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Tuesday, December 25, 2018

Why do dogs tilt their heads when curious / confused?

Why do dogs tilt their heads when curious / confused?

Why do dogs tilt their heads when curious / confused?

Posted: 24 Dec 2018 09:27 PM PST

Can the speed of light be theoretically calculated using quantum mechanics?

Posted: 24 Dec 2018 08:43 PM PST

I know the speed of light can be accurately predicted from Maxwell's equations, is there a mathematical way to arrive at the speed of light another way? Can you do it using quantum mechanics?

submitted by /u/yesireallyamthatdumb
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How do we know the age of the universe?

Posted: 24 Dec 2018 09:01 PM PST

And due to time dilation, does that mean that some parts of the universe are "younger" than others?

submitted by /u/AtLeastIHaveJob
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Are there any animals that don’t fit easily into a group (mammals, birds, etc)?

Posted: 24 Dec 2018 07:30 PM PST

Like a mammal that lays eggs or a bird that's cold blooded? Obviously that's pretty extreme. But are there any animals whose group is debated?

I find it kinda of amazing that in the process of evolution and natural selection, these groups would be so distinct and animals fit so well in them.

submitted by /u/ChuckSRQ
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How does luminosity scale with human perception of brightness?

Posted: 24 Dec 2018 10:17 PM PST

Bear with me; I'm struggling with the terms involved. I can find some information on this question concerning the use of apparent magnitude in astronomy. But I'm having a hard time comparing apparent (and absolute) magnitudes with SI units for luminosity and such.

Say I step into a closed room with a single light source that's a fixed distance from my eye. The light initially appears at the brightness of a "typical" candle. (So that would be one candela? which is 12.57 lumens?) I turn down the brightness until the light is JUST at my limit of perception. How many lumens is it now?

I guess we need to define a distance between the candle and the eye, so let's say 1 meter? I guess the alternative approach here would be to keep the brightness (luminance?) constant and move the candle further away until I can't quite see it. I found an article saying this distance is something like 2.5 km, but I didn't quite follow how they got there and I can't piece together how that relates to the "decrease the brightness" approach.

Ultimately it's about the number of photons hitting your eye, so distance means less flux. I get that much very well. There's just some link in the chain that I'm getting lost here as I've never worked with these units much.

(And yes, I'm specifically interested in a human eye. I'm aware that these units "filter" light wavelengths so they are weighted based on human perception.)

submitted by /u/jofwu
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Do we know exactly what the atmosphere was composed of when cyanobacteria producing oxygen 2.7-2.8bya?

Posted: 24 Dec 2018 08:58 PM PST

What is the minimum velocity an electron needs to escape through a vacuum after entering the conduction band of the metal electrode?

Posted: 24 Dec 2018 12:05 PM PST

Why does fish decay faster (and smellier) than meat?

Posted: 24 Dec 2018 01:06 AM PST

It looks like fish ---and i don't mean just zoological Fish, but seafood, sea dwellers in general, including mollusks, shrimps, urchins etc--- rots a lot sooner than land animals flesh.

It is as if the bacteria responsible of the decay in the dry find, in anything that has grown in water, their absolute favourite food.

Is there a reason for this?

submitted by /u/itsmemarcot
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Have any species followed an evolutionary path like cetaceans, only to revert to land-dwelling?

Posted: 23 Dec 2018 11:00 PM PST
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Monday, December 24, 2018

How did the physiology of the horse change once we started riding them?

How did the physiology of the horse change once we started riding them?

How did the physiology of the horse change once we started riding them?

Posted: 23 Dec 2018 07:46 AM PST

[Zoology] I recently learned that giraffes don't have the ability to cough. How do they survive when they get a bolus or some water stuck in their esophagus?

Posted: 23 Dec 2018 09:26 PM PST

Apparently it is due to their long neck, which seems to be an evolutionary glitch to me. I would assume they are in even more danger of restriction to their windpipes. Thanks in advance!

submitted by /u/FlammableFishy
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If you asked me if I had read a particular book, I could tell you instantly. However, if you asked me to list all the books I'd read, I'd not be able to recall them all - why is this?

Posted: 23 Dec 2018 05:06 AM PST

How do we precisely know how much gravitational force an object like a planet or a moon exerts on a satellite that is using it for a gravitational boost?

Posted: 24 Dec 2018 02:44 AM PST

How do we actually know how much mass a planet or moon has? Wouldnt its make up be kind of a complete ball park, therefore its mass be just a guess? Therefore its gravitational force be sort of a ballpark? But then how can we use it precisely?

submitted by /u/MyNameIsGladiat0r
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What factors cause/increase the chance of rain?

