From 3.5 billion Reddit comments

347 points

·
19th Jul 2011

Reddit had maybe 10,000 accounts five years ago - or less than the current readership of /r/TheoryOfReddit. We've got like 800,000 now. I don't know how many pageviews a month Reddit had back then, but it sure wasn't a billion. Hell, I don't know if MySpace had a billion pageviews a month in 2006. Digg sure didn't. I wonder if Wikipedia did.

If Reddit comments aren't 1/80th what they used to be, we're actually coming out ahead. I agree with you that there's a fair amount more chaff to go with the wheat, but that's more of a sorting problem than anything else. Yeah, we didn't have f7u12 cartoons but we also didn't have /r/askscience or /r/randomactsofpizza.

Growth isn't necessarily bad - but you *do* have to account for it. I think the lightning growth Reddit has experienced over the past year has ended up making "size" more visible than "sorting" but it appears that the admins are actively working to make the Beast That Is Reddit more manageable and navigable.

Reddit is bigger than 4chan, Digg and SomethingAwful combined. Anything with that much versatility and reach is going to be a little unwieldy, particularly when the architecture wasn't really designed for something a tenth this big. The amazing thing is we've still got a place on here to bitch about it... and that the worst blowback we've had is the 2XC/MR skirmishes.

Be patient and take hold of your front page. The old Reddit you love is still there; it's just easily overshadowed by the new Reddit you hate.

165 points

·
1st May 2011

Just to be accurate, the issue here is not in the order of same level expressions (the TI-85 also does left to right). The issue is that, for the parser of the TI-85, implicit multiplication (where you don't write the multiplication symbol) has priority over regular multiplication and division.

Before you discard it as the wrong way to do it, consider it actually makes sense for variables:

6/2x

Is this 6/(2*x) or (6/2)*x ? Most would agree that it is the former, including WolframAlpha, even though according to pure PEMDAS, it should be the latter.

Now replace x with (1+2) and you have the OP's equation.

134 points

·
11th Mar 2011

From WolframAlpha:

current distance from Earth: 394820 km

average distance from Earth: 385000 km

March 19: 357229 km

95 points

·
15th Jan 2011

Average distance to the moon 388 388 kms

Your height expressed in metres: 2.172 m

It will take 1.78816 x 10^8 of you to stack you to the moon.

84 points

·
25th Mar 2011

I don't think this is right:

>First calculate how many balloons you pop, falling 1m:

>V = 1,8m * 0,5m * 1m = 0,9m³

> >Vb = 0,05³m = 125*10^-6 m³

> >N = V / Vb = 7200 balloons

>The force would be:

>F = 0,15N * 7200 = 1080N

>With your weight of 80Kg you calculate the deceleration:

>a = F / m = 1080N / 80Kg = 13,5m/s²

The 1080 N is not a constant force on your body, but the total force exerted during 1 m of fall, so you wouldn't be decellerated at 13,5 m/s^2.

Think about it. During a fall of 10 meters you exert a total force 10 times higher, but your acceleration won't be 10 times higher.

I'm not sure what the correct way would be though, I suppose something with Kinematic energy and power.

**EDIT:** So I tought about it a bit, I think this is the way to solve it:

Impuls = Change in momentum

Momentum = mass * velocity

Impuls needed = Change in momentum needed = Current momentum - 0 = 80kg * 50m/s = 4000

Impuls = Force * duration

Impuls = 0.15 N * 1e-4 s (I could be way off on this duration) = 0.15e-4 Ns

Total balloons that need to be popped = 4000 / 0.15e-4 = 266 666 667 balloons

With 7200 balloons per meter this is about 37000 m or 37 km

**EDIT2**: Forgot about the gravity, so what I wrote is wrong as well.

**EDIT3**: Impuls in time interval dt = v(t) * 7200 * 0.15e-4 * dt - 9.81*80*dt +0.5*1.2*1.2*1.8*0.5*v(t)^2*dt

The last term is for the drag resistance. Calculus class has been a while so i put this into Wolfram alpha

Your velocity will never reach 0/ms. Which makes sense I guess, because if you would just lie on balloons in your needle suit the balloons would pop just because of your weight on the balloons.

82 points

·
20th Mar 2011

I've not heard of that stereotype before. It is recognized that many Americans are hard workers

"Americans take vacations so they can work more. Europeans work so the can have vacations." is a phrase I've read.

Are you confusing it with the Fat American stereotype? That is because you are fat.

http://www.wolframalpha.com/input/?i=obesity+rates+US+and+Europe

81 points

·
19th Jun 2011

Finite amount of throwaway accounts? Seriously?

Let's do some math...A reddit username can be up to 20 characters long (p) and can consist of any mix of 36 different characters A-Z and 0-9 (n). By summing n^p from p=1 to 20, we discover that the number of accounts available is **1.37 x 10^31 **, or **1.98 x 10^21 accounts per person** in the world. So yes, finite. I guess.

But yeah, anonymous accounts would be stupid.

67 points

·
9th Jun 2011

1/speed of sound ~ 4.689 seconds/mile. So for every 4.7 seconds, sound travels 1 mile. Granted the actual rate is dependent on air pressure, humidity, temperature, I'd say roughly for every 9 seconds, sound travels 2 miles. So when you see the lightning, that's so fast we'll say it's instantaneously at you, and if you hear the thunder 9 seconds later, then the sound has traveled 2 miles to get to you.

