First a caveat: An object with mass can’t move at the speed of light, but it could move at speeds arbitrarily close to that.

The most successful model of gravity isGeneral Relativity, which treats gravity as a curvature of 4-dimensional space time. Gravity’s influence travels at the speed of light. There’s a classic thought experiment that sort of answers your question: what would happen if the sun was teleported away? The answer is the earth would continue to orbit around the spot the sun was for 8 minutes, and we would continue to see sunlight for that same amount of time since that’s how long it takes light to travel that distance. Then after 8 minutes the sun would disappear and the first “lack of gravity” would reach us, and things would be bad for earth :(

The fact that gravity travels at the speed of light actually leads to an interesting phenomenon: Gravitational waves If a massive object rapidly accelerates (or decelerates), for example a star sized mass moving quickly and then coming to an abrupt stop, it will emit a ripple in space time called a gravitational wave that will travel outward at the speed of light.

It was big news about a decade ago when gravitational waves were first detected by LIGO, a series of large interferometers that look for expansion/contraction in spacetime. Their first detection was the collision of 2 black holes; as the black holes spiral around each other and eventually merge, they emit oscillating waves with increasing frequency. They made a cool video showing how the frequency increases by converting it to sound.

Since then LIGO and VIRGO (similar European collaboration) have detected multiple gravitational waves from the collision of black holes and neutron stars. So not only are gravitational waves a neat validation of general relativity, they’re actually being used to do astronomy.

if they don't want to get vaccinated then it still won't affect vaccinated folks.

This is actually not true, since enough people being unvaccinated can prevent herd immunity from protecting everyone.

Herd immunity is an indirect protection from an infectious disease that occurs when enough of a population has immunity (either from vaccination or prior infection). When enough people are immune, infections are unable to spread and outbreaks naturally end. This protects people within the population who don’t have immunity (unable to be vaccinated for medical reasons, vaccinated but didn’t get complete immunity, too young for the vaccine, immunocompromised, etc). It also protects those with some immunity who might still have a less severe infection.

The vaccination rate required for herd immunity depends on how infectious a particular disease is. Measles is particularly infectious, and a 95% vaccination rate is considered necessary for herd immunity. Many parts of the US have rates lower than that, which is why measles outbreaks are becoming common after the disease had basically been eradicated for decades.

Not exactly a scientific debate, but among the general public there was strong opposition to the idea that rocket engines would work in space, where there’s “nothing to push against.” Famously, the New York Times editorial board mocked Robert Goddard (the rocket scientist that now has a NASA space flight center named after him) in a 1920 article:

“That Professor Goddard, with his ‘chair’ in Clark College and the countenancing of the Smithsonian Institution, does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react — to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high schools.”

Image of the editorial

The New York Times eventually formally retracted that op ed, on July 17th, 1969 - while the Apollo 11 crew was already en route to the moon. The retraction is pretty funny:

Further investigation and experimentation have confirmed the findings of Isaac Newton in the 17th century and it is now definitely established that a rocket can function in a vacuum as well as in an atmosphere. The Times regrets the error.

Retraction source

The Milwaukee Protocol is a treatment plan that is essentially a more advanced version of what you’re asking. The patient is put in a medically induced coma and then given antivirals and IV fluids, which avoids the issue of hydrophobia.

It got a lot of press because one person survived on it (a big deal given that rabies is a death sentence once symptoms appear) but this success hasn’t been reproduced with other patients. A paper on the protocol has a remarkably blunt title: Critical Appraisal of the Milwaukee Protocol for Rabies: This Failed Approach Should Be Abandoned.

lmk if there's a better community to ask this in

Shameless plug: you could try ![email protected]

Neutron stars are the most compact form of matter that we know about; they’re even denser than the nucleus of an atom.

Neutrons, protons and electrons are fermions, meaning they must obey the Pauli exclusion principle. No two neutrons (or protons or electrons) can be in the same quantum mechanical state. If you take ordinary star matter (plasma made of dissociated protons and electrons) and squeeze it, eventually the electrons will nearly overlap in their states. You’d have two electrons with nearly the same energy, spin and location. They cannot overlap though, so this creates a repulsive force that prevents the matter from further compression; this is called the electron degeneracy pressure.

