Archive for the 'Science' Category

Creationist Double Fail

A common creationist objection to the theory of evolution is the orbital recession of the Moon. It is well known that the distance between the Earth and Moon is gradually getting larger. Every year, the Moon is roughly 3.8 cm farther away than it was the year before. What creationists claim is that if you run the clock backwards, and let the Moon approach the Earth at that rate, it ends up colliding with the Earth long before the supposed age of the Earth-Moon system, thus showing that the world couldn’t be that old.

The usual objection is over the past 4.6 billion years (the age of the Moon), the rate that it’s been moving away at hasn’t been constant. The mechanics of lunar recession is complicated, having to do with the distribution of oceans and landmasses on the Earth (different distributions produce different gravitational “tugs” on the Moon as it orbits). Today’s rate is actually quite a bit higher than it has been in the past. So directly extrapolating today’s rate into the past won’t actually give you the correct answer.

And then…there’s this:

The Moon is currently 385,000 km away (on average. The Moon’s orbit is actually somewhat eccentric).

385,000 km / 3.8 cm per year = 10.1 billion years. Far older than the accepted age of the Earth.

So even if you do blindly extrapolate backwards, the Moon doesn’t actually end up colliding with the Earth. So not only do creationists not do their research, they also suck at math!

Advertisements

Happy τ Day!

That’s right, its τ Day! Wait, what?

Recently, I have found an interesting proposal regarding the number π (the ratio of the circumference of a circle to the diameter, or, 3.14159265358979…and so on…). It states that using π is not the best choice and that we should use a constant that is equal to 2π, which is 6.283185307179586…and so on… Basically, the ratio between the circumference of a circle to it radius is more basic a concept than circumference to diameter.

So what’s the difference? Well the main point is that in almost every single equation that you encounter in math and physics that comes with a π in it, it actually comes as 2π or some multiple thereof. Therefore, it is more convenient to simply write τ (called “tau”), one character, than 2π, which is two characters. Physicists like to simplify things as much as possible when they can.

Therefore τ Day is 6/28, which is today!

There are other reasons too. Conceptually, it is more intuitive. Travelling τ radians takes you once around a circle. Travelling τ/2 radians takes you halfway. One tenth of a circle is τ/10, and so on. For π, the values would be 2ππ, and π/5, which don’t really make sense. Travelling π/5 takes you a tenth of the way around a circle, rather than a fifth?

Anyway, I love it, and maybe I’ll try to use it on some test and see what happens (initially noting that τ = 2π, of course).

HUGE Planet Discovery!

Scientists from the Kepler mission have just announced that they’ve potentially found more that 1,200 new planets orbiting other stars. That’s incredible!

Here’s a brief rundown: out of the potential 1,235 planets, 68 are approximately Earth-size, 288 are super-Earth-size (i.e. rocky planets that are several times the mass of Earth), 662 are Neptune-size, 165 are the size of Jupiter and 19 are larger than Jupiter.

Furthermore, they’ve found that 54 of these planets orbit within their star’s habitable zone, and that of these 5 are roughly Earth-sized.

Now, the Kepler survey covers roughly 156,000 stars, and detects planets by watching them transit across the face of their star, measuring the small dip in the star’s brightness. Naturally, the odds of an orbiting planet actually passing in front of its star is very low. Still, I estimate that, assuming there is a planet orbiting within its habitable zone, there is 0.3% it will be lined up correctly, which translates into about 450 stars.

Think about that, out of 450 candidate stars, 5 have Earth-sized planets in Earth-like orbits, or 1 out of every 90.  That would imply that there are a few billion potentially Earth-like planets in the galaxy, the closest likely being no more than 20 light-years away.

Even considering other planets, 54 out of 450 equates to 1 out of 9. Which means that there’s likely some Jovian planet (possibly with habitable moons) within 10 light-years.

Note, however that I say Earth-sized, not Earth-like. The survey can’t measure the atmosphere or anything like that, so they could all actually be uninhabitable. Venus would count along one of the five if it were in the survey. But still, given what it implies about the abundance of Earth-like planets, this is a HUGE discovery.

