/sci/ - Science and Mathematics

>>1247
I'm saying that a small impactor that hits us and launches matter back into space will be launching matter from the earth, not itself. Think about throwing a rock at a shallow angle into sand, the rock gets buried and launches sand into the air.

For it to be the same matter coming in and going back down then it needs to be big enough that a big chunk can break off and get buries while the rest bounces back into space.

>>1253
>and going back down
*and going back out

>>1243
A very poorly defined question. What counts as the earth. if it bounces off of the atmosphere does that count?

What does bounce even mean? Pray tell what the fuck on the earth is going to be able to absorb and release that much inertia without melting and crumbling?

Tl dr nothing large enough is going to bounce off the earths crust. It might be large enough to physically rip the earth apart releasing enough energy to eject random materials , most of which are probably not the asteroid) into a giant ejecta cloud some of which might escape gravitational pull.

>>1261
Also what would be the smallest size possible? A single molecule could theoretically make its way down to the earth and bounce and go all the way back up again and get flung into space and carried away by solar wind. The odds are astronomical, but it is theoretically possible.

>>1262
Photons do this all the time.

>they have zero mass
1/10 try again

01/04/15 (Sun) 05:19:32 No.1172

I sense tumbler

Good stuff but too short for the price you pay for it. Would also have liked to see more dinos instead of so many pages of making fun of shrink wrappers. Free sequel All Your Yesterdays is better IMO. http://irregularbooks.co/download.html

probably bullshit

>>1059
Why is this?
why does R=((A+B)/2) for the purposes of finding the area but not in other scenarios? I recognize that a lot of the reason is probably going to be axiomatic, but I'd still like to know because it seems like in such a simple deductive proof there's hardly any space for something to go wrong… unless one of our premises was wrong, which, upon doing some basic research, I find that my high school engineering teacher was a lying sack of shit, and I've been using and teaching the wrong equation to find the area of an ellipse for the past 7 years
noted: pi*A*B =/= pi((A+B)/2)^2, 4 is still the square root of 16, and I need to hunt down and murder my old engineering teacher, I always knew there was a reason I hated him.

>>1073
Although, we can… I do not know english term for this "flip-flop, swap, switch, finagle?" The terms around to get a roughly similar equation, merely having R^2 = AB and so R= (2rt(AB)), then we can replace R in our circumference equation with that equivalent value, yielding the final result, C=2Pi(2rt(AB)), another thing which a reason to be incorrect I fail to see, but it is also probably very, very wrong, just as my first equation.
explain to me how I am wrong, if I am, please.

An ellipse is a stretched circle. Stretching works well with areas, which is why the area equation for an ellipse is pi*a*b. Stretching doesn't work so well with lengths; lengths are affected depending on the direction of the stretching. Looking at the boundary of an ellipse, the direction constantly changes. It shouldn't be a surprise that the circumference doesn't have a very simple expression.

If you wanted to find the actual expression for the circumference of an ellipse, you'd need to go through some calculus.

>>1075
I know the actual, expression, I just don't like it and so attempt not to use it.
, but I definitely see why that is, and so eccentricity and other factors would have to be taken into account here to find the true answer. Though this equation is a fairly good approximate.

>>1075
That's what I was thinking:

arc length formula of one half of the ellipse (x^2/a^2+y^2/b^2=r^2). After integration, multiply by 2 and boom circumference.

>>83
Huh. For some reason, it refused to save the math tags when the code tags were already in place, but was fine with them if the code tags were added after.

Anyway, unless I fucked something up somewhere (which it doesn't appear that I did), the answer is yes. Enjoy.

how do i tag

halfchan style?

>>83
Tex

Tex doesn't work

I absolutely would volunteer for such a thing, however, it's likely I would be rejected.
I'd give everything I have to leave this rock and never come back.
It's a catch-22.
Only the most stable minds will be chosen for such a thing, and someone willing to throw away their entire home planet so easily will be classified as unstable…

>>1105
It's ok anon, I'd hang out and listen to jazz with you while we hurl through the void.
I mean, what is it you fear in a one-way-ticket?
The warmth of human kindness, yes?
The fear that you'll never have a friend again?
The obvious solution is to send a friend with you, who's just as insane as you are…

>>1094
I would love it, but under following conditions
>the ship is self sufficient and capable of self repair and modifications
>it has copy of my mind administrating it
>it has androids and clones of me which are connected by hive net
>it can either FTL or I mind can hibernate until we meet new objects to explore

>>1094
No. But I would pay big bucks for a LEO vacation.


Maybe I could retire on the Moon. When I'm old and weak the moon's gravity will make me feel young again.

>>1134
Rotation is around an axis: it is inhomogeneous and anisotropic. Dark energy is both homogeneous and isotropic. It doesn't fit.

Dark energy is an energy density. You could tie the value to a spin-like state of a particle in an n+1-dimensional box with a field that couples to spin to give the value of energy density we observe. The simplest field would be a scalar V, for an energy density of V*S, where S is the spin.

Because total radiation energy decreases as the universe expands, universe particles experience a force proportional to -V*S*dV/dx, where d/dx is the vector derivative along each of the box' n dimensions. This pushes positive S universes towards local absolute value minima, explaining the value more neatly than inflation which pushes towards regular minima, requiring anthropic reasoning to explain why we aren't negative-valued. Negative S universe are pushed towards local maxima.

