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https://sites.google.com/site/scienceandmathguide/
>>
If you want advice with college/university, go to /adv/.

>>>/adv/

Reminder: /sci/ is for discussing topics pertaining to science and mathematics, not for helping you with your homework. See the rules page for details.

BREAKING NEWS: NASA is sending HUMANS to Mars!!!!
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>>6930117

Top tier banter
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>>6918259
>meme-arrowing the entire comment
nigga what the fuck
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>>6919815
>>
If anyone is interested i'm working on a chemical/ drug cocktail to reduce the damage cause by radiation in space. AMA i spose.
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>>6921698
not surprisingly, there is already more than one anime with this idea

cute astronauts doing cute things!

/sci/, tell me your controversial opinion that mainstream science can't handle.
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>>6930436
Space Time is a misnomer. Time can be expressed as a number of cycles completed and is therefore an observation of a mechanical process. The number of cycles that mechanical process completes relative to another process can be decreased by increasing distance (through speed) or by increasing resistance (through gravity). And therefore Time does not exist, it is simply a measurement of number of cycles completed.
Any theory that states the "backward time travel" is possible has proven itself incorrect.
The only way to achieve backward time travel would be to reverse the cycles of all the processes in the universe concurrently, which is impossible. The universe only exists now, it does not exist in the past. A new universe is not created when you make a decision. There are no alternate timelines.
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>>6930436
Photons and electrons travel in predictable probabilistic causal wave forms. Until you measure the location of a photon or electron you must TREAT it as if it is in all the places in the probability wave at the same time, but as soon as you observe it the "probability collapses" and you observe the reality that there have always been only one photon or electron and it has always been in only one location at any time.
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>>6931177
You're saying there were no cavemen with the natural intelligence of an Einstein? We evolved Einsteinian like intelligence practically overnight?
>>
niggers
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>>6931268
We aren't really genetically different, at least in the sense of intelligence, from even the first humans that walked the Earth. The only difference is the access of knowledge we have. We still have all of the same cognitive areas and functions, but now we have a wealth of accumulated knowledge that can be learned over a time with the same tools that gave us an edge over our other, less evolved kin.

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Hey every one, i got banned from /sci/ for posting this:

Why are blacks inferior to whites?

Even if the cultural differences are important, the phenotype effect it will have, feral vs domestic homo sapiens, is significant enough to effect multiple generations. I cite the russian fox study on this one, it takes three or four generations to turn a feral species into a domestic one due to the slow change of the phenotype orientation.

On top of that black people, when compared to white people display primate feral traits much more clearly.

Suck my dick citation: http://www.auburn.edu/academic/classes/biol/5090/boyd/Captivity_effects.pdf
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>>6931270
Or better yet, /pol/
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>>6931246
>it takes three or four generations to turn a feral species into a domestic one due to the slow change of the phenotype orientation.

>due to the slow change of the phenotype orientation.

These foxes were selected by how docile they were. This has nothing to do with culture.
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>>6931275
Kek good one. He sounds like he just read an article supporting his bigotry with so scientific terms and though "Hey this should convince sci that I know science"

>>6931246
Yo OP go stick a Phenotype up your ass
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>>6931246
refugee from /pol/ detected
you fucked up your own board, don't fuck up this one as well
>>
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Considering most of the people who spout shit on 4chan, I doubt you're superior to anyone, regardless of race, OP.

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4chan, can you help me?
I must know why ℵ0 multiplied by itself gives itself

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New stupid questions thread because old one is at page 8.

