Birthday problem In probability theory, the birthday problem or birthday paradox[1] concerns the probability that, in a set of n randomly chosen people, some pair of them will have the same birthday. By the pigeonhole principle, the probability reaches 100% when the number of people reaches 367 (since there are 366 possible birthdays, including February 29). However, 99.9% probability is reached with just 70 people, and 50% probability with 23 people. These conclusions include the assumption that each day of the year (except February 29) is equally probable for a birthday. The history of the problem is obscure, but W. The mathematics behind this problem led to a well-known cryptographic attack called the birthday attack, which uses this probabilistic model to reduce the complexity of cracking a hash function. A graph showing the computed probability of at least two people sharing a birthday amongst a certain number of people. Understanding the problem[edit] distinct possible combinations of pairing. and .
Human observation of dark energy may shorten the life span of the universe Could humanity's observation of dark energy have shortened the life span of the universe? The answer is "yes" according to the author of a new scientific paper that has recently come to light. Featured in the latest edition of New Scientist magazine, the subscriber-only story, "Has observing the universe hastened its end?", discusses the paper and its claims. Now, before I go further, I must point out that this work has not yet appeared in any peer-reviewed journal. Their official paper, titled "The Late Time Behavior of False Vacuum Decay: Possible Implications for Cosmology and Metastable Inflating States," is far from grandiose. To understand the potential implications of the calculations in the paper, one must start at the beginning—the Big Bang, and even before. This idea was challenged in the late 1990's by the discovery of dark energy. How does this relate to the work in the research article? How could something like this possibly happen?
Human Evolution & Archaeology Earth's True Shape Revealed for 1st Time After two years in orbit, the European Space Agency’s (ESA) Gravity field and steady-state Ocean Circulation Explorer (GOCE) is nearing the end of its planned life span in February, producing the most accurate map ever of the so-called geoid -- an Earth-encompassing spirit level and global reference surface. An unused supply of xeon fuel will allow the mission to be extended until at least the end of 2012. Markedly different from a simple sphere or ellipsoid, the geoid is the mathematically 'true' shape of Earth. It represents a motionless global ocean but takes into account the effects of the Earth’s rotation, weight difference resulting from the position of mountains and ocean trenches, and uneven mass distribution and density variations in the planet’s interior. The resulting small variations in the Earth’s gravitational field feature on the geoid as ‘bulbs’ and ‘dips’ in an idealized ‘ocean’ surface. The Daily Galaxy via ESA
The 5 Scientific Experiments Most Likely to End the World Let's face it, we really trust science. In fact, studies suggest that the vast majority of people will murder another human being, if a guy in a lab coat tells them it's OK. But surely in their insatiable curiosity and desire to put knowledge above all things, science would never, say, inadvertently set off a chain of events that lead to some sort of disaster that ended the world. Right? Well, here's five experiments that may prove us wrong. Recreating the Big Bang Scientists are kind of pissed that they weren't around when the Big Bang happened. The solution, science says, is to make it happen again. God, 1. What Could Possibly Go Wrong? Well, first imagine an apocalyptic nuclear holocaust. So, Basically It's Like... Imagine you have a huge tanker truck parked outside a children's hospital. How Long Have We Got? Meet the Large Hadron Collider. This is not only the largest particle accelerator ever built, it's the largest anything ever built. Risk Level: 3 The Quantum Zeno Effect Risk Level: 5
Does the Color Pink Exist? Scientists Arent Sure | NewsFeed | TIME.com - StumbleUpon In a blog post, Robert Krulwich of the public radio show Radiolab noted that there is no pink in the colors of the rainbow. Pink is actually a combination of red and violet, two colors, which, if you look at a rainbow, are on the opposite sides of the arc. Remember the old colors of the rainbow mnemonic ROYGBIV? The R (red) is as far as it can get from V (violet). That’s where the trouble lies. I know, of course, that all colors are just waves of light, so every color we “see,” we see with our brains. (MORE: Hues You Can Use) So there you have it. We will leave the debate over the color pink to the experts, because we know one Pink who definitely still exists. PHOTOS: Color My Dog! PHOTOS: Color in the Midst of Protest
Your beliefs about intelligence affect your beliefs about learning Your beliefs about intelligence really matter. Learning is a lifelong process. Kids go to school to be exposed to new topics ranging from history to math to science. Adults need to pick up new knowledge to understand world events and to succeed at new tasks at work. Sometimes, of course, the things we learn are fairly easy to pick up. Many people watching the political events unfold in North Africa and the Middle East in 2011 may not have known much about the governments of countries like Tunisia and Egypt before protests brought down those governments. Other information is harder to pick up. How does the difficulty of learning about something affect your beliefs about how much you can learn about it? This question was explored by David Miele, Bridgid Finn, and Daniel Molden in a paper in the March, 2011 issue of Psychological Science . They were interested in the role of people's beliefs about intelligence on learning. This result is quite important.
