Wednesday, July 30, 2008

Christmas in July!

Truly, we live in an age of wonders.

A few months ago, I wrote about these news items, about a couple of (ahem) personal vehicles that I really, really want in my garage. Well, according to this article from the New York Times, I can add one more to my Christmas wish list.

A real, honest-to-God jet-pack that actually works!

Well, to be picky, it's not a jet-pack as much as it's a ducted-fan-pack, but I still want one.

(Hat tip: Instapundit)

Tuesday, July 29, 2008

NASA at 50

Fifty years ago today, President Dwight Eisenhower signed the National Aeronautics and Space Act into law, creating NASA. The agency thus created has led the American space effort, and has had its share of both triumph and tragedy. To mark the day, I'm hashing out a quick review of NASA's record: the Good, the Bad, and the Ugly.

The Good

Without doubt, NASA's signature triumph was putting an American on the Moon, and bringing him back safely. I think a good argument could be made that this was our finest hour. We built the most powerful machines in history, not for conquest, not for destruction, but for exploration ... to go somewhere we'd never been, and to learn something we didn't know before. And they answered the challenge head-on: between the day Kennedy laid the challenge down on May 25, 1961 and the day Columbia splashed down in the Pacific on July 24, 1969 was a span of only 8 years, 1 month, and 29 days. (Fun trivia fact: both dates were Thursdays, so the span was exactly 426 weeks.) Only eight years to invent procedures and spacecraft that had never existed before, to accomplish a task they weren't sure was even possible when they started. And they haven't slacked off on the unmanned exploration front: NASA's robots have visited every planet in the Solar System, saving only Pluto (which was a planet, at the time of NASA's inception). To this we can add Hubble, which has revolutionized our understanding of astronomy. Neither has aeronautics been forgotten: the laboratories continue to forge ahead with propulsion research, test-flying a Mach 8 scramjet for the first time last year. We have much to be proud of, for our paltry expenditures.

The Bad

There have been a few miscues, some would even say more than a few. The Block I Apollo spacecraft was a total goat-rope that ended up costing the lives of three good men in the Apollo 1 fire. A stem-to-stern redesign resulted in a pretty good spacecraft, but still. Your design process really ought not involve smoking a crew if you can help it. This is a pattern that seems to repeat itself every 15-20 years. Good engineering practice gets overtaken by hasty dumb-ass, and the predictable thing happens. Mind you, flight test is a dangerous business. Back in the late 50s and early 60s, when the early astronauts were cutting their teeth in the flight test business, you'd expect to lose several pilots during a test program. Losses incurred while you're pressing the outside of the envelope are one thing. Losses incurred through complacent inattention are another thing entirely. The former is a cost of doing business, the latter is entirely avoidable. And we've lost seventeen good men and women to the latter, seventeen too many. Let's hope the lessons stay learned this time, and we don't have a repeat in the 2016-2020 time-frame.

The Ugly

When you compare the agency in its early years to what you see today, you wonder why it only took a little more than eight years to go from a President's say-so to landing on the Moon, and today we'll spin our wheels for at least ten more years and still be a year or two away. The answer is really quite simple. It's a fully-matured bureaucracy now, in a way that it wasn't, back in the day. Young organizations travel light and move fast, everyone's focused on the mission like a laser beam. Nothing else mattered. Today, it's very much a 9-to-5 outfit ... and really, is that such a bad thing? When I think of all the wrecked families that littered the roadside on the way to Tranquility Base, maybe not. That's a bit of history we need not repeat. Still, they've developed a very strict, very rigid way of doing business that they will not depart from. That makes it hard to innovate. It makes for a slow-moving organization, one that people will begin to lose patience with, by and by.

The Future

They will continue to do their work, be it good, bad, or indifferent. It's a Federal bureaucracy, and therefore very unlikely to be shut down anytime real soon. And their best work is quite good indeed, even today. But what I do see happening, is that they'll lose the initiative in the American space effort. Maybe in fifteen years, twenty at the most, the center of gravity of the American space effort will be firmly in private industry, in places like SpaceX and Virgin Galactic. They're stalking the wild greenback, and won't let ceremony stand in their way. Which is fine. It may even allow NASA to rediscover what I think is, at bottom, its real mission.