Black Hole Power Generator Equations

For those interested here are the equations for the black hole generator. The three main pieces of information we are interested is the black hole’s mass M (in kilograms), the power output P (in Watts), and the time it will take to evaporate (basically, the safety margin) T (in seconds). If you know one, it is possible to obtain the other two:

P = 3.563 x 10^32 / M^2 = 6.838 x 10^21 / T ^ (2/3)

T = 8.407 x 10^-17 * M^3 = 5.654 x 10^32  /  P ^ (3/2)

M = 2.283 x 10^5 * T ^ (1/3) = 1.888 x 10^16 / P ^ (1/2)

Rechecking the numbers it appears I actually made errors in calculating the black hole’s parameters in the previous post, so I went back and corrected them.

Black Hole Power Generator

For the past few days I’ve been kicking around the idea of using a black hole as a power generator. It seems counter-intuitive: a black hole absorbs all matter, right? How would one use it to create power? The answer lies in the fact that all black holes emit what is called Hawking Radiation.

In 1974, Steven Hawking showed that black holes have temperature due to quantum effects, and anything with a temperature above absolute zero will create black-body radiation. This radiation obviously has energy, which comes from the mass of the black hole itself (the details aren’t particularly important, only the big picture). Essentially, black holes will slowly evaporate and thus shrink. Even stranger, as they get smaller, black holes will emit more and more radiation until they have no more mass left and completely disappear.

So, what if we were to construct a black hole and harness this energy as it is emitted? We capture it (more on this in a bit), build, say, power cells around it, use it as a power plant? Now obviously, it would be bad to let the black hole evaporate completely as the power output increases enormously as it shrinks. In a practical sense, the black hole “goes critical” and explodes. So…what if we continually feed it with matter to keep it at a relatively “tame” level? Say we have our black hole, and we’ve tuned it to produce, say, 10 TeraWatts of power, enough to power the Earth. It’s mass would be (if my math skillz haven’t failed me) about 1.9 million 6 million tons and be about one ten-millionth of a billionth two millionths of a billionth (2 x 10^-15) of a centimeter in diameter. 10 TeraWatts means it will lose roughly 0.11 gram per second in radiation and every year it will lose about 3500 kg in mass. If we continually input matter at that same rate, the black hole will remain stable and continually output 10 TeraWatts.

The reason this is so intriguing is because the conversion rate is (theoretically) 100% efficient. We put a kilogram of matter into the black hole, we’ll get (eventually) a kilogram of mass-energy back out, and the black hole will be exactly the same as when we began. Compare this to fusion where the efficiency is only around 0.7%. That’s a huge difference! Even better, any matter at all will work, not just hydrogen and helium. Elements that are past iron on the periodic table are useless for fusion, but work just fine with black hole generator.

Creating such a black hole is left as an exercise to the reader, but here’s how you hold it. Well you actually don’t have to “hold” it. If you’re building this power generator in space, you can just let the black hole freely orbit the Sun or the Earth and construct your power collectors around it, but it wouldn’t be very mobile. If you actually wanted to take it with you, you could initially feed the black hole with some amount of electrically-charged matter. If a black hole swallows an electron, the black hole itself will then have a negative charge. You can use this fact to electrostatically levitate the black hole, like how if you stack two magnets on a stick with the same poles pointing towards each other, one will stay hovering above the other in mid-air.  Neat huh? One just needs to continually input charged particles to keep the charge on it.

Even the threat of the black hole “going critical” is literally very remote. If left to physics alone our hypothetical 6-million-ton black hole won’t actually explode for over 18,000 568,000 years.

Anyway, looking around the web, it seems as though someone has already written a paper on this. I suppose I’ll take it as a good sign that my own musings are paper-worthy material (though in their paper they use the black hole to power a space ship), just the rigor is lacking.

The Electric Force

I love physics. Which is good because I’m majoring in physics. One of the many strange things in this universe is the fact that gravity is such an astonishingly weak force. It may seem counterintuitive since our world completely defined by gravity. We need giant rockets just to crawl into the nearest fringes of space. But compared to the other three fundamental forces of nature, gravity may as well not even exist.

To illustrate this point, imagine that you are a fairly tall (2 meters, about 6’6”) and muscular bodybuilder, capable of lifting 100 kg (about 220 lbs.) over your head. It’s a pretty impressive feat; most people would struggle to lift half that. But let’s imagine you were to replace the large weight with some hydrogen that’s been split into protons and electrons by some machine (hydrogen is the simplest element, consisting of a single proton surrounded by a single electron). The positive protons and negative electrons attract each other just like the Earth and the 100 kg weight. The question is: how much hydrogen do you need to replicate the same feat.

