# Q & A: Interstellar Squish?

Most recent answer: 10/22/2007
Q:
to travel long distances (eg. from Earth to Pluto) in a man’s lifetime, one requires a vehicle which is capable of travelling in high speed. However, human bodies can barely endure the increase in gee when a jet plane is travelling in the speed of sound (so much slower compared to the speed of light). Doesn’t this means that human will never be able to explore anywhere furthere into space....
- Wijaya
Australia
A:
Wijaya -

Here's a fact to think about... the speed of a space shuttle in orbit around the earth is about 17,500 miles/hour or 8000 m/s - this is about 20 times the speed of sound in air (340 m/s). So how come people don't get squished every time they go up into space? The reason is simple. The human body can endure ANY speed! The thing we can't endure is getting there. It's the acceleration that hurts.

Think about when you're riding in a car. You get pulled forward or backward when the car speeds up or brakes. But you don't feel much when you're just cruising at a steady speed.

I did a quick (REALLY simplified) calculation, figuring that one wanted to travel 109 meters (the distance from the sun to Pluto), accelerating with a rate of exactly 1 gee for the first half of the trip and then slowing down at the same rate for the second half of the trip, it would take a mere 6 hours to get all the way there! The fastest speed the shuttle would reach is about 100,000 m/s or 300 times the speed of sound in air!

Of course, there's a lot more to space travel than just speeding up and slowing down. You have to keep track of gravitational forces, fuel supply, and a gazzillion other things that make a 6 hour trip to Pluto impossible (at least for now). To learn about these things, check out from .

If you're talking about trips to other solar systems or galaxies, things get way more complex than even that. This is because then you're talking about going close to the speed of light, and then you have to start figuring for the effects of .

-Tamara

(published on 10/22/2007)