Things about science and nature you find interesting

[oktalist]

On topic, I just came across this: certain species of cicada have evolved life cycles 13 or 17 years long, in response to predation. 13 and 17 are prime numbers, so for a predator to synchronise its life cycle with a prey species that appears every 13 (or 17) years, it would have to live for 13 (or 17) years too, which would be too much of a disadvantage. But for example, 15 is not prime - it is divisible by 3 and 5, so for a predator to synchronise its life cycle with a prey species that appears every 15 years it would only have to live for 3 (or 5) years, any every 5th (or 3th) generation would be able to feed on the cicadas.

 

[hannahdonno]

A cat can get through any small space as long as it's head can get through.

I think that was the rat.

Yepp, through experience of owning a cat, they cannot fit through such small spaces.

 

[vague-rant]

Gibbs free energy

Summing chemistry up in a nice equation

 

[nathan-dts]

How you blow on your food to cool it, yet you blow in your hands to warm them.

 

[Danny Ocean]

I'd have to say the big bang, I mean nothing explodes and produces everything. One teeny problem I have with it though, how does nothing at all actually explode?

That's not it. Everything was concentrated to a single point, or singularity, which then expanded outwards with a massive outpouring of matter.

There's no explosion involved.

My point still stands though, nothing somehow became everything. Originally nothing existed, at all, and somehow the universe came into existance, thats what fascinates me, not whether its exploded or not. And technically and explosion is a rapid outpouring of matter, its not always a boom

No, technically an explosion is when something goes from a lower energy state to a higher energy state. Often this results in rapid expansion, also known as, "Ka-Bloomie!"

The point is that the Big Bang theory never says that nothing existed, just that it was all concentrated into a singularity which then expanded. If you want to go beyond that and ask where the singularity came from, well, no-one knows. Hence religion.

How you blow on your food to cool it, yet you blow in your hands to warm them.

Blowing on food both enhances convection currents in the air above it by giving the air an extra push, but it also cools it because the food is very hot compared to your breath. The opposite applies to warming your hands.

If you had a cold sandwich, and blew on it enough, it might even get warm.

 

[oktalist]

My point still stands though, nothing somehow became everything. Originally nothing existed, at all, and somehow the universe came into existance, thats what fascinates me, not whether its exploded or not. And technically and explosion is a rapid outpouring of matter, its not always a boom

Because it can. That's my explanation, and I like it. The multiplicity of universes exists so that everything that could ever possibly happen, has somewhere to happen in. Thanks Terry Pratchett.

But the way you phrased it is not quite right. I'm not sure you can say that nothing became something. It's just that there is something, and not nothing. "Originally nothing existed" implies there was "a time before the universe" but the concept of time only exists within the universe. There's no such thing as "before there was something" because time itself is something.

 

[cuddly_tomato]

--snip--

You still failed to do the exact thing that every other scientist working in the field has likewise failed to do - explain it how it came about in terms of natural selection, not just how it works now.

The only difference appears to be that proper scientists can at least admit this.

 

[GoblinOnFire]

[del]Black[/del] dark matter...

Can't be seen, can't be felt or tampered with, can't be contained by anything man made..

Who says it can't be felt, tampered with or contained?

Hey Oktalist!
wow, you've been busy on this thread, haven't you?

OK: Dark matter: Mass from atoms with no electrical charge

Since DARK matter (english is not my first language, but still: how did I miss that?) is something that, for the time being only exists i theory. In our universe (macro) were things are built up by electrical charged atoms, anything built from atoms with no electrical charge can not:
1: Be seen (Does not reflect light)
2: Can not be contained (the mass would not collide with anything in our universe)
3: Can not be tampered with (something that cannot be seen or contained can not be tampered with.)

Feel free to disagree, and please: explain to me what I've missed!

 

[Maze1125]

[del]Black[/del] dark matter...

Can't be seen, can't be felt or tampered with, can't be contained by anything man made..

Who says it can't be felt, tampered with or contained?

I was going to say, it's just a catch-all term for matter we can't see, isn't it?