67 points

·
11th May 2011

Actually, there are in fact 1000 MB in a Gigabyte. What most people think of as a Gigabyte is actually called a Gibibyte, and it's not 1024 Megabytes, it's 1024 Mebibytes. Windows lies and says that it measures data in Gigabytes (GB) and Megabytes (MB) but it is actually measuring in Gibibytes (GiB) and Mebibytes (MiB). So windows basically displays the wrong units. That's why when you buy a hard drive that says its 1TB for example, it is actually 1 TB, or 1000 GB, but its only 931 GiB, which is what windows shows as 931 GB.

Don't believe me? http://www.wolframalpha.com/input/?i=1TB+to+Gibibytes

/Melvin

58 points

·
28th Mar 2011

1 mole of carbon roughly = 6.02 x 10^23 atoms = 5.31 ml The size of the internet is estimated to be 5 billion gigabytes of data, which is 40 billion billion bits (4x10^19 bits). Thus 4 x 10^19 / 6.02 x 10^23 = 6.64 x 10^-5 ml or a cube of 0.405 mm edge. ~ 1.1 × volume of a medium grain of sand (~~ 62 nL ) (edited: formatting)

56 points

·
26th May 2011

Indeed, speaking in terms of expected value, we can expect about 4.8 million people to die, and thus fully warrants attention and investigation.

56 points

·
5th Feb 2011

I approve of the message, but this stats seem dubious.

The easiest one to disprove is that three billion people are illiterate. We have roughly seven billion people on the earth, so 3 billion is about 42% of the population. That means that the article is saying the world's literacy rate is about 58%. However it is much higher than that.

http://www.wolframalpha.com/input/?i=What+is+the+world's+literacy+rate%3F

http://en.wikipedia.org/wiki/List_of_countries_by_literacy_rate

55 points

·
15th May 2011

54 points

·
22nd May 2011

1 million yen, actually. At the time of its Japanese release, this was equivalent to $9581.30 Extortionate, yes but far more affordable than the price put forward

54 points

·
21st Mar 2011

(1+0.9Cos(8t))(1+0.1Cos(24t))(0.9+0.05Cos(200t))(1+Sin(t)), when plotted as a polar function over 0 <= t <= 2pi, looks like a marijuana leaf

53 points

·
28th Apr 2011

Nice, I like the way Wolfram represents the equation! I also like how it can tell me the amount of carbohydrates in a cubic light year of bananas, too.

49 points

·
9th Jun 2011

There are 2.27 popes per square kilometer in the Vatican.

Also, the last time I was pulled over for driving at 108 km/h in a 80 km/h zone, I was asked, "Do you know how fast you were going?" to which I replied, "10^-7 c" (where c is the speed of light)

49 points

·
8th Jun 2011

Either the twelve oranges problem or the red cap black cap problem.

You have twelve oranges, one of which is either heavier or lighter than the rest, which are all of equal weight. You have three chances to use a scale, which can balance some set of oranges to another set of oranges and tell you which side is heavier. How do you determine which orange is the special one and whether it's heavier or lighter?

There are at least two (apparently) distinct solutions I know of.

20 prisoners are told that they will be lined up the next day in a line such that each prisoner can see all those in front of him but none of those behind him. Each prisoner will be given either a red cap or a black cap. They will be able to see the cap of those in front, but not their own nor those of the prisoners behind them. The prisoners are to be asked one by one from the back of the line what color they think their cap is. Prisoners who answer incorrectly are shot and prisoners who answer correctly are set free. Prisoners can hear all the other prisoners' answers and whether they got shot or set free.

There is a strategy that, assuming proper execution, saves both the maximum expected and maximum guaranteed number of prisoners. What is it?

Clarifying point: prisoners are allowed to fully conspire the night before, but on the day they are lined up, they are no allowed to communicate to one another beyond the extent to which they can see people in front of them and hear calls and outcomes behind them.

**HINT:** The expected number of prisoners saved is found HERE. The maximum number is found HERE.

47 points

·
7th Feb 2011

Nice! My only comment would be, why do the moons look unnaturally large? Ganymede is the largest and it's only a fraction of Jupiter's size. That photo makes them look deceptively big when they should be just pin points compared next to the giant.

Edit: In response to a question I was sent, WolframAlpha has a nice comparison and illustration to give you a better idea of the sizes involved

45 points

·
3rd Mar 2011

with the captcha above there is a 1 / 5 chance of guessing correct or 20%. If a bot is trying to set up 1000 fake accounts ~200 will be successful. With your normal captcha you're dealing with a large group of words to choose from so about 1 / 600,000, probably less, but the probability approaches 0%. I'm sure someone will correct my math, but I'm hoping you get the picture.

this is dealing with a captcha attack that only uses guesses, there are other ways to break a captcha

44 points

·
13th Jul 2011

Oliver didn't really take until 2000 I'll just blame John Oliver because I can.

41 points

·
30th Apr 2011

If you had a monitor with a resolution such that there were 34 pixels in total (17x2 would be an example of such a resolution), you'd have roughly the same number of different possible combinations as there are atoms in the visible universe (10^80)

41 points

·
15th Mar 2011

If the moon were made of blue cheese, it would be enough food to feed the world's population for about 50 billion years.

calories in moon's mass of blue cheese / population of earth / rda calories / 365

39 points

·
25th May 2011

> I can only imagine how much larger that number would be if we were to spend $30,000 annually per student.

No problem with have math.

$17.9 billion / $7000 per student = 2.6 million students

This jives with the number of people under 18 in Michigan according to Wolfram Alpha. So at $30,000 per student you would spend $77 billion total on education which is $59 billion more than they are spending right now or an increase by 330%. The total state and local budget for Michigan is $80.4 billion (KalamMekhar's link) increasing education spending to this level would require a 73% increase in revenue, or elimination of every other function of government in including pensions, health care, law enforcement, and public transportation.

