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Saturday, January 12, 2019

If elements in groups generally share similar properties (ie group 1 elements react violently) and carbon and silicon are in the same group, can silicon form compounds similar to how carbon can form organic compounds?

If elements in groups generally share similar properties (ie group 1 elements react violently) and carbon and silicon are in the same group, can silicon form compounds similar to how carbon can form organic compounds?


If elements in groups generally share similar properties (ie group 1 elements react violently) and carbon and silicon are in the same group, can silicon form compounds similar to how carbon can form organic compounds?

Posted: 12 Jan 2019 12:37 AM PST

What are virtual particles? How are they theoretically real yet undetectable?

Posted: 11 Jan 2019 11:58 PM PST

Why can't we just use regular hydrogen for fusion instead deuterium and tritium?

Posted: 11 Jan 2019 03:41 PM PST

Can the electric field in a dielectric inside a capacitor be opposite of the field of the capacitor?

Posted: 12 Jan 2019 12:05 AM PST

I had trouble understanding dielectrics and so I tried modelling a capacitor with a dielectric inside and plotting the vector field. Doing this resulted in this image - blue is negative, red is positive and the yellow region is the dielectric. Darker arrows mean a stronger field at that point.

Each plane is a line of N point charges, each with charge of Q/N. I start with a Q for the capacitor, and then find the charge of the dielectric's "plates" with Qp = Q * (1 - 1/Er) where Er is the relative permittivity of the dielectric. Then I just plot the dielectric charges and finally calculate the total electric field for each point by adding up the fields from all the charges.

From what I've read, the field inside a dielectric should be weaker (which is the case when I make it cover the whole space between the plates, or lower the permittivity very close to that of vacuum), however I didn't find anything which says it can be in the opposite direction, i.e. the field from polarization being stronger than that of the plates.

I believe my model is correct, but I don't really have anyone else to ask, so I'd be very happy to hear your opinion.

submitted by /u/Madara1233
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How common are transuranics in the universe, and are they evenly distributed?

Posted: 12 Jan 2019 12:59 AM PST

Since elements up to iron produced by fission in a main sequence star, these are understandably very common in the universe. My question is how common are the higher numbered elements which are produced by fusion in a supernova, particularly the transuranics? Would it be reasonable to assume that the abundance of higher numbered elements has a linear relationship to the size of the supernova that produced them? Is there any way of detecting distant concentrations of transuranic elements, given their relative scarcity? Are we in an unusually rich area of space for these elements, the ashes of some massive supernova, or is the distribution of heavy elements reasonably constant throughout the galaxy? I think the answer has important implications for SETI, given that an argument can be made that complex life relies on the presence of transuranics in a variety of ways.

submitted by /u/ScruffyScirocco
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Astronomers. When does a "Dwarf Planet" become a "Planet?". What size and features must it have?

Posted: 11 Jan 2019 05:10 PM PST

If a person with a certain communicable disease dies of it and is buried, do the said pathogens continue to live, multiply and spread in the soil?

Posted: 11 Jan 2019 09:28 AM PST

By extension, like how vaccination improves herd health, shouldn't incineration be a preferred mode of disposal of the dead rather than burial?

submitted by /u/Saalieri
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At different temperatures, things are differently attracted or repelled magnetically?

Posted: 11 Jan 2019 11:38 AM PST

I mean magnets attract or repeal the same way at different temperatures? Like 0°C or 20°c or -270°C or at 2000°C?

submitted by /u/Arthas93
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What does "sp. n." means in a taxon's description?

Posted: 11 Jan 2019 09:32 AM PST

I am trying to create Wikipedia articles on some recently discovered animals. One has the name & authority written like " Neobuthus eritreaensis Lowe & Kovařík, 2016 " while the other one has it as "Neobuthus factorio sp. n. " what does that abbreviation mean? I think it means the species is being described in that same paper, so i should write it's authority like Lowe & Kovařík, 2018 but i would like confirmation from someone who understands taxonomy better than me.

submitted by /u/YuriNikolai
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In the concept of hybridization of atomic orbitals ,why is the dipole moment of a lone pair away from the nucleus?

