فَلَا أُقْسِمُ بِالْخُنَّسِ الْجَوَارِ الْكُنَّسِ
“I call to witness the orbiting stars, those that run on and then disappear”
When Imam Baqir (as) was asked about the above verses, Imam (as) replied, “Orbiting star” is the Imam who will disappear in the year two hundred and sixty (year of martyrdom of Imam Askari (as) and people will not know where he is. But then he will reappear like a shooting star on a dark night.”
Then Imam (as) added, O Um Hani! (narrator of the tradition) You will be delighted if you live long enough to see this. (Al Kafi volume 1 page 341; Al Ghaybah by Nomani page 75; Taweel Al Ayat Al Zahirah page 744)