Posted: 24 Dec 2018 04:34 AM PST

I am a student studying software and im playing around with a simple machine learning library. I want to create a small program that can predict if it is raining or not by looking at a list of numerical attributes that may suggest rainfall. Im dont have much knowledge of meteorology, what atmospherical attributes am i looking for? (things such as high humidity % or high pressure)

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thanks

submitted by /u/tom2kk
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How do you accurately calculate an azimuth between faraway countries?

Posted: 24 Dec 2018 02:43 AM PST

Hi, reddit! I am a travelling Network engineer about to travel to Poznan, Poland for work. Before leaving I wanted to give my son a compass because I thought it would be cool for him to be able to tell which direction I was. I started to do the math to calculate the azimuth between my (aprox) home and my (aprox) work location but I ran into some unexpected problems. I used online tools to help calculate, but all of them give impossible answers when I run the numbers.

EX. lat,lon: 16.9, 52.4 (Poznan, Poland) and -81.2, 33.9 (Columbia, South Carolina)

if I run the numbers with a standard azimuth calculator like: https://keisan.casio.com/exec/system/1317262499

then the answer I get is somewhere around 298 degrees in the northwest! I would expect some small margin of error, but results like this seem nonsensical. Can someone with more experience in this area help me find where I am going wrong?

submitted by /u/alexanderj1991
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Are atoms with a high electron count more likely to form bonds with other atoms because their valence electrons are far away from the nucleus?

Posted: 24 Dec 2018 06:38 AM PST

Do our ears adjust when listening to very quiet sounds?

Posted: 24 Dec 2018 06:36 AM PST

More specifically, is there a change that happens to our ears akin to pupils dilating in low light in order for quieter sounds (or sounds of different frequencies) to be picked up?

submitted by /u/AdamxKH
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Is psychopathy considered a binary diagnosis or is it seen as a spectrum?

Posted: 24 Dec 2018 07:36 AM PST

Basically, could a person who displays a lack of empathy for the most part but displays genuine empathy in certain situations be accurately diagnosed as a psychopath?

submitted by /u/Flumper
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After a critical point, in language acquisition, babies can no longer acquire new phonemes. Is it possible for a baby to acquire phonemes in a language, and use these skills to be able to pronounce phonemes in other languages as they get older?

Posted: 24 Dec 2018 07:28 AM PST

For example, if a baby were to learn a language (lets call it gibberish#1) that has every phoneme+more of another language (gibberish#2) could that baby learn gibberish#2 and speak it without an accent, having acquired all the required phonemes for gibberish#2 when they learned gibberish#1?

submitted by /u/TheMetaphorer
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How does the human metabolism change in response to morbid obesity?

Posted: 23 Dec 2018 05:35 PM PST

Are these changes permanent?

submitted by /u/MMMojoBop
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Were there changing seasons at all during the ice age, or was it like a long, harsh monotonous winter?

Posted: 24 Dec 2018 02:54 AM PST

What is the purpose of homosexual interaction between animals?

Posted: 24 Dec 2018 05:13 AM PST

I recently learned that about 90% of sexual interactions between giraffes happen between males. This surprised me, since I'd always assumed that homosexuality was a... genetic mutation that got passed down sparingly over time and was only ever present in a minority of a species? (not really sure about any of this tbh)
Yet, giraffes and I assume some other animals seem to disprove this idea.
Does this mean that homosexuality is actually useful in some way and (in some species) gets passed down a lot despite its nature? Are the animals in species that are prone to homosexual behaviour truly homosexual or rather just bisexual or something else entirely? Can the sexual interaction that happens between animals of the same sex be equated to the one with breeding purposes or is it rather a social interaction with some other type of purpose?

submitted by /u/SlimyFrog7
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What kind of soil and atmosphere analysis do Mars rovers do to test for extinct and extant life?

Posted: 24 Dec 2018 05:00 AM PST

What automated tests take place on these rovers to search for extinct and extant life?

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submitted by /u/_avp_
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What is the difference between Tinea Versicolour & Pityraisis Versicolour?

Posted: 24 Dec 2018 04:41 AM PST

In theory, have no two events ever occurred at the exact same time (because time can be broken down into infinitely smaller units)?

Posted: 23 Dec 2018 05:16 PM PST

Why do you taste things much sweeter as an adult than as a child?

Posted: 23 Dec 2018 10:34 PM PST

Why when someone eats a sweet thing from their childhood, it does taste much sweeter than what you recall as a kid?

submitted by /u/angry_pinata73
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How large is Earths temperate orbital butterzone?