Posted: 11 Jan 2019 05:49 PM PST

In NH3 the bond pair of electrons between hydrogen and nitrogen has a dipole moment towards nitrogen but the dipole moment of lone pair of nitrogen atom is away from it. I want to know why this happens ,as the electron is attracted towards the nucleus shouldn't the dipole moment of lone pair be towards the nucleus as the nucleus attracts the electrons.

submitted by /u/NAYAN_SEES
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What is the theory behind the general trend of the seebeck coefficient vs temperature curve for thermoelectric materials?

Posted: 11 Jan 2019 08:52 PM PST

For degenerate semiconductors, I have noticed that the general trend of seebeck coefficient (S) vs temperature curve are similar. It increases from room temperature to a particular temperature at which S saturates, and then it reduces on further increase of temperature. Can anyone help me to understand the theory behind this? I have gone through various published articles on thermoelectric materials, but I could not find any that explained it in layman's term.

submitted by /u/iaminredditforyou
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When you donate blood or let's say an organ to someone, what happens to your DNA in those cells?

Posted: 11 Jan 2019 02:21 AM PST

Why do copper IUDs increase intensity or womens' periods?

Posted: 11 Jan 2019 09:24 AM PST

What planets have we developed surface maps of?

Posted: 11 Jan 2019 07:34 AM PST

Stellar nucleosynthesis and transuranic elements (in theory)?

Posted: 11 Jan 2019 06:49 PM PST

Hi - this is chemistry, physics, cosmology

So this question is purely theoretical. When I ask if something is possible, I mean in the absolute sense, mathematically, in theory, not actually known or observed.

I've heard that under certain conditions, neutron stars (or even denser objects, if there are any) could produce all the elements. Even transuranic ones, ie element 118 and so on.

If this premise is true, does that mean that elements within the island of stability could also be produced?

The third tier is that if there are some super-stable transuranic elements, we might one day find them in the cosmos, even if it's just atoms of it.

Or am I all wrong? Thanks

submitted by /u/NullOfficer
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If the brain itself has no nerve endings, how do you feel a headache?

Posted: 11 Jan 2019 05:16 AM PST

Do insects get an Adrenalin rush or similar when we try to swat them?

Posted: 11 Jan 2019 02:18 AM PST

Why are complex logarithms NOT multi-valued for real integers?

Posted: 11 Jan 2019 09:08 AM PST

In my lecture notes, there is a derivation for complex logarithms, which is:

ln(z) = ln( reiθ+2niπ ) = ln(r) + i(θ+2πn) , for integer values of n

I understand how this suggests that there are an infinite number of solutions to w = ln(z) (due to the periodic nature of complex numbers on an Argand plane), where z is a complex number.

There is a portion which describes the case of z1z2, where z1 and z2 are both complex numbers. However, the next line then explains that z1z2 will be multivalued, EXCEPT in the case where z2 is a REAL INTEGER.

The derivation (for a real number, k, and general complex number, z) is as follows:

zk = ek ln z = ek ln r + ikθ+2nkiπ = rkeikθ

My question is, how can we just suddenly ignore the periodicity (ie the "+2niπ" portion of the equation), if we know the exponent is a real integer? Is there something distinct about real integers that separate it from other complex numbers? Would real numbers not display the same periodicity on an Argand plane as any other complex number?

submitted by /u/ThatCosmicGuy
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What exactly is soil leeching ?

Posted: 11 Jan 2019 06:55 AM PST

So I've lived in the Amazon region of Ecuador for the last 11 years, and I know that the soil is nutrient poor because of soil leeching , however, I've never really learned what this means. I know it has to do with heavy rainfall washing the nutrients out of the soil, but I don't really get what that means, conceptually. Can anyone help with a more thorough explanation of soil leeching? TIA

submitted by /u/misterjay26
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If energy output from the Sun is constant, why isn't every successive year a new "warmest year on record" due to climate change?

