Unfortunately for me, there is no community at Lemmy dedicated to the history of science

I agree! The history of science is often even more interesting since you get both the science and the personalities of all the people involved, plus the occasional world war in the mix. It’s a shame there isn’t an “askhistorians” type community here.

Sorry, physics can be cruel sometimes :(

Certainly! You can see discrete emission lines from the ionized air molecules, which only occurs because of quantum physics. I realize that’s not what you’re asking though.

I did a quick calculation and for a plasma torch (~27000 Kelvin) and assuming air molecules, the average velocity of the plasma ions would only be like 6000 m/s. That’s 0.001% the speed of light, so you aren’t going to see any relativistic effects.

Hi there! Can you please remove the word “retarded” in your first sentence? This word is now generally considered a slur, which runs afoul of rule 6 “Use appropriate language and tone. Communicate using suitable language and maintain a professional and respectful tone.”

I second the other poster’s suggestion to look into nonlinear optics. A really common application is frequency doubling, also known as second harmonic generation, which doubles the energy of the photons. So an 800 nm laser (red) can be converted to 400 nm (green) with this method.

The National Ignition Facility (NIF) actually uses frequency tripling of the laser pulses right before they enter the target chamber. That’s pretty wild, I had intended to look up NIF to give a high profile example of second harmonic generation, I hadn’t realized they were actually doing third harmonics.

Another optics-based phenomenon that I think maybe strays too far from the intent of your initial question, but is too cool not to share, is laser Wakefield acceleration. A very high power laser pulse will push electrons out of its path in plasma or materials via the ponderomotive force. This charge separation creates electric field gradients on the order of billions of volts per centimeter, which can accelerate electrons or other charged particles to relativistic energies. So you can start with a green laser pulse and wind up producing gamma-ray beams, either by slamming the electrons into a stopping material or by Compton scattering other low energy photons off the relativistic electrons.

This isn’t exactly my area of expertise, but I have some information that might be helpful. Here’s the description of the frame selection from a paper on a lucky imaging system:

The frame selection algorithm, implemented (currently) as a post-processing step, is summarised below:

1. A Point Spread Function (PSF) guide star is selected as a reference to the turbulence induced blurring of each frame.

2. The guide star image in each frame is sinc-resampled by a factor of 4 to give a sub-pixel estimate of the position of the brightest speckle.

3. A quality factor (currently the fraction of light concentrated in the brightest pixel of the PSF) is calculated for each frame.

4. A fraction of the frames are then selected according to their quality factors. The fraction is chosen to optimise the trade- off between the resolution and the target signal-to-noise ra- tio required.

5. The selected frames are shifted-and-added to align their brightest speckle positions.

If you want all the gory details, the best place to look is probably the thesis the same author wrote on this work. That’s available here PDF warning.

I’m glad to see this question has sparked a lot of discussion, but I’d like to remind everyone to please include a credible source for your answer.

Rule 9: Source required for answers.

Provide credible sources for answers. Failure to include a source may result in the removal of the answer to ensure information reliability.

That’s not really how quantum entanglement works. When particles are entangled, their quantum mechanical states cannot be described independently. So you couldn’t write down a waveform for just one particle and have it correctly describe reality, you would need the waveform of the entire state and therefore all entangled particles.

As a consequence, certain physical observables can be highly correlated between the particles. For example, if the spin of the overall entangled state of 2 particles is 0, then the spin of 1 particle will be exactly opposite the spin of the other. But these spins are only defined upon measurement (interaction with a system that is deterministic), and at that point the entangled state is collapsed. There’s no mechanism for transporting information while maintaining an entangled state.

Ignoring this fundamental issue, it still wouldn’t be possible to maintain an entangled state between particles in a pair of twins for any practical amount of time. Maintaining coherence in qubits (entailed bits) is one of the big challenges in quantum computing. If the qubits interact with the environment it breaks their entanglement. Even just thermal vibrations will destroy the state. So typically qubits are held at near absolute 0 in a dilution refrigerator. Even still, the longest a qubit has been kept coherent is 5 seconds.

Alternative theories of gravity are like alternative theories of medicine, they tend to be thoroughly invalidated and none are anywhere near as effective as the mainstream theory. As the wiki article you linked notes:

However, such models are no longer regarded as viable theories within the mainstream scientific community and general relativity is now the standard model to describe gravitation without the use of actions at a distance.

General relativitiy is one of the most tested, validated theories in physics. It is incredibly successful, not just describing the attraction of massive bodies but also describing frame dragging (solving a longstanding mystery on the retrograde motion of Mercury that Newtonian gravitation couldn’t explain), and predicting gravitational lensing and gravitational waves, both of which have been observed since and are perfectly described by GR.

An alternate model should attempt to solve a problem in the current leading one, for example giving a more fundamental explanation, or working at different scales where the current model fails (quantum gravity theories, for example). A good alternative model will also give results that are consistent with all existing observations, which is one area that every alternative theory of gravity I’m aware of fails. What problems in GR are you looking to resolve with an alternate gravitational model?

Any data is sent at or below the speed of light. Solar storms are charged particles (mostly protons) being ejected from the sun and eventually hitting the earth’s magnetic field, causing disruptions in the field (and potentially cool auroras).

Since these storms are just particles traveling from the sun to the earth, they travel slower than light speed, so our distant sensors can warn us in advance at/near the speed of light. This won’t work if the sun were to instantly disappear or change color though, that information would travel at light speed and the probe signals would arrive at the same time.

Hi, could you expand on your question (or questions) in the main post? The more clear your questions are, the easier it’ll be for someone to address them. Thanks!

/r/askscience was one of the highlights of Reddit - I’d love to help establish a similar community here in /c/askscience. I especially liked that posts and followup questions were rewarded for being inquisitive, and that off topic/inaccurate responses were removed. Posts on topics I’m familiar with were filled with scientific information, and I learned a lot from posts on topics outside my area of expertise (also the ones in my area of expertise, to be honest).

I have a science background (nuclear physics) and lots of experience communicating with remote collaborators. I’m fairly active on lemmy (on another account, I created this one to be my semi-professional one) and would generally have no problem checking the site at least 3 times a day. And I have no issues with mod coordination over Discord.