Since our universe has been stable, we are either alone, or spin-spin interactions are rare. If we were to get hit, however, a number of things could happen:

1. Our spin changes, our position stays the same. The energy density suddenly, globally, instantaneously changes. For the universe to be a point particle with a time dimension equivalent to ours, locality is already broken, tough luck.
2. Our spin flips sign.
The universe suddenly starts shrinking, and shrinking increasingly rapidly until a local maximum is reached. Destruction of the universe in anywhere between 10 billion years and an hour.
3. We are pushed out of the local mimimum, and fall back. A sudden increase in dark energy density which slowly returns to present values.
4. We are pushed to another local minimum. Weirdly continuously varying dark energy densities, slowly decreasing in rate of change, finally stabilizing at some other minimum. Could be zero, could be negative (contraction), or positive. Could be big enough to have a big crunch or heat death rapidly.
5. We are pushed, and spin flips. Similar to above, except a maximum is reached and doom comes considerably quicker as a result.
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How do?

I dunno, maybe because the juice for separating that shit has to come from somewhere?

I thought you guys were supposed to be smart. You can pass salt water through radio frequency and split the hydrogen from the oxygen. salt is radioactive.

>>1110
>>1135
>>1146
guis u got it all wrong! look, >salt water wheighs more than a kilogram per litre (becuz of the salt)
>E=M*C²
>more than 299792458 joule of energy in 1 litre of salt water
>???
>prophet :^)
u maaaaaad? :^)#epicwin

bump for interest

physics major here

I have no understanding of any of this ;__;

>Quantum Physics Thread
>Cherenkov Radiation
Those aren't even related.

bump

Okay, so researching this more I think I can rephrase this question to: What happens when a black hole shrinks enough to become a [Planck particle](http://en.wikipedia.org/wiki/Planck_particle)?

>>1111
Crap, what a waste of quads. Even an /sp/ post would have been better. Anyways, looking into this more it seems as if such a black hole would either decay to become a fundamental particle like an electron (if fundamental particles are simply miniature black holes), a virtual black hole (which would soon decay afterwards), or dark matter and a weakly interacting massive particle (WIMP).

>if fundamental particles are simply miniature black holes

mindblown.jpg

>>1103
It collapses long before that.
/thread.

>ib4 wat does that collapse entail
A really big explosion.

>>1093
>premise A: MIB exist as a function of human government
>premise B: They have a finite amount of intelligence and power
Reasonable assumptions.
However, from this, we can draw two more assumptions:
>premise C: Whatever alien civilization we're fucking with here ALSO has their own intelligence service
>premise D: This extra-terran intel unit is currently operating on earth

The question isn't: WHO are the mib?
The question is HOW MANY are the mib?
Food for though, earthlings, food for thought…

>>1126
It worked for Curiosity.

>>1127
>>1124

It's a fair point. A comet seems particularly difficult to predict available sunlight.

Maybe the prospect of landing in a dark zone wasn't actually an obvious problem.

>>1124
Rosetta was launched in 2004, Curiosity in 2011. The technology to do it cheaply might not have existed back then.

>>1132

Voyager was not done cheaply by any stretch of the imagination.

I'm still not sure cost was the ultimate factor in Rosetta not using it. Maybe it was because cost often drives everything so idfk.

>>1064
Related anecdote: A friend of mine got a government grant for "female accomplishment in physics in the Netherlands", and the (female) secretary of education who gave her the prize honestly asked her if she got her male colleagues to help with the hard math-y parts.

>>1065
Fight-or-flight is the sympathetic nervous system. Stress is also a manifestation, and being punched in the face would trigger the state in any neurotypical individual. A tendency towards violence is not an overly ready activation of flight-or-fight, but likely a limbic system issue: your emotions decide what to do with your 'againstness'. I don't know if emotional tendencies are genetic.

AFAIK, IQ tests in the US and Africa show a black average of over 85 (exact figure not important), so at least 40% of whites are less intelligent than over 40% of blacks. There's plenty of white trash material to turn into hood rats, so their existence is not evidence against the kind of racism not already debunked by intelligence tests commonly used by racists.

A genetic difference of intelligence of around 7-15 IQ points would be plenty to give any African organization a crippling disadvantage against international counterparts, regardless of any assistance efforts, as Watson suggests.

You don't need to see races as collectives to follow that line of reasoning.

>>1088
Same anon as the one you replied to.

>(female) secretary of education…honestly asked her if she got her male colleagues to help with the hard math-y parts
…Holy shit. I hadn't even thought about it with respects to gender equality, but that's a perfect example.

>A tendency towards violence is not an overly ready activation of flight-or-fight, but likely a limbic system issue
>I don't know if emotional tendencies are genetic.
Makes me want to read up on neuroscience… As for whether emotional tendencies are genetic or not, that's kind of a vague subject. We'd need to define what, "emotional tendencies", are first.

If by that we mean, "what we do when we feel certain things", then I'd say that's mostly learned responses, psychological. So with respect to blacks, again this is why I'd say I believe the problem is cultural, rather than genetic.

On the other hand, if we're talking about our emotional feedback in response to stimuli, that's certainly genetic to some extent, although also psychological in many cases. A person who is bipolar or schizophrenic would likely emotionally react in a completely different way than someone who is more neurotypical or someone with autism, if placed in the same situation. In any of those cases, the person may have limited ability to change the way something makes them feel. For instance, for someone with severe autism, loud and sustained noise may actually hurt them. In that case, genetics would be why they get so confrontational when someone forces them to expose themselves to, for example, an elementary school music classroom. For someone bipolar, this may change with their mood. For someone more neurotypical, they may enjoy such a thing by default, or they may be able to train themselves to enjoy it because it's much more a psychological issue for them. So here it's not necessarily a cut-and-dry genetics issue, though genes definitely play a role.

>AFAIK, IQ tests in the US and Africa show a black average of over 85 (exact figure not important), so at least 40% of whites are less intelligent than over 40% of blacks.
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>>1114
> I'd say that's mostly learned responses
Stop making stuff up.