What do you mean no advances in the last 70 years?! In the last decade scientists detected gravity waves and imaged an actual real black hole. Also they’ve been steadily chipping at quantum gravity, give it a couple decades they’ll get there.
unless we cancel all the funding
Aren’t the first two things just experimental proves of Einsteins relativity theory from over 100 years ago?
I don’t know about quantum gravity though.
I wouldn’t say “just”, experimental proof seems huge.
But if you want theories just go to PBS space time and open anything that isnt string theory or mond.
i say do watch the ones about string theory and mond so you can see why/how they’re wrong
As a layman who’s into physics it took me like a decade to understand what is “wrong” with them. No educational string theory video is prefaced with “Hey this is an old unprovable theory that is essentially dead in the water, but it has some cool math tricks and is fun to think about” as they should be.
PBS Spacetime’s approach was a pair of videos titled “Why String Theory is True” and “Why String Theory is False” and between them that pretty much put it to bed for me. cool math, cool worldbuilding, call me when they make a testable prediction. until then it goes on the scrap pile with aether and phlogiston.
A theory proven is progress, don’t you think?
Gravity was invented by Isaac Newton because he was invested in an airline.
That’s the real answer. Always check on whose payroll somebody is.
Gravity is caused by the fact that everything in the universe sucks.
So what you are saying is micro black holes everywhere, thats genius!
And here I thought it was just your mom
I’ve been reading a book about anti-gravity. I just can’t put this thing down.
I find it quite marvellous that the universe contains unexplainable stuff like this, actually.
There is an actual logical proof that there are propositions in mathematics that are neither provable nor refutable.
Everything we know about all space and time is technically just entirely made up by us.
It came from the Labratory of The Mind, yes, the work was entirely metaphysical, but here’s the wierd part. They used that mental experimentation and applied it to real life action, and it worked. It’s like imagining you have a magic carpet for years then you stand on one and it starts flying. It began as imagination of the world around us, then when checked against reality. It works. Someone figured out that if something was passing around a sun. A planet, that it would dim the light at regular intervals. They checked, it did, that’s the only reason we know there’s planets outside our solar system. Someone checked the lumens of stars and found the data matched the theory. We use the color variations of stars in a similar way to detect more data. It’s quite remarkable. A recent discovery in gravity is that while gravity is a ‘‘constant’’, it actually fluctuates from place to place, I’m not sure if anyone figured out why yet, but if and when, how they find out, will be their imagining a reason, imagining how to check, checking in real life, and getting the data on if it’s right or not.
A recent discovery in gravity is that while gravity is a ‘‘constant’’, it actually fluctuates from place to place,
I guess you are referring to the c9ncept of dark matter?
To anyone who does not know what dark matter is:
Dark Matter is the “solution” for differences in the real gravitational force a star has and how much gravity it should have based on calculations. Dark matter basically is matter that does not interact with light in any form (and therefore can not be detected) but still emits gravity.
Not “gravity a star has,” but the motion of stars around/near galaxies. It is the general motion of groups of massive objects that hints that there is a lot more mass ‘around’ most (not all) galaxies than what matter we observe could possibly account for.
The ‘not all’ part is critical, because it points to something actually being there as opposed to the theory of gravity or relativity breaking down at larger scales.
And now we have direct photographs of planets around other stars.
Made up, and then confirmed with experimentation against actual reality.
Let’s not pretend science is literature with extra steps. It’s a process whos aim is to confirm things in a way that removes all possible alternative explanation or influence. A good experiment completely and fully removes the human element.
Unexplainable yet. We may be able to understand how Gravity works.
But of course you are right, there are absolutely things that can not be explained. It is (very probably) impossible to explain why our nature constants are the way they are or why forces act the way they do. The easiest answer to why they are the way they are is to say “They are this way, because if they would be a little bit different we could not ask this question”. This sentence implies, that we live in some form of a multiversum and that there are multiple universes existent (in which form doesn’t matter) but it is impossible to detect them.
No, there actually are explanations for the effects as they exist in mathematical models. The problem is we do not yet have one single model that matches both quantum effects like superposition and cosmic scale effects like gravity and dark matter/energy.
There is almost certainly some truth in those mathematical explanations, simply because it’s unlikely that something that is 99.99% provably correct has no truth associated with it.
The problem is, it needs to be 100%, with proven and confirmed experiments, not 99.99% correct, before scientists will call it a “solved” problem.
Also the anthropic principle does not prove or disprove multiverses.
57k a year is a decent salary if you live in the UK.
A seasoned postdoc could expect to make 55K max. A professor a bit more.