You see, in my opinion, NASA's job isn't really to put a person on Mars. NASA's real job is to figure out the technology to let the National Geographic Society put some people on Mars. Or how about Survivor: Olympus Mons? Now, wouldn't that be a sight to see?

Thursday, July 10, 2008

It's Always April Fool's Day...

It never ceases to amaze me what can arouse fear and trembling here in the Land of the Tiny-Brained Folk. Just when I thought we'd put millennial madness behind us with the non-event that was Y2K, Lo! it just begins again. Case in point: this piece from the world-famous AOL newsroom about a bunch of mystics that have their shorts in a wad over the Long Count.

I've had a long-standing interest in calendars of all kinds. I think they're cool. I came to the study of calendars from my long-time interest in astronomy, and eventually got interested in them in their own right. It's a fascinating business, how people choose to mark time. Do they mark the passing of the Sun, or the Moon, or some combination of the two? What do they use for their epoch date, and why? That choice alone tells you a lot about the mind-set of the calendar maker.

The modern Julian Day calendar, for example, is in broad use by those of us who study the motion of the planets for both fun and profit. Its epoch was chosen purely arbitrarily. The Julian Day is the number of days that have elapsed since January 1, 1950, UTC. It's not a whole number, but a decimal, so that you can get as precise as you need to. Interesting factoid, useless to most people. But I find it curious.

The Byzantine calendar, now... They date their calendar from when they believe the world was created in Genesis, some 7500-odd years ago. The year 2000 AD, for example, would have been
Etos Kosmou 7508 on January 1, rolling over to 7509 on September 1, which was their New Year. Neat, but again, mostly useless.

Our calendar dates from the estimated birth of Christ ... but they got the year wrong. Whoops. The really funny thing about people getting their shorts in a knot about the passing of the 2000th year since the birth of Christ? They were getting excited about four years late. Maybe. We just don't know for sure. (I suppose I could ask when I get there... Provided that I still give a rip.)

And then there's the Hebrew Calendar, a combination lunar/solar calendar that I've never entirely understood. Their epoch date is a year before Creation. I find that slightly nuts. What, it took the Almighty most of a year to get His blueprints past peer review? But it's best not to consider such things too deeply. That way lay madness.

The point is, all calendars are arbitrary. They're tools for marking the passing of years, no more, no less. By far, their most important role in ancient societies was telling people when they should plant crops. That's serious business, because if you plant too early or too late, you go hungry. But aside from that, their use is purely ceremonial, and the Universe at large simply does not care how we measure time, or for that matter, if we measure it at all.

Which brings us to this barge of fools crying "Doom! Doom!" for 2012, because the Mayan calendar is running out. Why, pray tell, do they think the Mayans have a unique groove? Personally, I find it hard to take their word on the date of Doomsday if they never got around to inventing the freaking wheel. The second simplest machine of all time, and it never once occurred to them? Not one of them looked at the round calendar carved into the side of a temple and mused to themselves that something roundish might make hauling fifty-ton stone blocks easier?

You have to admit, failing to invent the wheel kind of disqualifies you from the leader-board of History's Cleverest People.

Besides, it's not as if they have the only cyclical calendar. The Hindu calendar, for example, will trundle merrily along for another 420,000 years give or take before its current age ends. But we don't see anyone getting excited about that bit of prophecy, do we?

Well, that's partly because no one seriously expects to be around then. But that's beside the point.

Or is it? After all, 2012 is tantalizingly close. Most anyone alive today can seriously expect to be around then. Whatever happens then, they'll be here to see it. There are always people just chomping at the bit to see Armageddon in their time. Some of them, I expect, bounce from one round of "Doom!" to another like Tarzan swinging through the Jungle of Life. Y2K proved a bust, and this was the next one to come along.

Me, not so much. I take great confidence in the fact that mystics have predicted 10 of the last 0 ends of the world. I expect December 21, 2012 to come and go just like any other day. No one from Galactic Utilities is going to come by and tell us that we haven't paid our calendar bill.

