km

Within 75,000 km of earth, it is bright enough to illuminate the night sky like twilight.

And so way above the surface, at 50km above, the temperature is just right for life.

When I was coming through this at 500 km/h, it felt perfectly level to me.

And yet, X-7 is ‘only’ 15.65 solar masses and 92 km wide, just big enough to cast a shadow on Corsica.

Orbiting earth every 27 days, at 3600 km/h.

They've been bred for this and can run at speeds of over 30km an hour.

And yet, it is thrown around by a tiny black hole just 17.2 km wide.

The main population of the invasive carp has reached about 70km away from here, and over the last few years, it hasn't seemed to move any closer.

In middle America, basically any soil, vegetation or animal is just shredded into pieces and catapulted thousands of km away.

When the barrier had to be shut down for maintenance in 2009, toxin was added to 10km of this canal, to kill everything in it, just in case.