Atop the Big Island of Hawaii, the observatories of Maunakea preside, an astonishing array of astronomical hardware built on ancient ground.
Long-hardened layers of lava, once spit from a now-dormant volcano, rest beneath the thirteen telescopes.
Far below, the Pacific Ocean looms. The water, breathtaking and scary, is more than two-and-a-half miles down.
But that's hardly a single step measured against the distances of Maunakea's otherworldly targets, so far above.
Those targets, every last one, reside trillions of miles away.
What happens here within the next few years, says astronomer Daniel Huber, “will bring us closer to answering the question—the holy grail question—of whether there is life on other planets.”
For now, however, Huber's team is waiting on TESS—NASA's newest planet-hunting probe, just shot out into space.
Looking at 200,000 of the brightest, closest stars, TESS will discover thousands of exoplanet candidates.
And that’s where the telescopes at Maunakea come in.
“Those candidates need confirmation,” says Huber, an assistant professor at the University of Hawaii's Institute for Astronomy. "TESS is not enough. You need follow-up observations on the ground."
Along with real planets, TESS will find thousands of phantoms—other phenomena masquerading as worlds. Maunakea’s follow-ups will toss the imposters out of the discovery pile.
It’s hard to say how many phantoms will hide in the data. Huber’s guesstimate: “About half might be false positives.”
To detect a world, TESS looks for a “transit,” an eclipse-like event, when a planet passes between a star and the spacecraft.
When that happens, the planet blocks a bit of the star’s light. That dip in the light, minuscule but measurable, might mean a world is there.
Or maybe something else. For instance, stellar pulsations—shifts in a star's brightness, but with no planet nearby—can occur.
“These variations are periodic, and can mimic what a transit looks like,” Huber says.
But Maunakea astronomers can tell the difference between the two; using spectroscopy, they can gauge a planet's gravitational tugs on its star.
“The one undeniable signature that the planet is real,” says Huber. “That is something TESS cannot do.”
Maunakea isn’t alone. Astronomers around the world, using their own instruments, will confirm TESS findings. “The combination of observations from space and from the ground go hand in hand,” says Huber.
The first collection of TESS data will download to Earth within the next several months. Early verifications will soon follow. But going through all the data will take years.
"We're gearing up," says Huber. "There's a lot of excitement in the astronomical community."
Especially about Earth-size planets orbiting in the habitable zone. Among the thousands of discoveries, TESS will likely find a few of those.
Understates Huber: "Confirming those kinds of planets—that's a very high priority."