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Thursday, November 15, 2018

How are quantum computers actually implemented?

How are quantum computers actually implemented?


How are quantum computers actually implemented?

Posted: 14 Nov 2018 09:26 AM PST

I have basic understanding of quantum information theory, however I have no idea how is actual quantum processor hardware made.

Tangential question - what is best place to start looking for such information? For theoretical physics I usually start with Wikipedia and then slowly go through references and related articles, but this approach totally fails me when I want learn something about experimental physics.

submitted by /u/kubazz
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Stupid question, If there were metal buildings/electronics more than 13k+ years ago, would we be able to know about it?

Posted: 15 Nov 2018 12:14 AM PST

My friend has gotten really into conspiracy theories lately, and he has started to believe that there was a highly advanced civilization on earth, like as highly advanced as ours, more than 13k years ago, but supposedly since a meteor or some other event happened and wiped most humans out, we started over, and the only reason we know about some history sites with stones buildings, but no old sites of metal buildings or electronics is because those would have all decomposed while the stone structures wouldn't decompose

I keep telling him even if the metal mostly decomposed, we should still have some sort of evidence of really old scrap metal or something right?

submitted by /u/TwitchyFingers
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How does the new kilogram work?

Posted: 14 Nov 2018 10:38 PM PST

Scientists are voting to redefine the kilogram using physical constants rather than the arbitrary block of metal we use now. Here's an article about it: https://www.vox.com/science-and-health/2018/11/14/18072368/kilogram-kibble-redefine-weight-science

From what I understand, this new method will allow us to generate "reference" kilogram masses by using fancy balances anywhere in the world. I'm confused how we can use the constant speed of light to do this. The speed of light in a vacuum is constant, but doesn't the time component change depending on the local gravity and speed? Wouldn't that mean that reference masses would vary slightly, depending on the gravity and the speed at that particular facility, according to general and special relativity? Is this canceled out somehow, or is it just so small that it's still an improvement in precision over what we have now?

submitted by /u/halberdierbowman
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How deep does dirt go?

Posted: 14 Nov 2018 05:25 PM PST

I am imagining minecraft, so this is probably a stupid question. But if I went to my backyard and got a shovel, how far would I go before I hit stone? Or is there even stone under? Earth science in high school covered types of rocks and and layers n stuff, but doesn't tell us where things are.

Are the tectonic plates made of rock? The education system has failed me, please help

E: so from what I'm getting - my education on earth science sucked. I loved physics and biology (chemistry sucked), but my "earth science" class was just "here are types of rocks. Here are the planets, good luck". From what I understand- it varies, bedrock isnt under 60+meters of stone as some childhood video games led me to believe, but could be 10-40ft below dirt. I think in my area, there is clay under me (my dad dug 6' holes for fence posts, and only got thick red stuff [probably clay]).

Thank you for all the help, I was up late at night and semi delerious when I got on this thought path, but I appreciate you all taking the time to answer :)

submitted by /u/Lorde_Farquad
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Where do meteorites gain their velocity?

Posted: 14 Nov 2018 11:23 PM PST

A recent news article states that a plasma's temperature, for self-sustaining fusion, needs to be around 100 million C - but the core of the Sun is only around 15 million C. Why does a plasma's temperature need to be so high for fusion to work? And why not for the Sun?

Posted: 14 Nov 2018 02:38 PM PST

The article in question is here: https://www.abc.net.au/news/2018-11-15/china-attempts-to-create-an-artificial-sun/10495536.

I get that the temperature must be high enough to generate a plasma, but to the best of my knowledge plasmas start forming in the 10,000 C range.

submitted by /u/Niccolo101
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Is it possible for a particle to be made of only neutrons?

Posted: 14 Nov 2018 07:01 PM PST

I've recently learned the functions and such of an atom, and was wondering if it would be possible for a particle to be made of only neutrons, and what would be the implications of such a particle?

submitted by /u/AnxiousMirror
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Can a recessive gene evolve into a dominant one after generations?

