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Where will we all be in 100 billion years?

StartsWithABang Oops (1 comments)

That should read "100 billion years from now", not "100 billion years ago". My typo.

about three weeks ago

Submissions

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An atom in the Universe

StartsWithABang StartsWithABang writes  |  12 hours ago

StartsWithABang (3485481) writes "It took 13.8 billion years of cosmic evolution and some 75 trillion cells consisting of 10^28 atoms to make you. About six years from now, you'll still be you, with the same number of cells, but practically none of those same atoms will still be in your body. Each one, though, as fleeting as it is, has its own unique cosmic story. Here's that story for just one of them, and yet, it's somehow the story of them all as well."
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How are neutron stars magnetic?

StartsWithABang StartsWithABang writes  |  yesterday

StartsWithABang (3485481) writes "The first (and simplest) force to be understood was gravity: there's only one type of mass (positive), it's always attractive, and it works the same on everything. The second force was electromagnetism: there are two types of charges (positive and negative), and the charged particles experience forces either in the presence of an electric field or from moving through a magnetic field. And magnetic fields can only be made when you have moving-or-spinning charged particles. So why is it, then, that a neutron star — a star made up of uncharged neutrons — has one that's a trillion times stronger than Earth's? As it turns out, neutron stars are both layered and aren't made of such neutral things after all, which make for some interested physics!"
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Mars Opportunity sets all-time distance record

StartsWithABang StartsWithABang writes  |  2 days ago

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!"
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The Truth About Solar Storms

StartsWithABang StartsWithABang writes  |  about a week ago

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!"
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Is our Universe left-handed?

StartsWithABang StartsWithABang writes  |  about a week ago

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?"
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What happens when the Universe's largest objects meet their twins?

StartsWithABang StartsWithABang writes  |  about two weeks ago

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!"
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What a quantum observation is (and isn't)

StartsWithABang StartsWithABang writes  |  about two weeks ago

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!"
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Experiment claiming dark matter detection explained without dark matter

StartsWithABang StartsWithABang writes  |  about two weeks ago

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!"
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Has dark matter's final prediction just been verified?

StartsWithABang StartsWithABang writes  |  about two weeks ago

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!"
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How deep does the multiverse go?

StartsWithABang StartsWithABang writes  |  about three weeks ago

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."
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Where will we all be in 100 billion years?

StartsWithABang StartsWithABang writes  |  about three weeks ago

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!"
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The Physics of Ninja Warrior's Warped Wall

StartsWithABang StartsWithABang writes  |  about three weeks ago

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!"
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Solved: why the Moon's far side looks so different

StartsWithABang StartsWithABang writes  |  about three weeks ago

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."
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What came first, black holes or galaxies?

StartsWithABang StartsWithABang writes  |  about a month ago

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."
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How to leave your planet for free (energy, not price)

StartsWithABang StartsWithABang writes  |  about a month ago

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!"
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The mass of elementary particles is fundamentally unknowable

StartsWithABang StartsWithABang writes  |  about a month ago

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!"
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What does alien life look like?

StartsWithABang StartsWithABang writes  |  about a month ago

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!""
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Happy Perfect Number Day

StartsWithABang StartsWithABang writes  |  about a month ago

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!"
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Where does Carbon-14 comes from?

StartsWithABang StartsWithABang writes  |  about a month ago

StartsWithABang (3485481) writes "With a half-life of "only" 5,700 years, you might wonder how there's any carbon-14 left on Earth at all. In fact, every single atom of it that our planet was created with is long gone by now, and yet every living creature has around one-in-a-trillion carbon atoms in their bodies represented by this unstable isotope. Believe it or not, this unstable form of this element has a cosmic origin, and has recently opened up a new mystery in our relatively recent history. Suddenly, carbon dating makes a whole lot more sense."
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Why do gravitational orbits decay?

StartsWithABang StartsWithABang writes  |  about a month ago

StartsWithABang (3485481) writes "One of the toughest things to get used to in this Universe is that our notions of eternal rarely pan out. The fixed stars move over time, their stellar fuel gets used up on timescales of billions or trillions of years, and even dark energy will cause all but the closest galaxies to recede away from us into the void of deep space. After the last star in the Universe burns out, you might think that the planets would continue to orbit, as at least gravitation isn't going anywhere. But as it turns out, gravitational orbits decay, too. A great primer on how, and how this helps show the insufficiency of Newtonian gravity."

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