Posted: 11 Jan 2019 04:54 AM PST

I often wonder why this is so, if the numbers are based on global temperature average.

submitted by /u/mistuhphipps
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Friday, January 11, 2019

Why is nuclear fusion 'stronger' than fission even though the energy released is lower?

Why is nuclear fusion 'stronger' than fission even though the energy released is lower?


Why is nuclear fusion 'stronger' than fission even though the energy released is lower?

Posted: 11 Jan 2019 04:30 AM PST

So today I learned that splitting an uranium nucleus releases about 235MeV of energy, while the fusion of two hydrogen isotopes releases around 30MeV. I was quite sure that it would be the other way around knowing that hydrogen bombs for example are much stronger than uranium ones. Also scientists think if they can keep up a fusion power plant it would be (I thought) more effective than a fission plant. Can someone help me out?

submitted by /u/looonie
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How can Antiprotons annihilate with Neutrons?

Posted: 11 Jan 2019 01:52 AM PST

I thought annihilation requires a particle and its specific anti-particle but I read in a book about antimatter that antiprotons annihilate with neutrons. How so?

submitted by /u/IgnorantAndApathetic
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How are astronomers able to determine the spin of a black hole?

Posted: 10 Jan 2019 06:32 PM PST

I saw a post about a black hole 300 million l/y away spinning at 50% the speed of light, but how are they able to determine that? As far as I know we are barely able to see Sagittarius A*.

submitted by /u/RickyThePigeon
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Do all elements have isotopes and how many can there be?

Posted: 11 Jan 2019 12:45 AM PST

Correct me if I am wrong, this is my understanding—an isotope is elementally the same except it has a different number of neutrons. So for instance, there is the carbon-12 atom which has 6 protons neutrons and electrons, now how many isotopes of this element can there be? When I search for carbon isotopes I only seem to find carbon-12 to carbon-14, so why is that? can there be a carbon-100? and do other elements have isotopes like this as well? do gases have isotopes? is there a helium-10 or something?

submitted by /u/PositiveWolverine
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How do charge and mass come from quarks and friends ?

Posted: 11 Jan 2019 08:37 AM PST

How can we deduce the (electromagnetic) charge and mass of protons/neutrons/electrons from the properties of quarks/muons/leptons ?

And where does the constants of forces come from ? (Like the gravity G) Are they purely experimental or can be computed from more basic concepts ?

submitted by /u/mederor
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Can you concentrate sound into a ‘laser’?

Posted: 10 Jan 2019 11:50 AM PST

How does electronegativity affect the distribution of electrons in a molecule?

Posted: 10 Jan 2019 05:51 PM PST

What are the curves in the bifurcation diagram of the logistic map?

Posted: 10 Jan 2019 07:05 PM PST

In the bifurcation diagram for the logistic map, it appears that there are some long curves of high density in the chaotic region. What are these curves and how do they arise?

submitted by /u/theabc123man
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Why does getting a vaccine leave the point of injection so sore? Why do some vaccines hurt more than others?

Posted: 10 Jan 2019 09:22 AM PST

What can the James Webb telescope see that hubble can't?

Posted: 10 Jan 2019 09:00 AM PST

What determine the melting and boiling point of a material?

Posted: 10 Jan 2019 04:56 PM PST

Why tungsten is heat resistant, and why is helium melting's point so low?

submitted by /u/Vindreddit
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What's the reason behind unpronounced letters?

Posted: 10 Jan 2019 09:12 AM PST

Started to wonder when thinking about the word 'beaucoup' (french for 'much'). There's languages where words are very long for how much is actually being pronounced. Is it just speakers being too "lazy" over a long time? But why hasn't the written word followed along?

submitted by /u/narcoticcoma
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Is it possible to achieve a gun-type nuclear fission reaction on a small scale?

Posted: 10 Jan 2019 04:24 PM PST

Hi all, I've been curious about nuclear physics for awhile, and was wondering if theoretically the conditions necessary to generate a supercritical mass for fission could be achieved on a very small scale through particle collision (i.e. inside a particle accelerator).