Posted: 14 Nov 2018 04:35 PM PST

How come our bodies can break down so many proteins but keratin is a big no no?

Posted: 14 Nov 2018 04:34 PM PST

How do atoms 'share' electrons?

Posted: 14 Nov 2018 12:31 PM PST

I understand that they do it to gain stability, but how does it actually happen? As I understand it, electrons orbit around a nucleus, so how do electrons orbit around two nuclei at the same time?

submitted by /u/Grits-
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Could there be a new quantum field that is not interacting in its vacuum state, but would be given high enough excitation?

Posted: 14 Nov 2018 04:30 PM PST

What happens during elastic electron collisions with a surface?

Posted: 14 Nov 2018 04:29 PM PST

I'm confused with what happens during elastic electron collisions with a surface. An example of what I am talking about would be back-scattered electrons in an SEM. There are representations of this I have seen that shows an electron "sling-shotting" around the nuclei, but this is an incorrect representation because that would cause the electron to produce bremsstrahlung x-rays, thus the interaction would not be an elastic collision. I was told that the electron "bounces" off the nuclei like a ball bouncing off a wall, but that explanation does not satisfy me. What force repels the electron away from the nuclei? Is it just electrostatic forces? Would an electron getting that close to the nuclei violate the pauli exclusion principle?

submitted by /u/PopularPlanet
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Can dogs (and cats) tell that human babies belong to "their" human?

Posted: 14 Nov 2018 11:05 AM PST

Like, if parents bring home their newborn, can the dog/cat smell the newborn and "know" that the baby came from the parents?

I've tried googling it, and a lot of what I've found is specifically about how to introduce your pets to your new baby/do animals know what a baby is, and while that's interesting, that's not quite what I'm looking for?

I assume that a human baby would, presumably, smell like whoever is holding them most often, but do humans have an inherent "smell", and is that passed on in a way that dogs/cats can understand to the best of their abilities?

submitted by /u/loracarol
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After a vasectomy, where does the stem go after an ejaculation?

Posted: 14 Nov 2018 08:46 AM PST

If the tube it self Is cut and there is now a open tube that's sitting in the sac, then the sperm would still come out but only into the sac wouldn't it? And even is it was closed somehow, then wouldn't a buildup of sperm cause a problem? Eventually an extremely high amount of pressure of the sperm would break through whatever closed the tube. And then you'd be back to the situation of having sperm floating in the sac.

submitted by /u/Noahwar97
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Why are Lauric-based surfactants preferred instead of Oleic/Stearic-based surfactants?

Posted: 14 Nov 2018 08:38 AM PST

In the cosmetics industry, more than 70% of personal soaps that are used today have sodium lauryl sulfate or sodium laureth sulfate as the main cleansing agent, but why is that the case? Lauric acid based soaps are often derived from tropical plant sources, like coconut and palm oils.

I have seen next to no information about the cleansing power or just the general properties of ethoxylated oleic and stearic based cleansers. Oleic acid is the primary acid that can be found in plenty of oils, like soybean, canola, olive etc. Stearic acid can be made from oleic acid by hydrogenation, turning it from an unsaturated to a saturated fatty acid, giving it more cleansing power. Wouldn't it be more economical and less consuming to use those fatty acids in soap making instead of lauric acid based soaps? And as a added question, why is there so little information on oleic based surfactants?

submitted by /u/M_An_M
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How does dark matter affect galactic orbital speed?

Posted: 14 Nov 2018 06:03 AM PST

I've been reading about the history of the Dark Matter theory and the evidence for it due to galactic spin speeds.

The way it is phrased in many articles is "without dark matter the stars would spin away, and the galaxy would rip apart." I understand this, but wouldn't this simplistic version of the evidence be answered by simply increasing the mass of the Galactic Core?

