Babylon's illusion of absolute security is shattered by a prophecy of sudden, devastating ruin. The mighty empire is destined to suffer two fatal blows simultaneously, striking without warning. These twin disasters are characterized as the loss of children and widowhood. On a national level, this represents the exile and death of the country's citizens, paired with the loss of its king and political sovereignty [רש״י, אבן עזרא, שטיינזלץ]. In a more literal sense, the women of Babylon will actually suffer the grief of becoming widows and losing their children [רד״ק].
This double tragedy is destined to unfold in a single moment. Historically, this materialized on the very night King Belshazzar was assassinated, leaving the state effectively widowed. Immediately following the assassination, the armies of Persia and Media breached the city walls and slaughtered its inhabitants, fulfilling the prophecy of lost children. The reference to these events happening in one day simply means they occur at that specific time, rather than strictly during daylight hours [רד״ק, מלבי״ם, מצודת דוד].
The intensity of the strike is absolute. The primary approach among commentators is that the disasters will sweep over Babylon in their entirety, bringing total and complete ruin. Alternatively, the timing of the destruction carries a deeper message. The disaster will strike specifically when global conflicts have ended and the rest of the world is at peace. This stark contrast will prove that Babylon's downfall is a deliberate, targeted strike by God, rather than the collateral damage of a worldwide war [מלבי״ם].
Babylon's deep involvement in magic and astrology plays a key role in its downfall. There are different ways to understand the relationship between the empire's sorcery and its destruction. One perspective is that the intense practice of magic is the very reason for the punishment, bringing absolute disaster upon the nation [אבן עזרא, שטיינזלץ]. However, the primary approach among commentators is that the destruction will happen in spite of these dark arts. Despite the sheer volume of Babylon's spells and the immense power of its astrologers and wise men, all their magic will prove completely useless when the moment of judgment arrives [מצודת דוד, רד״ק, שד״ל, מלבי״ם].