84106975
submission
StartsWithABang writes:
Recently, a team of international researchers has assembled the most comprehensive, up to date study on light pollution on Earth ever, including a full-Earth map of dark sky conditions or lack thereof. Its findings were disheartening but unsurprising, including the fact that 80% of Americans and 60% of Europeans cannot see the Milky Way. Although this may have detrimental effects to plants and animals, the largest negative may be humanity's disconnect from the night sky, and the Universe beyond our world as a result. If you're interested, it's not difficult to find a dark sky location within two hours of your location, pretty much independent of where you are.
84082967
submission
StartsWithABang writes:
In the beginning, before even the Big Bang, all that we had was space and time, expanding rapidly according to the rules of cosmological inflation. Today, we've got an observable Universe full of stars and galaxies, tens of billions of light years across, with at least one instance of intelligent life: on Earth. The story of how we got to be here was a mystery to philosophers, theologists and poets for all of human history, but advances during the last century have brought that from the realm of the speculative to firm, scientific knowledge. Here's that full story in 12 steps, totaling a mere 200 words.
84044783
submission
StartsWithABang writes:
Everyone knows that the Standard Model of particle physics cannot be all there is. It does a fantastic job of describing the known particles and interactions, but many mysteries remain, including the origin of the matter-antimatter asymmetry, the existence of dark matter and dark energy, the origin of the interaction strengths of the particles, and why they have the mass values that they do, among many others. Perhaps there are new fundamental particles and new fundamental forces out there, if only we can find them. Sometimes, clues come in the most unlikely of places. Investigating the excited state decay of Beryllium-8, a Hungarian team of researchers found a 6.8-sigma result indicating a potential new particle, a tremendous surprise to the physics community. But in order to be accepted, it needs further scrutiny and independent confirmation.
84025769
submission
StartsWithABang writes:
One of the toughest things to wrap your mind around in the natural world is the idea of special relativity: the faster you move, the closer you get to the speed of light, the more difficult it becomes to increase your speed at all. While you might approach the speed of light arbitrarily and asymptotically, you’ll never reach it. And yet, we have the Universe, expanding all the time, where the expansion rate itself is even speeding up. You might wonder, then, if these distant galaxies — the farther and farther away you look — might ever be seen moving away from us faster than the speed of light? Surprisingly and mind-bendingly, the answer is yes.
84009101
submission
StartsWithABang writes:
There are lots of things to worry about in this Universe, including falling into a black hole. But unless you happen to fall directly into the event horizon, an incredibly small region of space for most black holes, you very likely won’t be swallowed at all! Sure, you might be torn apart, accelerated, ionized, and spit back out at incredible, relativistic speeds, but at least you won’t be devoured. This is because black holes are incredibly messy eaters, spitting back out well over 90% of all the matter that falls into them, making them more like cosmic Cookie Monsters than any cosmic vacuum cleaner you might envision.
83986221
submission
StartsWithABang writes:
When we look out at the Solar System, the Sun dominates in terms of both light and mass. Responsible for nearly 100% of the light and for 99.8% of the mass, it stands to reason that stars would account for the vast majority of mass in the Universe. Yet when we apply what we observe of light and stars to structures like galaxies, clusters, and the large-scale structure of the Universe, not only do stars not get us there, but all the known forms of matter, including gas, dust, plasma and black holes, don’t get us there either. In order to account for the full suite of observations as astronomers’ and cosmologists’ disposal, there has to be something more to the Universe, outmassing normal matter by a 5-to-1 ratio, than all forms of normal matter can explain. At this point in time, the only explanation that nabs them all is dark matter.
83934735
submission
StartsWithABang writes:
For generations, if you wanted to know what the surface of the outermost known object in our Solar System – Pluto – looked like, you had to rely solely on your imagination. Sure, it was probably covered in ice, and large enough to pull itself into a sphere, but beyond that, little was known. Even with the Hubble Space Telescope, little detail could be made out; the best resolution was still hundreds of kilometers per pixel. That all changed in 2015, when the New Horizons spacecraft flew by Pluto for the first time. Reaching a minimum distance of just 12,500 km from this world, we were able to image large parts of its surface and atmosphere at resolutions of 80 meters (260 feet) per pixel. What we discovered was a diverse, rich world as geologically interesting as any planet we’ve ever found. Forbes has an exclusive video of the close-up of the terrain.
83929937
submission
StartsWithABang writes:
You might not think that boxing, the sweet science, and physics, the most fundamental of all the sciences, have much in common on the surface. But look a little deeper and you’ll find parallels between developing a unique skill set, solving problems, dissecting opponents and drawing the greatness out of the most difficult problems you can to increase your own glory. Many great scientists and boxers over the years have come and gone: Kepler, Sugar Ray Robinson, Faraday, Marciano, Schrödinger, Mike Tyson. All achieved greatness, but none achieved the same heights as Ali did in his sport. Even the greatest physicists of all, Maxwell, Newton and Einstein, were defeated in the end by contemporary problems (and, perhaps, arrogance) in ways that Ali never was.