Posted: 24 Dec 2018 03:08 AM PST

So, life on this planet is somewhat delicate. We are placed at the exact spot around a star the exact size necessary to support life on this planet and seemingly this planet alone. How large is the butterzone of this exact orbit? Would we have to move hundreds of thousands of miles in or out just to change 1 degree or is it one of those "3 asteroid strikes and you are out of bounds" kinda things?

submitted by /u/TheStreetForce
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When your body gets used to cold water, does it perceive it as a warmer temperature or does it just become less sensitive to the cold?

Posted: 24 Dec 2018 03:03 AM PST

A UFC fighter was recently revealed to have trace amounts of a steroid in his system. Authorities in the UFC and USADA said that they’re from the last time he got busted and a redditor attempted to debunk this theory, could someone have trace amounts of Turinabol 18 months after use?

Posted: 24 Dec 2018 03:00 AM PST

How does a microwave melt butter?

Posted: 23 Dec 2018 11:01 PM PST

Everything I've ever seen says that microwaves work by spinning water molecules, taking advantage of the fact that they're polar. If I put a stick of butter in a bowl and microwave it, it will melt, but butter is not polar as far as I know. So how does the microwave heat it?

submitted by /u/NastyDad
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Why do atoms not seem to bond in a "closed circuit" type structure?

Posted: 23 Dec 2018 02:23 PM PST

Not sure if I'm wording that right. Just recently started reading online about physics and chemistry. I have lot of questions but one that I asked in highschool and never got a satisfying answer from my teacher was why o3 (ozone) doesnt make a triangle like bond within itself and has a single bond double bond thing going on. Like o=o-o rather than 3 single bonds in which all the atoms share a bond with each other. Please help.

submitted by /u/myhamsareburnin
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How does speed affect time in our galaxy that is flying through space and spinning around a SMBH?

Posted: 23 Dec 2018 09:44 PM PST

From my understanding the faster you travel the slow time "tics" for you. Does that mean that time depends on how fast your host galaxy is traveling through the universe?

submitted by /u/MyNameIsDrewp
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Does your current level of health and fitness dictate the genes passed on to your kids? Like can I get really fit and then have a baby to pass on those traits, or similarly if I got really fat and then had a baby would it be more likely to inherit those unhealthy traits? Or is it all predetermined?

Posted: 23 Dec 2018 03:37 PM PST
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Sunday, December 23, 2018

How do some air-freshening sprays "capture and eliminate" or "neutralize" odor molecules? Is this claim based in anything?

How do some air-freshening sprays "capture and eliminate" or "neutralize" odor molecules? Is this claim based in anything?

How do some air-freshening sprays "capture and eliminate" or "neutralize" odor molecules? Is this claim based in anything?

Posted: 22 Dec 2018 05:17 PM PST

If a males testicles are removed before puberty occurs does the male grow to be the size they would have been if the testicles were still there?

Posted: 22 Dec 2018 05:00 PM PST

To add to my question, would the removal of the testicles before puberty cause the person to be uninterested in sex after they would have otherwise gone through puberty?

submitted by /u/ODE4555
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What is physically happening in the brain when we forget something?

Posted: 22 Dec 2018 05:54 PM PST

How are the voices of objects such as GPS systems or Alexa created? Do the programs use voice samples to create sentences in real-time, or is everything pre-recorded?

Posted: 23 Dec 2018 02:25 AM PST

How does herpes work? Why cant it be cured and how does it appear in specific locations on the human body?

Posted: 22 Dec 2018 04:03 PM PST

I know there are two major types of herpes virus but how is it possible that they appear in specific loactions? Why cant we get some type in some places?

Finally, how is this virus incurable?

submitted by /u/himaximusscumlordus
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Is real space and reciprocal space in condensed matter a covariant and contravariant basis respectively?

Posted: 23 Dec 2018 04:48 AM PST

I'm very familiar with the condensed matter principles but I'm self studying tensor Calculus over Christmas. It seems like they are very similar concepts, they obey almost the same othorgonality, and the unit vectors transform slightly differently. In one, by a mix of dot and cross products and in the other by a metric tensor. With these differences in mind, can these concepts be considered equivalent? Perhaps one is a generalization of the other?

Lastly, in condensed we transform functions into the reciprocal space via the Fourier transform, is this a general relationship between functions in covariant and contravariant spaces?

submitted by /u/digitalmus
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How does this "watercoloring" kid's book work?

Posted: 22 Dec 2018 11:19 PM PST

My Friend's Kid has this coloring book, how does this work?

For those of you who've never see this before it's a coloring book that's blank. When you add water, the colors appear. Once it dries the colors fade and you're left with a white page again.

