Evidence Definition and 367 Threads

This article about a recent experiment was just published the other day: http://phys.org/news/2015-02-hindsight-foresight-accurately-quantum-state.html I can't help but think that this is at least weak evidence in favour of the retrocausal interpretation. Of course other interpretations aren't...

This just in: http://www.nature.com/nphys/journal/vaop/ncurrent/full/nphys3233.html

I have always wondered if spacetime is actually smooth, or if it is granular such as a quantized spacetime. I remember learning that if you draw the smallest possible square around a circle, you will, of course, get a perimeter, 8 times the radius of the circle. Then if you draw in the...

Direct experimental evidence of time slowing down for moving clocks is well-known. With the advent of atomic clocks, round trip journeys taken by these clocks on slow moving(compared to light speed) jets show time differences with clocks that have not taken the journey. But is there...

I know MACHOS and WIMPs are leading candidates for Dark Matter, but is there any convincing evidence to support them?

Although the speed of light is constant in GR, within coordinate spacetime the speed of light varies. For example, light travels more slowly near a black hole than in remote space. The same is theoretically true of the speed of gravity. But is there any supporting empirical evidence?

This seems like a question that would be in the Relativity FAQ, but I didn't see it. Briefly: I've seen the claim made that there is plenty of observational evidence for the existence of black holes. But I don't understand how, from the outside, one can tell the difference between a black hole...

The multiverse is a theory that the are countless universes. What is the evidence for the existence of the multiverse?

I know that the example of time dilation and length contraction due to Special Relativity is usually given as the mountain top / sea level decays of muons created by cosmic rays but what is the evidence for mass change?

Recent data in qm suggest black holes could decompress into a white hole on either our universe or another as such is there any evidence of white holes in our universeSent from my iPhone using Physics Forums Jim P

Hi folks, I just read a passage by the great Ashoke Sen in which he writes that, due to the possibility of particle production in collisions, "strictly speaking there is no experiment possible even in principle that can distinguish elementary from composite particles." But how is this...

Apologies if this has been discussed - new experiments with oil droplets are helping to revitalize discussion of the pilot-wave theory for explaining quantum mechanics. I'm a bit of a novice in this matter, but I was curious on anyone's thoughts on this new discovery. Will it upend the general...

How does the blackbody radiation prove the existence of photons or quanta as Planck described it, I've understood how the photoelectric effect proves the existence of photons, but the blackbody radiation seems quite vague to me. I would like a basic explanation for this, thanks in advance.

So I have a question about Sagittarius A*, which more and more astrophysicists are certain is a supermassive Black Hole. But now for the evidence part: 1. An alternative model for this object was proposed http://journalofcosmology.com/RobetsonLeiter.pdf published 4 years ago. So is there any...

Hi to everyone! I'm searching information about evidences of photons existence. It seems like the photoelectric effect isn't for itself a proof of photons existence. Some people tried a semi-classical discussion of this effect (Lamb - "The Photoelectric effect without photons"). I'm...

Homework Statement I'm having a slightly hard time with a topic we are studying at school 'the evolution of the universe'. My first question relates to the Big Bang Model itself; does the Big Bang Model itself describe the evolution of the universe after the Planck time up to this point...

The paper goes on to describe asteroids "formed from supernova fallback material" falling into the pulsar. Why would the asteroids be formed after the supernova? More importantly, how could an asteroid form from supernova remnants? If a star with less than ~9 solar masses had planets and...

in order to explain the big bang theory and the expansion of space itself, people often draw upon the analogy of blowing air into a balloon and the 2 dimensional surface of the balloon expanding. isn't the 2-D balloon surface expanding in the third dimension, since the volume of the balloon is...

Consider our universe but with only two particles, say two protons. Inevitably they would orbit mutually about one another. As such, the time evolution of this trivial system would be cyclic, forever repeating their monotonous movement. This suggests that time is not absolute. It may not even be...

I'm aware of the doppler effect for sound waves. But light waves are different, e.g., light travels through a vacuum but sound does not. Has there been any laboratory confirmation for red shift for LIGHT. I could find only ONE paper by Bélopolsky, A. in 1901 using rotating mirrors. But there...

Considering that when we look at distant red-shifted structures of the universe we also look at their respective speed at that respective time of emission, is there any observational evidence that the acceleration is still happening today?

Simulations back up theory that Universe is a hologram http://www.nature.com/news/simulations-back-up-theory-that-universe-is-a-hologram-1.14328

Do we have any evidence that either: 1. There exist stellar black holes which orbit supermassive black holes in the centers of galaxies, or 2. There exist black hole pairs which orbit each other, around their shared center of mass?And if the second scenario were to exist, what would happen...

It seems many people in Science have gravitated towards some form of a multiverse. Whether it's a Cyclical Universe or some version of the Many Worlds Interpretation. The question is where's the evidence? I do think there's some evidence that points to this conclusion. If you look at the work of...

