The " I always wondered" thread

[TCO]

Ramo, by extension, should we expect a negative correlation between athletecism and IQ within the human race?

[DAVOUT]

Originally posted by Eli
Continuing Azazel's question... What's the explanation to this?

If I travel at 0.99c in a certain direction and a lightwave travels at c in the same direction I will measure it's speed as c, right? But why? Is it because the time dilation that I will experience?

Your motion does not change the laws of the universe. The relativist effects occurs only when more than one observer/object are in the game.

You cannot measure the time dilatation until ANOTHER observer somewhere tells you that his clock shows a different time.

[Bosh]

Thanks Ari neoteny was exactly the word I was looking for. Human evolution was a neotenous process!

[Urban Ranger]

Originally posted by Eli
Continuing Azazel's question... What's the explanation to this?

If I travel at 0.99c in a certain direction and a lightwave travels at c in the same direction I will measure it's speed as c, right? But why? Is it because the time dilation that I will experience?

You will experience time dilation, even though you cannot measure it, but that's not the cause. The cause is your "ruler" has shortened in the direction of your travel.

[Dauphin]

I thought life expectancy of various animals was generally related to metabolism. Turtles and tortoise may live upto 200 years, but then they aren't the most active of animals and have a low metabolism. Shrews, mice and such like expend a lot of energy relative to body size in order to maintain body temperature, and so have a high metabolism.

I also recall reading somewhere that nearly all mammal species have the same number of heart beats, give or take, before they die of old age.

[Japher]

If I travel at 0.99c in a certain direction and a lightwave travels at c in the same direction I will measure it's speed as c, right? But why? Is it because the time dilation that I will experience?

Just to note that if someone is traveling at 0.99c there is no time dialation, this only occurs during times of acceleration. Thus, compared to someone else, at a different relative we could be traveling 0.99c right now!

[johncmcleod]

Some animals live a few days, some animals live 200 years or more. Humans live around 80 years. Why?

It is determined by the length of the organisms telemeers. When they run out, the organism dies of old age. Genetic engineers changed the telemeers of a type of worms and they now can't die of old age. There's a site on it, but I forgot what it was called. I still don't understand why organisms with longer telemeers wouldn't be naturally selected. Think about it. If an organism could live for a really long time without growing too old to reproduce, it could reproduce many more times than an organism with a shorter life span. The organisms with longer telemeers would pass their genes on more often.

Whoever said "Halten Sie!" means hold this is wrong. To hold is behalten, to stop is halten. And Sie is addressing someone in the familiar form, not the word this. This is dies+(whatever ending is appropriate).

There's a ton of stuff I've always wondered about but I can never think about any of them when I need to.

[Ramo]

Ramo, by extension, should we expect a negative correlation between athletecism and IQ within the human race?

Probably not. If a person is athletic, he could just eat more. He doesn't need a less powerful brain to insure that he'll get enough energy. In hunter-gatherer societies, extraordinarily high strength probably would've been selected out of the population. Of course, minor variations in genetic diversity among the genes determining strength is kept within a population to insure adaptibility.

And I don't think there is significant diversity in energy needs for the brain among humans.

Until there was broze, most spears were constructed pretty much the same. Of course, after awhile, bows and arrows replaced spears as ranged weapons.

Right. I was speaking metaphorically. A greater capacity to think had been much more important to human survival than strength.

If I travel at 0.99c in a certain direction and a lightwave travels at c in the same direction I will measure it's speed as c, right? But why?

That's simply a postulate of Relativity. The speed of light in a vacuum is the same according to any inertial observer.

Einstein's logic went like this: Say, you've got a straight road and a huge magnet such that its poles are on the sides of the road at some point. And then you have a car, with a circular wire in it, travelling down this road at a constant velocity. According to you, there will be this magnetic field is affecting the moving charges in your wire loop, causing an EMF along the loop, the negative change in magnetic flux through the moving loop. Now, some guy sitting on the magnet could interpret the situation as a stationary car and the magnet travelling past it. He thinks that now the magnetic field is changing, causing an EMF along the loop, the negative change in magnetic flux through the loop. So, you get the same EMF regardless of which observer is watching the loop even if the physical interpretation, ostensibly, is different between the two situations. And if the prediction is the same, either observers are correct. So, the idea of absolute rest is bollocks, and physical laws are applicable in any inertial reference system.