Only sensible questions please.
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>>6931287
One more thing though - how can sound be transmitted through waves?
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>>6931294
what waves do you mean, sound or electromagnetic waves?
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>>6931298
electromagnetic
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>>6931137
Hahaahaha all this trouble for a such a trivial mistake i know you understand. As some1 pointed out it is not true that n/m=n/(n+m) i mean why would this be true haha?
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>>6931282
if you want to calculate the eigenvalues you sort of have a system of linear equations, dont you?
i mean if i have the equations Ax=0 with x!=0 and det A!=0 its solveable.
if i have (A-Ex)v=0 with v!=0 then i have to calculate det(A-Ex)=0, which doesnt make a whole lot of sense to me right now. i did a linear algebra class a few years ago, but i kind of forgot the reasoning behind the whole process

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Things that will always be impossible, regardless of any advancements the human race makes.

I'll start:

-reversing entropy
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touch the sun
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>>6930269
>offsets trilby
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>>6930847
it's turtles all the way down
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>>6930257
photon drives are reactionless in that they don't use reaction mass.
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>>6930866
that's easy,no reason at all

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There is a disgusting lack of Chemistry on this board. Why is that?

Chemists of /sci/, what are you studying/working on/etc.?
What is your favourite sub-field?
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This is pretty humiliating, bit I got my first orgo text when I was a middle school fgt and I pronounced it "carbokayshun" all the way until tenth fucking grade because I didn't know any better
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>>6927898

Lel, I remember pronouncing "cayshun" and "anyun".

Then again there are grads in my lab now who pronounce an equal mixtures of both enantiomers as a race-mate.
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>>6915404
Because chemists are so stupidly specific in their knowledge base that any thread that isn't on ENTRY level chemistry will not be understood 50% of people in the thread. To make it worse most of the entry level chemistry is BS taught to teenagers to give them a general idea.

So we have a topic we can't really talk about effectively.

Currently on a teaching course to be become a chemistry teacher here.
>>
Has anyone had a chemistry interview at Oxford? If so what was it like?
>>
Is Chemical Engineering/Chemistry a good double-major? Is it better to just do chemistry as a minor?

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Could one make a balloon or, getting bigger, blimp or zepplin made out of a block of aerogel wrapped up in an airtight layer and then vacuumed out till the overall density of the balloon was less than the density of air?

Buoyancy can then be adjusted by using air as ballast.
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/pol/ here.

I was wondering why I'm seeing a thread about science instead of warning me another attack by Der Juden.

So.....

You guys talk about science and math on a Saturday night?

How's that workin' out for ya?

Just going to leave this pic here to remind you who controls the media in America.
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>>6930328
That'd probably work just fine then.
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>>6930331
Is it invisible or just covered in fnords?
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>>6930340

Ok, so that was my pic about feminism...I know I promised you a pic on who controls the media in America.

I'm just going to stop now....

But in case you guys were wondering, the answer to the question:

"Who controls the media in America"

is

"The jews"

I hope this has been enlightening for you.
>>
>>6930333
why hasn't it been done? Seems like it would have if possible... because it would be so cool! Floating brick.

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What if a study was done and showed that there serious biological reasons for "hate crimes" (i.e. white men have increased adrenaline and other stress markers when in the presence of black men pheromones, etc.). Imagine the implications of that. I'm no scientist, but this seems like a fairly easy study to set up, assuming you could find willing participants.

There was a study done with pheromones before. Can't find it, so I'll paraphrase it:

>several men and women go running on a treadmill and sweat a lot into a shirt
>men and women each smell shirts of the opposite sex and rate the smell
>afterwards, the men and women are broken up into pairs to do activities
>those that cooperated and scored the best on these team activities were those who had rated each others sweat highly

Imagine this, but with African and Caucasian participants. The control group smells a shirt with no sweat on it. Then, random participants smell the shirt for a good 15-30 minutes, and bloodwork (or however else adrenaline is measured) is done.