Evidence has surfaced that the speed of light is not c in deep space. Is it true? <<unacceptable link removed>>

http://www.nasa.gov/content/goddard/curiositys-sam-instrument-finds-water-and-more-in-surface-sample/#.UkTyTz8pnjK Curiosity has found evidence of water in the martian soil – with its very first scoop. "One of the most exciting results from this very first solid sample ingested by...

Is there evidence of space surrounding the BB singularity?

I wonder if anyone knew of any credible evidence that exists in hypnosis doing what it is branded to do.

off the top of my head: - isotropic microwave radiation corresponding to 3.73K blackbody curve - hubble's law - red shift of galaxies - 3:1 ratio between hydrogen and helium, and the relative abundance of them is there any more? and also, can someone explain the hydrogen-helium ratio thing...

My friend keeps on harping on this sort of stuff. He says that there is a gravitational pull from other universes affecting the matter in this universe and creating imperfections in the cosmic background radiation. I find it hard to believe that any sort of boson would be able cross the...

Here is a new paper, and thorough discussion of dark matter: Non-Baryonic Dark Matter in Cosmology, http://arxiv.org/list/astro-ph/new

Hi All, Just wanted to know, is there any experimental or observational evidence today, that electromagnetic fields can cause spacetime curvature? Either direct or indirect?

Did The Dark Matter Really exist ? did we have an evidence ? and What is the compositions Of The Dark Matter ?

Homework Statement This is a subset of a larger problem I'm working on, but once I get over this hang up I should be good to go. I have a set of measurements x_n that are exponentially distributed p(x_n|t)=e^{-(x_n-t)} I_{[x_n \ge t]} and I know that t is exponentially distributed as...

I have read several posts asserting that mutation and natural selection cannot add complexity or useful functions to the genome. I'd like to add a link to an experiment that proves them wrong, and also teaches us a lot about how evolution works - the E-coli long term evolution experiment...

NOT including the prediction capabilities of the particular math equations of GR or SR. In particular, hard evidence such as, or close to; here's an electron, because we measured it directly, or saw it in an electron microscope. Or here's a cell under a microscope. Or this is a brain scan/MRI...

I know that Richard Feynman said that quantum physics has nothing to do with consciousness and that Victor J. Stenger is quoted as saying that there is no evidence for consciousness in quantum physics but I came across this << link deleted >> I have three questions: the first is this paper...

And within the near-galaxy too. If we can find some in close proximity, there's tremendous potential for research. I found these two conflicting articles: (both a few months apart) Survey finds no hint of dark matter near Solar System Astronomers Detect Dark Matter Near The Sun...

Hey all, Does anyone know of a paper or experiment that verified that a single photon is absorbed in exchange for electron excitation? Thanks

I understand that there are singularity and non-singularity theories of the big bang. Also that there are those that posit nothing (no time, no space) before the big bang and others that posit something. What I'm thinking is that if the big bang event was singular (or nearly singular) then...

All, Based on pointers that I have received from a number of people on the forum, I have been reading about the support that the time dilation of supernovae (type 1a) light curves provides to the standard model– thanks to all and a special thanks to GerogeJones. The material seems to fall...

BBC News reported this http://www.bbc.co.uk/news/science-environment-20300100 Here's the actual paper https://cdsweb.cern.ch/record/1493302/files/PAPER-2012-043.pdf What does this actually mean for Susy etc?

So apparently the 2 prior Navy Seals who died broke order to go and save unarmed personnel at the scene of the attacks and then were killed 7 hours later by a mortar round. http://www.foxnews.com/politics/2012/10/26/cia-operators-were-denied-request-for-help-during-benghazi-attack-sources-say/...

What experiments have been conducted to confirm that the Cosmic Background Radiation (CBR) is indeed cooling over time and at any specified rate? The time requirement for obtaining separate points for measuring change seems preclusive.

I hope this is a coherent question: Solving the Schrödinger equation for energy eigenvalues for a harmonic oscillator leads to the ground state of the energy for a particle being ω/2. What is the experimental evidence that this is, in fact, the lowest achievable energy and that zero energy is...

Basically, all more distant galaxies have a Red Shift that increases with the distance to the galaxy, the Universe is expanding. 1) If there are other pieces of evidence that indicate the Universe is expanding, what are they? 2) Any internet links describing exactly how the other...

In the Wikipedia article "Quantum Gravity", it claims that there is some experimental motivation for finding a quantum theory of gravity. In one of the experiments it cites, neutrons are found to jump between discrete quantum states in the Earth's gravitational potential, similar to the discrete...

Is this evidence for MWI?Or other explanations are possible? http://en.wikipedia.org/wiki/Elitzur%E2%80%93Vaidman_bomb_tester#Step-by-step_explanation Any thoughts?

Hello everyone. I'm a first time poster, but a long time lurker. I don't have a degree in physics, but I have always held the discipline and all its branches, near to my heart. A little background on the question. I got into an argument with a friend of mine about faith in religion and faith...

We know the exact age of Universe and the earth. We know when life began on earth. Is the formation of life a result of random grouping of atoms and molecules? Is evolution the outcome of random mutations? If so, is the chances of such series of random mutations resulting in formation of...