30 September 2008

An Old Warrior Passes On

This morning, Singaporeans woke up to the news of the passing of J. B. Jeyaretnam, the veteran political warrior who experienced an entire spectrum of political ups and downs of Singaporean oppositional politics.

While I may not agree with some of his views and actions, there is no doubt that he has impacted Singapore politics more than most other politicians. In fact, his shattering of the PAP's complete hegemony of the parliament in 1981 was considered, in the analysis of Singapore's political history, a critical event, a spike on the political radar just like Singapore's independence.

Many people, I believe, are looking forward to his return to Singapore politics, and see this warrior fight once more three years later. Indeed, I wonder how things would've been like. I'm uneasy with his confrontational style, but, just like in science, until someone finds a way that works, all ways to change the Singapore political scene are equally valid.

May he rest in peace, and his legacy lives on.

23 September 2008

Building a Space Elevator

Japanese scientists and engineers have set their sights on one of the most challenging tasks of a hard science fiction concept: the space elevator.

The space elevator, first popularised by Arthur C. Clarke in his novel Fountains of Paradise (an excellent read, if anyone's interested), appears to be a highly inexpensive way to travel to space, or at least to low-orbit space. It is a popular idea in science fiction and has also made it to scientific journals, being quite solidly based in proper physics.

The basic idea is that we connect a point on Earth to a geostationary satellite directly above it. This connection can be a tower (which is not feasible due to the weight) or merely cables that pulls a lift between these two points that are stationary in the reference frame of an Earth-bound observer. However, if we consider the Earth base as an anchor point and the cables plus satellite as a system, this system will start to swing sideways because its centre of mass is not in geostationary orbit, so we have to extend and attach some sort of mass beyond the satellite to counter this. In the novel, the construction started from the satellite and went both ways - up and down - simultaneously in such a way that the centre of mass stays in the orbit.

Of course, the cables will have a Coriolis force acting on it. On top of that, the length of the cable implies, even if it is of low density, a very strong tension throughout the cable. Therefore, this is the leap in this science fiction concept: a lack of such lightweight yet awesomely strong material. However, these Japanese scientists seem to have the solution: carbon nanotubes. But I think there is still a huge challenge since carbon nanotubes may not be strong enough yet, and mass production of large scale nanotubes are nowhere near a reality. Of course, this still does not take into account the multitude of engineering feats that has to be performed.

This space elevator, if ever built, will serve as a very cheap mode of space travel. Not only does it save the need to launch a space shuttle that gobbles fuel like an F1 race car, it also conserve energy just like a typical lift: as a lift comes down, it'll pull a weight of slightly smaller mass upwards, which will in turn act as a gravitational battery when the next lift goes up. It will also cut down the cost of space travel (to beyond geostationary orbits) by moving the launch site to the satellite, which bypasses a tremendous part of the energy consumption.

Personally, I'm sceptical about the plausibility of pulling this off. The material of the cable remains the greatest challenge, and I think carbon nanotubes are still way off from being a satisfactory material for such a construct. Moreover, as witnessed by the multiple failures in the Large Hadron Collider (LHC), new toys present new problems of their own, and this space elevator can be pretty disastrous if it fails in the wrong way. On top of that, such grand projects are bound to be costly, and I doubt Japan can pull it off by themselves. The LHC is funded by a collection of wealthy nations; I'm not sure if the space elevator will be any less.

Well, on the bright side, even if I'm wrong, at least there's a chance I can visit space in an environmentally friendly way. And what's more, the base station on Earth has to be on the equator (an off-equator geostationary orbit projects a sinusoidal curve on Earth's surface), so there's a chance the base station is in Singapore. If we reclaim southwards furiously enough, that is.