Scramjet goes (sonic) boom!

space travel? THERE IS NO OXYGEN IN SPACE, DUDES.

OH SHIT!!! TELL THE SCIENTISTS NOW!!!

but i guess once you're in orbit you don't really need the scramjet thing. which is probably the idea of the space delivery thing.

once again, it's good remind folks that the speed of sound is not a constant. it varies with temperature, altitude, etc. If i had my "Intro to Aerospace Engineering" book here, i'd be able to look up to see what density & temp of air at 30 klicks up is.

in the meantime, feel free to calculate it yourself.

suffice it to say that the speed of sound slows(usually, depending on which part of the atmosphere yer in) as you go higher. at sea-level, the speed is about 340 m/s, or 750 mph.

here's a better explanation

okay, the engineer dork that still resides within me needed to find this out, so after dinking around a bit, you can find that the speed of sound at 30 Km is 301.7 m/s = M1.

so! Mach 7 @ 30 Km = 7 *(M1) = 2.11 Km/s. Not bad.

At this speed, it would take me 1.53 seconds to get to work in the morning, as opposed to the usual 10-12 minutes. More sleepy time.