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+ - The independent lines of evidence that make dark matter all but unavoidable

Submitted by StartsWithABang
StartsWithABang (3485481) writes "When you hear about dark matter, you very likely put it up there with string theory in the pantheon of "well, that's a nice idea, now call me when you find it" style of scientific ideas. After all, direct detection of dark matter has proved elusive, despite many arduous experiments designed specifically to find it. Yet we continue to look, convinced that it exists. Why? Because of several compelling, independent lines of evidence that all point towards dark matter's existence. Here are the top five, and take note, modified gravity fans, that your best "theories" can only explain one out of the five!"

+ - Why didn't the Universe become a black hole? 5

Submitted by StartsWithABang
StartsWithABang (3485481) writes "With some 10^90 particles in the observable Universe, even stretched across 92 billion light-years today, the Universe is precariously close to recollapsing. How, then, is it possible that back in the early stages after the Big Bang, when all this matter-and-energy was concentrated within a region of space no bigger than our current Solar System, the Universe didn't collapse down to a black hole? Not only do we have the explanation, but we learn that even if the Universe did recollapse, we wouldn't get a black hole at all!"

+ - The Milky Way's Most Recent Supernova That Nobody Saw

Submitted by StartsWithABang
StartsWithABang (3485481) writes "The last two naked-eye supernovae changed the world: Tycho Brahe's supernova of 1572 and Kepler's of 1604 literally ushered in the modern age of astronomy, and yet despite the fact that supernovae occur about once-per-century in galaxies, we've never seen another Milky Way supernova since. But surprisingly, they've still been happening! It's only the fact that we're in the plane of the galaxy, whose dust blocks the visible light from such a large fraction of our neighboring stars, that's prevented us from seeing them. But we can look beyond visible light now, and have discovered at least two more recent ones since, including one that happened as recently as the 1860s!"

+ - How the Universe grew up... and stopped.

Submitted by StartsWithABang
StartsWithABang (3485481) writes "There once was a time when there were no stars, no galaxies, and no groups or clusters. These all formed, so at some point, the Universe was able to build these structures where there were none before. But today, everything that isn’t already gravitationally bound to itself never will be. How did we go from a perfectly uniform Universe to an almost perfectly uniform one, to one with stars, galaxies, and clusters, to one that won't result in any new gravitationally-bound structures anymore? The physics of gravitational growth (and its end); a fascinating story."

+ - The Smallest Possible Scale in the Universe

Submitted by StartsWithABang
StartsWithABang (3485481) writes "It's a question that goes back as far as inquiry about the physical world itself: is there a smallest, fundamental scale in the Universe? Yes, it's true that quantum theory tells us there's a limit to the resolution that we can measure (thanks, Heisenberg), but does that necessarily imply that there's a fundamental limit inherent to space (or physics) itself? Not necessarily, argues a new book from Amit Hagar, although both options are possibilities. Theoretical physicist Sabine Hossenfelder has a great take on it, exploring both sides and taking us right up to the edge of what is known."

+ - Floridian, (and Southern) governmental regulations are unfriendly to solar power->

Submitted by Anonymous Coward
An anonymous reader writes "Few places in the country are so warm and bright as Mary Wilkerson's property on the beach near St. Petersburg, Fla., a city once noted in the Guinness Book of World Records for a 768-day stretch of sunny days.

But while Florida advertises itself as the Sunshine State, power company executives and regulators have worked successfully to keep most Floridians from using that sunshine to generate their own power.

Wilkerson discovered the paradox when she set out to harness sunlight into electricity for the vintage cottages she rents out at Indian Rocks Beach. She would have had an easier time installing solar panels, she found, if she had put the homes on a flatbed and transported them to chilly Massachusetts.

While the precise rules vary from state to state, one explanation is the same: opposition from utilities grown nervous by the rapid encroachment of solar firms on their business."

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+ - Do Dark Matter and Dark Energy cast doubt on the Big Bang?

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Back in the 1960s, after the discovery of the Cosmic Microwave Background, the Big Bang reigned supreme as the only game in town. But back then, we also assumed that what we consider as "normal matter" — i.e., protons, neutrons and electrons — was, along with photons and neutrinos, the only stuff that made up the Universe. But the last 50 years have shown us that dark matter and dark energy actually make up 95% of the energy composition of our cosmos. Given that, is there any wiggle room to possibly invalidate the Big Bang?"

+ - The meteors you've waited all year for

Submitted by StartsWithABang
StartsWithABang (3485481) writes "It's finally here! Sure, we witnessed the birth of a new meteor shower earlier this year, but it was a flop. Many other showers have come-and-gone like they do every year, but none of them have given us a significant number of meteors-per-hour. But even with a near-full Moon out, it's finally time for the Perseids, the most reliable meteor shower year-after-year. Here's where to find them, where they come from and a whole lot more, including some surprising facts about where they don't come from: cometary tails!"

+ - Why the 'NASA tested Space Drive' is Bad Science

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Just over a century ago, N rays were detected by over a hundred researchers and discussed in some three hundred publications, yet there were serious experimental flaws and experimenter biases that were exposed over time. Fast forward to last week, and NASA Tests Microwave Space Drive is front page news. But a quick analysis shows that it isn't theorists who'll need to struggle to explain this phenomenon, but rather the shoddy experimentalists who are making the exact same 'bad science' mistakes all over again."

+ - The Man Who Invented the 26th Dimension

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Based on all the experiments we've ever been able to perform, we're quite certain that our Universe, from the largest scales down to the microscopic, obeys the physical laws of three spatial dimensions (and one time dimension): a four-dimensional spacetime. But that's not the only possibility mathematically. People had experimented with bringing a fifth dimension in to unify General Relativity with Electromagnetism in the past, but that was regarded as a dead-end. Then in the 1970s, an unknown theoretical physicist working on the string model of the strong interactions discovered that by going into the 26th dimension, some incredibly interesting physics emerged, and thus String Theory was born!"

+ - Where does cosmic rotation come from?

Submitted by StartsWithABang
StartsWithABang (3485481) writes "From the smallest scales to the largest, everything in the Universe spins and revolves. This is a good thing for galaxies and solar systems, otherwise there would be no such thing as planets or stars, as everything would simply collapse down into static, catastrophically massive-and-dense objects. But the Universe — as far as we can tell — wasn't born with any intrinsic angular momentum. And yet, everything rotates and revolves! Where did this cosmic rotation come from? From gravitation, the inevitable physics of torques, and the conservation of angular momentum."

+ - An atom in the Universe

Submitted by StartsWithABang
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."

+ - How are neutron stars magnetic?

Submitted by StartsWithABang
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!"

+ - Mars Opportunity sets all-time distance record

Submitted by StartsWithABang
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!"

+ - The Truth About Solar Storms

Submitted by StartsWithABang
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!"

The universe is like a safe to which there is a combination -- but the combination is locked up in the safe. -- Peter DeVries

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