My current understanding is that the stars don't just orbit faster than expected, but the Acceleration Curve (the amount the orbital speed decreases with distance from the center) is shallower than expected, i.e. stars distant from the center move too fast relative to stars near the center for any possible mass of the Galactic Core. Is that correct?

Finally, if the above is true, I find it hard to visualize. As a hypothetical, if dark matter were visible dust would that mean the Galaxy would be a big dust cloud with a few stars speckled in it and the whole thing would be rotating at a more constant speed because the gravitation of the giant dust cloud would offset the mass of the Galactic Core?

I guess I don't understand why having mass everywhere would make the whole thing spin faster unless the center is also more massive. If, for example, our solar system was filled with gas or dust, would we be orbiting the Sun at a noticeably different speed? I'd almost expect the opposite. Forgetting about friction, wouldn't the gas past the orbit of the Earth be slowing it's orbit down, not speeding it up?

submitted by /u/ovideos
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What happens to photons when they get absorbed by particles? What do they transform into? And do the particles ever get saturated?

Posted: 14 Nov 2018 10:26 AM PST

Wednesday, November 14, 2018

Why is there a time-energy uncertainty relation when time is not an operator in Quantum Mechanics?

Why is there a time-energy uncertainty relation when time is not an operator in Quantum Mechanics?


Why is there a time-energy uncertainty relation when time is not an operator in Quantum Mechanics?

Posted: 13 Nov 2018 10:58 PM PST

The Heisenberg Uncertainty Principle is based on the property of the commutators of two Hermitian operators. But time is not an operator in Quantum Mechanics, so what gives? How fundamental is this relation? Where does it come from and what does it mean?

submitted by /u/lAPPYc
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If there is an infinite amount of natural numbers, and one is chosen at random, mathematically the probability of choosing that number should be 0. Why can the number still be chosen?

Posted: 13 Nov 2018 01:57 PM PST

It seems fairly reasonable that the probability cannot be 0, as if you were to sum up all the probabilities, you have to get one as a result, while the sum 0 + 0 + 0 + ... + 0 + 0 (with an infinite amount of zeros) can never have any other value than 0.

But, the probability of choosing a specific number should be 1/(amount of natural numbers), which is 0, since the amount of natural numbers is infinite. Is it something about how the limit of 1/x for x -> infinity works, or am I missing something else entirely?

submitted by /u/Scutman
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How are satellite orientated in space?

Posted: 14 Nov 2018 12:39 AM PST

If down is relative to the ground for us how is positioning treated in space?

submitted by /u/Biboomer97
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Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

Posted: 14 Nov 2018 07:11 AM PST

Welcome to our weekly feature, Ask Anything Wednesday - this week we are focusing on Physics, Astronomy, Earth and Planetary Science

Do you have a question within these topics you weren't sure was worth submitting? Is something a bit too speculative for a typical /r/AskScience post? No question is too big or small for AAW. In this thread you can ask any science-related question! Things like: "What would happen if...", "How will the future...", "If all the rules for 'X' were different...", "Why does my...".

Asking Questions:

Please post your question as a top-level response to this, and our team of panellists will be here to answer and discuss your questions.

The other topic areas will appear in future Ask Anything Wednesdays, so if you have other questions not covered by this weeks theme please either hold on to it until those topics come around, or go and post over in our sister subreddit /r/AskScienceDiscussion , where every day is Ask Anything Wednesday! Off-theme questions in this post will be removed to try and keep the thread a manageable size for both our readers and panellists.

Answering Questions:

Please only answer a posted question if you are an expert in the field. The full guidelines for posting responses in AskScience can be found here. In short, this is a moderated subreddit, and responses which do not meet our quality guidelines will be removed. Remember, peer reviewed sources are always appreciated, and anecdotes are absolutely not appropriate. In general if your answer begins with 'I think', or 'I've heard', then it's not suitable for /r/AskScience.