And experimental evidence, Michelson-Morely, fit within this idea.

But according to Maxwell's equations, light travels at c in a vacuum. If there's no absolute rest - no ether, then light travels at c in a vacuum according to any observer.

I've always wondered:
Our entire galaxy is moving. wouldn't that mean that that inside the solar system, light would go slower one way than the other?
( I can't wait to get to Relativity in uni, finally, it will all be explained. )

Light won't go slower as it always goes the same speed according to any inertial reference system, but the frequency of the light would be shifted depending upon the direction the light is going.

Just to note that if someone is traveling at 0.99c there is no time dialation, this only occurs during times of acceleration. Thus, compared to someone else, at a different relative we could be traveling 0.99c right now!

There is time dilation according to the observer that he's going .99c with respect to.

[TCO]

Originally posted by Ramo


Probably not. If a person is athletic, he could just eat more. He doesn't need a less powerful brain to insure that he'll get enough energy. In hunter-gatherer societies, extraordinarily high strength probably would've been selected out of the population. Of course, minor variations in genetic diversity among the genes determining strength is kept within a population to insure adaptibility.

And I don't think there is significant diversity in energy needs for the brain among humans.

think about it for a second. Yes the differences in strenght are much smaller, but so are the differences in IQ as well. (taking the intraspecies comparison in analogy to the intraspecies comparison). And I'm not looking for a perfect correlation (rsq =.99), just anything that is statistically relevant at a 95% confidence versus noise. Even a 10% correlation would be interesting.

[DAVOUT]

Originally posted by Big Crunch
I thought life expectancy of various animals was generally related to metabolism. Turtles and tortoise may live upto 200 years, but then they aren't the most active of animals and have a low metabolism. Shrews, mice and such like expend a lot of energy relative to body size in order to maintain body temperature, and so have a high metabolism.

I would say that any particular metabolism is selected because it fits a particular average life expectancy required.

[Ramo]

The thing is, I don't think slightly stronger and slightly smarter people than average would be selected out of the population, and neither would slightly stronger weaker and slightly dumber people. I don't think the differences are significant enough. Selective pressures only come in when the differences become important.

[Starchild]

Regarding Environmentalism and Nuclear power:

Some greens are just nutjobs that want to see people eating granola on communes while some vague, environmentally friendly process lets them have electricity. These are the people that ***** about fossil fuels then go and complain about wind or tidal plants cause they also disrupt the natural environment. We ignore these people and wait for them to choke on their granola.

Personally, I consider myself a rational green and I dislike nuclear power on the following grounds:

It's unviable. British nuclear just got a huge state payout to keep them in business since nuclear power just isn't profitable. We're in the **** with the European Commission rules on state aid now and it's just been wasted money. (sink or swim by the energy market honey, don't come whining to the taxpayer.)

It's short term. Fissionable material isn't an unlimited resource that will last for the next 5 billion years (unlike any process such as winds, solar, or tides generated by the sun/moon).

The waste products are dangerous, no one wants them, it's a headache to get rid of them, and they'll last for quite a while.

Breeder reacters, ones that generate their own fissionable material, are expensive and attractive targets for anyone wanting to get their hands on weapons grade stuff. Maybe not a problem in the First World, but the gods know it's a bit frightening to see some countries build these things.

Personally I want us to decentralise power supply and move a lot of it off world. Easiest way to avoid polluting the Earth? Remove it from the Earth. A mix of space based solar energy collectors beaming energy to powernetworks supplemented by local wind/tide/hydro plants would be ideal. Most energy would of course go into the electrolysis of water to provide hydrogen.

[MrFun]

Why are Oreos made with trans-fat?

[Japher]

Why are Oreos made with trans-fat?

Why is toothpaste in a tube? Wouldn't it make more sense to put in a jar?

[Sandman]

Here's a question that's been bothering me:

Why in God's name do we have dentists? Surely their job could be performed by a standard family doctor? There are various specialisms within medicine, but dentistry seems to somewhat 'apart' from the rest of the medical world.