For the first time that we know, an interstellar visitor has zoomed through our solar system. The small space rock, tentatively called A/2017 U1, is about a quarter of a mile long and astronomers across the world are racing to study it before it departs just as quickly as it arrived.
“We’ve never seen anything like this before,” said Rob Weryk, an astronomer at the University of Hawaii Institute for Astronomy.
On Oct. 19, Dr. Weryk was reviewing images captured by the university’s Pan-STARRS 1 telescope on the island of Maui when he came across the object. At first he thought it was a type of space rock known as a near earth object, but he realized its motion did not make sense. It was much faster than any asteroid or comet he had seen before. He quickly realized that it was not of this solar system.
“It’s moving so fast that the Sun can’t capture it into an orbit,” Dr. Weryk said.
After contacting a colleague at the European Space Agency to discuss the find, he submitted it to the Minor Planet Center, which tracks objects in the solar system, to share with other astronomers.
“I was not expecting to see anything like this during my career, even though we knew it was possible and that these objects exist,” said Davide Farnocchia, a navigational engineer with NASA’s Center for Near-Earth Object Studies at the Jet Propulsion Laboratory in Pasadena, Calif.
Astronomers had predicted such an occurrence, but this is the first time that it has been recorded.
For the past few days Dr. Farnocchia has been calculating the strange object’s path.