THAT IS CLEVER
 

D Tel today.

Russia has previously tested a hypersonic cruise missile known as Zircon, but it flies below the atmosphere and uses fuel to power itself to hypersonic speeds rather than the Earth's orbit.

Presumably launched downwards. Sneaky. Could devastate Ayers Rock / Uluru if it strays off course.

Of course in that basis we are all hypersonic, the Earth’s orbital speed being 67,000 mph…

Ah. So that's why I feel wind-swept and interesting. Well, wind-swept anyway...

No connection with Duncan Campbell, presumably?!

We used to call them torpedoes.................

Speed of sound is ~1500m/s in water. How fast would a torpedo have to be to qualify as hypersonic? :eek:

Presumably faster than 6000meters/sec, if the old standard of Mach 4 still pertains.
Iirc, the average ocean depth is well below 6000 meters, so the guidance system needs to be on its toes

Would the proper term be Hydrosonic?
Just joking.

That's my stereo system.
Also just joking.

Hydro.

This seems to have gone underground..