38 points

·
6th Mar 2011

The answer is approximately 4.29733.

Use this image:

We've got two similar right triangles.

ABC is similar to EFC

BCD is similar to BFE

So using this and the Pythagorean formula we can come up with enough equations to eliminate our variables:

10^2 = x^2 + y^2

12^2 = x^2 + z^2

u^2 = w^2 + 5^2

v^2 = (x-w)^2 + 5^2

u/10 = w/x = 5/y

v/12 = (x-w)/x = 5/z

And it's a straightforward, but long, solution from there. So I just plugged it into Wolfram Alpha:

37 points

·
29th Jan 2011

Distance from earth to moon < Roche limit of jupiter

Even if it corrected for angular momentum, earth would be broken apart under Jupiter's gravity. It'd probably form some pretty rings, too.

36 points

·
26th Mar 2011

Consider the ocean. When you're near it, you notice the waves and the movement of the water, etc. When you view the ocean from far away, it looks relatively still.

That's the difference between Quantum and Classical. Particles never stop behaving with quantum rules, you just don't notice it from up here.

If you're better with math, look at the functions y = sin(x) and y = x here. Now, look what happens when you look at it from far away.

Classical Mechanics is like using y = x as an approximation for y = sin(x) + x because sin(x) is always going to be between -1 and 1 which isn't significant when you're dealing with large numbers, but makes a significant difference when dealing with smaller numbers.

36 points

·
18th Mar 2011

For some reason, I imagine a lost episode of Arrested Development.

On the next episode of Arrested Development:

Gob lost his job as a Magician (again) and somehow ends up in China. Wondering where to find a job as he walks down a busy business district, he is grabbed by a desperate Chinese business man who yells he needs a white man and will pay good money. Confused, Gob says he is flattered but he is only interested in the fairer sex. Suddenly, more businessmen appear and start grabbing Gob and pulling him towards a luxury car.

Next scene: As he is being fitted, groomed, and fussed over by people, Gob is being explained to by the businessman that he is to pretend to be the new CEO of the company to prevent their stock to devalue after the last one has disappeared due to mysterious circumstances.

One of the maids asks him if he would like a drink. A strange light glints in Gob's eye as he looks at his clothes fit for a CEO reflecting off the mirror.

Close up to Gob's face as a murmur escapes from his mouth: "no...I wanna spill booze all over my fucking forty thousand three hundred ninety Yuan suit, COME ON!"

*End Preview*

35 points

·
20th Jun 2011

Oddly enough, the bending stiffnesses of the two beams are *exactly the same*. The bending stiffness comes from this quantity: http://en.wikipedia.org/wiki/Area_moment_of_inertia and the calculations of that quantity for the two shapes are here: diamond and square. Basically, the diamond shape has more stuff out at the tip, while the square shape has more stuff away from the center at the left and right edges. Hooray math!

As for your project, I suspect you're going to find it much easier to drill holes into the flat side than the point. In fact, I suspect that's exactly why you've never seen the diamond config. Good luck with your hammock!

35 points

·
1st Jun 2011

All politics and opinions on the wars aside, YSK the Lancet figures are extremely controversial and tend to be higher than most other estimates.

As a statistician I am insulted by the way they calculate their averages. For example, they claimed the excess deaths in 2003 in Iraq was 98K. To get this figure they estimated a range of 8,000 to 194,000 and then averaged the two. This is a total abuse of statistics. When you have a huge range like that, you are basically saying "I don't know". If you want to average the numbers, you shouldn't do it in linear space like that, you should do it in log space. Intuitively this is because the relative error between 15K and 10K deaths is the same as the relative error between 150K and 100K.

If they averaged in log space, their figure would have been 31,600

34 points

·
25th Jul 2011

I got this. Start with the Stefan-Boltzmann law and call j*=dE/dt *1/Area. Use dE = c *m *dT, where c is the specific heat. Plugging in, integrating both sides from Tinitial to Tfinal we get:

t = c* r* rho/(9 *sigma)*(1/Tf^3 -1/Ti^3 ), which for a 1m ball of iron gives 2.3 days. This is of course assuming pure radiation cooling. No conduction.

34 points

·
17th May 2011

No your middle class has a higher median disposable income, but you also have to "voluntarily" pay for things that we don't - like health care.

Australia has a higher:

GDP per Capita: http://www.wolframalpha.com/input/?i=gdp+per+capita+australia+vs+us

Life Expectancy: http://www.wolframalpha.com/input/?i=life+expectancy+australia+vs+us

Human Development: http://en.wikipedia.org/wiki/Human_Development_Index

We also don't screw over poor people so that our mega-rich can have another couple of million.

32 points

·
1st May 2011

I didn't check the rest of the numbers, but there are 3.785 liters per gallon, not 4.54. That's going to affect your bigger numbers. An easy way to remember (for an American male) is that most urinals have a note on them saying they're 1 gallon (3.8 liters) per flush.

(Edit) Source: http://www.wolframalpha.com/input/?i=1+us+gallon+in+liters

31 points

·
11th Apr 2011

According to wikipedia the radius of the event horizon is 2Gm/c^2. A large stellar black hole, let's say 10 times the mass of the sun, will therefore have a radius of 2 * 6.67e-11 N m^2/kg^2 * 2e31 kg / 3e8 = 29530m.

