Looking for another blue dot: scientists are building a telescope to seek second Earth, with crowdfunding
On Valentine’s Day 1990, from a dark and frozen spot on the outer edges of our solar system, the spacecraft Voyager 1 turned around to take one last photo of the world it left behind.
Viewed from a distance of 6 billion kilometres, Earth was little more than a bluish pixel, a “mote of dust suspended in a sunbeam,” in the words of Carl Sagan. Although the space programme has produced countless gorgeous photographs of our planet - exquisite images of deep blue oceans and swirling clouds, of the incandescent spider web that is human civilisation at night - nothing else has captured so starkly the profound loneliness of this precious, pale blue dot we call home.
Now scientists want to find a companion for that dot.
On Tuesday, a consortium of private research institutions launched a crowdfunding campaign to help build a new space telescope capable of searching for and photographing planets in the star system Alpha Centauri - which holds the closest stars to our sun. They call the mission “Project Blue.”
“We are seeking to take another pale blue-dot image,” said Jon Morse, former director of NASA’s astrophysics division and current chief executive of the BoldlyGo Institute, a research organization that is co-leading Project Blue. “This is the holy grail of exoplanet research.”
Before December 20, Morse and his partner Brett Marty, executive director of the nonprofit Mission Centaur, aim to raise US$1 million via Kickstarter - enough seed funding to get their project going. The rest of their budget will likely come from foundations and wealthy donors. The telescope, which they hope to launch into low Earth orbit in 2019, would only be about the size of a dishwasher; its half-metre main mirror could fit on a coffee table.
Because their hardware is small and relatively modest in scope, Morse and Marty believe they can achieve their entire mission for US$50 million or less.
The project is the kind of high-risk, high-reward mission that NASA is typically unwilling to pursue. Focusing solely on Alpha Centauri will keep costs low, but there’s no guarantee that the system contains planets, let alone rocky bodies in the habitable zone.
But just this August, astronomers announced that they’d found a small, rocky planet orbiting in the habitable zone of Proxima Centauri, a star in the Alpha Centauri system that is 4.22 light years away.
The Project Blue telescope wouldn’t be able to image the new planet, dubbed Proxima b. It is too close to its star, making it impossible to distinguish the planet’s faint glow from the brilliant blaze of its sun. Besides which, Proxima b is an unlikely candidate for “Earth 2.0.” It orbits its star every 11 days and is likely tidally locked, meaning that one half constantly faces the sun while the other is cloaked in endless night.
But the discovery of Proxima b makes Marty even more optimistic that more terrestrial planets could orbit Alpha Centauri A and B - the two other stars that make up that system. He noted that our own solar system has three rocky planets in the habitable zone of a single star.
“It’s an old saying that if you can do it once, you can do it more than once,” he said. “Where there’s one there’s usually others because the process for forming these planets is common.”