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Thursday, June 29, 2017

From how high up can you dive before water may as well be concrete?

From how high up can you dive before water may as well be concrete?


From how high up can you dive before water may as well be concrete?

Posted: 28 Jun 2017 07:18 PM PDT

Diving is supposed to mitigate the resistance entering water, so would it be significantly higher than the point where, say, a belly flop has the effect of hitting concrete? Would it shatter your hands and wrists?

submitted by /u/RikuAotsuki
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Why is it believed black holes preserve mass, charge and angular momentum, but not baryon number, weak isospin and lepton number?

Posted: 28 Jun 2017 06:55 PM PDT

How are the ideas of particles being vibrations in fields vs. being made of vibrating strings (string theory and quantum mechanics) united?

Posted: 29 Jun 2017 03:38 AM PDT

Is the erosion of the Dead Sea in the Neolithic Levant the earliest known example of human impact on geological processes?

Posted: 28 Jun 2017 09:47 PM PDT

I came across this paper:

Increased sedimentation following the Neolithic Revolution in the Southern Levant http://www.sciencedirect.com/science/article/pii/S0921818116305227

The authors state that humans were responsible for the increased erosion of the Dead Sea.

We estimate that this intensified erosion is incompatible with tectonic and climatic regimes during the corresponding time interval and further propose a close association with the Neolithic Revolution in the Levant (beginning at ~ 11.5 ka). We thus suggest that human impact on the landscape was the primary driver causing the intensified erosion and that the Dead Sea sedimentary record serves as a reliable recorder of this impact since the Neolithic Revolution.

A few articles state that this constitutes the earliest evidence of humans influencing geological process.

Is this true? Are there any other examples of early environmental modification?

(originally posted this in r/anthropology, but no response so far)

submitted by /u/nwidis
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What determines left/right handedness in humans? Do other animals have a "dominant side"?

Posted: 29 Jun 2017 04:54 AM PDT

Why can't we use the "Infinite primes proof" to continuously find new primes?

Posted: 28 Jun 2017 08:48 AM PDT

In the infinite primes proof, you multiply all of the primes together and add 1, which creates a new prime. Why can we not use this method with the primes that we currently know to find new primes? People always talk about "finding" new primes, but it seems like using the method above would result in a guaranteed new prime number.

submitted by /u/Autistic_Aardvark
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How does lightning find the path of least resistance?

Posted: 29 Jun 2017 04:13 AM PDT

Hello there! I'd like to know why lighting chooses the path it chooses and not another one... I've heard it chooses the one with least resistance, but what exactly does that mean? Highest conductivity? And how does it know that before going through it Thank you very much and please excuse the shitty formatting....

Edit: Small mistakes

submitted by /u/MorphinMorpheus
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Why must we use radians (and not degrees) in calculus?

Posted: 29 Jun 2017 05:14 AM PDT

Why does space still appear to be dark, although it is full of bright stars?

Posted: 29 Jun 2017 03:27 AM PDT

Why are you at risk of getting a blood clot from long car/plane trips and from bed rest after surgery but not when sleeping 8+ hours?

Posted: 28 Jun 2017 06:39 PM PDT

Do gravity waves fade as they travel across space?

Posted: 29 Jun 2017 03:24 AM PDT

Eye drops can cause serious harm if ingested. Why is a substance that's safe to use on the eyes so dangerous if swallowed?

Posted: 28 Jun 2017 04:09 PM PDT

There have been multiple cases of people being hospitalized after ingesting eye drops, particularly Visine. The perpetrators of these poisonings often believed that taking the eye drops internally would cause relatively harmless nausea or vomiting, but the actual effects can be much more severe. What makes a substance that's safe for a sensitive part of the body like the eyes so dangerous when swallowed?

submitted by /u/MiklaneTrane
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Did the first milliseconds of the universe expand faster than the speed of light?

Posted: 29 Jun 2017 01:06 AM PDT

If so how?

submitted by /u/albanshqiptar
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Why do fevers cause weird dreams?

Posted: 28 Jun 2017 02:31 PM PDT

Why aren't there more huge canyons like the grand canyon?

Posted: 28 Jun 2017 03:23 PM PDT

Do we have any idea if ancient peoples had the sames types and rates of cancer that we experience now?

Posted: 28 Jun 2017 01:05 PM PDT

How do we know things in space are spinning if there is no single point of reference?

Posted: 28 Jun 2017 06:52 PM PDT

Also, would a star spinning so fast that its shape becomes non spherical appear spherical to an observer who was orbiting the star at the same rate which it was spinning?

submitted by /u/zip_dude
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On a planet like Mars, a planet with two moons, is it possible to have a double lunar eclipse? Or an eclipse where one moon blocks out another? What would that look like?

