Wee Shu Min Wikipedia-ed

This morning in my dish of daily websites, I came across something familiar:



Her name is really becoming an icon... except in a bad way, that is. Poor thing...

Fastest Spinning Black Hole on Record

Just had my SP2172 presentation on Monday at 1600. And then, an article closely related to our project appeared just less than 24 hours later.

This is especially related since during the Q & A session, people asked on the existence of a theoretical limit on how fast a black hole can spin.

As usual, I emphasized the more relevant parts.

Spinning black hole is fastest on record
15:39 20 November 2006
NewScientist.com news service
David Shiga

A black hole has been found to be spinning faster than ever seen before, a new analysis suggests. The finding supports the idea that only fast-spinning stars can collapse to create powerful explosions called long gamma-ray bursts.

To measure the spin of black holes, astronomers measure the size of the discs of matter that orbit them. A spinning black hole drags space-time around with it as it spins, boosting the speed of matter in orbit around it. That allows the matter to orbit closer in without getting sucked into the black hole itself – so the faster a black hole spins, the closer matter can stably orbit around it. [Pandemonium: technically, this means that the radius of the event horizon (or the point of no return), becomes smaller as the black hole spins faster; this agrees with our theoretical analysis and computer simulation.]

Watch an animation showing the difference between spinning and non-spinning black holes.

But the innermost edge of this disc is too small to see directly. So previous measurements of black hole spins have had to make assumptions about properties such as the tilt of the disc to Earth's line of sight.

Now, astronomers have measured the spin of a black hole with a new method that requires fewer assumptions. The team was led by Jeffrey McClintock of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US.

Hot gas

McClintock's team examined a black hole in our galaxy called GRS 1915+105, which lies about 36,000 light years away. Matter gets hotter as it gets closer to the black hole, so the team used X-ray observations from NASA's Rossi X-ray Timing Explorer to measure the temperature of the gas in the disc.

They found the innermost stable orbit around GRS 1915 is so close that the black hole must be spinning at nearly 1000 times per second – the fastest ever recorded.

"The application of this to understanding black holes and black hole physics are really quite important," McClintock told New Scientist. "It’s the most exciting thing I've worked on."

But a second study of GRS 1915 suggests that the spin could be lower, according to an analysis of the same RXTE data by Matthew Middleton of the University of Durham, UK, and his colleagues.

Stellar collapse

Chris Done, a member of Middleton’s team, says their analysis suggests the spin is “substantial but not extreme”. They argue that X-rays scattering off of electrons in the disc make the temperatures appear higher than they really are. This gives the illusion of a closer-in disc, and therefore a faster spin for the black hole, they say.

But if McClintock's team is right, the black hole is spinning at 98% of the theoretical maximum rate, which is calculated by how fast stars can spin before they collapse to form black holes.

The observation provides support for the idea that gamma-ray bursts – fleeting but powerful explosions – are produced by fast-spinning stars.

In this scenario, a black hole forms at the centre of such a fast-spinning star and some of the remaining stellar material forms a disc that spirals into the black hole.

High spin

The interaction of the black hole and the disc produces jets, which emit copious amounts of gamma rays. But the star has to be spinning very quickly when it collapses for this disc to form, and some astronomers have expressed doubt that stars would be spinning fast enough at this stage in their lives.

The new research may quell some of those doubts. "It says sometimes stars do find some path for dying with a huge amount of rotation in their middle," says Stanford Woosley of the University of California in Santa Cruz, US, who is not a member of the team.

Christopher Fryer of the Los Alamos National Laboratory in New Mexico, US, who is also not on the team, agrees. He says it is "strong evidence that nature can get the high spin rates in stars to produce gamma-ray bursts".

McClintock says he hopes that analysing similar observations for other systems will allow them get spin rates for half a dozen more black holes within the next two years. "We're going to apply it as widely as we can," he says.

Journal references: The Astrophysical Journal (vol 652, p 518)

Monthly Notices of the Royal Astronomical Society (DOI: 10.1111/j.1365-2966.2006.11077.x)

Sometimes you just wonder why such related articles cannot be published a day earlier.

Machine Gun Sentry

Samsung has developed a machine gun-equipped sentry that will be planted along the demilitarised zone border in South Korea (outside of it, of course). They have even produced a commercial for it, and frankly I found it pretty funny, in particular the way the "enemies" move "in stealth". Says a lot about South Korean's (or at least Samsung's) impression of North Korea military.

You can read the news and watch the video clip on this news site, which I got to via Slashdot.

GST: Reshuffling the Cards of Wealth?