The answer is really really surprising: only 10 nanograms. Yes, that’s only 0.00000001 grams (or 0.00000000002 lbs.) of hydrogen, split into protons and electrons, that will create the same force (if separated at 2 meters. Any closer and the force becomes stronger). In fact just separating that amount of electrons from protons would take as much energy as the entire human race uses in over 5 years. The electric force is that powerful, and it’s not even the strongest force in the universe. We’re lucky that nearly every positive charge in the universe is balanced by some negative charge, otherwise everything would be either crushed or repelled to infinity instantly.

Ethics and Science

One of the recurring arguments amongst more moderate religious and irreligious people is that science and religion really aren’t incompatible, it’s just that they concern themselves with different areas. Science is about observation and fact, whereas religion is about morality and ethics.

I am one of those people who thinks that religion and science are, at the most fundamental level, completely incompatible. I know that there are many religious scientists, and scientific religious people, but this does not mean that the two can really coexist. In these instances, it’s just that these people have erected some sort of partition in their head that has declared a certain set of beliefs (the religious ones) off limits to scrutiny, or at least subject to different standards of scrutiny. Science promotes free inquiry, and demands that all claims be backed up with empirical observation. Religion simply ignores empiricism and demands its followers believe based on faith. From a scientific point of view this is absurd. If you do not have any support for your hypothesis, no one is going to accept it. And, unlike religion, science won’t chastise other scientists for being “closed-minded”. No, it will in fact chastise you for not having any empirical backing.

                But, what about ethics? There is no doubt that being an ethical person is very important. But did you know that science has a lot to say when it comes to ethics? It may surprise you to know that, using evolution, you can not only predict the existence of an ethical code, but also which exact principles the code will have.

                This is a tremendous claim. Many religious people point to The Ten Commandments or some other code as a basis for their own morality, but, using science, we can actually construct a parallel list, derived solely through evolutionary logic.

                First, we must determine just what is an ethical code. I define it as something with which we have a “gut feeling” is right or wrong. We feel what is right and what is wrong, even if we can’t articulate it. Why would we have these feelings? From an evolutionary standpoint, we would have them if it would give us a competitive advantage to have them.

                So what ethical feelings would we have if they were evolved? Well, a taboo against murder would be the most obvious one. If you hang around someone who tends to murder people, you’re much likely to end up murdered yourself. Since evolution depends on creatures which survive and reproduce, shunning people who murder is evolutionarily prudent. A similar argument goes for stealing. Way back in time, whatever we bothered to lug around with us was very likely essential for survival. Without it, our odds for survival go down, and so allowing such behavior will be selected against.

                Helping others is also something that would selected for. If you help someone, say by bringing them food when they cannot hunt or gather themselves, they are more likely to survive, and if you are helped, you are more likely to survive. What is interesting is that we can winnow down all these ethical codes and declare that our ethical feelings are all based on what will help our social group remain cohesive. As group animals, we depend on others for help. By banding together, the odds for all of us to survive increases.

                This is why most animals in the world live in groups. There is an evolutionary advantage to it. And such groups will develop rather complex ethical systems, at least in higher animals. What is interesting is that we do see these complex social systems develop. Chimps instinctively know it’s wrong to murder another chimp within their own group. Wild dogs will develop social structures without fighting or bloodshed, because such behavior would be counterproductive. It all points to an ethical code that evolved naturally, rather than having it being dictated by a supreme being.

Of course, one could argue that a god could have simply given us and the animals these codes because they do help with survival, but that does not mean that god’s sanction infuses these principles with “right” and “wrong”. They are right or wrong regardless of a god’s sanction.

So what is our evolved ethical code? If we test each one of these, we see that evolution easily selects for them (note: not all ethical codes are listed, due to lack of ingenuity by the author).

1)      Do not murder

2)      Do not steal

3)      Submit to authority

4)      Take care of your children

5)      Take care of the females in the group

6)      Promote promiscuity, especially among males

The last one is interesting contrasted against traditional Christian values. We are hard-wired to intrinsically feel all of these (and more), and it’s almost impossible to break them. Four billion years went into their development and a few decades of trying to oppose it is futile.