Astronomers have discovered thousands of planets orbiting stars other than the Sun.
They come in all sizes,
at different orbital distances from their stars.
The closest of them are trillions of miles away,
and even the largest are just fuzzy patches
in the fields of high-powered telescopes.
But if one of these planets is close in size to the Earth
and orbits not too close and too far away from its parent star,
it could be rocky and warm enough to have oceans
and perhaps life.
Astronomers discover these potentially habitable planets,
and their eyes get big and wide.
Could one of these distant worlds carry the building blocks of life?
Or even a living, breathing, civilization?
Is the question, "Are we alone in the universe?" about to be answered?
But wait.
Maybe we should ask a different question first.
Should we try to find out if we're alone in the universe?
If we do find the atmospheric fingerprints of life
on one of these small, distant worlds,
should we try to contact any beings who may live there?
Is that wise?
Three decades ago, NASA decided the answer was yes.
Voyager 1 and 2 were launched in 1977
to explore the giant planets in the solar system.
Each spacecraft carried a golden phonograph record,
a time capsule of sorts that included clues and messages
meant to convey the story of human civilization.
The contents of these gold-plated copper disks were chosen by a committee
chaired by American astronomer and author Carl Sagan.
They included over 100 images,
and a range of sounds from the natural world:
ocean waves,
thunder,
the sounds of birds
and whales.
The records also included music from many different time periods and cultures,
greetings in 55 languages,
and messages from the President of the United States,
and the UN Secretary General.
They also included a map.
Each golden record displays the location of our solar system
with respect to fourteen pulsars.
Their precise, unique frequencies were indicated
so that intelligent, extraterrestrial lifeforms
could use them to find the Earth.
Many years later, renowned physicist Stephen Hawking said
that it was a mistake to give an alien species a roadmap to our planet.
Hawking suspected that any extraterrestrial life
probably wasn't any more complex than microbes,
but he warned that if an advanced alien species did visit Earth,
it could be as catastrophic as Christopher Columbus's arrival was
for the Native Americans.
Meanwhile, the golden records continue their journeys.
In 1990, both Voyager spacecraft passed beyond the orbit of Pluto.
Voyager 1 entered interstellar space in 2012,
and will reach the nearest stellar system in 40,000 years.
If either spacecraft is discovered by extraterrestrial life,
there's a possibility that they could decipher the clues from the golden record
and one day reach our planet.
That's particularly true
if theirs is a much more technologically advanced civilization.
That life could be benevolent,
as we would hope to be if humans are one day able to achieve interstellar travel.
Or it could be hostile.
Searching for planets that might have life means staring into a great abyss.
We'll likely have no clear knowledge of the evolutionary stage,
sentience,
character,
or intentions of the first form of life we discover.
So it's a risk to turn our eyes outwards.
We risk our very way of life.
But it may be a greater risk not to look,
to deny the very pioneering spirits that help shape our own species.
We are all born curious about the world and the universe.
Pursuing that curiosity is one of humankind's greatest achievements.
Perhaps there is room to push the frontiers of science,
provided that we cradle alongside our fervor
another of humankind's greatest assets:
hope.