Not really. It's theoretical matter that is postulated to exist to account for the fact that the rate of change of expansion of the universe is different from what we would expect from gravity acting on the mass of matter that we know about. We know we can't see it because we point our telescopes all over the sky and receive no electromagnetic radiation (light, radio, x-ray, etc.) consistent with its presence.

X = total mass of all matter that we know about;
Y = what the total mass of all matter would have to be for the universe to be expanding in the way it appears to be;
dark matter = Y - X.

Either there's dark matter (i.e. matter we don't know about), or we're measuring the expansion of the universe wrongly, or there's something wrong with our theory of gravity. Or there's something else crazy going on.

Actually that's dark energy.
Dark matter relates to galaxies, not the entire universe.

By current theories, galaxies are spinning too quickly to stay together, hence they must have more mass than we can detect.
Hence, dark matter.

In short:
Dark matter keeps galaxies together.
Dark energy pushes the universe apart.

 

[Zorg Machine]

Barnacles have the largest penis relative to their size of any animal.

this. btw what movie was this mentioned in?

 

[oktalist]

wow, you've been busy on this thread, haven't you?

This thread is awesome.

OK: Dark matter: Mass from atoms with no electrical charge

Since DARK matter (english is not my first language, but still: how did I miss that?) is something that, for the time being only exists i theory. In our universe (macro) were things are built up by electrical charged atoms, anything built from atoms with no electrical charge can not:
1: Be seen (Does not reflect light)
2: Can not be contained (the mass would not collide with anything in our universe)
3: Can not be tampered with (something that cannot be seen or contained can not be tampered with.)

Feel free to disagree, and please: explain to me what I've missed!

Two things:

1. Okay I might let you have "can't collide with anything." If it permeates the whole universe then I guess that's probably true. But to be clear, it can't be seen, can't be contained and can't be tampered with, yet. If we figure out what it is then maybe we will invent some way of tampering with it. But not necessarily in that order.

2. Lots of atoms are electrically neutral. Only when they react with other atoms to form molecules do they become electrically charged. Helium, neon, argon, krypton, xenon and radon all occur in nature with no electrical charge. All can been seen (by spectroscopy, for example) and all can be contained. So electrical neutrality is not enough on its own. And it's unlikely to be atoms at all. More likely some weird subatomic particle.

EDIT: thanks for the correction re matter/energy - galaxy/universe, Maze.

EDIT2: ah, I guess you might have meant particle, not atom, as English is not your first language, Goblin. EDIT3: but then I would have to point out that neutrons are also chargeless.

 

[oktalist]

--snip--

You still failed to do the exact thing that every other scientist working in the field has likewise failed to do - explain it how it came about in terms of natural selection, not just how it works now.

The only difference appears to be that proper scientists can at least admit this.

Science has done this. I explained not just how it works now, but also how it may have come about through natural selection. ("it" being eusociality) Allow me to summarise. Obviously we can't be sure about the exact details, and there is an inevitable oversimplification in describing a complex, continuous, interconnected nexus of partially simultaneous processes in the discrete, sequential medium of the written word, but it probably happened something like this:

- We start with a species that is experiencing high rates of predation, and is not social.
- Maintaining proximity to other individuals confers a selection advantage in avoiding predation.
- Building a shelter or burrowing into the ground confers a selection advantage in avoiding predation.
- In haplodiploidal species, there is a selection advantage to genes which cause individuals to gather food for their sisters instead of for their own offspring, and such behaviour is made possible by their proximity and fixed base of operations. Obviously such genes might eventually reach a point of such saturation in the gene pool that they are no longer advantageous as they would cause too few offspring to be produced -- as this point is approached the number of individuals in which this gene is expressed levels off to a steady optimum.
- These sister-rearers no longer use their reproductive systems, which become vestigial and functionless.
- The individuals which are still reproducing, and having their offspring cared for by that proportion of their older offspring who don't reproduce, don't need to do any rearing of young and so evolve towards immobility and putting all their resources into reproduction.

I thought that I, and the scientists referred to by Wikipedia, had explained this already. What's missing?