Physics

Let's say that we eventually progress to the point where we are able to (somehow) produce huge amounts of antimatter, at least by today's standards, and we build an interstellar spacecraft to travel to Proxima Centauri. Let's say that using antimatter propulsion, along with several other propulsion types, we are able to propel the spacecraft up to a significant percent of the speed of light, say 50%. If I'm not mistaken, at those speeds it would take approximately 9 years for the ship to travel to Alpha Centauri from the point of view of those left on Earth, and ~2.5 years from the perspective of those inside the ship travelling at 50% the speed of light due to the time d…

What's the difference between electric charge and magnetism?

Randomness is the new god. Well, I think so anyhow. To explain the result of a quantum measurement where you can predict the probability of getting various results, but cannot predict which of them you will get, it seems reasonable to say that it appears random. But if you go on to add that it is random; that is to say, that the reason you got a result is inherently unknowable (ie, metaphysical, not part of physics) -- that is an extra statement that does not explain anything new, hence could be removed by Occam's Razor. Not only that, but that extra statement completely changes the universe -- whereas without randomness the universe was considered deterministic, with eve…

science is about predicting physical behavior? Say, how would a planet's atmosphere be affected if it had no more heat source, like a sun for example.. Or say, if all the water on planet "a" rose to a level of 0.0006 nano meters, how would that effect orbital periods of its moons.. Or, if water reached 1/2 of its boiling point and you placed " some substance" in it how would that substance's atomic structure behave and or respond, if the water's boiling maximum was instantaneous?? These are just examples...

My apologies for so many questions, The Earth spins, and I have heard the spin is slowing down. Is this true?

A valuable thought experiment from neighboring thread - how would physics develop if there would be no Einstein, especially regarding gravity? While modern physicists might say that without him there would be "weeping and the gnashing of teeth", his introduction of general relativity a century ago seems to be event of extremely low probability (?) - so what if it wouldn't happen? Or imagine some hypothetical other civilization e.g. SETI is looking for - would it automatically get to GR? If not, how their physics would develop? Beside Newton's gravity, there was also known GEM before ( https://en.wikipedia.org/wiki/Gravitoelectromagnetism ) - just tak…

We know that there are lot of new inventions in physics so why are we still learning the old thing not mesons and quacks?

which is which?

I have a ski board Magnet that makes it float in the air has broken I do not know his name or type magnet in order to buy it I'm putting in your hands the red color images here have damaged portion http://im46.gulfup.com/rhsaMf.jpg http://im46.gulfup.com/Ym2t7X.png http://im46.gulfup.com/XkiqPo.jpg thanks for everyone

This should be in relation to rotational physics. Now, say you have a rotating person. Would it be possible to change axis of rotation/change direction of rotation while rotating? For example, say the person is doing a head-to-toe twist, but goes from that to a cartwheel or a flipping rotation. Would that be possible? Why or why not?

Does the cardboard material used in boxes protect from light and UV? I keep objects sensitive to light and UV inside these boxes example: DVD discs and plastics

I was reading up on dark matter and it is just molecules of energy that made up space. I was wondering if anyone knew if matter could be transfered to dark matter and back.

Could quantum electrodynamics theory be wrong ? Everything about this theory does not fit into shape in my mind. I am no expert on the subject, but maybe a better theory for explaining electromagnetism needs to found. Or is it so well founded and proven ? For example virtual particles and them being only "in the math". I even read they can go back in time, this seems ridiculous. Also being able to attract particles by sending or "shooting" particles seems very odd to me, seems to defy logic. This also being just "in the math". Another thing is how photons themselves are the quanta of electromagnetic energy. Electromagnetism works very simply and elegantly, it is odd tha…

As I understand entropy and the Second Law of Thermodynamics, things stand as follows: A closed system has a set Mi of possible microstates between which it randomly changes. The set Mi of all possible microstates is partitioned into macrostates, resulting in a partition Ma of Mi. The members of Ma are pairwise disjoint subsets of Mi, and their union is Mi. The entropy S(ma) of a macrostate ma in Ma is the logarithm of the probability P(ma) of ma happening, which is in turn the sum Sum_{mi ∊ ma}p(mi) of the probabilities p(mi) of all microstates mi in ma. The entropy s_{Ma}(mi) of a microstate mi with respect to Ma is the probability of the macrostate in Ma to which …

