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Showing content with the highest reputation since 11/22/18 in Posts

1. 8 points

Matter creates gravity

OK let's clarify something here. First consider the following definitions. Mass is resistance to inertia change Energy the ability to perform work. Spacetime a geometric model system with 3 spatial dimensions with 1 time dimension. In physics dimension is an independent variable or value that can change without affecting any other mathematical object. So how does mass curve spacetime. Well GR models bodies in free fall that is without any force applied. Time is given units of length and can be called an interval. This is done by setting c which is constant to all observers and adding a unit of time. So the time coordinate is given units of length by ct. $(t,x,y,z)=(ct,x,y,z)=(x^1,x^2x^3x,x^4)$ the last is in four momentum form for convenience as its useful to model a particle trajectory along the x axis. Now what is spacetime curvature. Well space is just volume... (Very important ) it isn't a stretchable bendable fabric... Those are just analogy descriptive. What spacetime truly means by curvature is the worldline paths for light it us the null geodesic. If you shoot two laser beams in flat spacetime those beams stay parallel. If spacetime is curved then the beams converge for positive curvature and spread apart for negative curvature. This is a consequence of how the mass term affects the time it takes for a particle to go from emitter to observer. That whole resistance to inertia. So let's drop two objects toward a planet. You have the usual Centre of mass. As the objects free fall they do not stay parallel. They will converge upon one another as they approach the center of mass. That what is really meant by curvature the free fall paths are curved. Not the volume of space.
2. 5 points

Sorry about the downtime -- we're back!

Fake news! It was a perfect renewal! Absolutely perfect. In a world where even my fridge can give me reminders, I still managed to forget. Luckily Capn was able to social engineer his way through my answering service who sent a page out to me stating "CAPN REFSMMAT - RE: WEBSITE". They even listed a hospital he was calling from 😂. I wasn't on call today so when I heard my answering service text me I about lost my mind until I saw who it was.
3. 4 points

4. 4 points

You think you've got problems America...

Do you understand that one side lied, broke the law, got prosecuted + fined + reported to the police for criminal action, and the other side didn't? Are you somehow pretending that the situation was symmetrical? Well, it's hard to say. But racism is wrong, and played in favour of "Leave" Xenophobia is wrong, and played in favour of "Leave" External interference is wrong, and played in favour of "Leave" And the margin by which thecheats won is small. Imagine this was a football game and, after the match, it emerged that the winning side had played a "ringer". The acceptable outcomes would be that (1) The cheats would lose by default or (2) there would be a rematch. Why does anyone think it is reasonable to hold the future of the UK to lower standards of propriety than they would for a game of football ?
5. 3 points

Nature of the soul (split from: When did God put the soul in humans during evolution?)

What's wrong with that? Compassion is a huge part of many religions: the academic study of compassion might be useful - but it's not the same as the practice of compassion. When was the soul put into humans? Who cares - the answer won't make you a better human being, which is what religious teaching should be trying to help with. All this pretence at academia by 'religious' people seems to belie an insecurity and need for validation with science. Spiritual practices should stand on their own merits, anything that needs propping up with pseudo-pseudoscience should be left to fall. And honestly Gees, though there are some aloof people on this site, likely including myself, you are among the worst for it. Look at yourself before casting stones.
6. 3 points

Jupiter Abyss: APOD:

There are many stunning photographs at APOD [Astronomy Picture Of the Day] some far more stunning then others...just type in APOD...a new one everyday. Here's another..... SEIS: Listening for Marsquakes Image Credit: NASA, JPL-Caltech, Mars Insight Explanation: If you put your ear to Mars, what would you hear? To find out, and to explore the unknown interior of Mars, NASA's Insight Lander deployed SEIS late last year, a sensitive seismometer that can detect marsquakes. In early April, after hearing the wind and motions initiated by the lander itself, SEIS recorded an unprecedented event that matches what was expected for a marsquake. This event can be heard on this YouTube video. Although Mars is not thought to have tectonic plateslike the Earth, numerous faults are visible on the Martian surface which likely occurred as the hot interior of Mars cooled -- and continues to cool. Were strong enough marsquakes to occur, SEIS could hear their rumbles reflected from large structures internal to Mars, like a liquid core, if one exists. Pictured last week, SEIS sits quietly on the Martian surface, taking in some Sunwhile light clouds are visible over the horizon.
7. 3 points

Officials at Glacier National Park making changes...