At 29530m, the gravitational attraction between a 10kg mass and the singularity is 30615229520301.633N. The gravitational attraction between a 10kg mass 2m lower, at 29528m and the singularity is 30619376941913.746N. The tidal forces are comparable to your head having 330 times the thrust of the space shuttle and your feet being anchored to the ground.

But this is a relatively small black hole; consider a supermassive black hole of about 10^8 solar masses. (I actually have no idea what the math will yield)

At the event horizon, 295300000000m up, the gravitational force is 3061522.9520301633N. Two meters lower, 295299999998m up, the gravitational force is 3061522.952071633N; a mere 40 micronewton difference. You probably wouldn't notice the tidal forces, unless you were in a sufficiently large craft; in which case you're have 'gravity' at the top and bottom, pulling you very, very gently towards the ceiling and floor, respectively.

Of course, this is all for a non-rotating, non-magnetic black hole. The article assumes a rotating black hole or one with a large electric charge.

31 points

·
3rd Jan 2011

For those of you who think this is easy, Jeopardy's question format isn't always that straightforward- they usually have categories with a theme, and the answer only makes sense in context of that category's themes. Often there's an entire category in which the clues are just one or two words, or a category of nothing but puns.

I'd expect the AI to be very good at clues like "This actress won the Oscar for Best Actress in 2003", but not so much finding "things you jump" as the response to the clue "A battery, a claim, a checkers piece" (in a category called COMMON BONDS).

30 points

·
18th Jul 2011

30 points

·
24th May 2011

Actually 5 feet 9 inches is an average for many countries. The US is abnormally tall.

I'm 6 feet 1 inches and only in the US am I considered average.

Correction: http://www.wolframalpha.com/input/?i=average+height+male

30 points

·
12th Jan 2011

Like this?: http://www.wolframalpha.com/input/?i=us+national+debt/gdp*100

edit: or this rather: http://www.wolframalpha.com/input/?i=us+federal+deficit/gdp*100 ? (edit, nvm, see Reductive's comment below - go with federal debt)

29 points

·
29th May 2011

Well, the estimated surface area of the Earth at ground level is 510,072,000 km^2, so that would be 1.992 times 10^12 chunks (1,992,000,000,000 chunks), which in the Beta format would be 20.01 KiB plus the number of bytes to store 1,992,000,000,000 chunks' worth of blocks, which varies upon the compression level. Assuming no compression at all, and one byte per block (x,y,z,and id; I know it's undersizing significantly), then the maximum size of the world would be 24.48 petabytes, which would be in one file. A non-complete list of filesystems that support files that large is: HFS+, ReiserFS, ZFS, XFS, Veritas File System, Btrfs, SquashFS, Tux3, CXFS, UDF, and NILFS.

Of course, the file would be split into smaller amounts, increasing the total storage volume by 20.01 KB per file, plus filesystem overhead, but you'd still need 24.48 PB + (20.01 KB * *n*) of storage.

29 points

·
4th May 2011

I spend a lot of time in BC Parks and I'm AGAINST getting rid of parking fees. This is a great PR move for Clark, it sounds great, but Parks needs that money. I haven't heard anything about the government stepping up funding for parks to offset the loss of revenue.

Garibaldi Park's staff, for example, has been slashed over the years so that they now have only a small handful of awesome, dedicated Rangers who are tasked with patrolling a park larger than 58 countries.

If the government wants to step up funding AND make parking free, then hey, that's awesome, but personally, I'm perfectly happy paying parking knowing that it goes to helping Parks do the awesome job they do considering how cripplingly underfunded they are.

29 points

·
28th Apr 2011

There should a be contest for finding the most absurd challenge Wolfram can handle

29 points

·
13th Apr 2011

I think he forgot a zero, i.e. is off by a factor of 10.

Volume of the observable universe: 3e80m^3

Volume of earth/volume of the universe: 3.6e-60

The number in the red-button comic is 3e-59, though.

edit: wolframalpha has it directly, nice http://www.wolframalpha.com/input/?i=volume+of+earth%2Fvolume+of+the+observable+universe

29 points

·
26th Feb 2011

Just some perspective:

It's 5 weight watchers points (on the old system) You're allowed 20 - 25 per day (depending on weight).

Most of the sugars come from fruit (raisins, cranberries, apples). Assuming they don't add sugar to it, that's fine.

300 calories for breakfast? That really not even enough.

Theres a solid amount of fiber. A snicker's bar has 1 g of fiber versus 5g for this oatmeal.

Using wolframalpha I compared Quaker instant oatmeal with some of the added toppings and mcdonald's oatmeal

It's really not that bad....

28 points

·
6th Jul 2011

I learned to control this with a sort of meditative exercise where I visualize thinking. I start by imagining a pitch black infinitely large space, with a black object shaped like the graph here in the middle. I visualize each word that I think as a short blue stripe that moves toward the object and goes up along its surface, disappearing out of view. I think exclusively in words so this works for me.

I then concentrate on reducing the amount of stripes that appear until the scene is pitch black again (and I'm no longer thinking of anything.) It took some practice, but now I can *always* fall asleep within five minutes of getting into bed.

28 points

·
9th Apr 2011

The circumference is fixed at 1, so each side of the polygon has length a = 1/N. A regular polygon can be broken up into N isosceles triangles with one angle of alpha = (2pi/N) and two angles of (pi - 2pi/N)/2. The side opposite the angle of alpha = 2*pi/N will have length a. Break each of these isosceles triangles again into two right triangles, such that tan(alpha/2) = (a/2) / b, where b is the height of the right triangle. Then b = (a/2) / tan(alpha/2). The area of each isosceles triangle is then A = (1/2) * a * b = a^2 / 4 / tan( alpha/2 ). Putting a = 1/N into this gives:

A = 1 / (4N^2 ) / tan( pi / N ).

