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Sunday, May 27, 2018

If the universe is (generally speaking) flat, how come, as seen from telescopes, nothing lies on a single plane? Images of the CMB aren't 3D models, so why do we see galaxies in every direction?

If the universe is (generally speaking) flat, how come, as seen from telescopes, nothing lies on a single plane? Images of the CMB aren't 3D models, so why do we see galaxies in every direction?

If the universe is (generally speaking) flat, how come, as seen from telescopes, nothing lies on a single plane? Images of the CMB aren't 3D models, so why do we see galaxies in every direction?

Posted: 26 May 2018 03:35 PM PDT

Is the speed of gravity constant?

Posted: 26 May 2018 05:03 PM PDT

So I know that gravitational waves travel at the speed of light (in a vacuum) but are there circumstances where the speed of gravity changes? If so what are these circumstances?

submitted by /u/The_Rickest-Rick
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How I can I picture a radio wave in 3d space?

Posted: 26 May 2018 03:58 PM PDT

I only ever see them depicted as sine waves online, but my guess would be that 'sine waves' are to radio waves as what '12' is to a carton of eggs.

Is it possible to picture how they are around me in my environment?

submitted by /u/browngirls
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How did terrestrial animals and insects like Mongoose and Spiders get to islands far from land like Hawaii or Guam?

Posted: 26 May 2018 11:14 AM PDT

Supermassive black hole accretion rates, are they constant?

Posted: 26 May 2018 04:28 PM PDT

This article: http://www.astronomy.com/news/2018/05/snapshot-second-gaia-release-results-so-far states that we have found a supermassive black hole of 20 billion solar masses 12 billion light years away that is accreting at the rate of 1% every million years.

That rather sounded like a compound interest statement, so I plugged the numbers into a calculator to figure out how large it would be after 12 billion years (now), and got 143,719,397,330,047,128,616,744,826,647,657,321,145,325,176,127,225,856 billion solar masses.

That seems like a lot. Do we expect it to have stopped it's accretion at some point, or is the article miss-stating that fact (it also breaks it down as solar masses per day).

Also, what's the Schwarzschild radius of something that massive?

submitted by /u/voidref
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If sex steroids pass through all cells, how can only one follicle be matured and one egg released at a time for women in the menstrual cycle?

Posted: 26 May 2018 11:27 AM PDT

What is “Cosmic Background Radiation”?

Posted: 26 May 2018 11:34 AM PDT

Are (metallic) superconductors good mirrors?

Posted: 26 May 2018 09:31 AM PDT

I recently gained the insight that mirrors work because the electrons in the metal sheet, when an photon hits, move until their electric field is equal in strength to the photons electric field, creating the reflected oscillating field- a reflected photon. The electrical resistance of the material hampers this flow to create an opposing field. So I wonder whether superconductors, having no resistance, are mirrors, and if they are, how good they are? Are all superconductors mirrors, or only ones made of specific materials? Do they reflect all wavelenghts equally?

TL;DR: Learned resistance makes mirros worse, asking if superconductors are great mirrors.

P.S. If you find my english objectionable, not my first language.

submitted by /u/MoeWind420
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Can you squeeze an electron?

Posted: 26 May 2018 08:22 AM PDT

Can you squeeze an electron and make its volume smaller?

This question came into my mind when I've heard that "If you remove all the space in the atoms, the entire human race could fit in the volume of a sugar cube". But to create a black hole, you would need to compress them in a smaller volume. So the conclusion is : black holes suqeeze electrons/protons. Is this true?

submitted by /u/Zapakitu
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Do Bees differentiate types of pollen/show a preference for one type of flower over another or is it all functionally the same to them?

Posted: 26 May 2018 11:56 AM PDT

In the many-worlds theory of QM, is there a theory of how many universes branch of from a single quantum observation?

Posted: 26 May 2018 06:22 AM PDT

Here are 3 examples that getting answers for might clear things up.

