Run The Sim

A 1 kg rock that doubles its speed every second starts slower than you can walk. After 29 seconds, it's heating the whole Earth faster than the Sun does.

The centre of the Earth is hotter than the surface of the Sun. It's a ball of solid iron at about 6,000 °C (10,800 °F), crushed by more than three and a half million times the pressure we feel, and the deepest hole anyone has ever drilled, 12 km (7.6 miles), barely scratches the skin of the planet above it.

This is how our planet looks from other worlds. From some of them it's a beautiful blue ball hanging in the sky. From others it's a tiny dot you could hide behind a grain of sand held at arm's length, and from the farthest you can't see it at all. Yet everyone you have ever loved and everyone you have ever lost lived on that dot. Every birthday and every funeral, every first kiss and every last goodbye, every flood, famine and plague and every time people rebuilt afterwards, all of it happened there.

An hour after sunset one mirror gives just a thirteenth of a full Moon's light, so lighting a single street would take about 520 of them at once, and about two hours after sunset they all drop below the horizon until they come back before dawn.

The light spreads into a patch about 12 km (8 miles) wide, and every mirror races past at 17,000 mph, so it can only hold the spot for a few minutes before the next one takes over.

Each mirror, about 18 metres (59 feet) across, flies 600 km (373 miles) up along the line between day and night, so it stays in sunshine while the ground below has gone dark, and it tilts to throw that sunlight onto one place.

A company is planning to sell sunlight after dark, beamed down from mirrors in space. Would you buy sunlight at night?

If the oceans drained, the air wouldn't stay where it is. It would sink into the empty ocean basins, and over a quarter of the atmosphere would end up below today's sea level. Standing on a beach would feel like standing about 2.7 km up a mountain, with roughly 28% less oxygen in every breath, while at the bottom of the old Mariana Trench the air would be almost three times thicker than it is at sea level today.

The worst place to be is on the equator, in places like Ecuador, Kenya, Indonesia and the Amazon. The safest place would be right at the poles, where you're barely moving to begin with, but not for long, because all the water will move to the poles.