If you would like to become a member of the AskScience panel, please refer to the information provided here.

Past AskAnythingWednesday posts can be found here.

Ask away!

submitted by /u/AutoModerator
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How do we measure the temperature of stars and quasars up to 100,000,000°? How do we know it's that hot?

Posted: 13 Nov 2018 05:53 PM PST

How does a high pass filter (RC) still pass high frequencies when actively charged to input voltage by the DC component?

Posted: 14 Nov 2018 06:26 AM PST

I have an understanding of why capacitors block DC and pass AC but i don't fully understand how this works with a mixed signal input on a parallel plate capacitor, AC is passed due to low plate charge accumulation but with a mixed signal the plate should remain charged and block AC too, can anyone help me to understand this?

submitted by /u/OnAPaleNarwhal
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How do 17 year life cycle cicadas "keep track" of the year count to know when to emerge?

Posted: 14 Nov 2018 05:59 AM PST

How do cell regeneration rates vary among animals? Would it take a dog longer than a cat or human to replace most of the cells in its body?

Posted: 13 Nov 2018 07:22 PM PST

Can the CBD part of cannabis influence your reaction time?

Posted: 14 Nov 2018 01:26 AM PST

Hello, I've been reading up on some of the functions of the endocannabinoid system, but I haven't found anything on all of the internet having to do something with CBD? I find plenty of experiments or scientific works talking about the influence of THC and it's effects, while with CBD I only find things such as it's healing effects and nothing about reaction time, nothing with the endocannabinoid system about reaction time either.

Excuse my grammar, simply an article would also be of great help :)

submitted by /u/darthvale
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Besides preventing fires, what impacts do fire retardants dropped from planes onto wildfires have on the environment?

Posted: 13 Nov 2018 02:56 PM PST

In California right now, fire planes are dropping fire retardants to help manage the wildfire burns. Obviously, one impact this has on the environment is minimizing the amount of fire.

What other environmental impacts are there? Does it hurt or help animals or plants, air or soil?

*I added "chemistry" flair since it's a chemical, but I imagine this involves other areas too...

submitted by /u/forcedguy
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Why do epithelial cells line the outsides of organs that never experience external stimuli?

Posted: 13 Nov 2018 05:43 PM PST

Why are some cells called endothelial and some epithelial? I read that epithelial cells are cell that cover outsides of the organs and body. Lot of organs never experience the external stimuli yet they have epithelial tissue. Is my understanding of epithelial tissue wrong or is there more to it?

submitted by /u/karrablaster123
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If I were to throw or shoot something downwards at a velocity greater than its terminal velocity, would it decelerate until it reached the terminal?

Posted: 13 Nov 2018 03:58 PM PST

How does an extended release pill work?

Posted: 13 Nov 2018 04:27 PM PST

For example I'm on a pill that is 100mg ER, so is the pill 100mg and it just gives you small amount over a certain time, or is the pill alot more, and gives you a constant 100mg in your system?

submitted by /u/bigz3012
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How are old films restored?

Posted: 13 Nov 2018 02:27 PM PST

I just saw a thing about a documentary being restored from WWII in colour, and it made me wonder how exactly they do that?

Edit: not sure if that's the right tag but I'm just curious about this...

submitted by /u/toy_machine21
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How come there is no motion blur in google street view photos?

Posted: 13 Nov 2018 02:12 PM PST

So i was just going down some random highway on Google Street View and started thinking about if the car had to stay under a certain speed to get a good quality photo and then I realized that none of the photos were blurry even though the pictures were taken at or above 50mph. this may be a very simple trick that most photographers know but I don't know very much about cameras so its something that I'm unable to figure out.

submitted by /u/fourkcchiefs
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Why are some medicines more bioavailable than others before or after a meal?

Posted: 13 Nov 2018 05:43 PM PST

What does it mean to "burn out a motor," exactly?