I'm really curious about the science behind this, what's happening here?

submitted by /u/phizrine
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What is the Hercules-Corona Borealis Great Wall?

Posted: 23 Dec 2018 12:01 AM PST

I have heard this mentioned as the largest structure in the universe at ten billion light years across. What is it, why is it classified as a single structure, what is it made of and how does it exist?

submitted by /u/Miloisprettycool
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How is yield on atomic and hydrogen bomb explosions meassured?

Posted: 23 Dec 2018 04:13 AM PST

I mean physically? What kind of device or contraption is actually used? Wouldnt the explosion just vaporize any meassureing device?

submitted by /u/overlydelicioustea
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What makes a programming language "good" for certain tasks?

Posted: 22 Dec 2018 06:39 PM PST

For example, I've heard that Python is a "good" language for data analysis, and C# is for building apps. Theoretically, all programming languages should be able to do the same things, so what makes one better for a certain task? Is it the standard libraries?

submitted by /u/graphicviolins01
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Why do MRI scans take a moderate amount of time to complete, while fMRI scans are able to function in near-continuous manner (i.e. on an order of seconds instead of hours)?

Posted: 22 Dec 2018 07:57 PM PST

What temperature is the surface of a puddle?

Posted: 23 Dec 2018 05:54 AM PST

The other day my friend said the surface a puddle was at 100 degrees. I explained the difference between evaporation and boiling.

Then they replied with this

'Some of the water will evaporate and you could work out how much energy that transfers and link that to a temperature, which would be surprisingly high. KE =3/2kT.'

Isn't that just the average Ke? If that equation was applied to one or two particles at the surface. What would the temp actually be? Can this equation actually be applied. I have confused myself.

Any help appreciated.

submitted by /u/RJ5xx
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How do snail’s shells stay on?

Posted: 22 Dec 2018 03:45 PM PST

How do humpback whales separate all thier food from the thousands of gallons of water it comes with?

Posted: 22 Dec 2018 06:07 PM PST

Is it possible to have two planets orbiting one star, but they orbit on opposite sides of said star?

Posted: 22 Dec 2018 10:09 AM PST

I know its been asked before, but I have specific questions I didn't see asked. The details of this scenario:

A Sol-like star (age, size, composition, etc.) with two planets in the exact same orbit, and inclination. I understand the mathematic improbability of this, and that this is, if it existed or exists, a most unlikely natural occurrence. But I just want to know, even if by unnatural means, this would be a stable system, or if they would be slowly torn up by gravitational effects between the three bodies?

I am rather ignorant to most of physics so barney-style this (simplify) as much as you can please!

submitted by /u/xKINGxJOLTEONx
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How did NASA first dealt with radiation in space ?

Posted: 22 Dec 2018 04:22 PM PST

Specifically with the computers. How could they function when first going to the moon?

submitted by /u/A_Tricky_one
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Could "active light cancelling" exist?

Posted: 22 Dec 2018 07:25 PM PST

As of today, we have developed efficient active noise cancelling technology that we can find in popular headphones. Could the same idea apply to light, even if we are talking about EM waves and not mechanical waves?

submitted by /u/Thmsrey
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Besides opposable thumbs, what other steps in evolution led to humans?

Posted: 22 Dec 2018 03:16 PM PST

I grew up taught that giraffes probably started as regular necked animals like horses, but the food was too high so "they evolved to have longer necks".

I now understand that life doesn't evolve intentionally. Mutations occur which the life form must use to survive, or die. Giraffes who just happened to be born with sightly longer necks could better reach the food, so they survived and bred, and over enough generations the longer necked ones continued to be better able to survive so the longer the neck, the better the chance to survive and breed.

Opposable thumbs gave us the ability to manipulate small objects and the smarter of us figured out how to make tools... From my limited understanding of human evolution, the fabrication of tools was one of the major steps in human evolution.

What other events/achievements were possible only for humans, due to an early mutation?

Thanks!

submitted by /u/infinitum3d
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What is the evolutionary advantage of the tibula and fibula being separate and not one combined bone?

Posted: 22 Dec 2018 12:21 PM PST

Are there any sub/species that feed solely through cannibalism? If not, is such a thing theoretically possible?

Posted: 22 Dec 2018 04:14 PM PST

Why do you lose consciousness when you get hit by something? And what exactly happens when trying to recover from it and how do you wake up? Is it like waking up when you are done sleeping?

Posted: 22 Dec 2018 12:24 PM PST

Title explains. Is there a specific process that affects the nervous system to be knocked out and what exactly does it do when trying to wake up?

submitted by /u/Edgardus
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