By Ken Croswell
A glimpse of our solar system’s future has appeared thousands of light-years away in the constellation Sagittarius. There a giant planet like Jupiter orbits a white dwarf, a dim, dense star that once resembled the sun.
In 2010, that star passed in front of a much more distant star. Like a magnifying glass, the white dwarf’s gravity bent the more distant star’s light rays so that they converged on Earth and made the distant star look hundreds of times brighter. A giant planet orbiting the white dwarf star also “microlensed” the distant star’s light, revealing the planet’s presence.
In 2015, 2016 and again in 2018 astrophysicist Joshua Blackman of the University of Tasmania in Hobart, Australia and colleagues pointed the Keck II telescope in Hawaii at the far-off system, which lies some 5,000 to 8,000 light-years from Earth. The team was in search of the giant planet’s star, but saw, well, nothing.
“We expected that we’d see a star similar to the sun,” Blackman says. “And so we spent quite a few years trying to figure out why on Earth we didn’t see the star which we expected to see.”