First is a fundamental uncertainty: let's say the universe consists of one electron, whose spin equally likely up or down. You observe it. Does the universe branch into two universes, one for each option? Or infinite universes, with half at spin-up and half at spin-down?

Next is a case where maybe the outside world matters: Let's say there's an electron, and an potential barrier, and the electron has a 50% chance of tunneling through it. When you observe it, does the universe split into two branches? Or infinite?

Finally, let's say the same electron has some irrational chance of tunneling through (lets say sqrt(3) chance). When you observe it, what exactly happens? I can't see how the universe would split into a finite amount of states after this.

The reason I ask about spin AND tunneling is, I don't know if many-worlds reasoning only applies to fundamental observations, or system-observations.

As a follow-up question: when people who know what they're talking about think about this stuff, do they picture universes being created for each decision, or two universes that were sitting on top of each other to begin with, diverging?

submitted by /u/asdfwaevc
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What size/speed/density would a meteor have to be to fly through Jupiter?

Posted: 26 May 2018 04:24 AM PDT

Do the laws of thermodynamics apply to subatomic phenomena?

Posted: 26 May 2018 05:53 AM PDT

I was studying thermodynamics for my materialsscience course and I started to wonder.

It is assumed in thermodynamics that energy is constant but I guess you could look at the fission of a nucleus as chemical reaction. Not sure, what do you think?

submitted by /u/RadChad14
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Why do height requirements exist for some rides and what studies have been done to determine the standards?

Posted: 26 May 2018 09:50 AM PDT

Does every closed system have a maximum and minimum value of entropy?

Posted: 25 May 2018 11:00 PM PDT
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Saturday, May 26, 2018

How do we know the age of the universe, specifically with a margin of error of 59 million years?

How do we know the age of the universe, specifically with a margin of error of 59 million years?

How do we know the age of the universe, specifically with a margin of error of 59 million years?

Posted: 26 May 2018 04:17 AM PDT

What causes different materials to expand or contract at different rates?

Posted: 25 May 2018 08:20 PM PDT

Recently finished the thermodynamics unit in physics, and wanted to know what causes different materials to expand or contract at different rates? Does it have anything to do with the heat capacity, or are they two separate things?

(I am aware that it is called the "coefficient of linear expansion" btw)

submitted by /u/superjes1
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Is there any wildlife at all in the Antarctic interior?

Posted: 26 May 2018 05:27 AM PDT

I saw this bit of a nature documentary about a penguin who goes marching off toward a mountain, away from the coast where all his penguin buddies hang out and occasionally go diving to eat fish. The narrator said the penguin was headed toward "certain death." Which makes sense, what's he going to eat? Is there anything at all in the interior of Antarctica away from the coast? It's frozen all year round and most of the land is covered by glaciers.

submitted by /u/big-butts-no-lies
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What makes paper fresh from the copier hot? Why don't inkjet printers produce the same amount of heat as copiers do?

Posted: 25 May 2018 09:20 PM PDT

What causes our throats to be sore after we use a loud voice?

Posted: 26 May 2018 06:21 AM PDT

I realized that this is something very basic that I don't understand. I can understand why using your voice for a long time causes a sore throat, from it getting dried out, hence why water is so helpful to broadcasters. But even if I yell for a short period of time, my throat becomes sore. Why?

submitted by /u/Aethi
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Colorblindness comes from a defect in the cones to perceive colors, is there a version where the cones work, and the rods are deficient?

Posted: 25 May 2018 10:24 AM PDT

Most of the information I see on color blindness is around the inability of eyes to detect specific wavelengths due to changes in the cones, however, I'm curious if there is a inverse colorblindness of sorts, where people are able to see all wavelengths of color, but aren't able to discern intensities or values coming from the rods.

submitted by /u/namingwaysway
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Do other animals get insomnia?

Posted: 26 May 2018 02:50 AM PDT

Why is your reflection in a spoon upside down?

