So they probably don't mass nearly as much as an asteroid of similar dimensions. SSD's are hollow metal lattices, with over a quarter million meaty bags of water aboard. The dimensions aren't as important as the mass. (Again provided it's not opposed by shields or surface weaponry).

It's a waste of a good Star Destroyer though, considering that a single ISD could use its guns to turn the entire planetary surface to glass and kill everything on it in about a day.

Though in practice in the Star Wars Universe, decent planetary shields would stop it. But with that speed meaning that kilo-for-kilo a Star Wars ship at full speed would be about a hundred times as destructive as a natural Earth impactor, and with the general scale of Star Destroyers, I feel confident that full-speed ramming would be immediately devastating and likely render much if not all life on the planet extinct. What about mass and density? Well, no idea, maybe I'll look into it later. The fastest anything on a solar orbit can hit Earth is 72 km/s. That's fast, even by full scale solar system standards. But it's probably 60 MGLT per hour, so 1.5 million km/h or 400-ish km/s. Yeah, Star Wars using the same unit name for speed and distance, whee. Then we know that the Imperial (I) Star Destroyer could do 60 MGLT. And the novel mentions it's about 'six planetary diameters' away, and Alderaan is about the size of Earth. It's shown, in a background shot, that the Death Star was about 3 Megalights from Alderaan when it fired. Its low-speed crash landing, slow enough for the ship to survive largely intact, did not significantly affect the planet.Īt the other extreme, a planet that was hit by a large starship in hyperspace was 'fractured to the core', likely rendering it uninhabitable.īut how fast might a Star Wars ship ram a planet in 'normal space'? It's hard to know, because they don't appear to follow normal orbital mechanics and their speeds are quoted in fictitious units of 'Megalights (MGLT)' or 'MGLT per hour'. Most obviously, we see the large spacecraft in The Force Awakens, and it turns out that's an Executor-class. As far as what actually happens in Star Wars and the 'Extended Universe' goes, there are of course a few examples.

Star wars star destroyer crash