Essentially, would it be possible to shoot particles of U-235 and Pu-239 at each other inside a high-speed particle accelerator/cyclotron and produce nuclear fission akin to larger gun-type atom bombs, like Little Boy? Or is there a certain mass threshold or other characteristics that would prevent this from happening? I know the required ratio of Uranium to Plutonium for such a reaction is abnormally high, but is it even possible?

(P.S. I swear I'm not a terrorist)

submitted by /u/ARandomHelljumper
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Do people born without a limb still feel phantom pain?

Posted: 10 Jan 2019 08:56 AM PST

Are there organisms better suited to recycling carbon dioxide into oxygen in a post-apocalyptic/off-planet scenario for human consumption than trees and if so what magnitude of efficiency do they provide?

Posted: 10 Jan 2019 09:03 AM PST

I've been considering the implications of a post-oxygen humanity and I'm wondering if the best way to generate oxygen for an individual human (or society of humans) is to utilise trees, or if there are more viable sources of oxygen from natural sources in a world without oxygen or with drastically reduced available oxygen. Is there any current research to support the use of non-arboreal organisms and are there any drawbacks, specifically considering that over-oxygenation can lead to hyperventilation?

submitted by /u/Omegate
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What are deja-vu’s exactly and can they be scientifically explained?

Posted: 10 Jan 2019 06:16 AM PST

How is the Power of Microwaves determined?

Posted: 10 Jan 2019 06:08 PM PST

I understand how 'frequency' of waves increases it's strength. Microwaves have frequency of around 2.5 Ghz. So, how does the microwave oven power (in watts)? What's the difference between ta 700 watt oven and a 1000 watt oven, if they both emit 2.5 Ghz microwave?

submitted by /u/osmium192
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What's the name of the cloud formation occurring on top of a volcanic pillar?

Posted: 10 Jan 2019 10:46 AM PST

Thursday, January 10, 2019

Why are there many different types of fuel (87, 93, diesel) and why can certain machines take only one type?

Why are there many different types of fuel (87, 93, diesel) and why can certain machines take only one type?


Why are there many different types of fuel (87, 93, diesel) and why can certain machines take only one type?

Posted: 10 Jan 2019 02:34 AM PST

How do we designate stellar areas?

Posted: 10 Jan 2019 04:21 AM PST

Just some curiosity about the correct terms.

If you're speaking about a planet it's: Earth in the Sol system.

How do we differentiate locations on moons of planets?

Is it "Moon base 6 on Luna near Earth?"

Or "Moon base 6 in the Earth neighborhood?"

submitted by /u/JDMoontreader
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Why inbreeding animals causes so much harm to offspring, but it is not the case in case of plants?

Posted: 10 Jan 2019 08:38 AM PST

I am curious what are the reasons that inbreeding animals leads to the higher probability of many genetics disorders, but it seems not to affect well-being of plants? Or am I wrong here and inbreeding plants also damages DNA of next generations, but maybe less, than these of animals? Also as far as I know number of chromosomes in plants can vary with no or little effect on them. Why is it like that? Would that be on of the reasons why inbreeding is not dangerous to plants?

submitted by /u/Swiatek7
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Since dolphins are mammals, is it possible to milk them?

Posted: 10 Jan 2019 06:00 AM PST

Electrical Muscle Stimulation (EMS) prevents muscle atrophy by causing muscles to contract. Why aren't we using this in hospitals and homes if immobility is such a problem for the older generation, disabled, or bedridden?

Posted: 10 Jan 2019 07:42 AM PST

How can a GPS receiver manage to pick up on a signal that's 10 orders of magnitude weaker than background noise?

Posted: 09 Jan 2019 08:51 PM PST

How does viewing an image or flash trigger a seizure?

Posted: 10 Jan 2019 08:37 AM PST

How do headphones change volume, whether plugged in or with Bluetooth? If the electrical energy is changed into sound, does the amplitude and strength of the electricity determine the volume?