Right, so I am taking a physics class this semester. Most of it is just reminding myself of my Highschool physics, but I encountered a conceptual problem I still remember struggling with in High School too. Disclaimer: I have no problems understanding the *formulas*. That's not my problem; I can either memorize them, or add them up to my formula page. The "what is torque Mathematically" is not the question here. What is Torque? Physically. Can anyone please explain to me what is this force? I understand it is created by rotation, but I can't manage to imagine it, or understand how I can 'feel' it. If I rotate something around my hand - like a wheel - where …

how is the earth not a perpetual motion thingy? what with it moving through space, presumably untill it desintegrates or the sun explodes? or is 'perpetual motion machine' more than just something that perpetually moves untill it breaks (i'm taking 'because it'll one day be destroyed' as a lame answre btw)

Hi guys, I'm having trouble, understanding the difference between AMPS and VOLTS, I'm not really good at electronics, My stronger points are astronomy and computer science. But I need help understanding, because I have two power supplies taken from old chargers, etc. I dont understand why a 9V 2.2A is more powerful than a 15V 1.2A charger? anyone care to explain? It is much appreciated if you help me. Thanks.

Before the aether thread was closed, the question emerged for me of whether such a thing as a "frictionless superfluid" is actually possible. My reasoning is that it isn't because particles have inertia and thus resist momentum-exchanges during collisions. Therefore any fluid/gas consisting of particles with mass and thus inertia should have friction. Am I forgetting something? Also, in practice how much fluid/gas friction is due to particle-inertia and how much is due to other things, such as electrostatic force among the particles or maybe the shape of particles causing viscosity. I guess a lot would depend on the particular substance in question.

Abstract Mass in our most up-to-date theory was beleived to be a by-product of a Boson and its respective field. Finding this particle, called the Higgs Boson has proven difficult. It seems likely that scientists will have to find a new mechanism for mass - and in this work, we will advocate one of those theories. What is Mass? So, what do physicists mean when they speak of a mass, or rather, a mass term? For a while, physicists tried to answer this question a number of ways. There was such a thing as an electromagnetic mass [1] at one point in physics. The was the idea that the electromagnetic field interacted with a quantum object in such a way that it…

If light doesnt degrade, can be used as a power source and can even be slowed down and takes up no space so can be stored in infinitely dense concentrations. Why dont they make batteries out of light? Sounds like they have the technology to do it. And I cant imagine cost is a factor, light is free.

Inspired by my own thread on forest fires. https://energyeducation.ca/encyclopedia/Betz_limit So basically, the Betz limit suggests that a theoretical maximum of 59.3% of energy could be extracted from wind at a time. That leaves 40.7% or more still in the wind. So, wind retains at least 0.407 times its maximum energy; which, by E=mvv/2, suggests it retains 0.638 of its speed. Does that mean that with a long enough row of closely-packed, highly-efficient wind turbines designed to handle hurricane-force winds, you could reduce the wind speeds from 120 km/h to about 77km/h, storing the excess energy until the power lines are repaired? …

I was just wondering, what exactly is movement? Like if we are all part of space, then what exactly is our movement within space? We can't move relative to space obviously, but what exactly is happening to space as we move? Wow this is hard to explain. I have this weird incomplete picture in my head of space like a thick web of strings and when we move its like the mass of strings moves with us but pulls and sways on other masses of strings from other objects. Why strings instead of water I don't know, probably just my brain trying to picture einstein's sheet metaphor in 3d. Point is I don't know how we move through space. I'm not even sure if space is an actual th…

I don’t believe the world is flat, but what is the evidence for the theory that it is a sphere? Is it approximately a sphere? And why would the planets form as a sphere in the first place? Would you say intelligent design or gravity is circular? Why can’t it be a cube with an irregular 3d surface that approximates a sphere? I’m quite serious. Why are we not looking for planets in different shapes? And why are black holes logarithmic spirals? I want to write a sci-fi story where instead of using ships to explore space we instead grow the Earths atmosphere. I mean we make space livable by growing the Earth’s protective atmosphere layers. No need for oxygen you already h…

I've been experimenting with capacitors (50-100uF from camera circuits). I'm wondering how I can charge a capacitor. I can't just plug it into a source of EMF, I probably need to design or find some sort of circuit, right? What's the best way to charge metallic objects? I don't have a Van de Graaf machine and can't produce enough charge by induction by rubbing two materials. Can I use a capacitor to charge metallic objects?

What if you could use gravitational forces to draw all this radiant energy into the small point? If there was some way to create a sufficient gravitational force you would avoid using materials like mirrors (which would absorb some of the energy you are trying to harvest) and get directly to the gathering of this energy.