Monday, August 13, 2007

Speed and Distance

Just to let you know, this was all done just to keep my brain occupied. I hate unoccupied brains. I think I'm going to research the foot-distance vs car-distance thing now.
If nobody has done it, I think I'll try and calculate it myself.





Thousands of years ago (I'd suspect in the tenish of thousands) mankind found our feet and walked. Wow, with a top speed of around a couple of meters per second for any distance at all, you couldn't go far. It was the walk to the next village sort of speed. Or follow the buffalo. Or trudge across the desert.

A day of walking and you could end up maybe 20 miles from where you started. Which is admittedly a long way. Running quickly you could run a marathon like Pheidippides and make maybe 40 miles in 3 hours and promptly drop dead after bringing news of the defeat of the Persians.

Let's call that order zero in meters per second. 0-9 meters per second. The entire limit of the speed of you on foot. Although no-one but professional marathon runners could run 9 meters per second (a shade over 20 miles per hour) for any length of time. I certainly couldn't.

But say we want to go a little farther and a little faster. Six thousand years ago the horse was first domesticated. Horses can go faster, up to say order 1. 10-99 meters per second, although the average horse isn't going to go much faster than 15 meters per second but their top speeds on distances longer than a sprint are around 30 mph. This was much better than on foot. You can go much faster than you could walk for hours. Ride a horse for an hour or walk for the entire day, or more! A horse can do the marathon in half the time of a the best marathon runners.

Who cares about horses though, we want FAST. Imagine another 6 thousand years whirling by and arrive in the modern era. Internal combustion engines put us at speeds in the upper reaches of order 1 rather than the lower bracket. Well at first they were actually slower than horses, but didn't shit and hardly ever exploded (or rather suddenly became EXTERNAL combustion engines). But they got better quickly (in a generation [of people!] or so). They're now the most common method of getting about in the world. I wonder if there was some way of counting up all the distance done by all the cars in a day vs all the distance done by people walking around in a day. How many trips to the fridge is the equivalent of driving down to the super-market anyway? (for me it's about 200 or so, surely there is more foot traffic distance in all of humanity than car distance, I wonder if this information already exists somewhere)

For those who REALLY want to go fast, you can. Fork over the million euros and buy the Bugatti Veyron: 252 mph or 112 meters per second. Order 2! On the ground! Street legal! Move to Germany and drive on the autobahn all day. That's like, crossing the distance between major cities in hours rather than days. Cross continents in days as long as there is the road.

But really cars almost never go order 2. So what does? Planes. Zoom. Order two is around 225 miles per hour as you can probably convince Google to tell you if you were so inclined. So although the Wright brothers didn't quite make it with mankind's first jaunt into powered flight in the early 20th century or for quite a while, modern jets makes 550 miles per hour at cruising. THAT speed is around the world in a day. And nicely makes the whole world interconnected.

But for those of us who look up and dream of space, this just is not fast enough to connect us to the worlds above. So we built rockets, and space shuttles and go faster than anyone has ever gone before. The fastest plane was the X-15 (manned) (and technically was a suborbital spacecraft if you want to get technical since it's top altitude was 60 miles up) is mach 6.72 (5115 miles per hour or 2286 meters per second). Order 3! Stable earth orbit, or where the ISS and space shuttles live and work usually end up in a 17-18 thousand miles per hour orbit or around 8000ish meters per second in the top end. The fastest manned vehicle was Apollo missions which got up to 25,000 miles per hour or 11k meters per second, order 4.

This is all well and good, but let's say we want to be interconnected to say, the moon. Or Luna as the science fiction novelists tend to refer to it. Interconnected would be say... one way in a day. Just like cars and trains united a continent, and planes united a world. The straight line distance is 363k km at perigee to 406k km at apogee giving us an average of 384k km. To get there in a day would require a paltry 16,000 km average speed! We could do it in a space shuttle if we could instantaneously accelerate it to that fast and send it on the way (if possible it would turn all the passengers into strawberry jam sadly). Thankfully instant deceleration would take care of itself as there is a big rock we're heading to. The current speed record to the moon is around 3 days. The latest go-to-the-moon planned missions are not going to beat this either. Still this is only a say, order 4 operation to go to the moon in a reasonable time frame. Three days there, 2.5 days there, take the red-eye home and you have to only take a week off work to go to the moon!

What about anywhere else? Well, you can toss right out the idea of a week. Mars is a multiple-month possibly years journey with today's technology.

When is some bright spark going to come up with warp drive so my dad stops telling ME to develop it. I'd hate to think that something we all think is impossible is ACTUALLY impossible. Science is all about cheating that sort of thing anyway.