thermodynamics - Cooling a cup of coffee with help of a spoon Stirring will win, hands down, every time. This is why physicists need to talk to chemists once in a while. As Georg correctly remarks, the latent heat of vaporization of water is enormous - but he's wrong about waving the spoon; stirring is the champion here. Why? It's similar to stirring iced tea. This kind of thing has a lot of applications to laboratory and industrial chemical processes, surface catalysis, petroleum cracking, yadda yadda. If you want an even faster way to cool a cup of coffee, here's a tip from my Granddad Parker: forget the spoon and saucer your coffee. Scientist creates lifelike cells out of metal | MNN - Mother Nature Network - StumbleUpon Scientists trying to create artificial life generally work under the assumption that life must be carbon-based, but what if a living thing could be made from another element? One British researcher may have proven that theory, potentially rewriting the book of life. Lee Cronin of the University of Glasgow has created lifelike cells from metal — a feat few believed feasible. The discovery opens the door to the possibility that there may be life forms in the universe not based on carbon, reports New Scientist. Even more remarkable, Cronin has hinted that the metal-based cells may be replicating themselves and evolving. "I am 100 percent positive that we can get evolution to work outside organic biology," he said. The high-functioning "cells" that Cronin has built are constructed from large polyoxometalates derived from a range of metal atoms, like tungsten. The metallic bubbles are certainly cell-like, but are they actually alive? The early results have been encouraging.
Spiders Fleeing Floods Build Mosquito Buffet in Trees Photo: Russell Watkins / DFID When heavy rains caused rivers to overflow and flood parts of Pakistan last year, it set into motion a surprisingly complex chain of events that scientists are only now beginning to understand -- and which may have ultimately saved countless human lives. As waters began to rise, thousands of spiders sought refuge in tall trees, cluttering the leaves and branches with their webs in a manner reminiscent of cotton-candy. That, of course, is just the beginning of the story. >> WATCH SLIDESHOW: 10 of the World's Weirdest Spiders In the heavily flooded region of Sindh, Pakistan, these spider-web laden trees seems to have been quite effective at catching insects. Unfortunately, the trees themselves didn't benefit from being host to the spider's buffet. From New Scientist : Although slowly killing the trees, the phenomenon is seemingly helping the local population.
I, For One, Welcome Our New Computer Overlords Last night, IBM’s Watson computer won the final round of the three-day Man V. Machine Jeopardy! competition. At the beginning of the show, the humans were fierce, proving that they could buzz in faster than Watson, even though the machine knew the answer. Both human competitors, Ken Jennings and Brad Rutter, got it correct as well. Rutter: $21,600Jennings: $24,000Watson: $77,147 But although Watson won the competition, humans still prevailed. On Jeopardy! In this video from IBM, project researchers describe how a computer system like Watson could be capable of reading an unlimited number of documents, understanding the information and completely retaining it. Financial companies could use a computer like Watson to read and analyze news reports, market reports, trade publications, world events, blogs — you name it — and extract meaningful information for investors or business owners. I think Watson is agreat achievement of our time.