Posted: 28 Jun 2017 07:38 PM PDT

Why can't the Melipona Bee that pollinates vanilla be introduced to other parts of the world?

Posted: 28 Jun 2017 07:29 PM PDT

So I've been reading about how there is a natural vanilla shortage, and that it's an extremely labor intensive crop because they have to be hand pollinated at a very specific time. But the only natural pollinator is the melipona bee. I'm wondering why people don't try to introduce this bee to madagascar (the leading producer of vanilla)? Wouldn't that make things cheaper and easier?

submitted by /u/Shalondrinkswater
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When ancient explorers traveled the sea by reading the stars, did it actually work or was it some placebo effect?

Posted: 28 Jun 2017 10:03 PM PDT

Wednesday, June 28, 2017

Why does the electron just orbit the nucleus instead of colliding and "gluing" to it?

Why does the electron just orbit the nucleus instead of colliding and "gluing" to it?


Why does the electron just orbit the nucleus instead of colliding and "gluing" to it?

Posted: 27 Jun 2017 10:27 AM PDT

Since positive and negative are attracted to each other.

submitted by /u/alos87
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Is it possible for an atomic sized black hole to exist in our galaxy? If yes could it's energy be harnessed at all?

Posted: 28 Jun 2017 06:47 AM PDT

Humans and animals get lots of diseases from mosquitoes, do they get any from us?

Posted: 28 Jun 2017 04:20 AM PDT

Do imaginary numbers have any practical applications?

Posted: 28 Jun 2017 12:00 AM PDT

How do dogs figure out which posts/trees they want to pee on?

Posted: 28 Jun 2017 07:43 AM PDT

My dog, like any male dog, does the whole 'marking his territory' thing about once a block. Sometimes more, sometimes less. I notice that a lot of times he picks the same spots, which makes sense to make a clearly defined territory, but when we go somewhere new, he'll still do it, but not on every pole. And when he does want to he's quite stubborn and won't move on until he marks it. Is this just random? Does he only do it on other dogs' marks? I'd assume just about every pole has been peed on at some point. How do they decide?

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

Posted: 28 Jun 2017 08:07 AM PDT

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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What happens if the event horizon of two black holes touch?

Posted: 27 Jun 2017 07:57 PM PDT

Can one be ripped apart or will they be forced to combine completely? If that's the case how long would it take?

submitted by /u/PutHisGlassesOn
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Why was it so much harder for a welder to weld my 2 pieces of Aluminum together than for 2 equivalent pieces of basically any other popular metal?

Posted: 28 Jun 2017 07:47 AM PDT

I recently had something welded for part of a project. 2 pieces of Aluminum. I talked to a local welder who said he wouldn't touch Aluminum but would have welded my design if it was stainless steel and that I needed to find someone else.

Why is Aluminum so much more challenging to weld? What physical properties for Al are different that make it that much harder?

submitted by /u/cfbnerd
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How can fusion reactors take the extremely high temperatures (100,000,000c+) without simply melting the casing?

Posted: 27 Jun 2017 01:07 PM PDT

Do black holes swallow dark matter?

Posted: 28 Jun 2017 07:14 AM PDT

We know dark matter is only strongly affected by gravity but has mass- do black holes interact with dark matter? Could a black hole swallow dark matter and become more massive?

submitted by /u/LegioCI
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Why don't you get shocked when touching a tree that is touching a powerline?

Posted: 28 Jun 2017 01:11 AM PDT

Most powerlines aren't insulated, so in the case of a powerline touching a tree, wouldn't you also be shocked if you touched that tree?

submitted by /u/yosimba2000
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What did earth look like 16 million years ago and 12 million years ago?

Posted: 28 Jun 2017 06:32 AM PDT

Hey. I'm a ranger working on a site with 12 myr old fossils and I'm trying to better understand the conditions in which they were created. Were parts of the modern continents still joined together? Or was it more or less the same as today? I'm in Iceland more specifically and the "earth" (can't remember the correct english term right now, the rocks) where I'm situated is around 16 myr old.

Thanks!

submitted by /u/liliannereid
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In Batman V Superman, the US government launches a nuke into space with seemingly no consequences or fallout. What would the effect of the nuke be in real life?

Posted: 28 Jun 2017 12:34 AM PDT

How would the nuke's blast affect Earth's atmosphere, (or the Earth itself) if at all? Would there be any other consequences?

submitted by /u/banterminator
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Why does water "stick" to surfaces while upside down and run down them without simply dropping off?

