A 30-metre-wide asteroid is heading for a close encounter with Earth and could come closer than some orbiting satellites.
But scientists are sure it will miss us by at least 24,000km on Sunday, and say there is no need to panic.
The space rock, named 2013 TX68, was spotted three years ago by astronomers in the US scouring the skies for potentially threatening near-earth objects.
Because it was tracked for only 10 days, its orbital path is uncertain.
Experts believe it will make its closest approach to earth on Sunday, although the forecast might be one or two days out.
Meanwhile, two astronauts whose journey has resulted in some of the most jaw-dropping images in the solar system have returned to Earth after spending almost an entire year in space.
NASA’s Scott Kelly and Russian cosmonaut Mikhail Kornienko landed in Kazakstan on Tuesday.
Sadly, it means there won’t be any more of Kelly’s mind-boggling photographic updates, like these below.
The men spent 340 days on the International Space Station. Typically, astronauts stay on the ISS for five or six months.
Returning home from nearly a year without gravity has its challenges and it is unknown how long it will take Kelly and Kornienko to recover from nearly 12 months at ‘microgravity’, since so few people have done it.
“Kelly has participated in a variety of research that will help scientists better understand how the human body reacts and adapts to long-duration spaceflight,” NASA said in a statement on Saturday.