Your childish antics are fooling no one and they are taking away from the debate. We all know the meaning of what you've said and you trying to obfuscate their meaning with your hand-wavy tactics are just making you look foolish. It would have been much simpler to simply say "yes, that may not have been quite accurate" and move on.
8. 3 points

Complex societies gave birth to big gods, not the other way around: study

An international research team, including a member of the Complexity Science Hub Vienna, investigated the role of "big gods" in the rise of complex large-scale societies. Big gods are defined as moralizing deities who punish ethical transgressions. Contrary to prevailing theories, the team found that beliefs in big gods are a consequence, not a cause, of the evolution of complex societies. The results are published in the current issue of the journal Nature. https://phys.org/news/2019-03-complex-societies-gave-birth-big.html
9. 3 points

Trigger happy mods?

Yes, he is, but QuantumT is using "you" to refer to all mods, and specifically referring to me in terms of shutting threads down. If the speculative thread dealt with physics, I'm the mod most likely to have interacted with you (over the years) Is it too fast? Well, that depends. We have received comments where people have complained about threads being left open too long, and begging us to close them. The people whose thread was shuttered rarely agree that they should have been locked. Bottom line is that there is no moderation strategy that will please everyone. The mods use their best judgement, built upon doing this for a number of years, and seeing a lot of people come and go. You in particular? In your first thread I tried to nudge you into compliance with our rules. That you needed to be more forthcoming with information. The thread was shut down after you announced "I will not participate in this open forum anymore" But you weren't true to your word. You came back, and to be honest, you lose a certain amount of goodwill from the mods when you pull a stunt like that. Once again, you were not forthcoming with information needed to support your position. That thread was closed, with a note that said if you did present supporting information, you could re-introduce the topic. I don't see where you took us up on the offer. The last one shut down was where you admitted you didn't understand the physics, and yet had a conjecture. I explained that this was not living up to our expectations, and at this point you had twice been given feedback on the matter of being able to support your ideas. Thus I had zero confidence that simply giving some feedback and letting the thread continue would improve matters. That was your third strike. The fact that you are placing the blame elsewhere tells me you haven't absorbed this feedback at all. So the question that I have is how many chances do you expect, when you show no improvement in your behavior?
10. 3 points

THE TIME-FLOW FALLACY

And I thought it was something to do with corona
11. 3 points

AOC as a politician- Split from: U.S. Democratic Primary

I'm not going to quote snipe back and forth. I'll just post my thoughts in hopes of finding places we agree again. When we discuss topics like healthcare, everyone always trots out the "how are we going to pay for it" canard. Some people object to this seemingly reflexive response because it never seems like we have that same response when discussing military spending, going to war, cutting taxes, etc. There is always room for spending. There are tools we can use to account for it. The government budget is not like a household budget. Taxes can be increased. Money can be printed and borrowed. There's always a need to be vigilant and not do these things in excess, and there's always room for discussion around what the threshold should be for what IS excessive and what is NOT excessive, but to boldly proclaim it all to be impossible then drop the mic and walk away is what is truly absurd here. I'm not arguing for pure spending or permanent spending. I'm saying we can shift money from place A to place B, and that we also need to account for future returns. After all, that's what the GOP does when arguing for tax cuts on the rich... I have seen many people (most often conservatives) frame government spending as a pure cost, and I personally feel that's a mistake... a completely unrealistic perspective on how economies operate. Now... This is my opinion, and it's perfectly okay to hold a different one, but I frame these issues instead as investments. What is the expected return? Will this increase jobs? Will this reduce poverty? Will this enhance wellbeing? How will these affects impact revenues and growth? What are the costs of inaction (this last one is especially relevant when rebuilding after hurricanes for not proactively addressing climate change). It's just that this constant and immediate shitting on ideas is so one-sided and so hypocritical from one topic to the next. These calls for detailed payment plans when the topic relates to healthcare or green jobs programs... these defeatist attacks that suggest forcefully that "WE JUST CAN'T DO IT!!1!!2!one!!"... yet at the same time and from the exact same people deafening silence when it comes to giving massive handouts to corporations or adding a few hundred billion for the military or lobbing a few multi-million dollar missiles into the desert overseas somewhere... Nope, not a peep! Nothing. Nada. Zilch... Crickets in an amphitheater. And don't even get me started about when actual payment plans are shared and just get swept aside in strawmen and scaremongering... The core issue here is about what we choose to value. It's the politics that are hard, not the economics, yet it's always the economics used to short-circuit the conversation and prevent us from even talking about these ideas or creatively finding ways to achieve them. Seriously... You're going on about how we cannot afford healthcare, yet today already we pay something like 3x what most other civilized nations do, and we have generally worse outcomes, lower quality care, and we don't even manage to cover everyone. We don't need to invent this from scratch, we just need to look at what's working elsewhere, claim it for our own, and stand up to fight for it in good faith. This is not a problem of budgeting, it's a problem of priorities. Now... AOC is just the newest foil for the right. She's the new bogeyman being used to get people all lathered up and wetting their pants and distracted from reasonable dialogue, but no matter how many times you repeat the word math or call her arrogant or pretend you're taking some arbitrary high-ground... no matter how many times you call her a liar for using poetic license on a single news article and no matter how much you get yourself all worked up into a tizzy and tell us all you're taking your ball and going home... there is just nothing about what she's suggesting that is either impossible or unworkable.
12. 3 points

You think you've got problems America...

