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Archive for August, 2012

Radar-like Solar System

You know how all the planets around the Sun move at different speed and distances from the Sun? Would it have been possible, by luck or extension of how the solar system was made, that all the planets would always be at the same angular position? Would it be possible that all the planets would always be aligned perfectly?

 

In the previous equation, the velocity of an object is its angular velocity times the radius. If we want all the planets to be aligned, T (how long it takes to do a complete revolution) must then be constant.

r (the radius, or the distance between the Sun and the body) is the variable here, which gives us the body’s speed through space.

Is that all there is to it?

 

Kepler’s Third Law of Planetary Motion indicates that

meaning that the time taken for one orbital period, squared, is proportional to the distance from the sun, cubed.

For the Earth, (149,598,261,000m)^3 / (31,556,736s)^2 = 3.362E9. For Mars, (227,939,100,000m)^3 / (59,354,294.4s)^2 = 3.362E9. Same thing for the other planets.

And that means that, for a given orbital period (say, one julian year), a planet can only be at a specific distance from the Sun.

 

So, no, a planetary system can’t have all its planets constantly aligned. But that would be eerily cool!

Categories: Science

Gravitational Pull of Distant Objects

I had a bit of fun today trying to explain to a friend how a star millions of kilometers away could have a gravitational pull on us.

It’s pretty simple, and still relies on Newton’s Law of Universal Gravitation.

 

 

Gaia, Mother Earth

Our planet has a mass of 5.97E24 kilograms, and a mean radius of 6.37E6 meters. Let’s assume a human mass of 75 kilograms (165 lbs) for the equations on this page.

The Earth pulls a 75kg person with a force of 736.22 N. One Newton is equal to an acceleration of one meter per second per second, for a weight of one kilogram. If we divide the force by our mass of 75 kg, we get Earth’s gravity, 9.81 m/s^2.

 

Sirius, the Brightest Star in the Sky

It’s actually two stars, Sirius A and Sirius B. Since Sirius A is twice the mass of the Sun, and Sirius B is about the same mass as the Sun, they have a combined mass of 5.96E30 kilograms. The binary star system is about 8E16 meters away.

All this means that Sirius pulls you with a force of 4.66E-12 N. If all the universe was to disappear, except for Sirius, we would initially fall towards it at a rate of 6.21E-14 m/s^2.

 

Polaris, the North Star

The north star is six times heavier than our Sun, and is 433 light years away. With values of m = 1.19E31 kg and r = 4.10E18 m, we can calculate that Polaris is pulling you with a 3.54E-15 N force.

 

Proxima Centauri, our Closest Neighbor

With a mass of 2.45E29 kg and a distance of 4.01E16 meters away, Proxima Centauri pulls you with a force of 7.62E-13 N.

 

The Andromeda Galaxy

Andromeda is 2.40E22 meters away (it takes light 2.5 million years to reach it), and has an estimated mass of 2E42 kg (one trillion Suns). It pulls you with a force of, wait for it, 1.74E-11 N. It pulls you stronger than Sirius, which is a million times closer.

 

Last but not Least, the Moon

The moon has a mass of 7.3477E22 kg, and a mean distance of 3.84399E8 meters from the center of the Earth.

If the moon happens to be exactly overhead, it pulls on you from a distance of 3.84399E8 m – 6.371E6 m (the radius of the Earth) = 3.78E8 m, exerting a force of 2.57E-3 N.

If, on the other hand, the moon would be on the opposite side of the Earth, its distance from you would be 3.84399E8 m + 6.371E6 m = 3.91E8 m, exerting a force of 2.40E-3 N. This is actually a big difference of around 7%!

Even at its strongest, we would not consciously feel the moon. After all, Earth’s pull is almost 300,000 times stronger!

And before you ask, even on top of Mount Everest wouldn’t change anything.

Categories: Science Tags: ,

Are Microwaves Bad or Not?

I’m not talking about a normal microwave usage, which can be dangerous if you lack common sense: Health Canada’s Microwave Ovens and Food Safety. Also, don’t heat your baby in a microwave oven.

I’ll talk about my point of view regarding the “conspiracy” that microwaves are inherently bad for the health.

 

The story goes like this: In 1991, a woman is at the hospital for a hip surgery, and is killed by a blood transfusion which has been heated in a microwave. There was then a lawsuit by the family against the hospital and many doctors.