83895445
submission
StartsWithABang writes:
Just thirty years ago, scientists argued over the value of the Hubble expansion rate, and what it meant for the age, history and fate of the Universe. Was the Universe expanding slowly (~55 km/s/Mpc), was it very old, and would it coast to infinity? Or was it expanding rapidly (~100 km/s/Mpc), was it young, and would it eventually recollapse? Since the Hubble space telescope was launched in 1990, those questions have been definitively answered, with a 13.8 billion year old Universe composed mostly of dark energy, with an expansion rate of around 70 km/s/Mpc. But recent measurements from one method give a value of 73 km/s/Mpc, while other method give 67-68 km/s/Mpc, each with an uncertainty of just 1 or 2. Rather than leading to a catastrophe, this tension likely represents a small but systematic error on the cosmic distance ladder, and becomes a big deal at the greatest distances.
83872925
submission
StartsWithABang writes:
On September 14, 2015, LIGO directly detected gravitational waves for the first time, from the inspiral-and-merger of two quite massive black holes. Despite the fact that no electromagnetic radiation signal was expected, the Fermi GBM instrument measured a high-energy X-ray event just 0.4 seconds after LIGO’s 200 millisecond detection occurred. According to NASA scientists working on the Fermi mission, there was just a 0.2% chance of a false positive. In a new paper out today, however, a reanalysis using a superior statistical method shows that the 0.2% chance is, in fact, true, and that LIGO’s black holes didn’t have an electromagnetic counterpart after all. This new statistical technique will be incredibly useful down the road for discriminating between robust astrophysical signals and spikes in the noise that have hitherto been a source of incredible confusion
83854115
submission
StartsWithABang writes:
If the Earth didn’t have any global warming at all, our planet’s mean temperature would be 255 K, or about -1 Fahrenheit: the mean temperature of the Antarctic continent. As it stands instead, our planet is much warmer than that, owing to the warming, insulating effects of the atmosphere, which is largely transparent to (incoming) visible light, but traps a fair amount of the (outgoing) infrared radiation. This effect is even more spectacular on our inner, sister planet, Venus. While Venus might be more reflective and twice as far from the Sun as Mercury, its greenhouse gases and insulating cloud layers are so effective that it’s actually the hottest planet in the Solar System, outstripping Mercury day or night.
83824521
submission
StartsWithABang writes:
Inside the nuclear furnace of the Sun, protons and other atomic nuclei are compressed together into a tiny region of space, where the incredible temperatures and energies try to overcome the repulsive forces of their electric charges. At a maximum temperature of 15 million K, and with a long-tailed (Poisson) distribution of energies at the highest end, we can compute how many protons are energetic enough to overcome the Coulomb barrier. That number is exactly zero. When you consider that 95% of stars are less massive and reach lower core temperatures than our Sun, the problem appears to be even bigger. Yet we’re saved by quantum mechanics, where spread-out wavefunctions can overlap, and nuclear fusion as we know it can proceed. At a fundamental level, it’s only the quantum nature of our Universe that enables the stars to shine at all.
83798667
submission
StartsWithABang writes:
Thanks to our position in space, the energy output of the Sun, and the right atmospheric conditions on Earth, we have temperatures conducive to liquid water on our planet. Over the past 4.5 billion years, that’s led to the flourishing and evolving of life, with our present existence marking something unlike anything else our planet’s ever seen. But it’s only a precarious set of circumstances that allowed it to be this way right now, and it won’t stay this way for long. The Sun is gradually warming, and has been its entire life. In another 1 or 2 billion years, it will increase its luminosity by so much that the oceans will boil, ending life-as-we-know-it on our world. We might be able to escape to other planets or star systems by then, but that doesn’t change the fact that global warming will eventually, if slowly, bring this all to an end.
83774137
submission
StartsWithABang writes:
When stars like our Sun run out of fuel, they expand into red giants, start fusing helium in their cores, blow off their outermost layers very slowly, and then their insides die. They heat up even further, contract down to white dwarfs, and the intense ultraviolet light ionizes and illuminates the blown-off material. But that material isn’t spherical, but rather lights up primarily as two bipolar jets! Even for stars that rotate slowly, the law of conservation of angular momentum still applies, meaning that even if it takes days, months or years for these giant stars to rotate, almost all of them still have a preferred axis. It also means our Sun very likely will, as well.
83739223
submission
StartsWithABang writes:
When people make claims that are patently untrue — like the Earth is flat — perhaps your knee-jerk reaction is to ridicule them. If you dig a little deeper, however, you'll likely discover a truth about your own past: that you once held views that flew in the face of the scientific evidence, only you weren't aware of it at the time. Hopefully, you changed your mind. Hopefully, the evidence was what compelled you to do it. And hopefully, if given the opportunity, you'd give that same gift to someone else. If you know someone who has an incorrect idea of how things worked, perhaps you wouldn't simply tell them the right answer; you'd give them a way to figure it out for themselves. Here's how you'd determine not only whether the Earth was flat or not, using technology available to people thousands of years ago.