I don't have a science degree, so this is up to one of you /sci/. Can you do this?
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>>6931208
I don't think anyone disagrees that the government is doing a shitty problem of handling the Black populations chronic crime spree, but before anyone can actually fix said problem it needs to be acknowledged that there IS a problem and it can't be fixed by just tossing money at ghetto's to get them to vote democrat.
>>
>>6931216
>>6931208
>>6931189
>>6931182
>>6931176
OP here, this is a bit off topic. If blacks and whites had raised anxiety/fear just from the body odor/pheromones they give off to each other, then having them taught that in school could help PREVENT hate crime. It could also help defend innocent people like Darren Wilson, if he was indicted and taken to trial.
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>>6931182
>cultural marxism

Stop fucking posting that you retard. "Cultural Marxism" is a conspiracy theory and has absolutely fucking nothing to do with Marxism.

Postmodernists should all be shot for fucking up the class war with irrelevant identity politics.
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>>6929977
What if such studies had already been done?

http://en.wikipedia.org/wiki/Monoamine_oxidase_A#Aggression_and_the_.22Warrior_gene.22
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>>6931220

Well the issue I have with the body odor/ pheromones theory is that centuries of admixture and close proximity should have lessen the effects if such effects actually do exist.

Though I would agree a class or two on self-control and logical reasoning in school could help avert hate-crime and crime in general.

>>6931216

The thing is I kinda think the issue itself is that there is in fact some form of acknowledgment to a problem but it's being constantly misdiagnosed and ill-treated by people who don't know any better.

Communities tired of constant crime demand more police, police presence increase and crime tempers down only to rise back up even more. Said communities get mad at the police for not doing enough but fail to realize the police aren't doctors and their job isn't to fix a problem but to only contain it.

Politicians on the other hand as you mentioned earlier believe that almost anything can be fixed by throwing money at the problem. Only to see that said money and resources are having minimal resolution to the problem. And since politicians aren't scientist they don't have the knack to research the mechanics involved in lowering crime rates.

what's /sci/ opinion on black science guy?
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He's a fucking genius. He created TWO memes.
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>>6929972
a great sagan successor
he inspires countless redditards to pursue careers in science and thats a good thing because they're less autistic than a typical anon browsing /sci/
>>
>>6929995
>>6930206
>>6930216
Gentlemen, do you desire to be nominated for a Nobel prize or is the contribution that you have made to the world enough reward for you?

>>6930216
:^)

>>6930218
>making up quotes.
what

>>6930283
It could be both, you know...
>>
>>6929972
Isn't promoting someone because of their race kinda racist.?
>>
>>6931289
Not if he's black.

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Is this a Iridium flare? Taken in Norway in the North-West direction
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a plane?
>>
date it was taken?
>>
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>>6930987
14. october
>>
iridium flare?!?!
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>>6931255
there is a constellation of low-earth orbit satellites called "Iridium" used for satellite phones. They have both flat solar panels and flat phased-array antennas which can catch the sun and "flare" when they are in the right orientation. It is observed often enough for the phenomenon to be given its own name.

(One thing I just learned, they called it Iridium because there were supposed to be 77 in orbit at a time, and that is the atomic number of Iridium!)

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Norman Wildberger's Youtube channel would be quite cool if he wasn't such a nutjob.

Are there any similar channels like Wildberger's on Youtube, i.e. where a prof talks about maths, without the "muh finitism"? And I don't mean just lectures.
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>>6931184
Nah, that's boring mang. I want some maths.
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>>6931234
>It is logically equally as sound believing the continuum hypothesis as rejecting it!
I kinda agree with that but what about empirical evidence? We are doing science right? How many examples of finite sets do we have and how many do we have of infinite sets?

I am not talking about the existence of the concept, life just writing inf and assuming its inf, I mean an actual representation of all its elements.

>>6931234
>Also, the continuum hypothesis has nothing to do with the existence of the reals

In mathematics, the continuum hypothesis is a hypothesis about the possible sizes of infinite sets. It states:
There is no set whose cardinality is strictly between that of the integers and the real numbers.

It actually has a lot to do with it.

>>6931234
>>What is an axiom
You may also Include the axiom of flying cows if you want to be "that" free with implementing axioms.
>>
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>>6931184
>2014
>Nietzsche
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>>6931247
>I kinda agree with that but what about empirical evidence? We are doing science right? How many examples of finite sets do we have and how many do we have of infinite sets?
I think you're confusing science with math, kid.