57k€/year is a professional’s salary in Italy.
Average is 32k€
With 57k€ you can afford to live comfortably, even get yourself a roomy flat, which is unusual for single individuals.
*Exceptions may apply, see Milan or other big cities
That is not a decent salary, that is so low. I made almost that much just out of college in the U.S. Once I made it just over 10 years as EE, I was double that.
in the uk
is the important part. you would be considered a high earner earning that
Well then I guess they don’t mean UK do they?
If you think my comment was vacuous, you should see the ones that replied to it
57k usd is a little less than 42k gbp
Which is roughly the pay for a staff scientist or lecturer
Postdocs are definitely not getting 55k in the UK except maybe if something like medicine is special? The range is like 36-45ish.
55k dollars in the US gets you a crappy apartment and a 7 year car loan.
you dont even need a phd to get that 55k salary, might as well not go to grad school.
Can confirm
Gravity is a fundamental force just like electromagnetism (supposedly)
Fundamental means it cannot be explained by being caused by something else.
But then they say gravity is an effect caused by spacetime curvature and electromagnetism is caused by quantum phenomena.
What is the cause for spacetime or quantummechanics? Idk but somehow they don’t make it on the list of fundamental forces.
Classical science, for all the good it did and does, is an unironic joke and if aliens knew about it they’d be laughing at us.
Fundamental means it cannot be explained by being caused by something else.
Fundamental force means we expect a carrier particle to explain it (for gravity that’s the Graviton, although it hasn’t been detected yet).
electromagnetism is caused by quantum phenomena.
Not even remotely true.
What is the cause for spacetime or quantummechanics? Idk but somehow they don’t make it on the list of fundamental forces.
Quantum mechanics is mostly that statistics is more complicated than we all thought . Seeking a cause for spacetime is interesting. It might be relevant to mention that there is a fundamental particle that imparts mass, which we call the Higgs Boson. I guess that could make mass and inertia something of a “fundamental force”.
Maybe i am wording it wrong. I did make the comment half joking but my current understanding of how magnetism really works, which my physics teacher was unable to answer has a chapter on wikipedia called Quantum-mechanical origin of magnetism
I have no degrees in this stuff though, i just think about them recreationally.
The carrier particle thing to describe a fundamental force is new to me, and honestly feels very counterintuitive to how i started to understand things.
Quantum mechanical particles are very different things to classical ones.
A slightly better way of thinking about them is quantised fields. Particles and waves are simplifications of the underlying effect. There is no classical equivalent to work with to this, so we try and understand it as particle-wave duality etc.
In this case, a carrier particle is a (quantised) disturbance in the underlying field. If it has enough energy, it manifests as a physical particle. The higgs boson is an example of this. Below the required energy, you get virtual particles. These “borrow” energy, and so can never be seen directly, only inferred.
By example. Photons are the carrier particle of electromagnetism. Give the field energy and you get photons (light). Without that energy, the photons are virtual. Existing only between the 2 acting entities.
Different fields have different carrier particles. The photon is quite simple. It’s effectiveness decays as 1/r^2 . The strong force carriers are more complex. They can emit more carrier particles, allowing the field to grow with distance rather than decay.
To add more complexity. The various fields look to be aspects of the same field. At sufficient energies, they behave identically. We have figured out how to combine the electric, magnetic and weak fields. We have a handle on the strong field. The higgs field seems to also match into this. Gravity is a pain to study. We assume it should match in, but haven’t managed to work out how yet.
As for why the underlying field exists and follows the rules it does? We have no clue right now. The ‘why’ tends to follow the ‘what’, and we have yet to get a good handle on the ‘what’.
diamagnetism, paramagnetism and ferromagnetism can be fully explained only using quantum theory
The magnetic properties of certain materials (e.g. why an unmagnetized piece of iron sticks to a magnet of either polarization), the way permanent magnets work, is best explained by quantum mechanics.
However, the electromagnetic force itself doesn’t “arise” from quantum mechanics, and you can explain things like electromagnets and a lot of common electric circuits (until you need a transistor) quite well without considering quantum mechanics.
Usually you take the “classical” formula for a force and to inform your quantum mechanical model of particles, and that’s how you can arrive at things like deriving how permanent magnets work with the help of w quantum mechanics.
Generally, a lot of material science and chemistry is inherently quantum mechanical because the way atomic orbitals and molecular bonds work is heavily quantum mechanical.
Thanks for a well written reply.
Though i still dont quite get this
the electromagnetic force itself doesn’t “arise” from quantum mechanics, and you can explain things like electromagnets and a lot of common electric circuits (until you need a transistor) quite well without considering quantum mechanics.
