 HKT)
Ruti Teitel says assigning a costly and humiliating "collective guilt" to Germany after WWI would end up teaching the global community hard lessons about who to blame for war crimes
July 25, 2014 -- Updated 1245 GMT (2045 HKT)
John Sutter responds to criticism of his column on the ethics of eating dog.
July 25, 2014 -- Updated 1302 GMT (2102 HKT)
Frida Ghitis says it's tempting to ignore North Korea's antics as bluster but the cruel regime is dangerous.
July 25, 2014 -- Updated 1850 GMT (0250 HKT)
To the question "Is Putin evil?" Alexander Motyl says he is evil enough for condemnation by people of good will.
July 24, 2014 -- Updated 1803 GMT (0203 HKT)
Laurie Garrett: Poor governance, ignorance, hysteria worsen the Ebola epidemic in Sierra Leone, Guinea, Liberia.
July 24, 2014 -- Updated 1349 GMT (2149 HKT)
Patrick Cronin and Kelley Sayler say the world is seeing nonstate groups such as Ukraine's rebels wielding more power to do harm than ever before
July 23, 2014 -- Updated 2205 GMT (0605 HKT)
Ukraine ambassador Olexander Motsyk places blame for the MH17 tragedy squarely at the door of Russia
July 24, 2014 -- Updated 1142 GMT (1942 HKT)
Mark Kramer says Russia and its proxies have a history of shooting down civilian aircraft, often with few repercussions
July 24, 2014 -- Updated 1853 GMT (0253 HKT)
Les Abend says, with rockets flying over Tel Aviv and missiles shooting down MH17 over Ukraine, a commercial pilot's pre-flight checklist just got much more complicated
July 24, 2014 -- Updated 1317 GMT (2117 HKT)
Mark Kramer says Russia and its proxies have a history of shooting down civilian aircraft, often with few repercussions
July 24, 2014 -- Updated 1637 GMT (0037 HKT)
Gerard Jacobs says grieving families and nations need the comfort of traditional rituals to honor the remains of loved ones, particularly in a mass disaster
July 24, 2014 -- Updated 1413 GMT (2213 HKT)
The idea is difficult to stomach, but John Sutter writes that eating dog is morally equivalent to eating pig, another intelligent animal. If Americans oppose it, they should question their own eating habits as well.
July 23, 2014 -- Updated 1630 GMT (0030 HKT)
Bill van Esveld says under the laws of war, civilians who do not join in the fight are always to be protected. An International Criminal Court could rule on whether Israeli airstrikes and Hamas rocketing are war crimes.
July 23, 2014 -- Updated 1408 GMT (2208 HKT)
Gordon Brown says the kidnapped Nigerian girls have been in captivity for 100 days, but the world has not forgotten them.
ADVERTISEMENT