Pages

Friday, October 21, 2016

Fusion via heavy water cavitation collapse?

Fusion via heavy water cavitation collapse?


Fusion via heavy water cavitation collapse?

Posted: 21 Oct 2016 04:05 AM PDT

Firstly, what kind of energy/temperature/pressure would you need to fuse Deuterium and/or Tritium atoms as components of heavy water molecules? Secondly, could that energy be achieved in the collapse of a heavy water cavity? If not on it's own, would it be possible if the cavity collapse was assisted with an additional wave pressure wave?

submitted by /u/graebot
[link] [comments]

How much more dangerous would lightning strikes have been 300 million years ago when atmospheric oxygen levels peaked at 35%?

Posted: 21 Oct 2016 04:34 AM PDT

Re: the statistic, I found it here

https://en.wikipedia.org/wiki/Geological_history_of_oxygen

Since the start of the Cambrian period, atmospheric oxygen concentrations have fluctuated between 15% and 35% of atmospheric volume.[10] The maximum of 35% was reached towards the end of the Carboniferous period (about 300 million years ago), a peak which may have contributed to the large size of insects and amphibians at that time.

submitted by /u/ergotpoisoning
[link] [comments]

Is Fuzzy Logic used in science, and more specifically in Quantum Mechanics?

Posted: 21 Oct 2016 02:40 AM PDT

So I am self studying Fuzzy Sets from George J. Klir's book. Chapter 1 concludes with a discussion on paradigm shifts, and how fuzzy logic is a new paradigm that will change science considerably. The book was written in 1995 though. So did scientists adopt this new paradigm, and more specifically did this new paradigm make its way to quantum mechanics?

submitted by /u/i_m_no_bot
[link] [comments]

Why does the CDC report on cases of B. pertussis (whooping cough) appear to show an increase in cases among children with 3+ doses of vaccination? [Links inside]

Posted: 20 Oct 2016 08:02 PM PDT

I'm not an antivaxxer, however, I came across the CDC's surveillance reports from the past few years that seem to show an increased risk for those children who have multiple doses of the vaccination.

(The links I am referring to are near the bottom of the webpage under "Surveillance Reports")

I do not intend to start any 'Vax or No-Vax' conversation, I simply desire to understand what this data is actually conveying.

Thank you!

submitted by /u/3434Anon3434
[link] [comments]

Why are free neutrons unstable?

Posted: 20 Oct 2016 03:25 PM PDT

Why is it that free neutrons are unstable whereas free protons are perfectly stable on their own? What is it about a free neutron that unstablizes it outside of the nucleus of an atom?

submitted by /u/Airstew
[link] [comments]

Pictures of the shade balls that LA dropped into its reservoir show organized groups of balls on the water that are reminiscent of the crystal structures on the surface of galvanized steel. Is this just coincidence or are there related processes at play?

Posted: 20 Oct 2016 11:06 AM PDT

Here are the pictures of the shade balls that I'm referring too:

Pic 1

Pic 2

Pic 3

And for reference, a picture of galvanized steel.

Are there related processes at play that influence both the formation of crystals in galvanized steel and the self-organization of the shade balls? Or are the similarities between the two simply coincidence?

submitted by /u/catch878
[link] [comments]

Why, in music, do scale modes appear to have such different tonal qualities?

Posted: 20 Oct 2016 08:50 AM PDT

Taking the C major scale for example, why does the Ionian mode (C major: CDEFGAB) sound so different from the Aeolian mode (A minor: ABCDEFG)?

I can appreciate that the intervals from the tonic are different, but the intervals between the same notes are the same:

C-D-E-F-G-A-B-C-D-E-F-G-A-B-C A-B-C-D-E-F-G-A-B-C-D-E-F-G 2-2-1-2-2-2-1-2-2-1-2-2-2-1-2-2-1-2 

So why don't I start hearing A minor in the middle of playing a C major scale? Or C major in the middle of A minor, or the Phrygian mode from III? How do we stay locked on a mode's tonal centre and hear such different qualities between modes, even lacking accompanying chords for reference?

submitted by /u/FretbuzzLightyear
[link] [comments]

When (and by whom) was it discovered that the brain is where memories are stored?

