Scientists may have found another Earth. This newly discovered exoplanet ticks all the right cosmic boxes: it orbits its star within the habitable zone, it’s similar in size to our planet, it’s probably rocky and, in astronomical terms, it’s just around the corner, circling ‘nearby’ star Proxima Centauri. But using current technology, it would still take 70,000 years to get there.
The trouble is that the rocket – the notion of burning a fuel to create hot gas that pushes a vessel upwards – is getting on in years. The Ancient Greeks had the idea first, around 2,500 years ago, though it wasn’t until 1232, when Chinese archers used gunpowder-fuelled rocket arrows to repel the Mongols, that anything recognisable as a rocket actually flew through the skies. The rockets that…