Unfortunately, I'm not sure how much the public has learned. For example, I saw the results of a survey where 26% of the people asked thought that "no deal" means maintaining the status quo. If a significant proportion are going to vote for the most damaging option because they think it will leave thing as they are, then I'm not sure another vote will be any more meaningful. But that isn't the argument being made. Let's say you agree with some friends that you are going to go out for a meal. So you follow one friend who takes you to a restaurant which is filthy but really expensive. You remember seeing news stories about people getting food poisoning there regularly. Do you: a) Ask you friends if that is really where you want to eat, or would they prefer that nice place next door? Or b) Say, "well we decided to go out to eat, so we have to eat this disgusting place, whether we want to or not." After all, it would be betraying the original decision if we voted on where to eat now we have seen the options. We should never have had the first one. They are a really bad idea. And if you are going to have one for a major constitutional change, then there should be a requirement for a 65% (or whatever) majority to change things. That doesn't make much sense. In a general election would you vote for the party that won last time, even if you voted against them "to honour the first result"? You should vote for what you think is right. That ship has sailed. We have lost any credibility or honour we had. People's trust in politicians (never high) has been destroyed. I think having the referendum was a monumentally stupid idea. I don't think a second one would make things any better. But with neither the government nor parliament able to make any sort of decision, it may be the only option.
13. 3 points

Why is it scientifically acceptable to hunt invasive species to extinction

Where have we hunted invasive species to extinction? I know we've removed invasive species from the place they've invaded, but that is hardly the same as hunting them to "extinction". Typically invasive species are removed from an ecosystem because their lack of natural predators in their new environment allows them to do undue harm to the existing and/or desirable ecosystem.
14. 3 points

Neil DeGrasse Tyson Misconduct

Interpreting the hidden meaning behind a person's statements is a fool's errand. His comments could have been exactly the same whether he is innocent or guilty. No matter what he says, some will believe him, some will not. Some will think it is thoughtful, some will think he is being aggressive. Some will find him credible, some will not. Discussing whether or not we believe him or what his intentions are may be an enjoyable pastime, but we shouldn't make the mistake of believing that after a long discussion we will be any closer to knowing the truth.
15. 3 points

I want to rebuild my house twice a year

One tip to go with all iNow's questions: Choose something which can be built in less than six months.
16. 3 points

Can you believe in evolution and in god?

I feel the real Scotsman fallacy coming... Who defines who is Christian? You? Or do Christians define themselves as Christian? Sorry, But I hate these kind of sweeping statements where you state what others should believe according the labels you use. Fascinating. The article is amongst others about Christians who accept evolution. Another one. If you had written 'most' I would have given you the benefit of the doubt, but you wrote 'all'. I know several people who also take Jesus' miracles symbolically. Yes, probably. Surely evolution made us prone to religious ideas. But religious ideas of individuals are mainly socially learned. So they may arise in the brain, but not necessarily caused by it.
17. 2 points

ISIS leader al-Baghdadi killed

US special forces staged a raid near the Syria/Turkey border and flushed out Abu Bakr al-Baghdadi, who then blew himself up with explosives when trapped. Apparently DNA confirmation of his identity is now possible 'in the field' and much quicker than the usual couple of weeks it takes for criminal cases. Obviously there is a need to be sure, as he has been 'reportedly' killed several times before. D Trump is either trying to draw attention from his escalating problems, or still trying to take wind from B Obama's sails ( the Osama bin-Laden takedown ), as apparently he posted a ( staged ) picture in the Situation Room from the wrong time; he was playing golf during the actual raid. Congratulations to American Special Forces and Intelligence Services. Also, our Allies in the area who supplied the intelligence; you know, those same people D Trump deserted and left to be slaughtered by the Turkish offensive two weeks ago.
18. 2 points

Likes

Why can't you see who giving you likes? Compared to some of the people on the forum, who actually know about science, my posts contain no substance whatsoever, yet I've got 22. I know there not important, I'm just curious.
19. 2 points