Posted: 27 Jun 2017 12:09 PM PDT

For example, when you're washing your hands and a water droplet runs down your arm into your sleeve.

submitted by /u/heat-illusion
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What is the relationship between 3G and 4G?

Posted: 27 Jun 2017 01:25 PM PDT

Rotating black holes can support orbits inside their inner event horizon. Can bodies in these orbits communicate out via gravity waves?

Posted: 27 Jun 2017 02:22 PM PDT

Can we derive the laws of thermodynamics from the laws of classical mechanics?

Posted: 27 Jun 2017 01:44 PM PDT

Suppose we had a box containing billions of tiny billiard balls, all subject to classical mechanics with perfectly elastic collisions. Could we then mathematically prove the thermodynamic laws and relations about temperature, pressure, entropy etc. for this system? It seems that most statistical mechanics books make the assumption that "all microstates are equally probable", but they never prove it.

submitted by /u/AxelBoldt
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Can you help me fix my confusion on gravity assists?

Posted: 27 Jun 2017 03:41 PM PDT

I know my reasoning or intuition is faulty but I just can't find why.

In understanding, one could define a gravitational potential field on our solar system but in that gravitational field, the energy is conserved. So how can different routes through this gravitational field result into different velocities? I mean, I gain energy by passing a planet but I lose it to when I leave it.

Obviously this thinking is wrong somehow, maybe some basic assumptions but I can't quite see how gravitational assists operate.

Can you solve this or re-explain it?

submitted by /u/TunnelFET
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What makes something an acid and what makes something a base?

Posted: 27 Jun 2017 11:09 AM PDT

I've heard somewhere that acids have a sour taste and a bases have bitter tastes. But I've heard that water is a base and acid? This confuses me a lot.

submitted by /u/overweight_cat1
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Can helium bond with other elements or with itself?

Posted: 27 Jun 2017 10:35 AM PDT

Is it possible for helium to bond to create other substances? I know helium is a noble gas and is extremely unreactive because of its full outer shell but is it possible?

submitted by /u/overweight_cat1
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how much more radioactive is enriched uranium compared to depleted uranium?

Posted: 27 Jun 2017 03:37 PM PDT

would strange matter blow up 'normal matter'?

Posted: 27 Jun 2017 04:55 PM PDT

I am asking if matter with strange quarks could be in the same nucleus as matter with just up and down quarks and still be stable, i am also asking if strange matter could possibly be included in atoms and molecules and if we really know any of its properties in the first place.

submitted by /u/Skout107
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Tuesday, June 27, 2017

When our brain begins to lose its memory, is it losing the memories themselves or the ability to recall those memories?

When our brain begins to lose its memory, is it losing the memories themselves or the ability to recall those memories?


When our brain begins to lose its memory, is it losing the memories themselves or the ability to recall those memories?

Posted: 26 Jun 2017 04:23 PM PDT

If the virtual particles exchanged to create forces don't really exist, then what are forces made of?

Posted: 27 Jun 2017 05:09 AM PDT

Hi, other /r/askscience posts I've read, such as this one, and this comment seem to imply that the virtual particles that are supposedly exchanged are more mathematical abstractions than literal objects. If that is the case, what are forces made of?

submitted by /u/butWhoWasBee
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I know that the sky is blue because our atmosphere scatters higher frequency wavelengths of light, but what happens specifically on a molecular level in the scattering process?

Posted: 27 Jun 2017 06:06 AM PDT

Why is it impossible to get suntan through glass?

Posted: 27 Jun 2017 03:12 AM PDT

What is the highest frequency of light that the human eye can detect/process? What is the lowest?

Posted: 27 Jun 2017 06:17 AM PDT

Where do bugs like Fireflies go during the 9 months of the year that I don't see them?

Posted: 26 Jun 2017 07:02 PM PDT

This goes for any seasonal insect, I guess. Are there eggs just sitting around on the ground during fall and winter waiting for spring before hatching? Are there any bugs alive during non-seasonal months? Do they migrate?

submitted by /u/Jonathan_Utah_Esq
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Why is the helium-4 nucleus (an alpha particle) unusually stable among lighter nuclei?

Posted: 27 Jun 2017 07:22 AM PDT

I know it has something to do with "magic numbers", but I don't really understand know about that also.

submitted by /u/fizzyfuzzball
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Does the outer space make a sound?

Posted: 27 Jun 2017 03:22 AM PDT

A cup of hot coffee is placed on a table inside a kitchen, is the temperature of the contents inside the cup ever the same as the cup, the table, and/or the room itself?

Posted: 26 Jun 2017 10:20 PM PDT

Is it possible to achieve absolute darkness ?