You seem to say if we can explain x without y then y cannot be fundamental to x.
But can electromagnetism at all emerge if the quantum mechanics dont exist to emerge things like magnetism and some of the behavior of electrons?
But can electromagnetism at all emerge if the quantum mechanics dont exist to emerge things like magnetism and some of the behavior of electrons?
Short answer: yes.
Technically the world can’t exist without all of its physics. But that’s kinda backwards from how you study it. Quantum mechanics isn’t “more correct” than classical mechanics, it’s more that it’s “more detailed”.
If you want to model an electromagnet, an electronic circuit, light (in most macroscopic situations), how permanent magnets interact, electrostatic situations like how static electricity makes your hair stand up, lightning, the magnetic fields of celestial bodies like the Earth and Sun (they are big electromagnets), etc. you will use “classical” electromagnetism (meaning Newton’s mechanics, possibly with Einstein’s modifications, and Maxwell’s equations).
If you want to model material science situations, like determining what material to make a diode or transistor out of, or if a given material can become a permanent magnet, you will likely need quantum mechanics to help model the interactions of electrons on the atomic scale. The section on Wikipedia you were looking at is about this kind of material science. You do this by combining the same “classical electromagnetic” equations with Schrödinger’s equations for quantum mechanics.
But can electromagnetism at all emerge if the quantum mechanics dont exist to emerge things like magnetism and some of the behavior of electrons?
Well yeah, sure. Earlier you said something like “electromagentism is caused by quantum phenomena,” but you can say that about almost every object and behavior in the universe! We don’t have a theory of everything but the standard model and quantum field theory explain a lot.
“Caused” was not a good term but like i said i made that comment half jokingly
I find that almost everything can be boiled down to just be a display of quantum mechanics which is why id place it as more fundamental.
I cant really say that about gravity/spacetime though. Maybe someday we do find that it also is but for now it seems to be distinct.
What is the cause for spacetime or quantummechanics? Idk but somehow they don’t make it on the list of fundamental forces.
Well, they are not forces.
electromagnetism is caused by quantum phenomena.
Lol what no
But then they say gravity is an effect caused by spacetime curvature and electromagnetism is caused by quantum phenomena. What is the cause for spacetime or quantummechanics? Idk but somehow they don’t make it on the list of fundamental forces.
I don’t think we know enough about quantum mechanics to even make a guess, yet. I do know that the reason we wanted to find the Higgs Boson so much was because we thought it could help explain how things acquire mass, which could lead to figuring out antigravity. But then we found it and it wasn’t doing what was originally thought. Or something.
Daily reminder that physicists contribute nothing to society /j
This is wholly inaccurate. We do know what causes gravity; time dilation near matter (at least for smaller objects like the Earth). What we don’t know is why gravity, because we have yet to produce a model that matches both quantum effects and cosmic behaviors like gravity and dark matter/energy.
“Quantum gravity” is the general term for what solution would describe something that ties these two universes of behavior together. The process of decoherence isn’t terribly well understood as far as carrying effects clear from particle scale to cosmic scale.
Even then, some of the mathematical explanations from current models are plausible, but unproven.
Gravity is what makes my feet hurt when I stand around too long without moving about.
No, it’s pain receptors
Gravity is pain receptors. Got it.
We’re unlearning a lot today.
Gravity is just a side effect of the fundamental laziness of all things. Causality moves slower near mass, so it’s kind of relaxing to move towards it. That’s why everyone does it.
PS: There is actually a SciShow Spacetime video about gravity being an emergent property instead of a fundamental force. And no I didn’t get this from ChatGPT, I’m just that dumb when it comes to advanced physics haha.
Oh hell yeah I love an emergent property. That’s my new favorite theory
It is what make it risky to jump from the Burj Kalifa, at least on the last meter.
And yet, jumping from the Burj Khalifa at 1m off the ground is not very dangerous, so it’s not the Burj Khalifa that’s doing it
And even if you jump from higher up, it’s the ground that does it, still not the Burj Khalifa.
It’s not riky while you are falling from 800m, only at the end
Wouldn’t the electromagnetic force be what makes jumping from the Burj Khalifa risky? It’s not the fall that kills you, it’s the sudden stop.
Mass go brrrr
Gravity is not what makes your body limp. It would just heavily influence a limp body. PhD my ass.
While reading this I had a sudden flash of inspiration in which I saw clearly exactly how gravity works, but then when I started typing I forgot again. It’s quite frustrating
Congratulations, here’s your PhD
