If 1 square meter of sunlight concentrated to a single point with a lens can melt metal, what could a 10 square meter lens do? Or a 100 square meter one? What about a fuckgigantic orbital lens? Couldn't we use big lenses to easily generate electricity somehow? This stuff looks so promising, I'm surprised it isn't widely used. https://www.youtube.com/watch?v=jrje73EyKag

Hi guys, i have this proof for =>. nullT\bigoplusimageT=V means that nullT\capImageT={0} and nullT+imageT=V. since the eigenvalue ?=0, then (T-0I)(v)=0, so Tv=0 and this will compose the null space for V. I have no idea where to go from now. i actually think what ive shown above might not be true in fact.

I have a question about the formality of a general solution. Suppose a problem has two general solutions: u(x,t)=f(x+2t)+2t u(x,t)=f(x+2t)-x If I had to provide 'the' general solution, would it be a combination of these or would either one work? I have been under the impression that there is only a single general solution to any given problem.

On an island, far, far away, live a tribe of 1000 people. These people have a very strange custom: While they can see the colour of everybody else's eyes, they cannot ever know the colour of their own. If, by some terrible misfortune, they do discover their own eye colour, island custom dictates that they must commit ritual suicide at noon the following day, with everyone else watching. Of the 1000 islanders, 100 have blue eyes, while the rest have brown eyes. Therefore everyone knows that there are both blue and brown eyes on the island, they just don't know the colour of their own. One day, a foreigner visits the island. He gains complete trust of the islanders, but never learns their strange custom. Therefore, on his farewell speech he makes a dreadful mistake: He announces, to all: "It is so nice to see that on this island, there are blue eyed people like myself". The islanders are perfectly logical people. 100 days after the speech, all 100 blue eyed people commit suicide simultaneously, despite the fact that the visitor told them something everybody knew anyway. Why?

The Dumbest scientist who ever lived Non-stop Hilarity http://www.xavierraja.com

Your opinions on Carl Sagan and his works. Great science apostle or mainstream pop-sci jew? And why? What is his best work? Where should I start?

I'm doing an assignment in which proteins are to be determined. During the preparation we are gonna add a 6M HCl to hydrolyze the proteins into amino acids. During this preparation the amino acid tryptophan will be degraded by the acid. I've tried to find out why that AA is degraded and not the others but couldn't find the answer. Could anyone help me out? This is not required knowledge for the lab other than to know that tryptophan is degraded but I am curious.

Why haven't we developed Cryochambers or Crytotubes in the video game series Halo? Most importantly why haven't we developed an artical antifreeze where we can prevent water crystals from bursting in our bodies and to consume and regurgitate it to start the process all over again to like in the books

Why is evolutionary psychology used to scientifically explain behaviors and cultural phenomenon when it's a completely theoretical field with no empirical evidence to back up the claims it puts forth?

Why usually people that are spaced out or have some sort of problem to focus themselves in real world have more ease to think about abstract subjects?

Why havent we solved chess yet?

should i kill myself if im 21 and struggle with highschool A levels math?

Hello /sci/. I need help. I was supposed to calculate the degree of ionization of a pure helium plasma at various temperature between 2000 and 20000 kelvins via the Saha equation. I got this, and I wonder are results accurate to an order of magnitude?

What's the best telescope to buy under $300? Preference for equatorial mounts.

why do rough surfaces have more friction? Like new asphalt is easy to ride a skateboard on, but old, more rough and weathered asphalt is near impossible to ride on. Is it because with erosion from weathering there is increased "surface area" as in more cracks which are more apparent than on smooth? idk i havent taken physics, but im just wondering.

Why doesn't the area of contacting surfaces affect on friction? Serious question

I want to pick up cryptography, what are some essential branches of math involved in it, the text i'm using, pic related, includes some number theory, discrete math, and abstract algebra involved, what other fields should I be versed in?

Why is this not correct (suppose n->infinity): nth root (n!) = nth root (n(n-1)(n-2)(n-3)...(n-n)!) = nth root (n) * nth root (n-1) * nth root (n-2) * ... * nth root ((n-n)!) = 1 * 1 * 1 * 1 * ... * 1 = 1 => nth root (n!) = 1 It is clear that nth root (n) = 1 as n-> infinity and that n! = n(n-1)! Yet jewframalpha gives me infinite as the limit and not 1

Does /sci/ like Less Wrong? http://lesswrong.com/lw/lm/affective_death_spirals/

I have 1/2(n^2+3n+2)-3 Which simplifies to 1/2(n^2+3n-4) What is this ruled called when you apply the 2/2*-3?

I recently had nothing important to do, so I made this as a result. Is what I made a true statement? If so, can a kind Anon explain why? And since it's all the same variables, I assume you can consider them as four individual variables, or "Nope" as one variable entirely. Does /sci/ feel like attempting this? I chose "Nope" due to a spider being 3 feet from my position within my peripheral view. There are no set values for the variables, so feel free to choose your own.

Explain the geometry behind this photograph. Distortion by projection doesn't speculatively seem enough to explain the size of landmasses, and the space left to Canada and South America seems to small. It looks like the North Pole and the South Pole are very close to each other behind the visible surface. Do you literally need to move away an infinite distance from a sphere in order to cover half its surface area in your field of view?

Anyone here good with statistics? I'm a retard so I need a little help with calculating the mode for grouped data. Here's the basic formula, what I don't understand is how to deal with intervals of different length, since this formula only applies if the intervals all have the same length. Now apparently there's a thing where you can adjust the length of intervals to match so you can apply said formula, but I just have no idea on how to do that. Also have a similar issue with finding the median in uneven intervals. Please help.

Sup /sci/ Im doing my Masters in Physical Chemistry, and Im currently browsing for software which would allow me to sketch/draw my current experimental setup. Anyone have any experience or recommendations? I have no experience with CAD programs, so I guess the easiest and fastest way would be to sketch it in 2D. Paint my best option?

please explain ;_;

would you use a tool or vehicle with a hydrogen cell battery?

What kind of ideas run through scientists minds when conducting experiments to find cures or methods of detection? I was reading up on Jack Andraka after watching the Ted Talk and came across a descriptive method he carried out to find an early detection for pancreatic/lung cancer. The fragment goes as follows: "Andraka cultured MIA PaCa cells, from a commercial pancreatic carcinoma cell line, which overexpress mesothelin, a biomarker[13] for ovarian, lung and pancreatic cancers. The mesothelin was isolated, concentrated and quantified with ELISA.[6] After optimization with the Western Blot assay, the human mesothelin-specific antibodies were mixed with single-walled carbon nanotubes and used to coat strips of ordinary filter paper. This made the paper conductive. The optimal layering was determined using a scanning electron microscope. Cell media spiked with varying amounts of mesothelin were then tested against the paper biosensor and any change in the electrical potential of the sensor strip (due to the changing conductivity of the nanotubes) was measured, before and after each application. Specifically, what happened was this: The antibodies would bind to the mesothelin and enlarge. These beefed-up molecules would spread the nanotubes farther apart, changing the electrical properties of the network: The more mesothelin present, the more antibodies would bind and grow big, and the weaker the electrical signal would become" To me, on reading it for the first time, it makes a lot of sense. How could scientists not come up with this sort of an idea and additionally, what sort of ideas do they actually think of instead? Thanks.