Posted: 20 Oct 2016 03:30 PM PDT

How did the volcanic ash of Mount Vesuvius preserve the people and items of Pompeii?

Posted: 20 Oct 2016 11:40 AM PDT

I know everything was covered in ash, but I don't see how that preserved everything.

submitted by /u/Zircon_72
[link] [comments]

How does weather affects voting statistics?

Posted: 20 Oct 2016 12:22 PM PDT

What would happen if another star collided with our sun, assuming the other star was equal size and mass and both were traveling at the same speed?

Posted: 21 Oct 2016 12:29 AM PDT

Would they combine together into one large star or collapse into a massive black hole? Would the energy released from the collision be enough to destroy the solar system? What about the galaxy?

Just curious.

submitted by /u/The_Iron_Zeppelin
[link] [comments]

What is the physiological purpose of RNA using Uracil instead of Thymine when all the other nitrogenous bases are the same as DNA?

Posted: 20 Oct 2016 09:32 AM PDT

How come the same hair color can look different in different light settings?

Posted: 20 Oct 2016 11:43 AM PDT

I got the same dark brown hair as my friend. In low- and medium/room light the hair color looks almost exactly the same but in strong light (like a bright sunny day outside or in bright spotlight) my hair looks more light-/chestnutbrown while his look more darkblonde-ish.

I've noticed similair things at other times with other hair colors, is there a science behind this?

submitted by /u/parkercannonball
[link] [comments]

What is the best definition of entropy?

Posted: 20 Oct 2016 10:54 AM PDT

I'm trying to understand entropy as fundamentally as possible. Which do you think is the best way to understand it:

  • The existence of a thermodynamic system in a generalized macrostate which could be described by any one of a number of specific microstates. The system will follow probability and occupy macrostates comprising the greatest number of microstates.

  • Heat spreading out and equalizing.

  • The volume of phase space of a system, where that volume is conserved or increased. (This is the definition I'm most interested in, but I have heard it might be just a generalization.)

  • Some other definition. Unavailability of thermodynamic energy for conversion into mechanical work, etc.

I suppose each of these definitions describes a different facet of the same process. But I want to understand what happens in the world as fundamentally as possible. Can a particular definition of entropy do that for me?

submitted by /u/ktool
[link] [comments]

Does a policy that allows passing on the right on multilane highways result in more or less efficient use of that highway?

Posted: 20 Oct 2016 02:04 PM PDT

Let's assume we're looking at 4-lane highways at a minimum (2 lanes in each direction). But it's common to find 6 or even 8-lane highways. I ask this from the US, where in SOME states, it is legal to pass on the right on a multilane highway. It seems that people frequently just drive in the middle lane or the left lane, so can, and do, get passed on both sides. If you drove like this in Germany, you'd be run over. It strikes me that this policy is both less safe and less efficient. Is it less efficient? Any modeling of this available?

submitted by /u/Creddit999
[link] [comments]

How can CRISPR/Cas9 target genes larger than 20 nucleotides?

Posted: 20 Oct 2016 09:04 AM PDT

If a point mutation occurs earlier than 20 nucleotides before the PAM sequence, how can CAS9 cut out this point mutation to repair it with a template? Do PAM sequences occur enough inside genes so that the entire gene is almost always targetable.

I am a biomedical science student and am writing a paper about the use of CRISPR/Cas9 (and dCas9 and other Cas enzymes) in future cognitive enhancement therapies by editing genes (no knockouts, just genetic variation to produce slightly "better" proteins).

As example; alteration of the CREB sequence to variations such CREB-y134F (mice) would be a possible target, however CREB is over 300 nucleotides long.

Am I misunderstanding (I never looked into the details of CRISPR before this paper) the CRISPR/Cas9 system or is there a lot less freedom than literature implies?

Thanks! -Dagl1

submitted by /u/Dagl1
[link] [comments]

Is there vocabulary in topology that could be useful for discussing so-called 'gerrymandered' political district boundaries?