Posted: 25 May 2018 07:48 PM PDT

How come when you look at something very bright like the sun, how come you can still see it briefly when you close your eyes?

Posted: 25 May 2018 06:43 PM PDT

Can real life sounds, like an alarm clock going off, carry over into a dream?

Posted: 25 May 2018 04:18 PM PDT

What makes certain materials perform well under pressure but poorly on impact(ie concrete, carbon fiber, etc)?

Posted: 25 May 2018 10:02 PM PDT

Does urine slosh around in the bladder?

Posted: 25 May 2018 11:08 PM PDT

There's probably not any air in the bladder so imagine the answer is no but the question occurred to me so here we are

submitted by /u/butterismygecko
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What makes water taste old?

Posted: 25 May 2018 01:14 PM PDT

What is the surface of diamond made out of?

Posted: 25 May 2018 12:47 PM PDT

I've been taught that diamond has it's specific properties because it is an allotrope of carbon with each carbon atom bonded to 4 other carbon atoms forming a tetrahedral structure. This structure repeats itself until you get to the edge or surface of the material.

Are there carbon atoms at the surface of a diamond only bonded to 1 only other carbon atom or only up to 3 carbon atoms and if so, is it still considered diamond at the surface?

submitted by /u/PocketCharacter
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What mechanic/s does Clear Eyes use to reduce/remove redness in the eyes?

Posted: 25 May 2018 11:13 PM PDT

How do we know that hunter-gatherer societies were egalitarian?

Posted: 25 May 2018 05:38 PM PDT

I've looked at a couple of artictles and they claim that hunter-gatherer societies didn't follow a hierarchical structure. Moreover, they di that in a way that seems to be implying that all individuals had approximately equal say in group decisions, with no "alpha male" or something similar. Is this true and what sort of evidence do we have to support it?

submitted by /u/skmmcj
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When wiping something down with alcohol, what is that filmy residue that's left behind?

Posted: 25 May 2018 11:13 AM PDT

When I take a fidget spinner by the centerpiece and launch the edge, it can spin for minutes. When I take it by the edge and launch the centerpiece, it stops after a few seconds. Why is there even a difference? Shouldn't the situation be symmetric? Something something frames of reference?

Posted: 26 May 2018 12:13 AM PDT

What happens in the eyes / brain during a migraine?

Posted: 25 May 2018 08:20 PM PDT

I occasionally get very severe migraines, to the point where all I can do is sit in my bathroom with all the lights off puking until it goes away in a few hours.

There are 3 main symptoms I experience:

  1. Loss of vision. Parts of things I'm reading or looking at will disappear from vision.

  2. Bright squiggly "auras". Basically lines of light that obstruct my vision.

  3. Intense pain in the back of my eye. Kind of like someone is pressing and holding down real hard on the back of my eye.

What's going on in my eye / brain that causes these symptoms?

submitted by /u/Malibu_Snackbar
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Why does the body/stomach hurt so much when we laugh really hard?

Posted: 25 May 2018 07:44 PM PDT

Always had this in the back of my mind, kinda funny to think about....

submitted by /u/hex_adapt
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Are our ears unable to detect pitches beyond human hearing? Or is our brain designed to ignore those pitches?

Posted: 25 May 2018 09:05 AM PDT

What is the difference between osmotic pressure, oncotic pressure, and hydrostatic pressure? (Renal physiology)

Posted: 25 May 2018 09:54 PM PDT

How can I predict how much a small particle of arbitrary shape will diffuse?

Posted: 25 May 2018 10:45 AM PDT

I understand the "Stokes-Einstein equation"#Stokes-Einstein_equation) and how much a spherical particle will diffuse when it is small and experiencing purely Brownian forces. But what about particles that are not spherical? Is there a process to calculate the translational diffusion coefficient for a particle of arbitrary size?

submitted by /u/RickAndMorty101Years
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Friday, May 25, 2018

How is laze formed by lava mixing with sea water?

