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Thx for the info Tim.

Hi https://www.physicsforums.com/member.php?u=332254 The reason i joined PF 5 years ago was with a similar question i had after finding this site http://www.besslerwheel.com/ This site concerns a perpetual motion machine. But after talking to the people on PF i now realize that there can be...

Just read this..http://www.world-nuclear-news.org/RS_Venting_at_Fukushima_Daiichi_3_1303111.html What are the implications of pumping sea water into the reactor, as this seems be a last resort?

Hi The shapiro effect... i'll look into that. Thx.

Hi. Thx so much for this info, i will read now.

Hi. Does the light from a lensed object take longer to reach us, than the light from an unlensed object at the same distance. I mean because the light from a lensed object has a curved path. Thx. Dave...

Thx for reply, i think i have found what i was looking for

Does a gravitational lense have a focal point, like a nomal lense but as a focal point sphere/horizon. if so is there a formula that relates the mass of the GL with the radius of its focal horizon. Happy xmas.

Thx for your answers, I'm still trying to find out what it was from searching the web. It might have to have it shifted into the unexplained file..

Looks to me like a band of water that is separating the still ice from the rotating ice. What gets me though, is, has this area of water any properties that differ from the normal (ice, water, steam) solid, liquid, gas? I mean, why is the band so wide if its only friction that's wearing...

After some very strong winds last night here, in the U.K. There is an oily type residue which is visible on external glass surfaces ie windscreens. This effect has happened over a 25 mile radius as i know off. Could this be any thing to with hurricane tomas, lifting oil from the surface in the...

Hi, Welcome to PF, Whats your main area of interest?

Thx for your reply Johnathan, i never thought to look on there. lots of interesting stuff.

Hello. In the attached a diagram there are 2 stars on the left, the upper star is the apparent position as veiwed from Earth and the lower star the true position. The central star is the Sun Could anyone give or direct me to an equation for the angle by which the light is deflected aº in...

This only happens when the atom has an energy level that matches the energy level of the photon. If the energylevel does not match the photon energy, it does not go back to the light. The energy instead goes toward increasing the motion of the atoms, which causes the material to heat up

Most colours seen in ordinary experience are caused by the partial absorption of white light. The pigments that give colour to most objects absorb certain wavelengths of white light(adding to the internal energyof the object) and reflect or transmit others, producing the colour sensation of the...

If you put your fingers over the body part and just look at the top of the head and shadow part, in my view the head is going a different way than the feet...

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Thx for a good puzzle..Dave

Is the energy of the x-ray equal to the transition from muon to electron or is there some energy taken from the nucleus..as in ccs to uud

Hi bob, If the muon decays whilst in the ground state where does the energy come from to keep the atom in the ground state

A hydrogen atom is consists of a proton (uud quarks) and an electron. Is there a heavier atom of hydrogen that consists of a type of proton (ccs or ttb quarks) and a muon or tauon respectively? Are these

Thx for that explanation Vanesch

I have heard that the chemical structure of boron carbide is unknown

What are the odds that any 6 consecutive numbers in any order can come in the UK lottery?

Hi all, just looking on google Mars and have found an unusual crater, it seems to me that a meteorite has landed in another meteorites crator. Has this really happened or is there some other way this effect could be created? The coordinates of the crater on google Mars are, 19°53'15.38"N...

Looks good to me..

I like your question.

You could take the temperature of the steak, then take it to the top of your chimney and dropit and retake the temperature Then work out the hieght needed for it to cook to your liking, taking into account things like decreasing air resistance, type of marinade etc

While just standing on creaking floorboard, i was thinking about where the energy came from to create the noise. I assume it came from me moving my mass over the creaky point, therefore do i lose more energy walking on creaky floorboards than just normal floorboards?

Hello mgb_phys, Thanks for your reply, is there a theory for inflation in general relativity? I'm a bit of a newbie on this subject.

Did anti gravity exist at the beginning of the universe when the conditions were hot/high energy, which repulsed matter at a rate proportional to the square of the distance (inflation maybe) until, the universe had expanded and cooled enough for this force (anti gravity) to return to normal...

Hi Bob i,m interested in acceleraters and have visited CERN do you work with acceleraters?

thx for reply Bob, where does the energy come from for synchrotron radiation... is there a change in mass of the charged particle, or is the amount of energy needed for S.R. equal to the magnetic energy/force applied to the particle.

Thanks for the link, it looks like good read. i just started reading the introduction and on page 3 Humphries states that " magnetic forces cannot affect a particles kinetic energy". 1 question. Do the photons of synchrotron radiation not carry away/convert the kinetic energy of the particle?

what i mean is... What is the mecanism for 1 photon in 2 photons out exactly matching the 1st photon...is this not a violation of energy conservation? thanks for your reply

thx Cthugha i will have a look at Fermi's golden rule.

Thx for your replies, but they really don't answer my question... Could the smallest/longest wavelength be ascosciated with zero point energy?

The above quote is from another thread about a month ago, so i started another thread. As above...red light about 600 nanometers, blue light about 400 nanometers, so what could the smallest possible wavelength of light be or is it infinely small? or the longest possible wavelength for that matter

hi Integral I've looked for the arago spot but noluck yet, have you any ideas on size of circular object or distance to shadow/object/laser thanks dave.

wow thanks for all your replies, the holography looks good especially when you read how it works...thats why i love physics... brilliant and thanks too Lambduh some good ideas there dave.

thx lok i'll try these (1st two) hi I've looked at holography, would it be possible to replace the photographic paper with a digital camera??

Hi all, I've just got hold of a used helium neon 1 mW laser (spectra physics model 155) and would like to some experiments at home, does anyone know any good examples Thx

Thank you for all your replies, its just that it seemed a lot redder than usual that night and i was watching for a few hours its been overcast since so not had a chance to see it recenctly, thanks again all.

Hello all I'm here in the uk just lookin at Betelgeuse and for some reason it looks redder tonight has anyone any idea why? thx

Hello all, i was just wondering if there ever will be or, could be an equation that describes gravity in relation to a constant, ie, g = ? x constant.

Do you think that the human race will still be around in a few billion years?

what does the m for stand for ? sry that's what i should have typed.

Hi all could anyone tell me what units are used in the equation E=MC. Thx, Dave.

oh yeah doh, thanks dick