You won't get off that easy, guys. You'll have to wake up the next morning and go to work, just like the rest of us. Get used to it.

Tuesday, July 01, 2008

Faster Than Light?

And now for something completely different ...

A long time ago, I read a compilation of Fred Saberhagen's Berserker short stories. The first one, I think, was a piece about the final battle between the Berserker fleet, and the humans that had united to resist them. One of the stranger things in the story was a weapon Saberhagen called the "C-Plus Cannon", a gun that launched its projectiles faster than light. There's an unfriendly weapon for you: first you get the kaboom that comes with getting hit, then you see a missile flying backwards to the ship that fired it. Weird.

But would it really work that way? Let's think about that for a moment.

Let's try a thought experiment. We're going to visit our experimental station on Eris, way the heck out in the Kuiper Belt. We're going to watch a demonstration flight of a prototype vessel capable of flying twice the speed of light. (Yes, this "experiment" contains a fatal flaw ... but bear with me, we'll come around to it presently.)

The flight plan is that it'll fly out twelve light-seconds, do a flip-turn, and fly back to base. At T=0, it begins to fly away. The image begins to fly off in the direction of the target, but not as fast as we'd expect. After three seconds, the image has only receded by two light-seconds. Huh? That doesn't seem right ... At six seconds, it's at the four light-second mark. It continues to crawl into the distance, reaching eight light-seconds away at the twelve-second mark. We're about ready to call it a bust, when BLAM! The vehicle suddenly re-appears at the dock! And, its image begins to shoot backwards at what appears to be twice the speed of light. We watch, boggled, as the two images converge on either side of the flip-turn, when they both vanish.

Weird enough for you? Except for one problem ... It could never actually happen that way. We'll show that by doing another thought-experiment. But we're going to lay down a few simple rules first. They're based on some simple principles that describe the way we think the world works.

One: It's a property of photons that they can only travel at one speed in a particular medium. That's to say, light always moves at the speed of light. It can't accelerate or decelerate, it can only gain or lose energy in frequency.

Two: There's no such thing as a universally-preferred frame of reference. Which is to say, there's no such thing as absolute motion. Motion is always relative to something else you can see.

Three: If you're way, way out in deep space, there's no way to tell if you're at rest, or if you're moving at a constant speed, in a straight line. That's a subset of the principle above. Absent a reference to the contrary, you may as well be standing still.

Four: The speed of light is the same in every inertial frame of reference. That means it doesn't matter who's looking at it, they all clock a beam of light at the same speed.

Bearing those four things in mind, let's imagine two ships out in deep space. Both are moving at a constant speed in straight lines. One of them is charged up to several million volts relative to the other, and they're going to pass very close to one another.

Let's look at the encounter from the first ship's point of view. Your instruments can't tell if you're moving or not, so you're perfectly justified in saying that you're sitting still while this other fool zips past you. At closest approach, a spark jumps between the ships, causing a flash. ZAP! You're now at the center of an expanding shell of photons, racing away at the speed of light in all directions.

The interesting thing is that we can make the exact same observation from the point of view of the second ship. You're minding your own business when this other guy flashes past, then ZAP! You're at the center of an expanding shell of photons.

Notice that we haven't said anything about the relative speed of the "moving" ship. It can be arbitrarily large, up to a point ... But do notice that from either point of view, both ships are within the expanding shell of photons!

Therefore, both ships must be traveling slower than the speed of light. However fast we imagine either ship moving, we cannot imagine a situation that places either ship outside of the flash zone, unless one of our four assumptions is incorrect.

Now, if we go back and look at our first experiment, we see that the way it's set up does violate the assumptions. It assumes a preferred, God's eye frame of reference that can't exist. And it ignores the fact that light always moves the same speed in every frame of reference. There are probably other problems too, but those are the major deal-breakers.

The sad and sorry fact is that faster-than-light travel does not appear to be possible within our space-time. There may be ways to cheat, by bending or folding space, but that's a story for another day.