What would happen if all the power went out worldwide?

Municipal water is pumped and treated electrically, so taps in most cities run dry or lose pressure within hours to a couple of days depending on reservoir head, and treatment stops immediately, making whatever remains unsafe. Sewage handling fails on the same schedule and in the same way, which is historically the faster killer. Refrigeration fails within a day, spoiling food and, more seriously, the vaccine and medicine cold chain. Hospitals have generators sized for days rather than weeks, and refuelling them requires fuel pumps that also need power. The 2003 North American blackout is the useful reference point: about 55 million people lost power for up to two days, and even at that scale and duration it caused significant water advisories, transport failure and excess deaths. Restarting a grid from a total shutdown is a genuinely hard engineering problem called black start, and it takes days at best.

What happens, in order

How confident this is

This is a reasoned extrapolation rather than an observation. The mechanism is understood, but the scale of the consequences depends on assumptions that could reasonably be argued differently.

Everyday systems

• What would happen if everyone on Earth jumped at the same time? Essentially nothing. All of humanity together is about one ten-trillionth of Earth's mass.
• What would happen if the internet went down? Payments fail first, then logistics — most physical supply chains now depend on network connectivity rather than the other way round.
• How much space would it take for everyone on Earth to stand in one place? About 2,000 square kilometres — smaller than Luxembourg, and less than twice the area of Los Angeles.
• What would happen if GPS stopped working? Timing, not navigation, is the real dependency — mobile networks, power grids and financial systems all use GPS clocks.
• What would happen if money stopped existing? Trade would collapse to what barter can support, and something money-like would be reinvented within weeks.
• What would happen if all the satellites stopped working? Weather forecasting would lose most of its accuracy beyond a day or two, along with navigation, timing and most long-range communications.
• What would happen if all refrigeration stopped? Food waste would rise enormously and the vaccine cold chain would fail — refrigeration is a public health system, not a convenience.
• What would happen if the water supply stopped? Three days for drinking, but sanitation fails first — waterborne disease is what historically kills people in a water outage.
• What would happen if all digital data was lost? Ownership would be the deepest problem — land registries, bank balances and medical records exist almost entirely as data.