Turtle v. Hare
spacetoday.net (and others) carried news at both extremes of the thrust spectrum today... the slowest rocket ever, SMART-1, has finally reached lunar orbit, 14 months after launch (it is now shifting to a more useful orbit for its instruments) using its Ion Drive... and the X-43A ScramJet project is making its final flight test run, expecting to hit Mach 10 (breaking its own previous record of Mach 7) after being launched from the tip of a Pegasus rocket, plane-launched off of a NASA B-52.
So, 240,000 miles/14 months is 10.5m/s; 7000 miles/hour is 3100 m/s - so, a factor of 300 in speed. But when SMART-1 is done, it's gotten to the moon; the end of X-43A's 10-second or so flight is a controlled splashdown in the ocean...
(Also, the scramjet is fundamentally atmospheric, and thus a lot less interesting :-) Cool physics, though.)
So, 240,000 miles/14 months is 10.5m/s; 7000 miles/hour is 3100 m/s - so, a factor of 300 in speed. But when SMART-1 is done, it's gotten to the moon; the end of X-43A's 10-second or so flight is a controlled splashdown in the ocean...
(Also, the scramjet is fundamentally atmospheric, and thus a lot less interesting :-) Cool physics, though.)