Posted: 10 Jan 2019 07:48 AM PST

How soon into a chess game could a computer calculate that you’re destined to lose?

Posted: 09 Jan 2019 06:23 PM PST

Tobacco plants have been genetically altered and are now 40% more productive. How can such an old evolutionary process as photosynthesis be inefficient?

Posted: 10 Jan 2019 02:27 AM PST

If I understand this paper* correctly, it is said that photosynthesis in C3 plants is really inefficient. Specifically the photorespiration part where carbon is transformed in CO2 again. Scientists see this as a waste of energy, and it has now been improved by constructing "a metabolic pathway in transgenic tobacco plants that more efficiently recaptures the unproductive by-products of photosynthesis with less energy lost [...]. In field trials, these transgenic tobacco plants were ∼40% more productive than wild-type tobacco plants."

How can we be so sure photorespiration is an inefficient process? Isn't it more logical that we don't fully grasp the complexity of the process yet? I mean it had billions year to evolve, it must have a benefit to do it this way right?

(This is not my field of expertise, so if I'm saying things wrong, please correct / teach me.)

*http://science.sciencemag.org/content/363/6422/eaat9077

submitted by /u/Quadricarus
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What if two oppositely spinning black hole ergospheres came into contact?

Posted: 09 Jan 2019 08:36 PM PST

Is there a precise cut-off point for the edge of the ergospheres, and would it destroy whatever was directly between them at point of contact?

And what if the rotating black holes moved closer together so the ergospheres overlapped, leaving a venn diagram shape ? Assuming the rotational speed and mass are the same, would the ergospheres cancel out and create a normal region of space-time?

submitted by /u/Mordred19
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When the Earth's equilibrium temperature increases, do the amounts of radiation absorbed and emitted by the Earth also change?

Posted: 10 Jan 2019 07:08 AM PST

I'm pretty terrible at science, but am trying to learn a little bit about climate change. Something that I've been struggling to understand is the concept of equilibrium temperature.

I know that the Earth's equilibrium temperature is the temperature at which the Earth is absorbing and emitting the same amounts of radiation. And I know that the equilibrium temperature increases, as the amount of greenhouse gases in the atmosphere increases.

What I'm curious about is this - do the amounts of radiation absorbed and emitted by the Earth also increase, when the equilibrium temperature increases? Or do both of those values remain constant?

It seems to me like the amount of radiation absorbed by the Earth would increase, because the increased amounts of greenhouse gases in the atmosphere means that more IR is being absorbed. But I'd like to have someone confirm whether or not this is accurate.

Thanks!

submitted by /u/JFox93
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Is it possible to get two different colds at the same time?

Posted: 09 Jan 2019 11:32 AM PST

How and why are teeth used to identify murder victims?

Posted: 10 Jan 2019 06:46 AM PST

You hear from the media that sometimes the murderer(s) cuts/burns the fingers of the victim and remove their teeth to make them unidentifiable.

I understand that fingerprints (and also teeth) are unique and that the government has a database of fingerprints (I remember in primary school the policemen came to take our fingerprints but teeth...?

How does the government identify you through your teeth? Does the government have some sort of database? How do they get your teeth 'data'?

submitted by /u/onionlolz
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What are "non-reliable" vegan sources of B12?

Posted: 10 Jan 2019 06:25 AM PST

Most articles on B12 suggests that the only reliable vegan sources of B12 are foods fortified with B12. E.g https://www.vegansociety.com/resources/nutrition-and-health/nutrients/vitamin-b12/what-every-vegan-should-know-about-vitamin-b12

This implies there may be unreliable sources. As B12 is only produced in nature by certain bacteria, and archaea, surely some fermented foods will contain B12?

Why is this unreliable?

submitted by /u/yeast_problem
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How do they calculate the 1.5B ly distance from the source of the recent fast radio bursts (FRB) received from space?

Posted: 10 Jan 2019 02:21 AM PST

What is the significance of an 7 nm node and what happens when we can’t go any smaller?

