Forgot your password?

+ - What a quantum observation is (and isn't)

Submitted by StartsWithABang
StartsWithABang (3485481) writes "You've probably heard of the double-slit experiment, where you can pass even a single electron through a double-slit, and it interferes with itself, behaving like a wave. But if you observe which slit it passes through, you don't get any interference at all, and it behaves like a particle. You might have thought that you need a physical observer to do this, but as it turns out quantum observation doesn't have anything to do with an anthropomorphized "observer" at all; it's solely dependent on whether you have a quantum interaction capable of constraining the system. Come find out what a quantum observation is, and how it applies to Bell's Theorem, too!"

+ - Experiment claiming dark matter detection explained without dark matter

Submitted by StartsWithABang
StartsWithABang (3485481) writes "The astrophysical evidence for some type of non-baryonic, gravitational source of matter is overwhelming: hence dark mater. For the past two decades, a myriad of experiments searching for weakly interacting massive particles (WIMPs) — the leading dark matter candidate — have come up empty, placing tremendous constraints on whatever properties dark matter can have. But one experiment, DAMA, has seen an annual modulation in its experimental signature that's consistent with dark matter. Other, conventional explanations like nuclear decays, neutrino interactions or atmospheric muons have failed to explain the same observed signal. But a new explanation may have solved the mystery, and provides us with a definitive prediction that should be able to discriminate between dark matter and conventional sources. Very interesting stuff!"

+ - Has dark matter's final prediction just been verified?

Submitted by StartsWithABang
StartsWithABang (3485481) writes "On the largest scales — whether you're looking at the cosmic microwave background, large-scale structure or gravitational lensing — there's no viable alternative to a Universe with dark matter. But on the smallest scales, a number of predictions have gone unrealized for a long time. The worst culprit? The expectation of very small, low-surface-brightness dwarf galaxies as both satellites around larger galaxies and existing in isolation in what's presently identified as intergalactic space. Three years ago, we had nothing, and now we think we've found the first examples of both missing populations. If the Hubble Space Telescope's follow-up observations confirm this, dark matter will rule both the small-scales as well as the large ones!"

+ - How deep does the multiverse go?

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Our observable Universe is a pretty impressive entity: extending 46 billion light-years in all directions, filled with hundreds of billions of galaxies and having been around for nearly 14 billion years since the Big Bang. But what lies beyond it? Sure, there's probably more Universe just like ours that's unobservable, but what about the multiverse? Finally, a treatment that delineates the difference between the ideas that are thrown around and explains what's accepted as valid, what's treated as speculative, and what's completely unrelated to anything that could conceivably ever be observed from within our Universe."

+ - Where will we all be in 100 billion years? 1

Submitted by StartsWithABang
StartsWithABang (3485481) writes "We've come a long way in the Universe to get to where we are: we had to form protons and neutrons, atomic nuclei, neutral atoms, many generations of stars and galaxies and clusters on the largest scales to create the Universe we see today. And yet, the 13.8 billion years that have passed since our Big Bang is just a drop in the bucket compared to what's coming in our future. How would we perceive our Universe differently if we, instead, came about in this Universe 100 billion years ago? The differences are shocking, but maybe even more shocking is how much we'd be unable to know about our cosmic origins!"

+ - The Physics of Ninja Warrior's Warped Wall

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Even with a brief running start, how can you expect to run up a steeply-curved wall and grab the top when it's some fourteen feet off the ground? Yet, this is one of the obstacles you must overcome if you wish to achieve total victory, and it was recently accomplished by a woman who's all of 5'0" (152 cm). There's a technique to doing it right, and it's based 100% in the physics of the human body. A great, educational read for those of you who like exclamation points!"

+ - Solved: why the Moon's far side looks so different 2

Submitted by StartsWithABang
StartsWithABang (3485481) writes "55 years ago, the Soviet probe Luna 3 imaged the side of the Moon that faces away from us for the first time. Surprisingly, there were only two very small maria (dark regions) and large amounts of mountainous terrain, in stark contrast to the side that faces us. This remained a mystery for a very long time, even after we developed the giant impact hypothesis to explain the origin of the Moon. But a new study finally appears to solve the mystery, crediting the heat generated on the near side from a hot, young Earth with creating the differences between the two hemispheres."