Spectrum of sunlight

The Sun is so hot that most of the gas is ionised. Free electrons and protons are allowed to have (almost ) any energies. When they crash into eachother some fraction of the energy- depending on angles of impact etc, is sent out as em radiation. Also, at those temperatures the "lines" are broadened by doppler shift and at the high pressures involved they are also broadened by collisions. https://en.wikipedia.org/wiki/Spectral_line#Line_broadening_and_shift The overall effect is a mass of overlapping emission bands which approximate (rather well) to a black body spectrum.
20. 2 points

A brief history of you

I'm a welder. It's a steady income now that I have a family. I failed out of a biochemistry program years ago. The hardest thing I've had to overcome was depression. Hindsight I've learned a lot about the value of education. I'd cut off my arm to go back to school. I have no idea what I would tell myself in the past. And I really think I should know. I didn't make this topic because I wanted to talk about myself. I want to know how smart, successful people came to choose their careers and if anything helped make them into who they are today.
21. 2 points

Exotic Physics Phenomenon Observed

Here is the arxiv article https://arxiv.org/abs/1906.03369 Hrrm how to simplify this. Ok let's give this a shot. In classical physics you have the E and B fields for electromagnetism however in QM those fields are replaced by the probability potentials $\phi$ and $\mathcal{A}$ now in regions where the E and B fields are zero you can still have potential via the wavefunction that the $\phi$ and $\mathcal{A}$ are non zero This tells us that the QM and QFT subsequently treatments is more fundamental than the classical treatment in that it is more complete in the information of the EM field. In essence the paper helps confirm that the probability wave functions do have a physical and measurable effect through their potentials. For example it's also a key aspect to how a particle wave packet can go through two slits at once.
22. 2 points

How Much Can US Health Care Progress If Donald Trump Allows More Money to Invest?

This is the key. Right now, insurance money (which the taxpayer has paid) and tax subsidies (which the taxpayer has paid) are being based on maximum profit like any growth business model. The problem is that healthcare needs to be aimed at caring for people's health in order to be effective. In the US, the focus on profit allows businesses to leech away funds that the taxpayer needs. One example among many is durable medical devices. Businesses are allowed to create monopolistic deals with doctors offices for oxygen, blood, and sleep devices. There's no competition for them with your provider, so you have no choice when they fail to provide their services, or overbill, or send the wrong filters/tubes/parts. They learned this from the cable TV giants, who similarly have no competition within their protected areas. Customer service becomes a big joke (google Apria Healthcare or Comcast customer service and look at the comments!). We definitely need a more European attitude about spending on social requirements (which I feel healthcare is). In the US, we let capitalism build the paths our socialism takes, and wonder why all our money gets leeched away.
23. 2 points

About life and consciousness.

It doesn't have to. But as Strange already notices a lot of people like to understand their world and themselves. I belong to these kind of people. Fully agree. But I do not see why that contradicts the will to understand consciousness. For me it is just the opposite. Depends on the subject: but if people as a group want to decide on actions they should agree on the facts and the norms, and be able to distinguish them. And science is the most objective search for facts. Just think about climate change deniers. I definitely want to hear what science has to say here, and I am disgusted by the science denial of the so called 'climate skeptics'. That is what happens if you follow gut-feelings. It is very comforting 'to know' there is a fire ladder when the building burns. Except that objectively there does not exist one, it was just your gut-feeling. When the fire breaks out, it would have been good for you to know you shouldn't have gone that way to escape the fire. No. However, I would prefer that people act from the best knowledge we have available. See climate denial again. Why would you think I do not grasp the immediate reality of death? I dismissed nothing, except the categorising as 'metaphysical'. I agree that such experiences can change your gut-feelings. Ideally you develop your gut-feelings in such a way that they correspond with what we know to be objectively the case. But that requires a lot of training, but staying in your comfort zone, you will never get there. Your life will be a lie. Me neither, but in a different way you do. Physical reality is able to produce such beautiful things like galaxies, paintings, music and humans. The problem is that some of these (except maybe galaxies), cannot be understood from their basic building blocks. Even the essence of certain things is independent from the exact way it is implemented in the physical world. A house is a house, but it can built it with concrete or wood. Being human, however I agree that our essence is not that we are built up of matter: it lies in the ways processes take place in this matter. And to know these, both from the inside (studying my own mind) as from the outside (science) might be the best way to live a balanced life: accept what just is so, change what can be changed, and the wisdom to distinguish between the two (paraphrasing I think an Irish prayer). Yes, you are afraid to leave your comfort zone. And the closed mind is yours, and is exactly what I named it here: your comfort zone. But be sure, nobody got enlightened by staying in their comfort zone. It is, to use another dangerous word, not very spiritual not to accept ideas because you do not like them. Physical reality is the ocean. And the truth at the bottom of the mind might be emptiness. As practicing Zen Buddhist, I think that would be the last truth (not experienced myself, therefore 'I think' and not 'I know'). Which you of course you do not like, and therefore you refuse to accept reality.
24. 2 points

New Approach to Anti-gravity [Split from: A New Area Law in General Relativity, questions.]

