/sci/ - Science & Math

wrong on many levels

you mean, wait, you... er.... wait... what the fuck? my brains!

>>4782932
>but is capable of moving objects with radiation pressure

nope.jpg
also lrn2reletivity

That's like saying if you push something one light year long you will have transmitted an object faster than light. Things may be able to move faster than light (hartmann effect, epr paradox) but it's not that fucking simple. Also photons do not have mass, so momentum does not work like regular objects with them.

>>4782950

>also lrn2reletivity

E=PC - Lrn2physics

There was an experiment where they put a very thin aluminium sheet in a glass tube after vaccuuming all the air inside. Then spinning the thin sheet with a strong light source. Does anyone know that video ?

WTF IS that a picture of... because I'm seeing eyes, ears, ribs, heart and hipbones.

>>4782962
Yeah, radiation is a form of energy. Not in the way the OP describes, though.

>>4782932
>>4782962
>>4782990
http://www.youtube.com/watch?v=vnBRdNuEvsU&feature=related

>>4782976
its a photograph of the known universe. The known universe looks like a giant skinny rat gerbil super being.

>>4782932
HURR DURRR, you are choosing a reference frame which is "convenient" for you. Conservation of energy does not hold in such a frame, neither does relativity, QFT, or ANYTHING FUCKING ELSE. You do not understand the origin of radiation pressure, either. Photons and other particles ARE NOT FUCKING LITTLE BILLIARD BALLS THAT BOUNCE OFF OF OTHER BILLIARD BALLS. Particles are WAVE PACKETS. If you've taken any fucking physics above babby level classical mechanics, you'd see this.

OP is thinking this:

Take a free electron at rest, so the total energy is simply the rest energy <span class="math">m_oc^2[/spoiler], and a photon of energy <span class="math">E_{ph}[/spoiler]

Apply momentum conservation <span class="math">E_{ph}\,=\,m_e vc\,=\,\gamma m_o vc[/spoiler], where <span class="math">\bar{u}[/spoiler] is the unit vector in the direction of the photon and recoiled electron, <span class="math">m_e[/spoiler] is the relativistic electron mass, and <span class="math">m_o[/spoiler] is the rest mass.

Energy is then <span class="math">E_{ph}\,+\,m_o c^2\,=\,m_e c^2\,=\,\gamma m_o c^2[/spoiler], so <span class="math">E_{ph}\,=\,(\gamma - 1)m_o c^2[/spoiler], then you get <span class="math">E_{ph}\,=\,\gamma m_o vc\,=\,(\gamma - 1)m_o c^2[/spoiler] after substituting for <span class="math">E_{ph}[/spoiler], which simplifies to <span class="math">\gamma v\,=\,(\gamma - 1)c[/spoiler], requiring <span class="math">v=c[/spoiler]. THIS DOES NOT FUCKING HAPPEN.

>>4783060
Instead, you have 4-momentum transfer via Feynman rules on the electron like this <span class="math">q^2=q^\mu q_\mu = (p^\mu_f - p^\mu_i)^2 = -4E_f E_i sin^2 \left ( \frac{\theta}{2} \right )[/spoiler], with <span class="math">p^\mu_f=(E_f, p_f)[/spoiler], <span class="math">p^\mu_i=(E_i, p_i)[/spoiler] and with a cross section <span class="math">\frac{\mathrm{d}\sigma}{\mathrm{d}\Omega} \propto |M|^2 \propto \frac{e^4}{q^4} = \frac{16\pi^2 a^2}{q^4}[/spoiler]

If you don't know QFT (which I'm assuming you don't if you're retarded enough to use the wrong frame of reference) look at this http://www.gwyndafevans.co.uk/thesis-html/node11.html#SECTION00311000000000000000 or READ A FUCKING BOOK (pic related)

\thread

>>4782957
>hartmann effect
Bullshit PSEUDOSCIENCE, incorrectly formulated with virtual particles, and inaccurate measurements.
http://adsabs.harvard.edu/abs/2010arXiv1003.3944N

>>4783063
>>4783060

calm down bro, not everybody is a physicist.
Some people just know how to make a damn good hotdog, and are probably appreciated by more people for it.

>>4783154
>Some people just know how to make a damn good hotdog, and are probably appreciated by more people for it.

>>4783063
>>4783060
Go man go!