>It actually has a lot to do with it.
Only if you care about constructing the reals, which is not necessary to use them logically.

>You may also Include the axiom of flying cows if you want to be "that" free with implementing axioms.
I doubt that would have any use.
>>
Norman has uploaded a new Video!!!

https://www.youtube.com/watch?v=VUdFdlQNfpg&list=UUXl0Zbk8_rvjyLwAR-Xh9pQ

I have a question regarding stereographic projections and how to use them with ray tracing. More details are in the thread.
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>>6930553
And here is the same scene rendered with traditional perspective projection. Notice how the field of view in both images is the same, yet the perspective render distorts the scene terribly, especially near the edges. Since stereographic projection preserves angles, none of this distortion will ever occur.
>>
Here's a (desktop) GLSL shader which renders a raytraced sphere:

pastebin.com/5cFSWb24

The texture coordinates are +/-1 at the corners of the (square) window, so they're effectively just normalised window coordinates. The "matrix" variable is the composition of the camera's inverse transformation and the object's transformation (using an identity matrix as the object transformation results in a unit sphere centred on the origin).

Within the shader, q0 and q1 are the homogeneous coordinates of the pixel's projection onto the near and far planes respectively. p0 and p1 are the corresponding Euclidean coordinates. a,b,c are the coefficients of the quadratic equation in t, the interpolant between p0 (t=0) and p1 (t=1). p is the 3D point where the ray intersects the unit sphere. phi and lam are latitude and longitude respectively.
>>
tl;dr but when you're choosing a perspective keep in mind the user's distance from the monitor. You will want to render the scene onto the screen in such a way that it will appear to be a window into the area, and if they move their head the image will appear to be flat on the screen, destroying the illusion.
Look at how the image warps so badly towards the edge of the image in the perspective render, that's because the user is supposed to be seated right up to the screen, and the elongation of the image at the edge of their view would appear less elongated (put ur face up to ur screen and look out ur peripheral vision to the sides and see how the screen appears less-long, it's the same with holding a pen with one end up to your eye, the other end of the pen will appear one cm away, when the pen itself is 10cm long).
The other stereographic render looks more "correct" because it's drawing the image 'flat' onto the screen and will appear "correct" from all angles, but will never give the "window" illusion.
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>>6930680
Forgot to mention, the camera's position is the virtual representation of the user's relation to the monitor. Or at least this is how you should think about it.
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>>6930686
Very nice! Glad you got it working. Thanks for posting the pics.

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Will Skylon make space travel affordable to average people?
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>>6928861

>A couple of launches with a massive payload is preferable than 10 or 20.

Watch Falcon Heavy outfly SLS.

>The ISS construction is something no one wants to go through again.

Strawman argument. No one is reconstucting ISS, and ISS is atypical to an exploration missions construct, and ISS was a unique clusterfuck built around astronaut make work ideology, and Falcon Heavy isn't the space shuttle at 1b a pop.

>but for massive development of space infrastructure and fast trips to the moon and Mars we will need huge rockets.

Try a handful of lunar orbit missions because the sheer expense of SLS/Orion has choked off anything more ambitious.
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>>6929602
No, you don't have to consider "they actually have to make a profit" unless you're estimating prices based on costs. They're giving cost estimates.

However, you do have to consider that the cost estimate is given in GBP, not USD, that humans need a vehicle to ride in (and no, Skylon is not a manned spacecraft, it's a launch vehicle), and a $/kg figure is generally a simplistic best-case example, to make different launch systems more comparable, not the actual price you'd pay if you wanted to launch a single kg of cargo into space.

Falcon 9 1.1 is supposed to be capable of launching over 13 tons to orbit, but the Dragon V2 spacecraft will have a maximum capacity of 7 passengers. Furthermore, the spacecraft costs about as much as the launch vehicle.

