A new study suggests that the sun's gravitational field may be used as a giant magnifying glass to monitor distant exoplanets in much greater detail than is currently possible.
Astronomers have discovered more than 5,000 planets orbiting other stars since the first exoplanet was discovered in 1992. However, when astronomers discover a new exoplanet, we learn very little about it: we know it exists and a few characteristics about it, but the rest remains a mystery.
Stanford University astrophysicists have already been working on a new conceptual imaging technique that'd be 1,000 times more accurate than the best imaging technology currently in use to get around telescopes' physical limitations. Scientists could potentially manipulate the warping effect of gravity on space-time, known as lensing, to create imaging far more advanced than any currently available.
Because even the closest exoplanets are tens of light-years away, observing them in detail without gravitational lensing would necessitate an extremely large telescope. According to the researchers, a telescope 20 times wider than Earth would be required to view those worlds in detail.
Even so, the technique described in this study has only been tested in theory so far. According to the scientists, a telescope would have to be 14 times farther away from the sun than the dwarf planet Pluto to be able to use gravitational lensing with the sun. There has never been a human-built spacecraft that has traveled that far.
"This will allow investigation of the detailed dynamics of the planets' atmospheres, as well as the distributions of clouds and surface features, which we have no way to investigate now," Alexander Madurowicz, a Ph.D. student at KIPAC and lead author of the study, said in a statement.
The team believes that using gravitational lensing, they will be able to see surface constructions on these planets with observatories the size of the Hubble Space Telescope.
According to the researchers, the gravitational lensing method described in this study would allow astronomers to reconstruct an image of a planet's surface from a single photograph taken directly at the sun.
A telescope's view of an exoplanet would create a "ring of light" in the sun's gravitational lens using this newly described technique. The light could then be undistorted using a special algorithm developed by the Stanford University team, which "reverses the bending from the gravitational lens, turning the ring back into a round planet," according to the researchers.
The research was inspired by a previous paper published by scientists at NASA's Jet Propulsion Laboratory in California. This work proposes a space-based telescope that would use rockets to scan around light rays from a planet to reconstruct a clear image. The technique, however, would require a significant amount of fuel and time, according to the researchers.