If the compressive force overcomes this pressure, then the electrons can capture on the protons to form neutrons. Neutrons and protons also have degeneracy pressures, but they can be packed much more densely than electrons. This is because their wavelength is shorter. The wavelength of a massive particle is inversely proportional to its mass, and protons and electrons are about 2000 times the mass of electrons. So compressed ordinary matter will inevitably become pure neutrons, simply because this is the most compact form.

A pure electron or pure proton star wouldn’t be as compact because both are charged particles so there would be Coulomb repulsion (this isn’t an issue in ordinary matter since the number of electrons and protons is roughly equal). You’d also need to somehow separate the electrons from the protons, and this isn’t a process that would naturally occur in a collapsing star.

Yep. In fact there’s a process called inverse Compton scattering that essentially works this way. In ordinary Compton scattering, a photon scatters off a stationary electron and typically leaves with less energy (since the electron gets a kinetic kick). In inverse Compton scattering, a photon collides with a moving electron which can cause the photon to gain energy.

One application of this is to produce gamma-ray beams. You take a beam of light (often from a laser) and collide it head on with a beam of relativistic electrons traveling in the opposite direction. In the electron rest frame, the photon has gamma-ray energy, while in the lab frame it might only be visible light. The back-scattered photon can then be boosted to the gamma regime in the lab frame, and now you’ve got a gamma-ray beam.

There isn’t a link in your post, but it looks like you’re referring to this preprint. The article has been published in a peer reviewed journal paywall warning.

This is a review article, so it isn’t proposing anything new and is instead giving a summary of the current state of the field. These sorts of articles are typically written by someone who is deeply familiar with the subject. They’re also super useful if you’re learning about a new area - think of them as a short, relatively up-to-date textbook.

I’m not sure how you’re interpreting this review as an alternative to the standard model of cosmology and the Big Bang. Everything is pretty standard quantum field theory. The only mention of the CMB is in regards to the possibility that gravitons in the early universe would leave detectable signatures (anisotropies and polarization). They aren’t proposing an alternative production mechanism for the CMB.

I’m locking this post because while we don’t currently have a rule against soliciting medical advice, it goes beyond the scope of the community. I highly recommend discussing your concerns with your new doctor, or getting another doctors opinion. Medical advice from internet strangers can be dangerous.

Haha it’s in the title: “Cosmological Particle Production: A Review”. Also the journal it was published in is for review articles: Reports on Progress in Physics. Mostly though the abstract promises to give a review of the subject.

Another indication is its lengthy (28 pages) with tons of citations throughout. If someone is doing new work, citations will mostly be in the introduction and discussion sections.

in the photon's frame of reference

There are no valid inertial frames for an object moving at the speed of light. The idea that “a photon doesn’t experience time” is a common, but misleadingly incorrect statement, since we can’t define a reference frame for it. Sometimes this misconception can be useful for conveying some qualitative ideas (photons don’t decay), but often it leads to contradictions like your question about Hawking Radiation for black holes.

That’s correct, but I wasn’t implying the opposite; I hope my comment doesn’t read that way.

A fraction of the vaccinated population will not have 100% immunity. Even among healthy, non-immunocompromised people vaccines generally don’t have a 100% efficacy. For example, annual flu vaccines vary in efficacy, but are often around 50%.

As I said in my comment, herd immunity is a form of indirect protection. Keeping a disease from being able to spread prevents people from being exposed at all, regardless of their immunity status. If enough people are unvaccinated and there is no herd immunity, then that increases the risk for the whole population - even those who were vaccinated since generally that doesn’t guarantee immunity.

There are certainly arguments to be made about bodily autonomy and weighing individual rights against those of society. However, the idea that “the decision to not be vaccinated is an individual choice that doesn’t harm others” is incorrect, and therefore not a great argument against vaccine mandates.

I’ll echo the other replies that the gravitational waves from black hole mergers have been detected by LIGO. In fact, the 2017 Nobel Prize in physics was awarded to members of this collaboration specifically for this feat.

We haven’t (yet) seen a pair of black holes collide using light directly, but the gravitational waves have been perfectly consistent with general relativity calculations. Here’s a video from LIGO that shows what one of these simulations looks like, for a simulation that reproduces a detected gravitational wave.