How is laze formed by lava mixing with sea water?

How is laze formed by lava mixing with sea water?

Posted: 25 May 2018 12:10 AM PDT

Do internet cables behave the same way as power cables, as in, are there are different "internet" capacities for different internet cables?

Posted: 24 May 2018 09:16 PM PDT

Will a new internet port on computers have to be created to handle the climbing internet speeds?

submitted by /u/FerrumCenturio
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How can a black hole have angular momentum? What is rotating?

Posted: 24 May 2018 11:16 PM PDT

I am under the impression that a black hole is a region more than a physical object. Is space itself rotating along with the black hole singularity? Is the singularity rotating?

submitted by /u/themaskedserpent
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Are there more men or women in the world? And how do we know?

Posted: 25 May 2018 04:23 AM PDT

It seems crazy that there would be a true 50/50 split. Wouldn't it be more like 49.7/50.3 or something? Does it matter?

submitted by /u/stumblecow
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How does anthrax as a type of bacteria exist in spore form? Are there other types of bacteria similar to anthrax and can they be weaponized too?

Posted: 24 May 2018 04:15 PM PDT

How does lava stay hot until it hits the surface?

Posted: 24 May 2018 06:13 PM PDT

It seems like a cools pretty rapidly once it hits the surface- why doesn't do this when it's 8 feet below ground? Or even a hundred feet below ground?

submitted by /u/coolhandhutch
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What causes nuclear pressure?

Posted: 25 May 2018 04:03 AM PDT

From what I know (which might be wrong), nuclear pressure is a force that pushes outwards that keeps stars from collapsing in on themselves. What causes this force?

submitted by /u/aj11783
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How does the Riemann Hypothesis make sense?

Posted: 24 May 2018 06:50 PM PDT

The Riemann Hypothesis states that all the zeros of the zeta function lie for the real part being half and s being negative even integers. How can this be possible?

If we take s = -2, don't we still get a positive sum which is not 0? Similarly, the same thing goes if we take s = -4,-6,... and so on. Does this mean we have some negative terms somewhere? If so, why do we get some negative terms which cancel out the positive terms in the first place? And even if we do, why do we get 0? I don't understand this at all.

submitted by /u/shoaib98libra
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'Chemistry' - After the discovery of oxygen, when was it founded that oxygen was a molecule(O2 instead O)? 'Chemistry'

Posted: 25 May 2018 12:40 AM PDT

Specifically how was it discovered that most oxygen is 2 atoms of oxygen?

Did they use the same process for H2 and N2 as well?

submitted by /u/novalavaly
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Does Volcanic activity cause global warming?

Posted: 24 May 2018 09:19 PM PDT

Understanding the nature of applied Lorentz force, and back-motional emf?

Posted: 24 May 2018 04:46 PM PDT

When I studied how a current carrying loop, that is designed in a rail configuration, I understood how charges moving in that wire(while constrained within) exposed to an exterior magnetic field that is generated by the loop, it will follow Lorentz law. However, integrated across the whole wire's length, expressed as:

F = IL × B

If a component is able to move freely(for the case of the figure-1, the projectile), the length element dL will begin to accelerate, due to the reasons explained above. However, what boggles me is when I imagine the consequence of that motion in relation to Faraday's law.

The loop is now changing, the whole system's area is now expanding as the element moves further away, a consequence of that change in flux is stated in Faraday's law:

ϵ = −d(ϕ)/ dt

Specifically,

ϵ= −B d(A)/dt = −BL d(x)/dt

Simplified,

ϵ = −vBL

Assuming, that this is not a varying magnetic field, the potential difference induced due to motion of the projectile within that length(L) is due to the build-up of charges created from the Lorentz force as well,** are there two forces here? Or is the same force that resulted in motion also separates the charges**?

Full system diagram.