Posted: 13 Nov 2018 07:32 AM PST

I have an ice cream maker and the manual has several warnings about not letting it run for too long. In particular, I'm not supposed to let the ice cream freeze to the point where it stops the mixing blade from moving since this will cause damage to the motor.

So today I've done that, and there's strong burnt smell coming off of it now. Very distinct. It still seems to work, but I'm wondering how much damage I've done.

submitted by /u/PM_your_cats_n_racks
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creating better water pressure with a siphon?

Posted: 13 Nov 2018 08:54 AM PST

It seems crazy that this isn't something that's done regularly, so I bet it won't work, but:

in an attempt to get more water pressure through a pipe/hose than would happen if the hose is hooked to the bottom outlet of a tank, what if I were to create a siphon, but put the siphon hose way up high? As though the side of the tank were at the max (10 meters). Would the water coming out the hose, just slightly below the floor of the tank have MORE pressure than it would if it was just flowing out? That is, would the drop in height from the 2nd half of the hose create more PSI?

Practical scenario: a tank just slightly above a house that needs good pressure. hang a hose a couple stories up in a tree, create a siphon. would the house get better water pressure?

submitted by /u/Tyssniffen
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Where did all the dirt on top of dinosaur fossils come from?

Posted: 13 Nov 2018 03:10 PM PST

Tuesday, November 13, 2018

If Hubble can make photos of galaxys 13.2ly away, is it ever gonna be possible to look back 13.8ly away and 'see' the big bang?

If Hubble can make photos of galaxys 13.2ly away, is it ever gonna be possible to look back 13.8ly away and 'see' the big bang?


If Hubble can make photos of galaxys 13.2ly away, is it ever gonna be possible to look back 13.8ly away and 'see' the big bang?

Posted: 13 Nov 2018 01:21 AM PST

And for all I know, there was nothing before the big bang, so if we can look further than 13.8ly, we won't see anything right?

submitted by /u/-SK9R-
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AskScience AMA Series: I'm Carlos Zarate Jr., and my research team at the National Institutes of Health Intramural Research Program works on new, fast-acting therapeutics for treatment-resistant depression, bipolar disorder, and suicidal thinking. AMA!

Posted: 13 Nov 2018 04:53 AM PST

My name is Carlos Zarate Jr., and I am the Chief of the Experimental Therapeutics and Pathophysiology Branch and the Section on the Neurobiology and Treatment of Mood Disorders at the NIH's National Institute of Mental Health (NIMH).

In 2016, more than 1 in 20 American adults and 1 in 10 adolescents experienced at least one major depressive episode. Depression can massively affect people's lives, removing the pleasure they receive from their hobbies and social interactions and reducing their ability to work. In the most severe cases, individuals who suffer from depression tragically choose to end their lives - suicide was the 10 th leading cause of death overall in the U.S. in 2016, claiming nearly 45,000 lives, and it is the second-leading cause of death among Americans ages 10 to 34. In fact, in that year, there were more than twice as many suicides in the U.S. as homicides.

The medications currently available to treat depression typically take up to six weeks to start having full effects. To improve treatment and accelerate symptom relief, my research focuses on developing new medications for this often-debilitating condition, along with identifying new potential drug targets and objective measures called biomarkers that yield information about how a patient is responding to treatment. In recent years, my lab has extensively investigated and assessed the effects of the anesthetic drug ketamine on depression and suicidal thoughts. Many of the patients in our trials have had marked and rapid responses to ketamine, sometimes within a single day or just a couple of hours. We have also made major headway in determining how ketamine produces such dramatic changes so quickly. However, because ketamine can have serious side effects, we are working to identify ketamine-like drugs with similarly rapid effects but fewer problematic side effects.

For more information on my work, check out this story and video on the NIH Intramural Research Program (IRP) website: https://irp.nih.gov/our-research/research-in-action/from-despair-to-hope-in-hours. You can also read my investigator profile at https://irp.nih.gov/pi/carlos-zarate.