Edit: Left off the total area: The total area is then N * A = 1 / (4N) / tan( pi/N ).

Also, note that as N goes to inf, the above approaches 1/(4pi), the area of a circle with circumference 1.

Plot.

28 points

·
17th Feb 2011

Still annoys me that I can ask who is the director of ET and how old is steven spielberg but not how old is the director of ET.

28 points

·
16th Jan 2011

i live in canada and am canadian. i have 2 brothers that moved to the usa years ago and are living there now... very happily. they both went to further their careers.

this daily circlejerk of how canada or the usa is superior is getting fuking annoying. both countries have pros and cons but for the most part the countries are extremely similar with the exception that the usa is 10x as big. context.

as for political ideals... seems like everyone on reddit dislikes their pm or pres. the laws suck... healthcare sucks... blah, blah, blah. it's really just a lot of the same. i suspect the top comment on this thread will be about someone's ideology which really has little practical implication regardless on which side of the border one chooses to live.

27 points

·
24th Apr 2011

I'm guessing he's trying to say that at sunrise you're moving towards the sun, and away from it at sunset. The velocity of the Earth's surface (at the equator) due to its rotation is about 465m/s. At sunrise/sunset, this velocity is directed towards/away from the sun. From the equation for the Doppler shift, we get that the sunlight's frequency will change by 31 parts in 20 million, or about 0.00015%. This is so small as to be immeasurable. The reason it is so small is because 465m/s is *so* much less than the speed of light.

This calculation does not take into account the tilt of the Earth on its axis, this would change the answer by some amount, but definitely not change the answer's order of magnitude.

So, the concept in edifus's comment is not *wrong*, but it's a very small effect, and they admitted that they're just guessing, so its still against the askscience guidelines.

26 points

·
5th Jul 2011

Perhaps they switched to a log scale, one possible conversion function which would put warp 13 at 0-10 warp scale 9.7. Honestly, this would make sense once you build warp drives that are pushing more decimal places.

edit: that function goes above 10, this is better, w13 = w9.3

26 points

·
7th Jun 2011

I live in a country where bicycling is disproportionately much more common than other places, particularly the US. Our traffic laws are adapted for a traffic system with bikes everywhere (it's illegal to ride a bike without lights at night), and bike lanes are plentiful and almost certainly present even on smaller city roads.

And yet, when Americans drive in my city, they *still* tend to be incapable of paying the right amount of attention to bicyclists, even though the bicyclists mostly follow the same traffic rules as everyone else.

I tend to think that it's much less a question of some "death wish" and much more a question of knowing what you have to be aware of. If you're used to never seeing bicyclists, it's not that weird if you suck at driving around them.

On top of that, it's significantly harder to get a driver's licence here — you have to attend actual classes, and it takes longer. The US has around 3 times more fatal road accidents per year per capita than my country (Denmark).

So yeah, do with that what you want. :)

25 points

·
10th Jul 2011

25 points

·
11th Jun 2011

Wolfram Alpha can actually calculate any of these relationships:

http://www.wolframalpha.com/input/?i=cousins+daughter (your cousin's kid's relationship to you)

http://www.wolframalpha.com/input/?i=mothers+cousin (your relationship to your cousin's kid)

http://www.wolframalpha.com/input/?i=mothers+cousins+daughter (your kid to your cousin's kid)

25 points

·
9th Mar 2011

As naughtius pointed out, it's not actually heading towards Alpha Centauri. The first star it will pass "close" to (close = 1.6 light years) is AC+79 3888 . This will happen in 309,600 years.

**edit** My value disagrees with the value on the Wiki page of the star, because the star is actually moving towards us. Taking this into account it will be much less, around 40,000 years according to Wiki. Someone who's not supposed to be doing real work could check this.

24 points

·
22nd Apr 2011

Can somebody help me out here? I don't quite understand that counter. For starters, it's at 99.5%, which is less than 99.95%. Secondly, 0.05% of downtime in a year is about four and a half hours right?

23 points

·
11th Jul 2011

(a*b)^n =a^n * b^n is only a property when you have positives (technically nonnegative reals), as the "primary" solution to these problems is always positive (ex. square roots of positive numbers are always positive).

When a and b can be nonpositives, then your solutions can start branching out in different directions, which causes some trouble when you multiply them back together.

Consider, for example, that (-1 * -1)^(1/2) != (-1)^(1/2) * (-1)^(1/2), as the former is just the square root of 1 (which is 1) and the latter is i^2 = -1.

Since WolframAlpha uses a nonreal principle branch for radicals of negative numbers (there are reasons why this makes sense), you end up getting a similar phenomenon with your inputs.

23 points

·
30th Jun 2011

A black hole with the mass of the earth would have an event horizon radius of 8.87 mm.

23 points

·
15th Jun 2011

Actually, it'd be free at 62,700 likes.

You'd have about a 133% discount at 0 people, which means they'd be *paying* you to buy the game.

23 points

·
6th Mar 2011

We Americans have shit for infrastructure for trains / public transport and our nation is larger than your continent. And less populated in the central areas.

http://www.wolframalpha.com/input/?i=Size+of+united+states+versus+size+of+Europe

23 points

·
20th Feb 2011

The video states at 1:41 that the star is 2.8 billion kms in diameter.

Wolfram Alpha states that Uranus is approximately 20.1 AU in distance from our Sun which works out to be about 3 billion kms, give or take a poofteenth.