Here is what one average person (me) thinks. Trying to make big progress is good! But you reference concepts such as bosons, gravitons, entanglement, spin, black holes, invariant speed of light from currently accepted theories. That means you are working in the framework where those concepts makes sense and are applicable. Things that are inherently incompatible with these concepts will not impress on professionals. Example; faster than light travel and information exchange and anti gravity cannot work in the current theories of relativity and standard model of particles as far as I know. That means that your proposed ideas is not possible within the currently accepted theories and models as pointed out by members more skilled than me. And these theories are supported by loads of evidence. You need to find some way to make progress outside current theories. Something completely new and novel is required by you. Not adjustments or adoptions of concepts in current theories, that is not enough to fundamentally change the basis for current theories.
25. 2 points

Reflexivity

This site supports Mathjax with the "math" and "\math" tags in square brackets surrounding your markup. In (1) your proof is fine but I'd reword it for clarity. You wrote, "I assumed $A = \{2,3,4,5]\}$ is the subset of the power set ..." I would reword that as, "Suppose $A = \{2, 3, 4, 5\}$. Then $A \cap A = A \neq \emptyset$. Or you could just say, For any nonempty set $A$, we have $A \cap A = A \neq \emptyset$. That would be sufficient for me. Also note that you meant that $A$ is an element of the power set. It's a subset of the integers, but an element of the power set.
26. 2 points

Experiment to reveal parallel universe

Not quite. There are multiple symmetries. Some lead to anti-matter, others to supersymmetric particles, others to mirror matter. (There may be others ...)
27. 2 points

Mueller indictments (split from Collusion with Russia)

I was really impressed by this quick summary series on the Mueller Report done by PBS NewsHour. In 5 short videos about 5 minutes a piece, they give a summary of the nearly 450 page report in a way that’s easily consumable for those who have been paying close attention or even no attention at all. Here’s a link to the 5 video playlist:
28. 2 points

Direction of time

The only centers and boundaries we can logically speak of, is the center of our "observable universe"...which of course anyone can legitimately claim, from wherever he is. While knowledge and data of BB model only goes back to t+10-43 seconds, cosmologists are able to reasonably speculate re those early times. During those early times, the four forces we know of today were united in what was called the "Superforce" As space expanded and temperatures and pressures dropped, this superforce started to break up or decouple, gravity being the first. This created what we call phase transitions and false vacuums. eg: the phase transition of ice to liquid water. These false vacuum states may also be responsible for the Inflation epoch. http://cse.ssl.berkeley.edu/bmendez/ay10/2002/notes/lec19.html During this epoch as temperatures and pressures continued to drop, excesses of energy went into creating our very first fundamental particles, quarks, electrons and such. At three minutes the first atomic nucleus was formed [protons and neutrons] The rest is pretty reliable history. The universe over large scales is homogeneous and isotropic. The same can be applied the the expansion rate...that is, it is only applied over large scales.
29. 2 points

Evidence of Human Common Ancestry

No, when has history ever happened twice? It's like trying to walk over the same river twice; at some point it didn't/doesn't have a bridge... Or water.
30. 2 points

A very interesting publication about Free Will

Hi all, I came across a very interesting publication about Free Will: In short: https://newsroom.unsw.edu.au/news/science-tech/our-brains-reveal-our-choices-we%E2%80%99re-even-aware-them-study and the publication itself: https://www.nature.com/articles/s41598-019-39813-y Just one thing I didn't understand from what written there, what was the accuracy of the prediction? They say that they could predict what people will consciously chose about 11 seconds before they choose it (which sounds amazing!) but in what accuracy? 70% of the times? 85% of the times? Please let me know if you find this information, Thanks!
31. 2 points