Would it be reasonable to conclude that microwaving something changes the molecular structure in a way that is harmful to us? Biologically, it’s more reasonable to say that the blood cells were killed by the microwaves, and that it’s the transfusion of dead blood that killed the patient, not the fact that a microwave was used. But I’m assuming that the blood was heated to the same temperature normal transfusions are heated to by traditional methods – why, then, did it kill the cells? Are microwaves only dangerous towards living things, and don’t change the molecular structure of others?

I’ll talk very briefly about Hans Hertel, and you can read more about his experiment. Basically, his experiment was to monitor blood before and after eating various meals. Some were raw, some were heated on the oven, and others were heated in a microwave. If we can trust the results, using a microwave is unhealthy (decrease of all cholesterols, short-term decrease of white blood cells followed by over-normal levels, …). All pointing towards the conclusion that the body fights microwaved food and shows cancer-like symptoms. Meh…

 

Normally, you have to take a study or research with a grain of salt, even if published in a prestigious journal. So much data can be tweaked to make it look favorable to the author’s goal, and this experiment is no exception.

But. I know enough about how big companies work, and the way they don’t want attention to some… things. The FEA (Swiss Association of Dealers for Electroapparatuses for Households and Industry, and couldn’t find a website) issued a gag order against Hertel, effectively telling him to stay quiet about this, or else. I didn’t find the gag order on the Internet, but it took him five years to revert the ruling at the European Court of Human Rights.

Now I think the FEA went a bit berserk. Companies usually counter with their own studies or experiments (whether they are true or false), or just continue as if nothing ever happened (like the government of the USA concerning 9/11, or NASA against conspiracy theorists saying that nobody ever went to the moon).

 

Let’s just assume that the FEA were just very angry. What do we actually know about microwaves (and please understand that my knowledge of microwaves is not very deep)? The microwave oven generates an alternating electromagnetic field, which causes the molecules inside the food to realign, if they can (if they are electric dipoles, like water molecules), to follow the field, absorbing energy as they do.

I wouldn’t want the water molecules inside my body to rotate and absorb energy, so it’s a bad idea for me to step into a microwave oven. But what about, say, a glass of water? What difference does it make if the molecules inside were wildly dancing before you put your tea bag in it? Maybe nothing. Maybe there is no difference, and heating, say, an apple will leave it’s molecular structure intact.

Then again, nobody knows. The only thing that microwave oven manufacturers have to do is to show that the microwaves do not leave the oven. There is no law, and there never was any, that required any company to publish a study that showed that food heated in a microwave is totally safe to eat. The government is doing the same thing they do with chemical fertilizers, pesticides, food preservers, etc…

 

Some will say that everything around us throws various photons of different wavelengths. Light, cellular phones, radios, IR remotes… With the amount of electromagnetic radiation we’re submitted to on a daily basis, 24/7, microwave heating would not change anything.

Actually, the key point here is that the microwave oven generates an “alternating electromagnetic field”. All these things around us are direct electromagnetic fields – light starts from the sun and hits you, then scatter away. Radio frequency starts from the top of the tower, and everything can catch the radio field. If you were inside a microwave oven, the microwaves would oscillate back and forth very quickly inside and around you.

It’s akin to direct and alternating current. For a house current voltage (110V), you need about 60mA of AC (alternating current) to cause fibrillation (unsynchronized contractions of the heart, usually leading to cardiac arrest if untreated), while 300-500mA of DC (direct current) is needed. 10,000V of AC is usually fatal, while you have a 1:4 odds of dying from a lightning strike (3,000,000V). Does alternating electromagnetic field do anything to the food that the body doesn’t like? Your bet is as good as mine.

 

Maybe it’s my pessimistic nature, but I know that people don’t like to change, especially if they lose convenience. They don’t care about their long-term health if they can have a dinner ready in 3 minutes instead of 30.

Also, according to an article in Pediatrics (vol. 89, no. 4, April 1992), heating breast milk, even at low power, destroys some disease-fighting properties of the milk (which is very important to the baby). And don’t get me started on cow milk, please.

 

So, is microwave ovens bad or not? No one knows (or do they?), but that’s enough to make me suspicious. After all, think about your microwaved apple – playing with the molecules inside really doesn’t seem natural!

I’ve used a microwave oven only about two or three times in the past five or six months, and I’ve learned something: I don’t really need it. I don’t know why, but eating cold leftovers doesn’t bother me anymore. It also seem like another kind of meal, and tastes different, than the first one that was hot. Also, taking the time to cook something the traditional way seems more appetizing now.

And that’s the person I’m evolving into: someone more natural. Until I have a reason not to, I’ll just live my life more naturally, without microwave ovens.

Categories: Health, Thinking