+ - What came first, black holes or galaxies?

Submitted by StartsWithABang
StartsWithABang (3485481) writes "It was one of the most hotly contested questions for decades: we first expected and then found supermassive black holes at the centers of practically all large galaxies. But how did they get there? In particular, you could imagine it happening either way: either there was this top-down scenario, where large-scale structures formed first and fragmented into galaxies, forming black holes at their centers afterwards, or a bottom-up scenario, where small-scale structures dominate at the beginning, and larger ones only form later from the merger of these earlier, little ones. As it turns out, both of these play a role in our Universe, but as far as the question of what came first, black holes or galaxies, only one answer is right."

+ - How to leave your planet for free (energy, not price)

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Sure, many of us have dreams of leaving this world at one time or another. How wonderful it would be to leap from one giant rock to the next, if only it were easier. But the sheer amount of energy it would take leaves it well out of reach for most of us. But what if it were easier? What if we had a gravitational assist from another, nearby, massive world? We might not have such a thing in our Solar System, but what if things were different? Couldn’t that be a lot of fun, and wouldn’t that open up a whole new realm of interesting possibilities? Maybe, but there would be dire consequences, too!"

+ - The mass of elementary particles is fundamentally unknowable

Submitted by StartsWithABang
StartsWithABang (3485481) writes "You might think there are few physical quantities that are absolutely fixed when it comes to matter: properties that are so fundamentally inherent that even the weirdness of quantum mechanics can’t touch them. But the quantum nature of the Universe will have none of our prejudices, and will simply do what it does whether we like it or not. And that means, puzzlingly enough, that it’s physically impossible to know, exactly, what the mass of any one particle actually is!"

+ - Red sneakers and hoodies: The surprising upside of standing out->

Submitted by v3rgEz
v3rgEz (125380) writes "The casual outfit that Facebook co-founder and chief executive Mark Zuckerberg sported in front of elegantly dressed bankers and investors just before his company went public generated much clamor in the media. While some observers judged the young entrepreneur’s choice to wear his typical hoodie and jeans on such an official occasion as a mark of immaturity, others defended it as a sign of boldness that helped spread publicity about the deal. The research seems to be on Zuck's side: Dressing down might help you get ahead in many environments."
Link to Original Source

+ - What does alien life look like? 1

Submitted by StartsWithABang
StartsWithABang (3485481) writes "When you look up at the stars in the night sky — bright and dim, young and old, near and far — can you help but wonder which ones of them might house life of any variety? And if so, how similar or different it might be from that on Earth? It’s one of the greatest as-of-yet unanswered questions in all of science. Yet there's plenty of science about this topic that we do know, and it allows us to make quantitative predictions and explore the likelihoods of various possibilities in as robust a way as possible. The most important takeaway, "We learn none of this if we don’t look, and we close ourselves off to the possibilities of ever discovering what else is out there—however unlikely we may think it is—if we don’t seek. That sense of curiosity, of exploration, of looking for that next untapped niche to fill is the driving force behind our very existence. Let’s not turn back now!""

+ - Russia Moves from Summer Time to Standard Time->

Submitted by jones_supa
jones_supa (887896) writes "Russia's legislature, often accused of metaphorically turning back the clock, has decided to do it literally – abandoning the policy of keeping the country on daylight-saving time all year. The 2011 move to impose permanent "summer time" in 2011 was one of the most memorable and least popular initiatives of Dmitry Medvedev's presidency. It forced tens of millions to travel to their jobs in pitch darkness during the winter. In the depths of December, the sun doesn't clear the horizon in Moscow until 10am. The State Duma, the lower house of parliament, voted 442-1 on Tuesday to return to standard time this autumn and stay there all year."
Link to Original Source

+ - Happy Perfect Number Day

Submitted by StartsWithABang
StartsWithABang (3485481) writes "You've heard of Pi Day and maybe Tau Day, but as far as math holidays go, those are just approximations. But today — June 28th — is special whether you write it 6/28 or 28/6, because 6 and 28 are the first two perfect numbers, and the only two perfect numbers you'll find on a calendar in your lifetime. For an exact math holiday, try Perfect Number Day, going on right now!"

A method of solution is perfect if we can forsee from the start, and even prove, that following that method we shall attain our aim. -- Leibnitz