Dropping VY Canis Majoris where our Sun should be will put Uranus about 200 million kms out and make it noticeably warmer.

23 points

·
28th Jan 2011

22 points

·
19th Apr 2011

To drain all the energy in one AA battery, you'd have to completely convert its mass to energy. A AA battery weighs about 23 grams, which via E=MC^2 is equal to 574.2 Gigawatt Hours.

A very extreme form of death results.

22 points

·
22nd Mar 2011

HA I got it, 2764.6015 / (2 Pi) == 440 which is the standard tuning for an A!

EDIT: http://www.wolframalpha.com/input/?i=2764.6015+%2F+%282Pi%29

EDIT: http://www.wolframalpha.com/input/?i=440hz

EDIT: BTW 2pi comes from the wave formula y = a * sin(2 pi f x)

EDIT: BTW A 440 is the sort of core note that sort of defines the tuning, not just a random note http://en.wikipedia.org/wiki/A440_(pitch_standard)

22 points

·
30th Jan 2011

21 points

·
27th Jun 2011

No, pressure becomes important at low temperatures as well. Take Helium for example:

http://www.wolframalpha.com/input/?i=phase+diagram+helium

We call this chart a phase diagram. It shows pressure on the up and down axis, and temperature on the left and right. You can see that He is a liquid below ~1 mega pascal at absolute zero, but above a solid. This means you have to cool, and compress helium for it to solidify.

21 points

·
3rd Jun 2011

Taking your line of thinking a little further VY Canis Majoris has an average density of .000002077 times that of the air we breathe! That's something like 15% the density of the air 50 miles above the surface of the earth!!

21 points

·
1st Jun 2011

Actually, it's a thermistor.

WIKIPASTE:

> PTC thermistors are used as timers in the degaussing coil circuit of most CRT displays and televisions. When the display unit is initially switched on, current flows through the thermistor and degaussing coil. The coil and thermistor are intentionally sized so that the current flow will heat the thermistor to the point that the degaussing coil shuts off in under a second. For effective degaussing, it is necessary that the magnitude of the alternating magnetic field produced by the degaussing coil decreases smoothly and continuously, rather than sharply switching off or decreasing in steps; the PTC thermistor accomplishes this naturally as it heats up. A degaussing circuit using a PTC thermistor is simple, reliable (for its simplicity), and inexpensive.

So, if you do it again straight away, the thermistor is still hot and won't pass as much current.

Edit: To degauss the monitor you need to use a big oscillating field. So you have a sine wave, and using a thermistor causes the amplitude to decrease over time, like this.

20 points

·
3rd Jun 2011

Black coffee. Just suck it up for now. It gets better. It's an acquired taste, like beer.

Also, to put it in perspective: 400 calories is 3 POUNDS of broccoli

20 points

·
3rd Jun 2011

it's more likely an ISP thing. most ISPs provide a quarter or less upload speed than download speed based on the assumption that most users are only receiving content. 35GB in 48hrs is about 1.5Mbps which roughly matches the upload speeds I've seen on many 5-20Mbps down cable connections.

trust me, if you could upload at 100Mbps, Google could receive it.

20 points

·
12th Apr 2011

It has to do with the order of operations. People arguing over whether the answer is 288 or 2. (48/2)(9+3)=288, but 48/(2(9+3))=2. The question is whether you divide 48 by 2 or multiply 2 by (9+3) first.

Following the formal rules of the order of operations, the answer is 288.

There was a link on reddit the other day in which someone had two different Texas Instruments graphing calculators that gave two different answers for the question.

I hope that answered your question.

20 points

·
17th Feb 2011

Yeah, one of the comments on the page is about a user's frustration with not getting the expected results for "which has the greater area, the atlantic or the pacific?",but you can easily get the answer a number of ways, such as "Is the area of the atlantic ocean greater than the area of the pacific ocean" or "area of the pacific and atlantic".

There's an art to formulating questions that Wolfram Alpha can process correctly.

20 points

·
12th Jan 2011

Using this query http://www.wolframalpha.com/input/?i=us+federal+deficit+in+2010%2Fgdp+in+2010*100 I created this table. I'm at work, so I didn't put every year in there. Hopefully I did it right.

Year | (Deficit/GDP)*100 |
---|---|

1935 | 3.824 |

1940 | 2.88 |

1945 | 21.32 |

1950 | 1.062 |

1955 | 0.7217 |

1960 | -0.05718 |

1965 | 0.1962 |

1970 | 0.2737 |

1975 | 3.251 |

1980 | 2.648 |

1985 | 5.034 |

1990 | 3.811 |

1995 | 2.211 |

2000 | -2.374 |

2005 | 2.519 |

2010 | 9.166 |

19 points

·
3rd Jul 2011

nope it doesnt work that way. It also has been growing like crazy since the 70's when the us started to cut their taxes like crazy while raising crap like payroll taxes which put more burden on the lower classes. ANd if you look other nations like luxenburg have a higher per capita income and yet dont have the gini problem

western europe has most millionaires per capita

All it takes is a tiny bit of research and you will see things are getting worse in the US. The american dream is disappering, freedoms are disappearing.

You do know we used to use the gini to attack south american countries? the right used to use it tall the time to explain what was wrong with socialism and how capitalism actually produced a more fair distribution. But since the 70's those south american countries have lowered theri gini, while ours exploded.

and you dont ever see right wingers on tv, pointing out the gini of ven, or chili or columbia anymore, cause we are worst than all of them down there now.

