61864771
submission
StartsWithABang 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.
61829357
submission
StartsWithABang 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!
61788313
submission
StartsWithABang 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!
61776871
submission
v3rgEz 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.
61755761
submission
StartsWithABang 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!"
61748685
submission
jones_supa 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.
61627015
submission
StartsWithABang 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!
61606107
submission
StartsWithABang 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.
61606049
submission
StartsWithABang 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.
61543821
submission
StartsWithABang writes:
You might have heard over the past few years of black holes that have been discovered that have only a few times the mass of the Sun, approaching the theoretical limit of around three solar masses. This is not only true — as there are a few good candidates for the smallest at present — but it's conceivable that there are even smaller ones than we can produce by having a star right on the neutron star/black hole threshold going supernova! How do you make the smallest black holes in the Universe, and how could the Universe make ones that are even smaller? Answers here.
61380039
submission
StartsWithABang writes:
There’s a big difference between the Summer Sun and the Winter Sun, and it's something that you can feel here on Earth simply from the Sun’s rays. There’s no doubt that the Sun warms the Earth, and that it warms your portion of the Earth very differently during the Summer months as opposed to the Winter months. But did you ever stop to consider why? Is it the Sun’s fault? Our orbit’s fault? Something else? It turns out that all of the factors can be measured and quantified, and only two truly matter. Axial tilt is the reason for the season, and this is how the Sun's rays make it happen.
61344579
submission
StartsWithABang writes:
If you took a picture of the Sun at the same time every day for a year, what shape would it trace out, and more importantly, why? As it turns out, there's a huge variety among the planets: here on Earth, as well as on Uranus, Neptune and Pluto, it would make a figure-8 shape; on Mars and Saturn, you'd get a teardrop shape; on Jupiter and Venus you'd see an ellipse! Why isn't the shape simpler? Two reasons: axial tilt and orbital eccentricity. See how they come together and make this unique shape here!
61313709
submission
StartsWithABang writes:
With the World Cup in full swing, you might be wondering how the most spectacular set shots in history — the ones where the ball appears to break and accelerate sideways in mid-air — actually work. They might seem miraculous, but in reality the physics behind it has been understood for more than a century! In addition to gravity and air resistance, the right conditions can create a third force, the Magnus Force, on a spinning ball, causing it to break sharply at the last minute. If you ever wanted to understand the physics of football/soccer, this is a must-read! (Note: the physics works for baseballs, too.)
61191179
submission
StartsWithABang writes:
You might think all you have to do, if you want to know how far back in time you're looking, is to measure the distance to an object, know the speed of light, and it's a piece of cake to calculate how long ago the light left that object before traveling through the Universe to arrive at your eyes. That's a very good method so long as we're talking about planets, stars or even the nearest galaxies, but the farther away we look, the worse that method's going to do for you. You see, the Universe is expanding, and that complicates things greatly! But we now know enough about the Universe that we can figure it out for pretty much any object just by making a few measurements. Even the most distant supernovae we've ever observed.
61160493
submission
StartsWithABang writes:
You've likely encountered one of many amazing videos showcasing the phenomenon of quantum levitation, where a supercooled, superconducting disk levitates above a magnetic track and appears to move perpetually, without any loss of energy save for what air resistance takes away. But how does this phenomenon actually work? From the superconductivity to the magnetism and the configuration of the track, here's the physics of how it all works!
