Unless there’s a planet more advanced existing in the Milky Way using their star as a lensing telescope, odds are that the “terrascope” proposed by Columbia University’s David Kipping, will be the largest in our home galaxy beyond the black-hole Event Horizon Telescope. The terrascope turns Earth into a kind of lens that could filter out light pollution and artificial satellites, and help find the signatures of life on exoplanets.
The “terrascope” works with nature, taking advantage of the physics of light which deflects as it passes through Earth’s atmosphere. “This deflection means that distant light sources of stars and exoplanets beyond the Earth will have their rays converge towards a focus point, and that’s where we place our detector,” says Kipping.
Kipping details his terrascope in a new paper published on the pre-print server arXiv, but he’s also created a 30-minute YouTube presentation.
Rays of light traveling at higher altitudes deflect less, so they would meet further away from Earth. All the different meeting points create a focal line, along which detectors can be placed at the Earth’s Hill sphere,” says Kipping. The Hill sphere is the region where Earth’s gravity is the dominant force, extending to around 1.5 million kilometers away, one hundredth of the distance to the sun.
Kipping says the light rays that would meet there travel no closer than 14 kilometers to Earth’s surface, avoiding buildings, mountains, clouds and most of the degrading effects of the lower atmosphere. Kipping estimates a detector 1 meter in diameter placed there would be the equivalent of a 150-metre class telescope on Earth. That is more than 14 times bigger than the biggest telescope on Earth today, the Gran Telescopio Canarias.
Kipping says the terrascope would cost a fraction of the $10 billion 6.5-meter James Webb Space Telescope
scheduled for a 2020 launch.
The inspiration for Kipping’s terrascope described in the video above derived from the futuristic concept of using the sun as a cosmic telescope to harness its spacetime-warping gravity as a lens to image the surface of exoplanets in astonishing detail
Within just a few years, astronomers may at last find a planet that shows signs of life as we know it, in the form of atmospheric gases that betray signs of biological activity reports Scientific American (SA).
“This would be a transformational event for our civilization” SA reports. “But, what would we do next? How could we explore this alien world? With the current state of our technology, sending a robotic spacecraft to visit a planet that is light-years away is simply not possible. And no telescope in existence or even in the design stage would be capable of imaging such a world except as a pinpoint of light—a single pixel in the most advanced detector, which would give no details at all about what the surface of this exoplanet actually looks like.”
Scientific American calculated that a modest telescope located approximately 50 billion miles from the Sun, at the focus of its lensing effect, could magnify the image of an exoplanet 100 light-years away by a factor of 100 billion –an image a thousand pixels wide. That’s vastly more detailed than pictures of Pluto taken with the Hubble Space Telescope prior to the New Horizons mission—detailed enough to see surface features such as continents, oceans, mountain ranges and deserts.
To get this resolution without the magnifying power of the Sun, SA calculated that you would need a telescope with a diameter of about 75,000 kilometers, or about six times the diameter of the Earth.