We have mapped the surface of Mars, the Moon and Venus in sharper detail than the floor of our own ocean, most of which no human instrument has ever seen up close

We have mapped the surface of Mars, the Moon and Venus in sharper detail than the floor of our own ocean, most of which no human instrument has ever seen up close

Here is a claim that sounds like an exaggeration and is not: the best global maps of Mars, the Moon and Venus resolve finer detail than the best global map of the floor of our own ocean. The other worlds have been surveyed from orbit down to a few hundred metres, and in places a few metres. Most of the seabed has never been measured directly at anything close to that. The comparison gets repeated so often that it has started to sound like a slog…