Astronomers have captured images of a new visitor to our solar system - the first known comet or asteroid to visit us from another star.
The Queen's University Belfast scientist, who is part of an international team studying the object, said it "sends a shiver down the spine" to look at it and to think of where it has come from.
Professor Alan Fitzsimmons, from the School of Mathematics and Physics at Queen's, together with colleagues in the UK, USA and Chile, has been tracking it using powerful telescopes across the world.
The fast-moving object, now named A/2017 U1, was initially spotted on October 18 by the Pan-STARRS 1 telescope in Hawaii.
The university said initial data implies it is a small rocky or icy object that may have been drifting through our galaxy for millions or even billions of years, before entering our solar system by chance.
The object flew into the solar system from above, was close to the sun last month, and is now already on its way back out to the stars.
Astronomers believe it was probably thrown out of another star system during a period of planet formation.
The same process is thought to have unfolded 4.5 billion years ago around our own star, when Jupiter and Saturn formed.
Despite suspecting such objects existed and looking out for them over past decades, scientists have never seen such an interstellar visitor until now.
During rapid investigations, Prof. Fitzsimmons's team has now captured images of the unusual object, and obtained data on its possible chemical make-up.
Prof. Fitzsimmons said: "By Wednesday this week it became almost certain this object was alien to our solar system.
"We immediately started studying it that night with the William Herschel Telescope in the Canary Islands, then on Thursday night with the Very Large Telescope in Chile."
He added: "It sends a shiver down the spine to look at this object and think it has come from another star."
Queen's said more information is needed to pin down the exact details of where the visitor came from and what its properties are, but said the object should be visible in powerful telescopes for a few more weeks, allowing scientists to continue their investigations.