StartsWithABang (3485481) writes "After more than 10 years on the surface of the red planet, the Mars Opportunity rover has finally broken the 41-year-old-record (set on the Moon) for the distance traveled on a world other than our own. But unlike Lunokhod 2, there was no human driving Opportunity; it made its navigation decisions itself! If 1969 was a small step for man, this is one giant leap for robotics and engineers everywhere. Go read the full story, with a look back at its highlights, milestones and achievements!"
StartsWithABang (3485481) writes "On Wednesday, The Washington Post ran a story about a very large solar flare two years ago that missed Earth, but not by too much. From a scientific point of view, what is it that happens when a solar flare interacts with Earth, and what are the potential dangers to both humans and humanities infrastructure? A very good overview, complete with what you can do — as both an individual and a power company — to minimize the risk and the damage when the big one comes. Unlike asteroids, these events happen every few centuries, and in our age of electronics, would now create a legitimate disaster!"
StartsWithABang (3485481) writes "We generally think of the laws of physics as symmetric: there's no preferred location or direction in the Universe that's more physically valid than any other. And yet, there are some fundamental asymmetries: matter dominates over antimatter, muons decay in one direction and not the other 99.9% of the time, and left-handed spiral galaxies are more common than right-handed one. What, didn't know that last one? Turns out that's a real effect, and it's been noticed in more than one study. But is the fault in the stars, or is it ours?"
StartsWithABang (3485481) writes "You can imagine all sorts of objects in the Universe, from the very low mass like meteoroids to planets, stars, and even incredibly dense ones like white dwarfs, neutron stars and black holes. But what happens to these different classes of object when you allow them to merge with another object that could pass for its identical twin? The answers are varied and spectacular and show us all sorts of things about the Universe, from blue stragglers to supernovae to gamma-ray bursts and more!"
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!"
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!"
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!"
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."
That should read "100 billion years from now", not "100 billion years ago". My typo.
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!"
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!"
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."
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."
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!"
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!"