Now, Dragon V2 is a fully independent spacecraft. It has an abort system, maneuvering thrusters, a heat shield, landing systems, solar collectors, etc. It may also be lighter than Falcon 9 1.1's capacity. A Skylon passenger unit might simply be bolted in, so it could be lighter.

Allowing at least half a ton per passenger and then doubling the launch price seems like a reasonable minimum price estimate, and once converted to American money, the Skylon $/kg figure is about $1000/kg. So we're still looking at a million dollar ticket price for a ride to space, assuming all seats are filled. This for a ride in a can with no windows to look out of (SSTOs are extremely mass-sensitive, so it would take a major redesign to add windows to Skylon).
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>>6929514
>Not when the massive payload launcher ends up costing $10 billion and you can only launch it once every few years

This is a matter of political will.

In the context of mass infrastructure development, assuming we get to that point, you would be launching more than once every few years.

With 4 or 5 launches per year the cost would go down to under $500 million each, if not lower.

>Saturn V is pretty close to the upper limit of a superheavy launcher in size.

>Even that is grossly inadequate for single-launch manned missions into deep space beyond useless stunts.

The theoretical BFR with methalox Raptor engines can put 200 mt into orbit. Over 80mt more than the Saturn V. That's not near the limit.

And sending people to the moon and mars are not useless stunts.
>To do anything interesting, you're going to need multiple launches, whether that's assembling a monster mission in LEO to depart together, or throwing a flotilla of payloads to rendezvous at their destination (such as all landing together on the Moon or Mars).

>There's still an advantage for large payloads, but if it's a choice between large payloads and flights so scarce that missions have to be single-launch vs. small payloads and frequent flights adding up to orders of magnitude more total tonnage, the latter is clearly preferable.


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>>6929705
>Watch Falcon Heavy outfly SLS.

Falcon Heavy is not meant for deep space. Not my words, Elon Musks himself.

It has no advanced upper stage and can only get a few metric tons to Mars.

>Strawman argument. No one is reconstucting ISS, and ISS is atypical to an exploration missions construct, and ISS was a unique clusterfuck built around astronaut make work ideology, and Falcon Heavy isn't the space shuttle at 1b a pop.

There is nothing strawman about it. We have multiple examples of space stations being put into orbit by different nations that we can compare to the ISS.

>Try a handful of lunar orbit missions because the sheer expense of SLS/Orion has choked off anything more ambitious.


Lack of funding has choked off missions. Deep space exploration is expensive no matter who does it.
>>
>>6931185
>This is a matter of political will.
>In the context of mass infrastructure development, assuming we get to that point, you would be launching more than once every few years.
It's not a matter of will, it's a matter of competence. There's a political will to spend $40 billion on SLS and Orion to do a few lame demo flights. NASA just asks for more money instead of doing better.

>With 4 or 5 launches per year the cost would go down to under $500 million each, if not lower.
Absolute nonsense. SLS is not a remotely economical design. They wouldn't even be able to get the marginal cost of launch that low. Delta IV Heavy costs nearly $500 million. The same contractors aren't going to be able to provide a much bigger rocket based on shuttle-legacy parts at a similar cost.

>>6931194
>Falcon Heavy is not meant for deep space. Not my words, Elon Musks himself.
If you're going to make this kind of claim, you should provide both an exact quote and the context, not an out-of-context paraphrase and "these are his words".

From the SpaceX website, Falcon Heavy page:
>Falcon Heavy was designed from the outset to carry humans into space and restores the possibility of flying missions with crew to the Moon or Mars.

It was absolutely meant for deep space.

However, they may now expect that the BFR (a fully-reusable rocket intended to outperform the SLS on a per-flight basis) will be ready soon enough that they'll never get around to using the Falcon Heavy for deep space missions before this far superior vehicle is available.

>It has no advanced upper stage and can only get a few metric tons to Mars.

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