Terrascope: Scientist Proposes Using Earth As a Massive Space Telescope

A scientist from Columbia University has put forward a proposal to turn Earth into a giant telescope, using the planet's atmosphere to bend light and peer deep into the cosmos.

Astronomer David Kipping says a three-foot-wide telescope placed in an orbit about 220,000 miles from Earth could have the same capabilities as a 500-foot telescope on the planet's surface—and at a fraction of the cost.

In a video posted to the YouTube channel Cool Worlds, Kipping goes back 400 years, explaining the advent of telescope technology, and how this moved on to what we have today—multi-billion-dollar machines that can peer billions of light-years into the universe. However, the technology is stagnating, he says. Sites on Earth are getting crowded and the trend of building bigger and bigger telescopes is becoming unsustainable—something referred to as a "crisis in astronomy."

"Are we approaching a limit?... Are we approaching a stagnation point for telescopes?" he said.

Kipping first started thinking about natural satellites over a decade ago. At Harvard, he heard about a proposed mission—called FOCAL—that would have used our sun as a gravity lens. The mission never came to be, but it got him thinking: "Maybe you could use earth as a refractive lens."

In his new paper, which has been accepted to the Publications of the Astronomical Society of the Pacific, Kipping puts forward a new idea for future telescopes—a "terrascope" positioned at a similar distance that the moon is from Earth.

"The basic idea is that the Earth's atmosphere refracts light by a small amount (about half a degree at sunset, for example) and so light from a distant source will be bent to a focus at a distance of 85 percent the Earth-Moon separation," he told Newsweek in an email.

Diagram showing the terrascope David Kipping/James Tuttle Keane

"The system is really for amplification of distant light rather than magnification (imaging) because of the way the Earth's atmosphere can distort images."

Explaining what you could see with the terrascope, he said: "Very faint things, like distant galaxies or small asteroids, unseeable by other telescopes or brighter things where you need extreme precision e.g. exoplanets for measuring their atmospheres, topography and satellite systems."

There are plenty of limitations to the research—as Kipping acknowledges. The terrascope would only be able to see what was directly behind Earth, while all background sources would also need to be removed, he said, adding these are "valid reasons to have skepticism."

"I'm not going to sit here and tell you this is a silver bullet to astronomy," he said in the video, adding that he hopes it is an "exciting enough concept to deserve attention."

Kipping is now waiting to see how the scientific community reacts to the concept and respond accordingly. "I've got many other projects on the go, some even more ambitious than this so I'm trying to focus on the next challenges now," he added.

earth from space
File photo depicting earth from space. iStock