Okay, the bomb is out, and the blogosphere is, expectedly, buzzing like a disturbed hive. The primary reason outlined for the hike is

to finance the enhanced social safety nets, needed to help the lower income group

That sounds great, huh? Why then is the blogosphere so angry? Is it an instinctive response to blast any penalising policies of the hegemonic government, or are they seeing something I cannot? Seriously, if we raise taxes to help the poor and bridge the rich-poor divide which is dangerously becoming a threatening social issue, what's wrong with that?

Unless you're in financial difficulties, the rise in GST won't pose much problems for you. Certainly with my stingy lifestyle, it will be the least of my worries. Of course, the poor still has to buy stuff and hence the increase will affect them, but as mentioned, there are social nets that'll help them overcome this barrier. Furthermore, it is usually the more affluent that makes more purchases, so they will be the one who pay more. And if this money they pay gets channeled back to the poor, then isn't that a good idea?

Of course, there are better ways to fund this purpose, specifically a rise in income tax instead of GST. However, income tax hikes will pinch the richer citizens much harder than a rise in GST, and since most (if not all) of the MPs and ministers earn five digit salaries every month, they naturally won't support such a motion. (This assumes that our MPs and ministers are selfish, which I see no reason why not to, given our fanatically meritocratic and elitist system. It's no use challenging this assumption; it is a fact of reality.) So that leaves GST as the second best option available (enlighten me, anyone, of better plans that I've missed).

That is not to say I support the hike, however, at least not yet. The principle of the hike is good, but I must wait for the details first before deciding if I really agree with the hike. It is no use if the "safety nets" mentioned is just an appeasing farce, an empty gesture. It is redundant if these nets have holes big enough for the likes of Tan Jee Suan to fall through. In another words, my official stand is: I'm neutral with the hike; I need to see the details before making my decision.

A Scientific Reason Why We Should Emigrate

(...or why we should air-con the island.)

Sorry if this is turning into a news aggregator, but these few days I've really been lacking in time, thanks to an upcoming report deadline for my SP2172 project as well as three term tests. So, again, no more comments on this articles except for some highlighting of interesting details.

(From New Scientist via Slashdot)

Cool down – you may live longer
11:20 03 November 2006
Roxanne Khamsi

The refrigerator is used to lengthen the life of your food, and a new study suggests a similar principle could prolong your life, too.

Researchers have found that lowering the body temperature of mice by just 0.5°C extends their lifespan by around 15%. In the future, people might be able to take a drug to achieve a similar effect on body temperature and enjoy a longer life, they say.

The only previously proven method of significantly increasing the lifespan of an animal has been through a restricted calorie diet.

Bruno Conti at Scripps Research Institute in La Jolla, California, US, and colleagues designed genetically engineered mice with a specific brain-cell defect in a region called the lateral hypothalamus. The defect forces brain cells into "overdrive", causing the region to heat up and become warmer than in a normal mouse.

Female benefit

Since, in mice, the lateral hypothalamus sits just 0.8 millimetres away from the brain’s body-temperature-controlling thermostat – called the preoptic area – it was tricked into thinking its body temperature was too high, causing the mouse to cool down.

The average body temperature of the genetically engineered mice was about 0.6°C lower than that of their control counterparts.

Even this small decrease in body temperature appeared to have a noticeable effect on lifespan, extending their lives by 12% to 20%. And the decrease in body temperature extended the lifespan of female mice more than male mice, the team found, although they are unsure why.

Free radicals

Caloric restriction, another method shown to extend animals’ lives, also causes a decrease in body temperature, Conti notes. In his study, both groups of mice ate about the same amount. In fact, the genetically engineered male mice ended up about 10% heavier than the normal male mice.

Conti says the findings show it is the lowering of body temperature – and not necessarily the consumption of fewer calories – that plays the most important role in extending lifespan.

This may be because the body burns less fuel when it is at a lower temperature, which results in the production of fewer free-radical compounds that damage cells and promote the wear and tear of ageing. Previous studies have shown that worms and fish that have decreased body temperatures live longer.

Conti says that in the future people might be able to take a drug that specifically targets the preoptic “thermostat” area in their brains to trick the body into cooling down slightly. Coming up with such a drug “will be very challenging”, but he hopes it would allow people to live longer without cutting back on the calories.

Journal reference: Science (DOI: 10.1126/science.1132191)

3 Best Stalls in NUS Canteens

Okay, here's a meme I'm starting off. I'm hoping that, through this meme, I, as well as others, can know which stalls in NUS canteen are more popular and thus perhaps more worth eating there.