If you or someone you know is in crisis and needs immediate support or intervention, call the National Suicide Prevention Lifeline at 1-800-273-8255. Trained crisis workers are available to talk 24 hours a day, 7 days a week. Your confidential and toll-free call goes to the nearest crisis center in the Lifeline national network. These centers provide crisis counseling and mental health referrals. You can call for yourself or on behalf of a friend. If the situation is potentially life-threatening, call 911 or go - or assist a friend to go - to a hospital emergency room. Lives have been saved by people taking action.

AskScience Note: As per our rules, we request that users please do not ask for medical advice. Please see above for specific actions to take in the event of a situation.

submitted by /u/AskScienceModerator
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What was/is the actual damage from plastic microbeads?

Posted: 13 Nov 2018 06:20 AM PST

Why is the Milwaukee protocol not recommended?

Posted: 13 Nov 2018 01:15 AM PST

The Wikipedia page about rabies states the following three things. About the disease itself, it says:

In unvaccinated humans, rabies is almost always fatal after neurological symptoms have developed.

About the Milwaukee protocol, it says two things. First, it states

The protocol is not an effective treatment for rabies and its use is not recommended.

and it concludes by saying

An intention-to-treat analysis has since found this protocol has a survival rate of about 8%

Can someone explain to me how these three statements are logically consistent? The way I see it, if you get symptoms of the rabies, you have two options. One is certain death, one is death in 92% of cases. Now I know option 2 isn't particularly good, but it's better than option 1, right? Isn't "not recommending" the protocol basically saying "just let these people die"? Isn't some result, no matter how marginally good, better than certain death?

submitted by /u/5xum
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Why does Turner syndrome have consistent symptoms when the X chromosomes should be redundant?

Posted: 13 Nov 2018 02:23 AM PST

Do people with lots of kids have better immune systems due to constantly getting sick?

Posted: 12 Nov 2018 09:56 PM PST

Why are parasites considered true living organisms while viruses are not?

Posted: 13 Nov 2018 12:30 AM PST

Also would there be some parasites that are not considered true living organisms while some are? To me it seems like both a virus and a parasite operate in the same way and going off the definition of what a true living organism is I feel like both of them do not meet all the standards required.

submitted by /u/Elitefire001
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Where did all the water on asteroids come from?

Posted: 13 Nov 2018 01:38 AM PST

This post on /r/science got me wondering about the origins of water in the universe.

The post itself seems to imply that nebulae naturally form water, thus over time creating asteroids loaded with it.

But is that the generally held belief of the science community, or is there a more popular theory?

submitted by /u/Zermer
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How do fertility/sperm tests work?

Posted: 12 Nov 2018 10:05 PM PST

Would it be possible to test sperm/fertility at home?

submitted by /u/Theprogrammingshow
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Is there a limit on the number of radio telescopes that may be networked together?

Posted: 13 Nov 2018 01:28 AM PST

I'm just curious because it seems like covering a desert with a million, 1m diameter telescopes would give you the most sensitive radio telescope on the planet. Is there a reason no one has done this yet?

submitted by /u/chased_by_bees
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Were there wild pigs or were they breed from domesticated boars?

Posted: 13 Nov 2018 01:17 AM PST

Is Tungsten Carbide an alloy?

Posted: 12 Nov 2018 12:25 PM PST

I've always thought an alloy is a base metal mixed with another metal(s)/non-metal(s) to change physical properties. I've asked a few people if Tungsten Carbide is considered an alloy. I've got some wild answers:

  1. Tungsten Carbide is a metal

  2. Tungsten Carbide is not an alloy; it is a compound. Tungsten alloy is a mixture of metals, but not chemically bonded to each other.

I'm not an expert with material science.

submitted by /u/sqrt69
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If solar sails are possible, why EM Drive isn't?

