Starcross said:
Larklight's gravity engine explosion creates a crater 1000 miles (1609.344km) wide and at least as deep as Starcross is. We don't have many references to how big Starcross is that I can recall, but it's well over 100 yards (91.44m) wide.Starcross said:
Volume of the crater as a spherical cap.Starcross said:
V = (π X 91.44^2/3) X (3 X 1609344 - 91.44)
= 4.227299e10m^3
The average weight of Mars per m^3 is 3933kg.
M = 4.227299e10 X 3933
= 1.6625967e14kg
Escape velocity of Mars is 5.03km/s, or 5030m/s.
E = (0.5) X 1.6625967e14 X 5030^2
= 2.10325964e21 joules
= 502.691118547 gigatons
Final Results
Larklight's gravity engines explode = >502.691 gigatons
Starcross is a lot bigger than that, so this is very much a low end.