1

New Theories / Solution for global warming?

« on: 25/08/2009 20:17:15 »

The problem is that physical processes that can separate the CO₂ all take energy to drive them. Unless lots of energy is available to you from a very low carbon source (e.g. nuclear) you're going to emit more CO₂ than you remove - and yes I do know that some materials naturally absorb CO2 but again these take energy (and hence, usually fossil fuels) to manufacture.

And, if you overcome all that, it'll take an awful lot of work to remove billions of tonnes....

I'm not saying it'll never be done, but it doesn't appear to be practical at the moment?

2

Physics, Astronomy & Cosmology / Do hydrogen bombs cause radioactive fallout?

« on: 25/08/2009 20:07:15 »

As you say, most natural hydrogen is not radioactive (i.e. excluding a small natural tritium content. But, during a fusion reaction both ionising and non-ionising radiation (e.g. neutrons, gamma rays, x-rays and alpha and beta particles) will be produced. Some radioactive isotopes (e.g. tritium) will also result from the reaction.

More signifcantly, if a fusion bomb is exploded close enough to ground level a significant quantity of surface soil, water, plants etc.. will be lifted and activated by the intense radiation. This can give a very wide variety of radioactive isotopes which will be manifest as 'fallout'.

Tests have shown that a fusion bomb exploded high enough produces less fallout, but syphrum says, the fission trigger can be significant on its own.

3

New Theories / Do physicists understand physics?

« on: 17/01/2008 19:33:37 »

All guilt lies on physicists.

So to use mathematics makes me guilty...? Of what? Believing that there might be some correspondence between a mathematical model of the world and my perception of the world?

Ok. Lock me up.

(That's what Physics is for).

4

New Theories / Philosophy of Physics and Religion.

« on: 17/01/2008 19:28:22 »

In what way does any of this constitute an "Explanation"

5

New Theories / The darkness and the light....

« on: 17/01/2008 19:27:09 »

So following that line:- If We are in the end, all Gods children, it follows that we all have the light of God within us.

Alternatively, there is no god and you have to make the effort to find your own answers...

6

Physics, Astronomy & Cosmology / Another Question About The Speed Of Light

« on: 22/11/2007 20:39:36 »

I know the feeling.

But sometimes Mr Fry is just plain wrong; his 'electricity' themed programme made a few errors anyway.

7

Technology / how many Megapixels would the human eye have?

« on: 22/11/2007 20:37:37 »

Just had another thought - if the above post is true why can I see the difference between a 1 milllion pixel image and a 4 million pixel image?

Answer: I don't see the whole image all at once unless I'm standing back from it, in which case I probably won't be able to tell the difference...

I remember I saw the way we 'see' demonstrated in a science documentary where the motion of the eyeball was tracked as people looked at images (paintings etc...). The track of the eye over a few seconds traced out the significant parts of the image. An unmoving eyeball rarely picked-out any detail from the edges of the picture..

8

Physics, Astronomy & Cosmology / Another Question About The Speed Of Light

« on: 22/11/2007 20:32:22 »

Nice. []

9

Physics, Astronomy & Cosmology / Causality

« on: 22/11/2007 20:28:47 »

Sorry,

Re-reading the posts I think you've already covered this.

But, don't you find the idea of an electron as a 'point-like' particle quite appealing (regardless of the wave-like behaviour you can also measure)?

10

Technology / how many Megapixels would the human eye have?

« on: 22/11/2007 20:14:39 »

I accept that diffraction and dispersion are going to be important to the maximum resolution in vision and that the brain plays a big part in what you recognise of what you see.

But...

They eye is composed of discrete photoreceptor cells, which are finite in size. In this respect we have 'digital' vision.

According to one reference I found, the peak light-recieving cell density in the retina is about 4000 cells/mm²; with a total of around 130 million cells - or 130 megapixels! In reality, the optic never is more limiting at only around 1.2 million fibres, so your retina 'pre-processes' your image down to around a megapixel.... it's like we're seeing in JPEG rather than BMP.  []

11

Physics, Astronomy & Cosmology / Why Does The Earths Poles Switch ?