---

Instructions:
1) List three stalls (in no particular order) in NUS canteens that you like the most.
2) Explain briefly your choice for each.
3) Tag three people (NUS students and staff... duh!).
4) Link back to the person who tagged you so that backlinks/trackbacks will appear.

1st Choice: Char Kway Teow stall in Arts Canteen
Tucked at the quiet corner of the canteen, there are very few reasons why I would like this stall. Firstly, the food is slow. Also, the selection is extremely minimal. Yet, manned by a friendly couple, their Char Kway Teow is amazing, though it may be considered unhealthy by some. The orders are even flexible; you can ask for a $2.50 plate (despite the listed standard $2.00 and $1.50), or request for more egg, for example.

2nd Choice: Chinese Food stall in Science Canteen
Except for the sotong which I felt was a bit substandard, the food there in general is pretty satisfying. The price is reasonable, the food is great; the only thing I can complain about is the length of the queue. Not surprised though... Try to go there after 2: the queue will be short by then. Most of the time it's not opened for dinner though.

3rd Choice: Yong Tau Foo stall in Science Canteen
To begin with, the stall has some pretty neat selection of food (unless you're eating dinner). The stuff there tastes pretty nice, and what's more, their fried bee hoon or fried noodles make a good breakfast (together with an egg and a slice of luncheon meat).

Tagged:
Currytan
NinjaLZG
warhammer

---

The "Erotic" NTU Lecturer: A Discourse on Morality

By now I presume every single (online) soul in Singapore has watched the antic video clip of the NTU lecturer showing some ludicrous feedback about him. No doubt all found it hilarious, so does Yao when I first showed her, but she had reservations about the lecturer's actions.

She felt that the lecturer's behaviour is unbecoming of the supposed way he is expected to carry himself, because by screening such crass comments, he is simply encouraging his students to become cruder. He is, in a way, consciously or unknowingly, influencing them to think this way. This, to her, is inappropriate, be it for pure entertainment or scoring popularity among students.

She raised an example. Suppose in a lecture the students all like pornography. Is it then okay, on moral grounds, for the lecturer to screen pornographic materials to entertain the students? If the lecturer forbids that because of his own moral standings, then can we say that the lecturer is upholding his/her code of conduct, that this is an absolute moral expectation from people of his/her stature? If the lecturer allows, does it then mean that there is no absoluteness in morality? That morality is defined by the majority, or more appropriately, the society at large?

(At this point I think it'll do good to apologise to Yao and everyone reading this, in case of any mistakes I might've made in representing her stand above. After all, I'm writing this from my memory, which is mired by my own arguments.)

Naturally, from her comments on the NTU lecturer, it is clear that, in the hypothetical example above, she believes that the lecturer should choose the first option, because this conduct is demanded of him/her, and that despite morals changing over generations, there are some morals which are completely absolute, such as this, and the wrong in murder, for example.

She further expounded that in the past, after the age of mankind's amoralism, people did not stick so closely to these absolute morals because they are not easily known and understood. In addition, akin to technology, morals have been changing, and mostly for the better, and we get closer and closer to these absolute morals. Where this source of absolute morality comes from or by what it is driven, she is not so sure, but she believes there is some factors that forms this basis.

However, I beg to differ. I believe that morals are everchanging, never absolute. This does not mean that I expect the lecturer in the hypothetical example above to choose the latter option, mainly because morals are not defined by those inside the lecture theatre at that instant of time. It is formed, shaped and influenced by history, politics and society of the entire civilisation over a period of time. But the fundamental idea remains: morals are never absolute. Never fixed. Shifting with time. Changing always.

Slavery is largely seen as a barbaric act today, but it is quite widely accepted in many societies in the past. Then okay, now not. Suppose in the future because of overpopulation, governments have begun selective killing of genetically inferior human beings. And they have been doing it for, say fifty years, such that it has developed into a social norm. Universally accepted. Agreed by all. Is that bad?

Morals change. We cannot use today's moral standards to judge yesterday's actions. In fact, it we were to use our morals to look at times other than ours, we will probably be repulsed by what the humans were/are doing. We are stuck in today's morals; what we see in the past and in the future will not appeal to our moral tastes. It's just like asking someone from the ecclesiastical past to judge the role of today's institutionalised church.

Expectedly, our arguments glanced off each other as we assume differing bases. She assumed that there is some unyielding force driving morality; to me, morality is everchanging. Of course, we did not come to a consensus, but it was a good philosophical exercise nonetheless.