This is from a post I originally published in 2010. I’ll keep trotting it out until it’s not cool anymore. (Which I don’t think will ever happen.)
On February 14, 1990, after nearly 13 years of traveling the solar system, the Voyager 1 spacecraft passed the orbit of Pluto and turned its camera around to take a series of photos of the planets. The image above shows those photos, isolated from the original series and are left to right, top to bottom: Venus, Earth, Jupiter, Saturn, Uranus, and Neptune.
From that distance, over 4 billion miles from the Sun, the planets each appear as little more than a bright dot against the vastness of interplanetary space. And Voyager was still a long ways off from reaching the “edge” of our solar system, the bubble of energy emitted by the Sun in which all of the planets, moons, and asteroids reside. In fact, Voyager 1 still has an expected five years to go before it crosses that boundary and truly enters interstellar space.*
“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. … There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”
– Carl Sagan
It was the unique perspective above provided by Voyager 1 that inspired Carl Sagan to first coin the phrase “pale blue dot” in reference to our planet and in the title of his book. And it’s true…from the outer solar system, Earth is just a pale blue dot in the black sky, just another light in the dark. It’s a sobering and chilling portrait of our world…but inspiring too, as the Voyager 1 and 2 spacecrafts are the furthest human-made objects in existence. And getting further every second. They are still transmitting data back to us, although faintly, as they are very far now…almost 10 billion miles away.*
And who says long-distance relationships can’t work? 😉
Although Voyager 1 no longer has the power or software on board to take any more images of the planets, in February 2013 it was spotted from Earth by the National Radio Astronomy Observatory’s 5,000-mile-wide Very Long Baseline Array (VLBA), a telescope network that stretches from Hawaii to St. Croix. Here’s what Voyager 1 looked like in radio wavelengths:
Voyager 1’s main transmitter radiates around 22 watts, which is comparable to a typical ham radio or a refrigerator light bulb. Though incredibly weak by the standards of modern wireless communications, Voyager 1’s signal is bright when compared to most natural objects studied by radio telescopes.
*Update 14 Feb. 2014: Voyager 1 is currently 19,030,746,000 km (11,825,157,331 miles) away from us…that’s over 126 times the distance between the Sun and Earth. It’s now passed beyond the heliosphere, the “bubble” of charged particles flowing outward from the Sun, and is traveling into the exotic realm of interstellar space. Launched in 1977, Voyager 1 is the most distant human-made object in existence.