Posted: 12 Nov 2018 04:42 PM PST

Title, pretty much. I mean if all photons have momentum, what is the difference? Edit: as far as I understood, electromagnetic waves from the source (heated wire in bulbs, induction coils) are propagating in EVERY direction, making overall momentum conserved at 0.

submitted by /u/LordCrispyCloud
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Is this a reasonable simulation of tension across a hanging rope?

Posted: 12 Nov 2018 04:35 PM PST

Hi!

I was debugging some game physics/kinematics and noticed something I found interesting: the tension across my hanging rope was assuredly not equal across its entirety, which goes against one of the few things I remember from my physics classes a decade ago. However, the simulation seems to match most of the rope characteristics that I can think of having observed in real life (it's actually uncanny; I hate it), so I'm reexamining my understanding of physics.

Attached is a screen grab; the red circles represent the tension at each point (the radius of each circle is equal to "tension", which is a variable in the engine with a magnitude and no real units). Is this pattern reasonably representative of what I would expect to see if I were to measure across a real rope with a... tension...ometer?

Note: I haven't seen any posts like this, before, so I'm not sure if I'm allowed to do this; I notice that media posts are disabled, but I'm not sure if that means that they're not allowed, or if they're disabled to weed out low-effort spam. I'm assuming the latter (and also assuming that this isn't a low-effort question); please let me know if I'm wrong!

submitted by /u/Introsium
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Questions about behavior of electrons in an atom?

Posted: 12 Nov 2018 12:27 PM PST

Hello I've been learning about Quantum Physics recently, it's super interesting, and it seriously has left me with more questions than answers. Crazy to think that matter is probabilistic on the most fundamental level.

I've been thinking about some of the features of the quantum mechanical model of the atom for a little while, and I've tried to combine all questions that I had in my head over the past month into one post. I'd really like to get some intuition on this mind bending topic (full disclosure: contains a lot of questions beginning with "what exactly").

First off, what exactly does it mean for an electron to behave both as a particle and a wave? I know that by calculating the de Broglie wavelength of an electron we get a wavelength that is pretty significant at the atomic scale, but what exactly is the 'wave' that we are referring to here? What exactly is the quantum wave function? Is it a mathematical representation of the probabilities of the electron's position at any given time, or is it referring to the electron as a physical wave in space? What do people mean when referring to an 'electron cloud'? Is it the probability of the position of a single electron, or the electron 'wave' being spread throughout the atom? If it's a physical 'wave', what exactly is it made of, and does it mean that the charge and mass of the electron is distributed across the wave?

These are some of the questions I have for now. Just for context, I have a pretty intuitive understanding of Bohr's model of the hydrogen atom, and a basic intuitive understanding of spectroscopy (The photoelectric effect, transition of an electron across energy levels after interacting with a photon of a certain frequency, emission and spectra, etc.). I really don't get the intuition behind electrons treated as 'standing waves'.

Thanks for your time!

submitted by /u/RyukSkywalker
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How does angiotensin 2 affect GFR?

Posted: 12 Nov 2018 06:40 PM PST

Im finding the notes in my lecture rather contradictory at the moment and I hope someone can clarify it for me.

Note 1: GFR can be regulated by Angiotensin II. When renal blood flow is low, Ang II is released by RAAS pathway and vasoconstrict afferent and efferent renal arterioles decreasing GFR.

Note 2: Decrease in BP triggers release of renin which will ultimately produce Ang II through RAAS. This will then lead to increase blood volume due to vasocomstriction of peripheral arterioles-> blood pressure rises, which causes an increase in renal perfusion and therefore an increase in GFR.

I understand note 2, as RAAS is stimulated to increase BP through increasing Blood volume. This means that there is more perfusion to kidneys and hence GFR will increase until renin is inhibited. Hence note 1 seems contradictory to me. Please someone clarify!!

Thanks in advance

submitted by /u/asujinn
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