« on: 22/11/2007 19:56:02 »

If the earth's core is acting as self-exciting dynamo then (if I recall corectly) the magnetic field can be reversed without reversing the physical direction of rotation.

12

Physics, Astronomy & Cosmology / Another Question About The Speed Of Light

« on: 22/11/2007 19:53:49 »

And another quote from Wiki:

It is sometimes claimed that light is slowed on its passage through a block of media by being absorbed and re-emitted by the atoms, only traveling at full speed through the vacuum between atoms. This explanation is incorrect and runs into problems if you try to use it to explain the details of refraction beyond the simple slowing of the signal.

The alternative explanation offered involves a 'mixed' wave of electromagnetism and mechanical oscillation within the material. This sems more credible to me... as:

(1) the absorbtion/re-emission explanation doesn't look to likely in a low-scattering media i.e. why wouldn't a light beam lose direction and/or coherence?

(2) it ignores the wide range of wavelengths over which media (such as glass) are continuously transmissive whereas absorbtion tends to occur at relatively well defined frequencies.

13

Physics, Astronomy & Cosmology / Causality

« on: 22/11/2007 19:35:00 »

Electrons have no measured size.

You are confusing the DeBroglie wavelength with physical size; see http://en.wikipedia.org/wiki/De_Broglie_hypothesis. The low momentum of thermal electrons is what gives rise to the small DeBroglie wavelength and hence the high resolution of electron-microscopes.

The physical dimensions of the electron have never beem measured; even clasical physics arrives at a size <3 x 10^-15m. But they could be genuine 'points'..?!?

14

General Science / Why would anyone put TSP into their foods??? (Trisodium Phosphate)

« on: 22/11/2007 19:20:20 »

Other uses for TriSodium Phosphate...

We have hundreds of kilos in porous bags in the bottom of our Reactor Containment Building! The idea is that if the Reactor Coolant System ever developed a leak, the TSP would re-balance the pH of the 1600 tonnes of slightly acidic water that gets pumped into the building to keep the core cooled (the water is lightly acidic because it is dosed with boric acid, a good absorber of neutrons).

The only real problem with the TSP is that it slowly absorbs water from the atmosphere - so the bags eventually swell and split.

15

General Science / Can we talk ourselves into liking a certain food?

« on: 22/11/2007 19:15:34 »

I heard a radio programme in which it was claimed that deliberately eating something you didn't like would eventually remove your dislike for it. I'm 41 years old and up 'until very recently never ate carrots, green beans, broccoli. I tried what was suggested and after half a dozen meals now find that I really enjoy the beans and broccoli. I'm still not keen on carrots and can't bear the thought of peas, but what they suggested certainly had some truth in it - my grandmother couldn't believe I was finally eating some greens!

16

New Theories / sticks,string, and mud.

« on: 16/09/2007 09:48:11 »

so can anyone name any man made thing that does not involve mud,sticks or string in some form or other?

Mathematics...
Language...
Philosophy...
Religion...
Music... (the sound not the instruments!)

17

Physics, Astronomy & Cosmology / Is ' DARK' Something...like ' Light' is ?

« on: 16/09/2007 09:39:02 »

In fact any'thing' , as well as being what it is is also a 'lack of everything else'. Owch.

So what about a lack of vacuum...?

Or maybe a lack of Dark...?

In other words, can you have a lack of a concept that is itself a lack....

Batroost

18

General Science / What exactly is that??

« on: 30/06/2007 13:38:15 »

Or none of these are true - more to do with spiritual beliefs than science.

There is a quantum mechanical force that can be measured between two closely spaced conducting surfaces; known as the Casimir effect....

19

Just Chat! / Fantasy dinner party

« on: 28/06/2007 21:27:26 »

Someone who could cook.

Someone who could do the washing-up.

Someone who could pour me a drink whilst the other two were busy....

20

New Theories / Thought Predictor

« on: 28/06/2007 21:23:38 »

But, the questions to answers do not vary.

OK.... Answer: "None at all"

Question 1: "How much Beer did you drink today?"

Question 2: "How many ducks did you see today?"

Two completely different questions, same answer..?!?