Posted: 20 Oct 2016 08:49 AM PDT

I understand that many factors will go into organizing the population geographically (e.g. following a river), but are there concepts coming from mathematics that could be used to describe potentially gerrymandered districts in a concise and precise way, and maybe even (when combined with with historical, geographical, or social science information) could inform certain initial arguments about whether a district may have been gerrymandered for political purposes?

submitted by /u/wjrii
[link] [comments]

Will two cars with three seconds following distance always have three seconds of following distance?

Posted: 20 Oct 2016 08:40 AM PDT

CarB is three seconds behind CarA going 35mph; CarA crosses into a 45mph zone and accelerates. CarB crosses into the 45mph zone with the exact same acceleration as CarA.

The physical distance would be longer, but the two cars would still be exactly three seconds apart, right?

submitted by /u/JaeHxC
[link] [comments]

Would a "base-prime", number system be useful in any way?

Posted: 20 Oct 2016 10:13 AM PDT

I just watched the most recent numberphile video and it got me thinking about base systems. In most base systems, the length of the written representation of the number grows with the log of the number in a constant base. (for example in base 10, each time we multiply by 10, the number grows by 1 digit). However each integer can also be represented by a unique prime factorization. Therefor we could create a "base system" in which each number is represented by the number of times each prime occurs in its prime factorization. Some examples would be:

1 ---> 1

2 ---> 10

3 ---> 100

4 ---> 20

5 ---> 1000

6 ---> 110

Is there any merit to using a system like this? Can it be expanded to include more numbers like the rationals or reals? What does arithmetic look like using this system?

Just wondering if anyone has tried this before.

Thanks

submitted by /u/graciousgroob
[link] [comments]

Thursday, October 20, 2016

Aside from Uranium and Plutonium for bomb making, have scientist found any other material valid for bomb making?

Aside from Uranium and Plutonium for bomb making, have scientist found any other material valid for bomb making?


Aside from Uranium and Plutonium for bomb making, have scientist found any other material valid for bomb making?

Posted: 19 Oct 2016 05:50 PM PDT

Im just curious if there could potentially be an unidentified element or even a more 'unstable' type of Plutonium or Uranium that scientist may not have found yet that could potentially yield even stronger bombs Or, have scientist really stopped trying due to the fact those type of weapons arent used anymore?

submitted by /u/MScrapienza
[link] [comments]

When birds fly south for the winter, how exactly does the population Distribution change? Do they all fly south an equal distance and displace each other, or do those that spend summer farther north have to fly farther south to find unoccupied territory?

Posted: 20 Oct 2016 06:34 AM PDT

I think the question is pretty well contained in the title text, but for reference, I was looking at the range of the Canada Goose.

They're a permanent resident in the upper half of the US, but they're seasonal in most of Canada and the southern US. How exactly do the populations migrate? Do they replace each other linearly, where they all more or less fly an equal distance south, or do the birds present in the upper US mostly stay put in their 'territory' while those from Canada have to migrate all the way to Texas to find an unoccupied area to spend the winter?

submitted by /u/VeryLittle
[link] [comments]

Does the ISS ever have to adjust its velocity and if so, how does it accomplish it?

Posted: 20 Oct 2016 06:45 AM PDT

Why don't Cats need haircuts?

Posted: 19 Oct 2016 08:25 PM PDT

How do scientists know the chemical components of far away planets?

Posted: 20 Oct 2016 05:40 AM PDT

Is it known when/where Rh negative people first appeared, or have they always been around?

Posted: 20 Oct 2016 08:05 AM PDT

I stumbled upon a clickbaity article claiming that 'Rh negative people are aliens' and a bunch of other nonsense, so I started looking around and it turns out there isn't much info online about the 'genealogical history' (probably not the right technical term for it) of Rh negative people. A quick look at the Wikipedia page for blood type distribution by country tells me it's mostly European lineages that are Rh negative, so intuitively I would think that a mutation occurred in Europe at some point, but this is really just a guess. Is there currently any consensus about this?

submitted by /u/1AwkwardPotato
[link] [comments]

[Physics] If strong force is strong enough to keep protons together, why do atoms need neutrons to keep the protons from tearing apart?

