The object is about the size of a car and was spotted by the NASA-funded Catalina Sky Survey.
The HKEAA will also require students to wear masks and check their body temperature; candidates who cannot wear masks for medical reasons will sit separately.
An internal memo to students and staff announced it will discontinue lessons in May; those enrolled have the option to transfer to the US or learn online.
Meanwhile, education sector calls for mask manufacturers to dedicate a portion of their output to smaller masks for children.
Coronavirus: Greta Thunberg urges students to rally for a "digital strike" against the climate crisis
The Swedish teen wrote a plea to fellow activists to continue the #FridaysForFuture strike online in light of the spread of the Covid-19 virus.
Two secondary school students also taken into custody; incident occurred after police halted Chater Garden rally in January
The World Health Organisation announced the decision on Wednesday.
Coronavirus: NBA suspends season until further notice after Utah Jazz player tests positive for Covid-19
ESPN columnist Adrian Wojnarowski reports that the player in question is centre Rudy Gobert.
The beloved actor is in Australia filming a movie; he said they will be isolated and monitored for as long as is needed.
Infections outside China have risen 13-fold as US authorities say 20 to 60 per cent of the world's adult population could catch the virus.