It confuses me that the initial force that causes the electrons to move(current flow) is due to the battery, and from that motion of charge within the magnetic field created by the loop, the Lorentz force would move rod, at the same time... the Lorentz force would also generated a separation of charges that would create an opposing emf to resist the applied one from the battery.

submitted by /u/tinkenieer
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How did we evolve from reptiles to mammals?

Posted: 25 May 2018 04:27 AM PDT

So my understanding of evolution is that over millions of years, random gene mutations lead to a particular species being more and more different to its ancestors to the point where it can be called a different species entirely. I get that when it comes to things like Giraffes evolving longer necks to eat grass or humans evolving finer motor capabilities to create tools and farm and hunt. But how does evolution lead to amphibious, egg-laying reptiles evolving into live-birthing mammals? How could the offspring of, say, a reptile that mutates to give birth via live-birth instead of eggs survive being live-birthed instead of egg-birthed? Or am I thinking about this all wrong? In short, how did we make the transition across classes of animals (fish --> reptiles --> mammals)?

submitted by /u/CountAardvark
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How do we determine temperature from millions of years ago from sediment?

Posted: 24 May 2018 10:17 PM PDT

In another post I learned that ice cores only go back hundreds of thousands of years. I asked where we get climate information for millions of years back and was told sediment cores. I'm vaguely aware of how we determine climate from ice core samples, but how do we figure climate from sediment? And how far back do these cores go?

submitted by /u/thechairinfront
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What came before Pangaea?

Posted: 24 May 2018 11:22 PM PDT

The lessons I've been taught in school all my life have always started with Pangaea in explaining life. Which is fine, seeing as there is so much information to condense in Earth's entirety. Regardless of life, were there other arrangements of super continents that were equally as prominent or even just notable in Earth's past?

submitted by /u/BillnTedsTelltaleAdv
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Why does nuclear fusion release energy?

Posted: 24 May 2018 06:05 PM PDT

I'm sorry if this is a dumb question, and please correct me if my understanding is wrong. I'm far from knowledgeable in this field and just want to understand this in a semi-basic way.

I understand that as more protons are added to the nucleus, the Coulomb force causes them to repel one another more, and the less the nuclear force is able to hold the particles together.

What I don't get is why this results in a output of energy. As the repulsion between them increases and the nuclear force weakens, why don't they just cancel each other out, and instead they output energy. If the protons are repelling each other, and the nuclear force is holding them together, shouldn't they just add up to zero?

Another thing, why does so much energy get generated? I always see it explained using E=mc2 and that c is so huge is means lots of energy, but I'm not sure I see any mass being converted to energy, so why does it even apply?

Any help would be appreciated.

submitted by /u/Send_Me_Tiitties
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Why can't new cartilage be put in to counter osteoarthritis?

Posted: 24 May 2018 07:50 AM PDT

Are there any languages that are easier or harder for AI systems to sufficiently "learn" for translation purposes? If yes, what are the aspects of a language that make the process easier or harder?

Posted: 24 May 2018 04:34 AM PDT

How would viscity effect vibrations in a fluid? Would a lower or higher viscocity be more effective in dampening them?

Posted: 24 May 2018 03:04 PM PDT

What caused the geology of Watson Lake, near Prescott Arizona?

Posted: 24 May 2018 01:43 PM PDT

The strata patterns of Watson Lake are striking, with alternating layers of white and greenish-gray, and still other tones, stretching out seemingly for thousands of feet, if not miles. The pattern of width and color of layers seems very uniform. My understanding is that these rock layers are about 1.7 billion years old and igneous rock (or metamorphic from igneous origin). Could someone with a better understanding of geology answer a few questions, please? What causes the color differences between the layers? How were they laid down so uniformly over such a large area? The rocks are volcanic in nature and uniform in composition, and yet (I'm assuming) were weathered away to produce a set of islands; can you provide some insight into the processes behind that?

submitted by /u/j_from_cali
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