Global/Generalized Sagnac Effect Formula

Please don't.
32. 2 points

light speed

As already pointed out, we take the light travel time into account when we determine simultaneity. So judging the synchronization of another clock would involve not just what you see, but how far away the clock is. If we assume that the clock never moved between the light leaving it and the light arriving, it is one light year away, and you read a time 1 year behind your clock, you will say that they are synchronized. (This would not be true for someone moving with respect to the two clocks, but I'll get to that later.) There is a quote by Robert Heinlein that may be applicable here: "You can go wrong by being too skeptical as readily as by being too trusting." There are a lot of resources you can try, but no matter which one you choose, you are going to have to approach it with an open mind, and be aware that you will likely have to discard some notions you already have about how things work. I'll try to get you started. First off, we need to start with Special Relativity. This is basically General Relativity when you assume no gravitational fields. SR is based on two postulates: 1. The laws of Physics are the same in all inertial reference frames. 2. The speed of light in a vacuum is a constant in all inertial reference frames and is independent of the relative velocity of the source. An example of an inertial reference frame would be a spaceship coasting in space. If it fires its engines to change speed, while doing so it would be considered a non-inertial reference frame. Once it starts coasting again it will once more be a inertial frame, just a different one than it was earlier. What the first postulate mean is if you had a lab in your spaceship and used it to do any conceivable experiment, you would not get any different results between before you accelerated the ship and after. If you hadn't been aware of the acceleration, there would not be any way for you to tell that there had been a change in velocity in the lab between the two sets of experiments. The second postulate basically means that this also applies to any measurement of the speed of light. Measuring the speed of light always gives the same answer: c ( 299,792,458 m/s), and it doesn't matter if the source is moving relative to the lab or not. In other words, we would measure light as moving at 299,792,458 m/s relative to the lab, both before and after the acceleration and it would not matter if the source of that light was moving or at rest with respect to the lab. This also means that two different labs moving relative to each other would each measure the same light as moving at c relative to themselves. So for example, if you have two labs, A&B, in relative motion with respect to each other, and as they pass each other a flash of light is emitted from where they meet, Lab A, will measure events like this: With itself in the center of an expanding sphere of light as B chases after one edge of that expanding sphere. However, B would measure this as happening: B would remain at the center of the expanding sphere and A would be chasing after one edge. And as counter intuitive this may seem, countless experiments and measurement have confirmed this. So how does this effect how we measure simultaneity? Imagine you have a set of train tracks with an observer along side it, there is also a railway car on the tracks, moving relative to the tracks. the track observer is halfway between two light sources that emit flashes of light that meet at the track observer at the same moment the railway car passes him. For the track observer, events unfold like this: with the expanding circles representing the light flashes. Both flashes are emitted at the same time, and reach both observers at the same moment. For the railway car observer however, things occur differently. He agrees with the track observer that the flashes arrive at the same time as they pass each other, but not that they were emitted at the same time. Here are events as they unfold for him: Unlike the track observer, who remains a fixed distance between the two sources, the railway car is only halfway between them when he sees the flashes. When either of the two flashes is emitted, he was closer to the left source than the right source. Since each flash must travel at c relative to this observer in his frame, the only way for the two flashes to meet when he is half way between the sources is for the right flash to be emitted before the left flash. Thus according to the track observer, the emission of the two flashes are simultaneous events, but according to the railway car observer, they are not. If we were to put clocks at the sources and each flash carried the information of the time stamp for the clock reading when the light left, then if the track observer reads identical time stamps when the flashes arrive, he can conclude that the clocks at the sources are synchronized and read the same at all times. The railway car observer will see the same two identical time stamps, But for him, the light from one flash left earlier and took longer to reach him then the other, So the two clocks can not be synchronized with each other and don't read the same at the same time, and that one clock always reads ahead of the other. This is known as the "relativity of simultaneity". This is a fundamental concept in Relativity, and one you really need to come to grips with if you wish to understand it (many of the "contradictions" people think they have uncovered in Relativity stem from not grasping this concept.) Other concepts such as Time dilation and length contraction build from here. I'll leave it here for now, but first I want to make one thing clear. In these examples we use light. But Relativity isn't really about light itself. It's really is about the nature of time and space. Light behaves the way it does because of this nature. Light doesn't dictate the rules of Relativity, it adheres to them. Because of the nature of time and space, the speed c is special. Light travels at c in a vacuum, and since it is something we can detect and measure, it is a good tool for examining those rules that govern time and space. Light is convenient for use in these examples, but is not required for Relativity to hold true.
33. 2 points

Do most humans need to believe in God

When I open my eyes in the morning I don't see God's love. Instead what I see is Capitalist cruelty and people dying by the numbers every day. I see a world ruled by radical patriarchy and the strong dominating over the weak. This world cannot be the work of an all-loving God. If God created this cruel and corrupt world then he is evil and sadistic and not a loving and caring God at all and especially not one worth worshipping.
34. 2 points

Time standing still?