Posted: 26 Jun 2017 11:17 PM PDT

Is it possible to achieve absolute darkness , as in no photons emitted across the whole spectrum of light (not only visible light ) or does that requires absolute zero temperatures due to black body radiation?

submitted by /u/darkfloo16
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Why companies can't chemical ananalyze, for example, Pepsi, and produce identical mixture on their own?

Posted: 26 Jun 2017 09:03 AM PDT

I believe some things are patented out - but then are not a secret. For example WD-40 oil is not patented and its recipe is secret, why people just don't analyze it's contents to produce a copy and gain huge cash?

submitted by /u/panoczekkurwa
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When a person is blind from birth, what is their perception of sight and color? Do they have one?

Posted: 26 Jun 2017 11:50 PM PDT

If the remote control for one electronic item cannot be used to control another electronic item, how do gadgets such as universal remotes and phones with IR blasters work?

Posted: 27 Jun 2017 05:08 AM PDT

Are there 'superbugs' in animals?

Posted: 27 Jun 2017 05:00 AM PDT

Hi all, I'm just trying to explore how antibiotic resistance can affect the ecosystem. I understand that animals can increase antibiotic resistance by passing on resistant bacteria into human food.

In that case, can animal species have superbugs like humans do? If so, are there animal species that are being ravaged at the moment?

submitted by /u/graveed
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What are the similarities and dissimilarities between sleep and unconsciousness?

Posted: 27 Jun 2017 01:14 AM PDT

Could this "bubble" protect Mars from radiation and solar winds?

Posted: 26 Jun 2017 09:08 PM PDT

About the Cognitive Ease Experiment on pg.70 of "Thinking, Fast and Slow", what does Daniel Kahneman mean by "emotional changes are NOT linked causually to the words"?

Posted: 27 Jun 2017 03:59 AM PDT

English is not my first language so please bear with me.

So I have been reading this book for some time now and found a great deal of interesting information about how the mind works. There is this particular section that I am having trouble trying to understand however. The text is as followed:

Cognitive ease and smiling occur together, but do the good feelings actually lead to intuitions of coherence? Yes, they do. The proof comes from a clever experimental approach that has become increasingly popular. Some participants were given a cover story that provided an alternative interpretation for their good feeling: they were told about music played in their earphones that "previous research showed that this music influences the emotional reactions of individuals." This story completely eliminates the intuition of coherence. The finding shows that the brief emotional response that follows the presentation of a triad of words (pleasant if the triad is coherent, unpleasant otherwise) is actually the basis of judgments of coherence. There is nothing here that System 1 cannot do. Emotional changes are expected, and because they are unsurprising they are not linked casually to the words.

-- page 70, "Thinking, Fast and Slow", Daniel Kahneman

What does he mean in the last sentence?

I understand that the participants were led to think that the music played was the only agent that affected their mood. I also understand that their System 1 was fully engaged because the participants expected some emotional changes along with the music playing to their ears; i.e., they feel safe and their System 2 has no influence here.

What I don't understand however is how their emotional changes are NOT linked casually to the triads of words. Didn't he just say earlier that the triads of words (their coherence) caused pleasant or unpleasant responses on the participants?

submitted by /u/UncleBaldy
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Why do batteries catch fire when you take them apart?

Posted: 26 Jun 2017 10:29 PM PDT

I've been watching some electronic hobbyist videos on YouTube and I'm curious as to why batteries seemingly explode when they are opened up.

submitted by /u/HereticalHermit
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What exactly is taking place to allow a substance to exist at the triple point?

Posted: 26 Jun 2017 11:19 AM PDT

How are ccv codes on the back of credit cards so secure?

Posted: 27 Jun 2017 01:10 AM PDT

How are those three digits on the back secure enough to prevent fraud using just the front numbers? They're just an algorithm, right? How have people not figured out the algorithms and then used that knowledge to vomit fraud with just the normal cc number, or even more so how have people not created credit card generators that give you a cc number with a matching ccv?

submitted by /u/CommanderClit
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Are there any studies that compare the levels of "death acceptance" between terminal patients with and without descendants?

Posted: 26 Jun 2017 08:50 AM PDT

Sorry for possible /r/titlegore.

The commonly-held evolutionary explanation for the desire to have sex and procreate is the need to pass on one's genes. I'm wondering if there's ever been a study that measured how "at peace" terminal patients were with their impending death based on whether not they've already passed on their genes (ie, parents, grandparents etc. are more accepting of their demise than childless patients, because the former group "lives on" through their descendants).

If so, what were the results?

submitted by /u/JamalBruh
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