Interesting the same people who used to use this tool as an attack on socialism, now say it is totally meaningless, I guess kinda like exit pollls

19 points

·
14th May 2011

Let's say that the jumbo-jet is 3/4 the angular width of the moon. And let's say that's a Boeng 767 (I'm not good at Jet Identification (this is a very ironic statement if you know my research ;-) )). Using this picture, and the fact that the angular width of the moon is about half a degree, we can actually figure out how far away the plane is from the camera.

[The jet is 7639 meters away](http://www.wolframalpha.com/input/?i=sin\((90-3%2F16\)degrees\)*25%2Fsin\(\(3%2F16\)degrees\)&t=crmtb01)

And in the amount of time it took me to make this surely someone's already answered it :-p

19 points

·
24th Apr 2011

The total mass of all the humans in the world is 4.2x10^11 kg. The mass of the Earth is 6x10^24 kg. So humans weigh less than the Earth by a factor of roughly 10^13 . That's 10 trillion. This is the same ratio as the masses of a grain of sand (10^-10 kg) and a small car (~1000 kg). So *all* the humans running at once only amounts to the effect that a grain of sand would have on a car, i.e. so little as to be immeasurable.

18 points

·
26th Jul 2011

Whoa, Wolfram|Alpha speaks TeX! Not just the super-light version, either! Example (another one)

18 points

·
17th Jul 2011

Ternary computers are more efficient (Or they would be given equal development efforts to binary computers). They used to be popular within the CCCP, and even now some of their computers hooked up to their cold war era radios still use trinary.

Trinary is the most efficient. You can calculate this yourself by taking an arbitary number (bigger is better), lets say 1,000,000. Take the base and multiply it by how many digits are needed to represent 1,000,000. The lowest number wins(Eg is most efficient).

so x=ln(1000000)y/ln(y), e is the most efficient but you can not have a computer using a non integer base.So 3 is the best choice.

EDIT: Why the hell am I being downvoted? My post is mathematically correct and logically correct.

18 points

·
19th Jun 2011

Holy crap, the comments on that page gave me a headache.

EDIT: Also, instead of using this you could just add WolframAlpha to your browser's search engines. It not only lets you do 7*12 but also some more interesting queries.

18 points

·
4th Jun 2011

As I said in your other instance of this thread :

The sun already has approximately 1.988×10^26 kilograms of iron in it*. For reference, that's 33 times the mass of the entire planet earth. So, no, iron is not deadly to stars and no, there isn't enough iron in the solar system to have a measurable affect on the sun.

*The sun is approximately .01% iron, the mass of the sun is approximately 1.988435×10^30 kilograms. .01% of that is 1.988×10^26 kilograms. The mass of the earth is approximately 5.9721986×10^24 kilograms.

18 points

·
19th Apr 2011

I love puzzles.

Wolfram suggests 1157 hits/second. Now, there must be a reason he picked 1.6 and 1.4, and not 0.8 and 0.7. The vague units he is talking about is most likely thousands.

It seems to be a drop of about 200 requests/second. That's quite a bit of traffic.

18 points

·
12th Apr 2011

>are *we* poor?

Technically, yes. What you're saying is that the distribution doesn't matter, the global mean does. But if you were to average the value of everything produced on earth in a year, then yes, we are all impoverished - and *that* is scarcity.

If you take the GDP of earth and average it among the entire population, you get about 8000 USD per person per year. That's GDP, mind you - total value of goods produced, and not income. Total income is often much lower, by at least an order of magnitude.

Would you consider making around 2000 USD a year (or less) an acceptable loss in your quality of life? I'm guessing no, as it probably means a loss in tens of thousands of dollars of net income. That's what scarcity is - not enough to go around for everyone to make a comfortable living.

18 points

·
25th Feb 2011

No, the nanobots are using IPv6, but are running into the same address exhaustion problem we are having. 2^128 is about 3.4*10^38, and Wolfram Alpha says 40% of the volume of the earth in cubic microns is 4.3*10^38.

18 points

·
16th Jan 2011

How much would a full inventory of gold blocks weigh?

Wolfram Alpha says that a 1 meter cubed gold block weighs 42,599 lb or 19,300 kg

So max inventory of 36 64 count stacks would be 98,148,096 lb or 44,467,200 kg.

17 points

·
27th May 2011

17 points

·
9th Apr 2011

I got 0. Everything cancelled out Wolfram alpha even checked my work

17 points

·
31st Mar 2011

Just nonsense, probably just to see if they could get people all across the city to get out of their cars and jump up and down. The moon is not nearly close enough or large enough to have an effect anywhere near that large.

For you to be able to jump 50% higher (from the same initial velocity), gravity would have to be reduced by one-third, plus slightly more since I'm neglecting drag. The mass of the moon is about 1.23% the mass of the Earth. For it to exert a gravitational attraction of g/3, you'd have to be only 1223 km from the moon's center of mass -- physically impossible, since that's considerably less than the moon's radius. WolphramAlpha agrees.

17 points

·
27th Feb 2011

>America is on a crash course for some nasty overpopulation,

(US population growth is currently a little less than 1% annually (and falling). This translates to about 3 million people per year. About one third of those people are new immigrants)

17 points

·
16th Feb 2011

Whip out your calculator before opening your mouth. Cruise speed of a 747 is about 900 km/h or 250 m/s. The 747 is 70 meter long, so lets say 60 meters between the front door and the tail fin. That would mean around 4 plane lenghts a second.

Lets ask wolfram how long it takes to fall a few (3) feet: http://www.wolframalpha.com/input/?i=gravitational+drop+3+feet

0.43 seconds. 250m/s for 0.43 seconds = 108 meters. You'd get twice smacked in the face by the tail fin before falling a few feet.