Time always passes at one second per second, period, in your own frame of reference. It is only when observing the passage of time in another frame that dilation and length contraction occurs. And in that other frame, according to whoever resides there, he or she will like you see time also passing at one second per second in that frame. Like you though, if he observes your passage of time, he will see it dilated and length contracted. Each frame of reference is as valid as the other.
35. 2 points

Essay about General Relativity

Gravity doesn't bend spacetime; gravity is bent spacetime. Matter tells spacetime how much too bend. Conversely, spacetime tells matter how to move i.e. its trajectory. 'Fabric' is just a metaphor and not to be taken literally. I think the term originates from the 'heavy ball on a trampoline' idea of bent spacetime, which the fabric represents. It only shows two dimensions; when there's actually 4. It's a very crude idea, not really representing the facts but just gives a glimpse of the concept. 'Spacetime' is actually a 4 dimensional map of the gravitational distribution in a space...it's a mathematical construct. It allows people to plot mass- energy values in time and space on co-ordinates in the spacetime map and see how they change under different scenarios... amongst other things. As you should see, spacetime is not a 'thing' but a way of describing how things behave and interact in space. That behaviour is what we call 'gravity'.
36. 2 points

Question about methods for creating hidden symbols for a board game

I couldn't resist another attempt... how about writing symbols on the back of paper and use back-light? Could work with the right combination of paper thickness, light and ink. Quick experiment, using office paper, ball pen and flashlight from behind paper. Flashlight off: Flashlight on:
37. 2 points

How do you feel about being dead forever?

AKA 24/7 Reality TV shows. Binge-watching all 21,650 seasons of Man vs Beast. You will LONG for death.
38. 2 points

The nature of time ( question).

What is a shadow made of? Shadows certainly 'exist' - whatever that means. A shadow is a prime example of zero something. I think the english language offers a good construction. it = a thing is a noun. Nouns can be 'concrete nouns' like an apple or water or well, concrete. Or nouns can be abstract nouns like anger, a shadow, weight and so on.
39. 2 points

40. 2 points

The Fifth Force

It all comes down to the fact that the Earth is not a perfect sphere and its axis of rotation is not perpendicular to its orbit around the Sun or the Moon's orbit. Because of the Earth's slight oblate shape, the differential in force acting across it due to the gravity of these two bodies, applies a torque to the Axis in an attempt to align the axis to being perpendicular. But the mass of the Earth has a set angular momentum that it tries to conserve. the end result is the This torque ends up being "deflected" into producing the "wobble" known as precession. If the Earth were a perfect sphere, there would be nothing for the gravity differential to get a "handle on" and we would get no precession.
41. 2 points

Plate Tectonics: A Modern Myth?

You still need to show that the rock types and ages conform, particularly at your proposed match points. You have steadfastly avoided this question. This is even more basic than expanding Earth proposals. For instance this statement is false. Geologists acknowledge the sedimentary fascies you are ignoring in Kamchatka. Here is a description by geologist Susan Hough about Japan Sediment again! Also in your tilt against plate tectonics I certainly understood your opening post to include a direct refutation of plate tectonics. But again we come back to the age (and type of rocks) Folding action of the type you describe would leaves its mark in evidence, just as ancient folds, erosion surfaces, beaches and other features that are buried today, can be detected by seismology, boreholes and other means. There is a significant problem you face in the dramatic difference between the oceanic crust and continental crust, both in age and nature. You cannot close your eyes to all the other evidence and expect to be taken seriously, even though your shape alignments could be quite interesting.
42. 2 points

The Border Wall or Fence

Now it will happen...
43. 2 points

Black Hole Energy Distribution

But it is still talking about the temperature at the event horizon.
44. 2 points

'Stupid Woman'

@MigL you are setting a rather ridiculously high standard for opinion forming. Whether or not an individual approves or disapproves of a comment is not equal to a formal judgement in a court of law. Everyone I speak to or that over hears me speak on a daily basis form opinions about me. People who dislike things I say are under no obligation to withhold their judgement. One doesn't have to read my mind or have a list of facts on the ready to make up their own minds about how they feel.The burden of maintaining my reputation and image is on me and no one else. People do not view everything I say favorably by default. Regardless of my true intentions I must be aware of my environment and audience when opening my mouth. How I represent myself to others matters. Making sexist comments isn't a crime and Corbyn is not facing formal charges. The legal standard for evidence doesn't apply. We all have the right to feel however we want about what was said.
45. 2 points

can plants adapt?