As an aside, right around the time the LIGO team was awarded the Nobel prize, they detected the collision of a pair of neutron stars. They alerted the astronomy community to the direction they saw the signal from, and within a day there were telescope observations of light from the kilonova that resulted from the collision. Ultimately various sensors recorded optical light, infrared, ultraviolet, gamma rays, and radio waves being emitted from the explosion. The hope is that someday we’ll get lucky enough to see similar photon signatures from a black hole merger!

But in order to do that photon actually needs to be created and travel from one particle to another.

The electromagnetic force is mediated by virtual photons. These don’t exist as free particles, such as a photon emitted by a light source, but only as an intermediate particle. Because they’re only intermediate states, virtual photons can have non-physical energies (so long as they’re within the uncertainty principle), resulting in some having an effective mass. Suffice it to say virtual photons are quite distinct from real ones! Technically, I believe you could have some of the basic features of the em force (namely attraction/repulsion by 2 point charges) with just virtual photons. Things get tricky once charges begin accelerating though, as this leads to the emission of real photons.

If Higgs works in a similar way also being a boson

The short answer is, it doesn’t. The Higgs Field gives mass to fundamental particles. Existing in that field causes certain particles to have mass due to their coupling to the field. The W and Z weak gauge bosons gain mass through electroweak symmetry breaking, quarks and leptons gain mass through a different coupling. I realize this is a very unsatisfying answer as to “how” the Higgs field creates mass, but the mechanism involves some complex math (group theory and non-abelian gauge theory), so it kind of defies a simpler explanation. Regardless, it’s through interactions with the Higgs field (which can exist without any Higgs bosons around) that fundamental particles gain mass. The search for the Higgs boson was just to confirm the existence of the field, because while the field can exist without Higgs bosons present it must be possible to excite it sufficiently to create them.

Going back to your original question: these particles have almost certainly been created “naturally” in high energy collisions between particles and matter. Nature can achieve much higher energies than our particle accelerators. The highest energy particle ever observed was a cosmic ray. However, Higgs bosons are extremely short lived, with a lifetime of 10^-22 seconds. So whenever they’re created, they don’t stick around for a meaningful amount of time.

Yes, the wavelength of photons will be preserved if they travel through non-expanding space. If the photon is emitted by a source that’s in motion with respect to a detector, there could still be redshift or blueshift from the relativistic Doppler effect. This would only depend on the relative velocity between the emitter and observer, and not on the distance the photon traveled between them.

So unfortunately the article they reference by Parker is paywalled. I have access but can’t share it easily. The article is essentially the foundation of quantum field theory in curved space time - in other words the genesis of the standard cosmological model. Cosmological particle production in an expanding universe isn’t an alternative to the Big Bang, it’s an essential part of it.

Leonard Parker’s work is summarized on his Wikipedia page. You can also read an interview with him on the arxiv

Assuming a spherical earth, if you doubled its mass but kept the radius the same then the gravitational force on the earths surface would be twice that of the current earth.

As long as you keep the earths mass reasonable, you’re in the realm of Newtonian gravitation. Newton’s law of gravitation depends linearly on the mass of the attracting source. So doubling the mass doubles the gravitational force.

At 1 billion solar masses (firmly in the not-reasonable mass range for the earth), you’d need to consider the formation of a black hole. The Schwarzschild Radius for a 1 billion solar mass black hole (aka the event horizon) is almost 20 astronomical units or 2 billion miles. So in that case you wouldn’t be able to measure the change in gravity as you’d be within the event horizon of a black hole.

At an intermediate mass there might be some general relativity effects that could alter the linear relationship between earth mass and gravitational force as measured on the earths surface, but I’m not sure what that would be. If you were to measure earths mass from a large distance, then it should follow Newtonian dynamics and behave linearly with mass.

No.

Micronovae are a recent theory for explaining observational data, having been suggested only a few years ago. So it will be difficult to make specific predictions about whether they will occur for a specific star system.

That being said, they would occur in a binary star system (2 stars in a gravitationally bound orbit) when a white dwarf accretes matter from the other star in the pair. Our sun is not in a binary system and isn’t a white dwarf, so a micronova can’t happen.

I haven’t watched the videos you linked but I would caution against listening to someone making that sort of claim. They aren’t operating in evidence based science.

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.

Hah tell me about it. The 2017 neutron star merger happened while I was writing a proposal for an experiment where the physics was sort of related. So of course I completely reframed the proposal around that event, and it got funded! And that was just a few years ago, right?

Man I really need to publish the results of that project…