Posted: 09 Jan 2019 02:36 PM PST

I read that AMD announced a 7nm GPU. What does "7nm architecture" mean and why that over a larger number? Also, what happens when we can't go any smaller? I heard at one time people thought anything smaller than 10 was impossible.

submitted by /u/RiceKrispyPooHead
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How can this visual illusion be explained biologically? What is happening to the eyes?

Posted: 10 Jan 2019 02:08 AM PST

The illusion.

Does this have to do with the brain filling in the colors while still focused on the dot? And why does the illusion cease to work once you look away from the dot? Does this have anything to do with the thresholds of the rods and cones in the eye?

Thanks in advance!

submitted by /u/DerpyBush
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How is sound, decibels, loudness, and intensity related?

Posted: 10 Jan 2019 05:33 AM PST

Sorry for the somewhat misleading title, but here's the jive. I'm a natural resource manager, not an acoustics expert and need help in writing a rebuttal to the following comment, which has been slightly edited:

Vehicle A produces 68 decibels and Vehicle B produces 78 decibels.

The decibel scale is logarithmic, therefore sound from Vehicle B at 78 decibels is 10 times louder than Vehicle A emitting 68 decibels.

Sound emissions from more than one source have an additive effect. Therefore, if there are 4 Vehicle Bs emitting 78 decibels the total sound impact on the listener is 84 decibels (6 more decibels than a single Vehicle B). 10 Vehicle Bs in a group will create 10 more decibels than a single Vehicle B.

10 Vehicle Bs, each emitting 78 decibels, will produce a combined sound impact of 88 decibels, or 100 times that produced by a car emitting 68 decibels.

Research on the mitigation of road noise indicates that a distance of 1000 feet is needed to reduce road noise by 10 decibels (further arguments will use this distance as a standard to reduce road noise for simplicities sake although it is a much more complicated matter).

The 1000-foot mitigation zone reduces the sound of one Vehicle B emitting 78 decibels to that of one Vehicle A emitting 68 decibels.


Here's what I essentially need help answering and gaining a basic understanding of:

1) Is 78 decibels 10 times louder than 68 decibels?

2) I know that sounds can have an additive effect, but only when all sound sources have the identical sound/similar frequencies. So, I'll assume that all Vehicle As emit the same frequency and that all Vehicle Bs emit the same frequency and that the two are distinctly different from one another. However, do 10 Vehicle Bs in a group produce 10 more decibels (88 decibels) than a single Vehicle B (78 decibels)?

3) Is 88 decibels 100 times louder than 68 decibels?

4) Assuming the 1000 foot mitigation zone is correct, if a person was standing 1000 feet away would the sound from Vehicle B be reduced to the sound of Vehicle A if you were standing next to it?

A scientific and basic response to each question would be appreciated. Thanks for all the help because this is way outside of my realm!

submitted by /u/ClassyCanids
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Is there a particular reason that we use virtualisation in computers and servers?

Posted: 09 Jan 2019 08:22 PM PST

I know that there are benefits to security using virtualisation in such that the computers can`t infect each others and that it is easy maintenance.

But isn`t the fact that running computers inside a computer (multiple OS`s inside an OS) a big bottleneck when it comes to performance?

submitted by /u/vimsee
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What happens to an interferometer moving relativistically fast?

Posted: 09 Jan 2019 09:41 PM PST

Say you have a Michelson interferometer with one leg in line with the motion of a spaceship and the other leg perpendicular to it. As the leg in line with direction of travel Lorentz transforms, would the fringes look different?

submitted by /u/OrganicBenzene
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What are the chances animal larger than blue whales ever existed ?

Posted: 09 Jan 2019 09:43 AM PST

The blue whale is the largest animal to have ever lived, as far as we know. But how likely is it that there were some larger animals in the past we know nothing about ?

Considering how large some kinds of animals could get during some geologic periods (like amphibians during the Carboniferous, then dinosaurs during the Mesozoic, etc), do scientists assume that there was a period when it's likely that creatures larger than those of our time lived in the ocean ? Is there a limit as to how large an animal can get ?

submitted by /u/orcstew
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