Posted: 20 Oct 2016 05:35 AM PDT

I was watching Crash Course Chemistry and watched the lateral SciShow video about how quarks are held together with strong force, which keeps protons together and also ties together the whole atom through nuclear force. When I got back to the video on the nucleus, however, Hank stated that neutrons are important because without them the protons would tear each other apart.

Wouldn't the strong force be more likely to pull the protons in close? What force would be pushing the protons apart and creating a need for neutrons?

submitted by /u/lipglosschaos
[link] [comments]

How can we know about a 20-mile wide Kuiper belt red object (MU69), but just now be "discovering" two new moons over Uranus?

Posted: 19 Oct 2016 05:57 PM PDT

Microwave cavities are necessary to generate microwaves, so where is this component on a wireless router?

Posted: 20 Oct 2016 06:08 AM PDT

I quit smoking after 20 years. What is my body doing to heal itself?

Posted: 19 Oct 2016 10:09 PM PDT

How long for the heavy metals to leave my body? How long for my lungs to detox themselves?

submitted by /u/DoYouEnjoyMy
[link] [comments]

Can we accurately calculate the rate at which heat will travel through an object? How do we do that?

Posted: 19 Oct 2016 09:18 PM PDT

For example, if I have a cup of coffee. How would I find out how quickly the heat will take to reach the outside of the cup?

submitted by /u/Meekswel
[link] [comments]

Are the limits, or bounds, to the electromagnetic spectrum?

Posted: 19 Oct 2016 08:40 PM PDT

What is the heritability of Ehler's-Danlos Syndrome, and chance of a child being born with it if one parent (mother) is affected with the condition (hypermobility type) and the father does not have the condition?

Posted: 19 Oct 2016 06:37 PM PDT

Very specific question, but I'm actually just curious. I recently learned of the condition from a female speaker and an event, and I looked it up on my own, to learn more, and one part I could never find was the heritability.

Thank you in advance.

submitted by /u/ThenWhatDidYouExpect
[link] [comments]

How do radio stations judge their number of listeners?

Posted: 19 Oct 2016 06:02 PM PDT

Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science

Posted: 19 Oct 2016 08:05 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
[link] [comments]

Is there something like the "double dabble" algorithm, for trinary/base 3?

Posted: 19 Oct 2016 09:26 PM PDT

I want to use an algorithm to convert trinary (base 3) to trinary coded decimal. Is there such a thing? What's it called? (Maybe tripple trabble, idk).

submitted by /u/0Zyn
[link] [comments]

If a vacuum is an extremely effective insulator, how does the ISS and other space vessels handle dissipating heat?

Posted: 19 Oct 2016 11:59 AM PDT

Confusion about the inverse square law. Can someone please explain?

Posted: 20 Oct 2016 06:22 AM PDT

I'm just gonna warn anyone who loves and/or works in physics, now...this post is going to be straight cancer to your eyeballs.

From what I know, 1 / distance2 is what determines the intensity of a light source, or gravitational pull, or whatever you're observing. I've heard, many times, by actual physisists, that the simplification is "Double the distance, divide the intensity by four."

This is easily put into practice just by using a torch on a wall. If I stand a meter away from a wall, and hold a torch towards it, a part of the wall is lit up. If I stand two meters away from a wall, and hold that same torch towards it, four times the area is being lit up, but it's (roughly) the same amount of photons. By the logic in the above paragraph, that means the same area that was being lit up when I was standing one meter away is only being hit by a quarter of as much light, right?

That all makes sense to me, but when you turn what you're observing into gravity, my brain has a fit.

So, if I double my distance from Earth, I'll divide its gravitational pull on me by four? I'm currently sitting on a chair, with my feet up on my desk, suspended about 60cm from the ground. So, if I run this through a calculator with that equation up the top of this post, I get ~0.00027. Let's times that by Earth's surface gravity (9.8m/s, but because I punched in 60cm, not 0.6m, I'll convert it to 980cm). Interesting. I get 0.2646cm. So...Earth's current gravitational pull on me is 2.6mm/s? But it's not, otherwise I'd be knocking myself out on my roof every time I farted. Hell, if I double my distance, again, so I'm 1.2m away, its gravitational pull should be 0.65mm.