Also, most passenger planes have the doors in a different level than the wings and the engine. In the 747 you'd actually fall above the wings and below the tail fin, simply because the wings are not in line with the doors.

And finally, you wouldn't even care about any of this, as you'd most likely snapped your neck from the airflow when jumping out. Unless you are Dwight Schrute. Which I doubt, as Dwight would already know this.

16 points

·
8th Jul 2011

It is exactly 800 calories according to Wolfram Alpha!

16 points

·
1st Jun 2011

16 points

·
20th May 2011

There is a lot of debate still about what the cores of gas giants look like. We know, for example, that Jupiter is mostly hydrogen and helium and we know that the pressure is so intense that they become dense plasmas - "metallic hydrogen". Whereabouts this happens, and whether or not the hydrogen and helium are mixed together, is not known. Or rather, we have several models which all fit the observable data but predict different phases at different depths. We currently have no way of telling which one is correct yet.

I'm not sure whether an asteroid would make it all the way to the centre. The pressure in Jupiter reaches over 100 GPa, so asteroids are likely to get crushed way before they reach the centre. Also, because the core is so dense, the rock would most likely float on the dense hydrogen plasma.

EDIT: A quick back-of-the-envelope calculation makes me think that an asteroid would almost certainly float on the hydrogen plasma core (assuming it didn't get crushed...). Average asteroid density = 2x10^3 kg m^-3, hydrogen gas density at 1 atmosphere= 0.08 kg m^-3. But the hydrogen is at 100 GPa or 1 million atmospheres, so would be a million times denser in the core of Jupiter, i.e. way denser than an asteroid... Ok, so the ideal gas law is a pretty shitty assumption (as in, *definitely* not right), but I don't currently have the Wolf equations of state to hand. I think we can safely say that at some point the hydrogen/helium becomes denser than rock.

16 points

·
2nd May 2011

Or in 1960, during the time of his presidency, about 6%

15 points

·
19th Jul 2011

>Reddit is bigger than 4chan, Digg and SomethingAwful combined.

This is a bit misleading/incorrect. If you measure a site based on pure pageviews, reddit is just barely below the rest combined (100 million vs 102.1 million). If you measure by unique visitors a day, reddit is at 10 million while digg is at 9.5.

I agree with your overall point, though. Reddit is huge and got this way in a relatively short amount of time, but it's not bigger than the rest combined. Not yet anyway. It probably will be in a year if not less.

15 points

·
30th Jun 2011

They are as compact as possible considering all of the physics involved. Atoms are about 10^-10 m in size or so. And the meaning of "empty space" doesn't really exist within an atom. It's all... probability of electrons existing in a space or not. But it's not exactly empty..... but let's go crazy. Let's eliminate the idea of atoms and let's just convert the whole mass of the earth into neutrons, for instance. That's about 3.6*10^51 neutrons. Then let's say that the size of these neutrons don't change from free neutrons (they would, but let's pretend they don't). Neutrons have a size of about 10^-15 m. The radius of the whole would be about proportional to the cube root of the number of neutrons, so about 10^17 *10^-15 = **100m in radius**.

15 points

·
21st May 2011

You're completely ignorant--there is just no nice way to put that I'm afraid. 1000 is a very typical sample size for the US population (which is 309 million, with an adult population of 207 million, not 600 million).

If the number were higher than about 1400, that would be a huge, instant red flag. Larger sample sizes do not make for better samples.

Unsurprisingly, you can find information about this topic in Gallup's FAQ section, or in any statistics class.

> For example, with a sample size of 1,000 national adults, (derived using careful random selection procedures), the results are highly likely to be accurate within a margin of error of plus or minus three percentage points.

> ... if we increase the sample size to 2,000 rather than 1,000 for a Gallup poll, we would find that the results would be accurate within plus or minus 2% of the underlying population value, a gain of 1% in terms of accuracy, but with a 100% increase in the cost of conducting the survey.

You should be instantly wary of anyone doubling the cost for that extra percentage point, when it is sufficient instead to understand what a 3% margin of error is.

15 points

·
19th May 2011

The first dummy to leave the vehicle takes roughly 2.6 seconds to reach the ground again which means he reaches about 8m height. Impressive.

15 points

·
15th May 2011

15 points

·
18th Feb 2011

At 40,000 feet, it would be more like 1039.5 mph [wolfram](http://www.wolframalpha.com/input/?i=(24901.47+miles+/+24+hours\)++%2B+(7.576+miles+*+2+*+pi+/+(24+hours\)\))

NINJA EDIT: all sorts of url escaping stuff...

REGULAR EDIT: my bad - my basic geometry was off. let's try 1055.7 mph [wolfram](http://www.wolframalpha.com/input/?i=(radius+of+earth+%2B+(400000+feet+in+miles\)\)+*+2+*+pi+/+24+hours) - a 1.75% increase is nothing to scoff at!

15 points

·
17th Feb 2011

http://www.wolframalpha.com/input/?i=air+pressure+at+3300+ft returns "0.89 * standard atmospheric pressure at sea level" in the comparisons section.

My favourite feature is using English inside an equation to look up common physical constants. I have had issues where it could find two or more constants described in English individually, but in the combination failed, as in your example.

14 points

·
3rd Jul 2011

That's way more complicated than it needs to be, who shows their work? [](/bepislaughingatyou)

(x + (x+1) + 9) / 2 - x = 5

http://www.wolframalpha.com/input/?i=%28x+%2B+%28x%2B1%29+%2B+9%29+%2F+2+-+x+%3D+5