With this misconception/misinterpretation you're just giving bullets to guns of climate change deniers. It's not so simple. Global warming will melt ice on the North and the South poles. Right. It'll change e.g. underwater sea current in Atlantic. This current is causing warm winters in U.K. Now, if climate change supporter is simplifying global warming to just words like you said, and people see exactly reverse, like it can happen in UK after disappearance of underwater sea current, they will be confused, and say you're talking nonsense about global warming, if they will have severe winters.. Global warming is global change of moderate environment, to the more extreme environment.. Extremity not just in hotness (in some regions), but also extremity of coldness (in some regions).
46. 2 points

The end of gasoline/diesel powered cars?

Beware newspapers need to catch the public's attention. When Angela Merkel said "I can imagine that no car with an Otto or Diesel engine is sold in 2030", in some newspapers it became "Merkel decided to ban Diesel cars in 2030". You believe electric cars are unrealistic... But humans have this ability to make unexpected things possible. For electric cars there is a very strong incentive. Think at LED lamps. Based on the ruinous tiny things just capable of telling "on-off", I thought all plans of LED lighting were foolish. But recently I replaced all my lamps by LED, because they work and are better. Companies have invested billions in that technology. One key is that it suffices when a few people (at the right place!) believe a progress is possible and useful. Never mind if 99.99% of Mankind don't believe it. This is a superiority of a free country, where people can explore new direction and are allowed to fail, over a dictatorship where one single person decides everything and can only try to catch up what was done abroad. Batteries are already good enough to move cars. In California, in Norway, electric cars sell very well. Trucks may be the next big market. Companies invest billions to develop batteries, they will improve. Whether the next ones will use lithium (which isn't expensive nor scarce), zinc or sodium, I don't know. It's impossible to predict 10 years in advance and with limited data. You know, all companies have long thought through before their heavy investments, and they made different decisions. My preferred one is liquid hydrogen at 1atm with vacuum insulation. Decent density, and the tank is only as heavy as the hydrogen. I'd have nothing against adsorption, but it seems to need a high pressure, which makes it less attractive. Aeroplanes will use hydrogen soon, much more so than batteries, and their tanks will spread to cars.
47. 2 points

Distances of radiaition

It's not quite that simple, though. Neutrinos travel (slightly) slower than photons but are far more penetrating because they don't interact the same way. You have to look at the interaction probability as well. Alphas are more likely to interact owing to their larger charge. They will ionize surrounding atoms, which causes them to lose energy and slow down. Neutrons will tend to penetrate better than protons, because even though they have roughly the same mass, the neutron has no charge. Alphas don't. They have a pretty well-defined penetration depth. "The range of alphas of a given energy is a fairly unique quantity in a specific absorber material." https://sciencedemonstrations.fas.harvard.edu/presentations/α-β-γ-penetration-and-shielding There's a plot here of what the alpha count typically looks like with distance. https://physics.stackexchange.com/questions/308359/does-alpha-radiation-penetration-depth-decrease-exponentionaly-with-distance/308428#308428
48. 2 points

The ice core enigma

Why not do a little research? e.g. where is your evidence that in warm periods the temperature everywhere on earth is above say -5C so that the 'top ice' everywhere melts? No. Lots of independent checks before any ice core is considered to be valid evidence of anything.
49. 2 points

Moms and kids tear gassed at southern US border

There are billions of options in between. Comments like this suggest a profound failure of imagination and experience, not some fundamental truth. Really, much of this is about which visual we choose to look at. THIS: OR THIS: I, for one, feel that as a country of nearly 350 million people and more wealth than the planet has EVER seen, we CAN find a way to include these folks within the population of “us.” I see neighbors and friends and colleagues in these photos and I don’t wet my pants when a mommy fleeing violence with her babies walks cross an arbitrary line looking to work hard and contribute, but YMMV
50. 2 points

The Official JOKES SECTION :)

4 nuns arrive at the Pearly Gates of Heaven. St. Peter is there to meet them with a bowl of Holy Water. St. Peter goes up to the first nun and says, "Have you ever touched a penis?" The first nun responds, "Yes I have. I have touched a penis with the tip of my finger." St. Peter holds out the bowl and says, "Dip your finger in this Holy Water, and be free to enter the Kingdom of Heaven." The first nun gladly follows the instruction and proceeds to enter Heaven. St. Peter goes to the second nun and again asks, "Have you ever touched a penis?" The second nun replies hesitantly, "Yes. I have touched a penis with my whole hand." St. Peter smiles and says, "Do not despair, simply dip your whole hand into the Holy Water and enter the Kingdom of Heaven." The second nun quickly does as she is told and gladly steps forth into Heaven. At this point the fourth nun cuts in front of the third nun and says, "Listen, I better go next because I'm not gurgling that shit after she sticks her ass in it."
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