Can you see where my confusion is coming from?

Keep in mind, try to keep any explanations simple for my layman, little mind.

Just a side, but related question, if anyone knows, is there a simple equation I can punch into a calculator that can determine how far away from an object you need to be in order for its gravitational pull on you to be almost 0? I know that it can never be 0, because gravity will always affect you no matter how far away you are, but, for example, I'm working with limited decimal places, like 3. I mean, in the real world, once the gravity is as low as 0.001m/s, and you increase the distance further, it's going to go to 0.00099999999999999--etc, but if I'm working with 3 decimal places, maximum, it will just become 0.000.

Say I make up a fake planet with a random surface gravity off the top of my head. I'll choose 20.9m/s. Is there an equation I can pop into my calculator with "20.9" somewhere in it , that will spit out the distance from the planet a fictional rocket would have to be in order for that gravitational pull to be less than 0.001?

submitted by /u/Zentopian
[link] [comments]

Could a single molecule of water conduct electricity?

Posted: 19 Oct 2016 06:19 PM PDT

AFAIK, Metal is a good conductor because it has a sea of delocalized electrons that are able to move charge across it. So, in theory, since water is covalently bonded, and the hydrogens, and oxygen, are "sharing" electrons, a single molecule of water should be able to conduct electricity.

submitted by /u/The_abster
[link] [comments]

Do nyctinastic plants absorb the same amount of sunlight when closed?

Posted: 20 Oct 2016 06:12 AM PDT

I raise tropical bonsai, and have a Tamarind with curious leaves that close and make me feel weird for leaving the light turned on.

submitted by /u/JustLikeAmmy
[link] [comments]

Is there a need for a larger particle accelerator?

Posted: 19 Oct 2016 07:09 PM PDT

Do bigger accelerators mean better results? Is there even a plateau for how large one can be and still be an improvement? Is there anything we could even discover with them after the Higgs Boson particle?

submitted by /u/master_of_disgust
[link] [comments]

How fast is lightning in a vacuum?

Posted: 19 Oct 2016 05:17 PM PDT

Been wondering if it's the same as the speed of light, I would assume not but thought I'd ask.

submitted by /u/ThatClanGuy
[link] [comments]

How are the strong/weak nuclear forces stronger over a short distance compared with electromagnetism/gravity, yet weaker over longer distances?

Posted: 20 Oct 2016 05:00 AM PDT

Wouldn't the strength of the fundamental forces decrease at equal rates? IE, if there is an electromagnetic force of 5 arbitrary units (AU), and it decreases by 1 AU over 1 arbitrary distance (AD), then a strong nuclear force of 5 AU would also decrease by 1 AU over 1 AD.

submitted by /u/SomeAnonymous
[link] [comments]

How does molecular structure search work?

Posted: 19 Oct 2016 10:19 AM PDT

How does molecular structure searches like PubChem work? I had assumed they were using Smiles but a number of smiles can be obtained from a given molecule which would not work with a simple string search. Does it convert molecular data into a different format that allows substructure search?

submitted by /u/the_terran
[link] [comments]

Wednesday, October 19, 2016

When you eat various foods (fruits, meats, vegetables) do the microbes in your guts which specialize in breaking down those foods grow or simply become active while the others wait for their turn?

When you eat various foods (fruits, meats, vegetables) do the microbes in your guts which specialize in breaking down those foods grow or simply become active while the others wait for their turn?


When you eat various foods (fruits, meats, vegetables) do the microbes in your guts which specialize in breaking down those foods grow or simply become active while the others wait for their turn?

Posted: 18 Oct 2016 08:26 PM PDT

Do endothermic organisms have higher entropy or greater entropy production than ectotherms?

Posted: 18 Oct 2016 09:36 PM PDT

I've studied endothermy and ectothermy but I have never seen this topic contextualized in terms of physical entropy, and a preliminary literature search returns no results. I suppose this question is quite interdisciplinary...maybe if I finish What Is Life? Schrödinger will tell me, but I figured I would ask the panel and see if anyone has anything insightful to say.

submitted by /u/ktool
[link] [comments]

Why can't nuclear half life decay be sped up with heat?

Posted: 18 Oct 2016 07:38 PM PDT

If you add energy to a reaction normally it quickens so why doesn't that apply to nuclear decay?

submitted by /u/ProcessingVisuals
[link] [comments]

What notation or nomenclature system gives us chemical formulas that look like Et20 instead of C4H10O or (C2H5)2O (Diethyl Ether) ?

Posted: 18 Oct 2016 09:47 PM PDT

What is the nomenclature system that includes abbreviations? What are they and where/how do you reference it?

In looking through actual chemistry documents and trying to reproduce lab experiments I keep coming across two possibly archaic nomenclature systems. One is just totally random English language abbreviations like THF for tetrahydrofuran (which is fine if the name and its abbreviation are still in use but that is not always the case) and the other is partial formulas that include abbreviations or truncation of names of chemical groups as the example in the title (Et for Ethyl group). The wikipedia page for ethyl group just says "very often abbreviated Et" with no explanation or further reference (i.e. what freaking nomenclature that comes from).

I ask because they seem relatively consistent for coming from different labs (i.e. I've never seen Eth2O or something, so it's not improvised notation) but a lot of this is not used anymore and therefore difficult to reference online.

Incidentally when did everyone suddenly become sane and start using fairly consistent naming usually providing at least 2?

Also here is the title formatted with sub reddit style (I don't normally use it because headlines are white on white in night mode):

What notation or nomenclature system gives us chemical formulas that look like Et20 instead of C4H10O or (C2H5)2O (Diethyl Ether)

submitted by /u/0000010000000101
[link] [comments]

How is a particle's spin measured?

Posted: 18 Oct 2016 05:00 PM PDT

I get how charged particles can be measured magnetically, but what about neutral ones?

submitted by /u/chunkylubber54
[link] [comments]

If I were traveling at the same speed as an electron, would I observe it generating a magnetic field?

Posted: 18 Oct 2016 03:35 PM PDT

In other words, I know that a moving electric charge produces a magnetic field. So assuming there was a lone electron flying through empty space and I could match speeds with it and observe it while travelling parallel to it. Since, from my frame of reference, neither of us are moving, is it generating a magnetic field?

If not? Intuitively I would think someone traveling slightly slower WOULD observe a magnetic field.

I know this is somehow deeply tied to the questions which sparked Special Relativity, I can never find a good answer as to WHY though. It's been bugging me since I first started learning about Maxwell's Equations.

Thanks!

submitted by /u/Hulkhogansgaynephew
[link] [comments]

Why does certain foods stain your skin with its smell?

Posted: 18 Oct 2016 04:44 PM PDT

I've noticed that some foods (such as: garlic, onion, oranges, etc) stain your skin with an either pleasant or disgusting smell even after you washed your hands several times. My first guess would be that it depends on the pH level of each food, but I'm not really sure. Why does this happen?

submitted by /u/Swokut
[link] [comments]

How do we know there's a super massive black hole in the center of the Milky Way?

Posted: 18 Oct 2016 04:16 PM PDT

Do molecules that are polar, but do not contain a metal ion, have some degree of magnetism?

Posted: 18 Oct 2016 05:35 PM PDT

Specifically polar-covalent molecules, wondering if they are affected in some way by a magnet or something of the like.

submitted by /u/jbodie7
[link] [comments]

What's with elements 113-118 on Periodic Table of Elements? Why do some have 3 letters and start with "Unun-"?

Posted: 18 Oct 2016 04:02 PM PDT

What was the geological aftermath when the Twin Towers fell?

Posted: 18 Oct 2016 08:41 AM PDT

(x-post from /r/morbidquestions)

A few days ago there was TIL post that while re-excavating Ground Zero they found a shipwreck from the 1700's, uncovered in part by the damaged ground from the fall.

It occured to me - Manhatten's an island. Partially man-made. The Twin Towers were at the time, the largest buildings on the planet.

So what kind of geologic result occurred from almost two billion pounds of weight slamming into the earth at full speed? That much force had to have set off Richter scales in the surrounding region at the very least.

submitted by /u/axslayer33
[link] [comments]

Which languages can we say are least evolved from their ancestral forms?

Posted: 18 Oct 2016 09:19 AM PDT

I understand that languages evolve over time.

I do not know whether languages all evolve at the same rate over time, or if sometimes languages or dialects will go through bursts of change or periods of long stability.

If sometimes one language will evolve faster than another, can we say that some languages are very much like their ancestral forms and others are very changed? And if so, what languages do we know of are very much unchanged?

Like to make an analogy, a modern coelacanth and a human are both lobe-finned fishes that share a common lobe-finned fish ancestor, but the modern coelacanth looks almost indistinguishable from that ancestor and humans look quite different by comparison.

submitted by /u/CalibanDrive
[link] [comments]

Why can a baby live on milk only, but not an adult?

Posted: 18 Oct 2016 07:42 AM PDT

What do adults need that babies don't? Or would it technically be possible for an adult to live on milk alone?

submitted by /u/hoopsrule44
[link] [comments]

Can an axon glue together with a dendrite without any gap between them? What prevents them from gluing in a normal behaviour?

Posted: 18 Oct 2016 06:19 AM PDT

Yesterday a psychiatrist told me that I might need an electrical brain stimulation because some of my dendrites and axons were glued together and electricity would unglue them. Is that true? How can electricity unglue them?

submitted by /u/zzz0
[link] [comments]

How does conductivity in metallic glasses work?

Posted: 18 Oct 2016 12:14 PM PDT

In crystals we have the Bloch waves which lead to the band structure, which then explains conductivity, but Bloch waves need translational periodicity. We obviously dont have that in metallic glasses.

So how does electric conductivity work? And is there a (well defined) band structure for electrons in metallic glasses?

submitted by /u/lalilu123
[link] [comments]

How to calculate the area of a circle in curved space?

Posted: 18 Oct 2016 09:16 AM PDT

Is there a general form to describe how to calculate the area of a circle in curved space? For example, this link describes the area of a circle covering a hemisphere and gives the formula

Area = (8/π) * Radius2

(where radius is the one inscribed on the sphere rather than the radius of the sphere). We can also assume that for a small radius of circle / radius of sphere the curvature of space is less relevant and the formula will look more like the flat space one:

Area ~ π * Radius2

So the question I ask, is there a general formula to describe the area of of this circle for any radius that exists on a sphere? What would the be steps for getting the formula for non-spherical curved space?

submitted by /u/Mylon
[link] [comments]

What role or roles do archaebacteria play in humans?

Posted: 18 Oct 2016 09:08 AM PDT

I've been given this topic to present on, and I know nothing about it. My presentation thus far is very bland; can one of you smarter people share some "exciting" or at least moderately compelling information about this subject?

submitted by /u/renoscottsdale
[link] [comments]

How does the band structure in solids (metals/ insulators) arise? Are'nt energy levels supposed to be discrete?

Posted: 18 Oct 2016 08:16 AM PDT

Basically I attended a talk yesterday on the recent nobel in physics tailored for someone with no background of physics. The speaker discussed what creates a insulator (large gap between conduction and valence bands). I know that energy levels are supposed to be discrete. Why do they form a band in materials?

submitted by /u/Et_labore_nihil
[link] [comments]

Is noise additive in terms of causing hearing damage?

Posted: 18 Oct 2016 08:29 AM PDT

For example, say I'm listening to my non-isolating headphones in a quiet room with the average level from the phones being 80 decibels (or whatever is considered the max for longer-term safe listening). Now say I take the same phones, music, average playback level, etc. and fly across the US in a shitty economy class seat near the engines. I can still hear my music okay over the rumble of the engines, but they certainly are loud. Am I now damaging my hearing as a result of the combined sounds or does it just not work like that? If not, why?

submitted by /u/oncerydia
[link] [comments]