71620213
submission
StartsWithABang writes:
With hundreds of billions of stars in the Milky Way, you’d think the largest star we’ve ever discovered would be in the most intense star-forming regions here, perhaps towards the galactic center. It’s a good thought, as we’ve discovered stars up to 175 solar masses there, but we can do better. The largest star we know of is located some 160,000 light years away in the local group’s fourth largest galaxy: the Large Magellanic Cloud. At the very center of the Tarantula Nebula, itself 1000 light years across, lies the star cluster R136, which contains at its core a single star some 260 times the mass and more than seven million times the luminosity of our Sun. And it might already be dead, having run out of its fuel while its last light still journeys towards us.
71540959
submission
StartsWithABang writes:
When we look at the planets in the solar system, it's perhaps surprising that they all orbit in the same plane to within just seven degrees. In fact, if we remove Mercury, they're in the same plane to within a mere two degrees. But the laws of gravity are the same in all three dimensions, and so you can easily imagine it could've been vastly different. Theory has told us, for some time, that a combination of angular momentum, gravity, and the "sticky" properties of matter should lead to a disk-like structure for all solar systems, but only recently have observations come along to confirm this. At the end of the day, we finally believe we have the full story.
71519399
submission
StartsWithABang writes:
There are many scientific facts that are simply remarkable when it comes to the Universe, including the stories of the stars, of galaxies, of matter, of life, of atoms and of subatomic particle. In short, every aspect of nature we can think of has its own unique, remarkable story. But there’s one fact that supersedes them all: the fact that the Universe itself can be understood, scientifically. This is much more profound than most people realize, and also the most powerful guide we have to unpacking and understanding the cosmos itself.
71515433
submission
StartsWithABang writes:
Black holes are some of the most extreme examples of physics in the Universe. Space is curved tremendously, there’s an incredible concentration of energy all in one, singular point, and everything that occurs, in theory, outside of the event horizon can be seen in our Universe. But what if one of those things that it can do is make the quantum vacuum in this incredibly curved space unstable? What if it can allow the vacuum to tunnel from its metastable state into one that’s truly stable? In theory, this can destroy the entire Universe.
71482617
submission
StartsWithABang writes:
When it comes to the very nature of quantum mechanics — about the inherent uncertainty and indeterminism to reality — it’s one of the most difficult things to accept. Perhaps, you imagine, there’s some underlying cause, some hidden reality beneath what’s visible that actually is deterministic. After all, a cat can’t simultaneously be dead and alive until someone looks can it? That’s one of the problems that both Einstein and Schrödinger wrestled with during their lives. An investigation of that story, their work on that front, and their friendship that ensued as both pursued that same end is thoroughly investigated here by physicist Paul Halpern.
71450757
submission
StartsWithABang writes:
It’s the simple formula we all know and recognize: inner, rocky worlds closest to the Sun, an asteroid belt farther out, and then gas giant worlds out beyond them. That’s how our Solar System works, at any rate. We’ve finally got enough data to determine whether other planetary systems are like us or not, and it turns out our configuration is quite rare. Simulations have caught up to this as well, and we've learned that Jupiter basically 'cleaned house' early on, a rare story explaining why our Solar System is so unusual!
71428017
submission
StartsWithABang writes:
When you think about our world and our place in the Solar System, you very likely think about Earth, spinning on its axis, with the Moon orbiting around it, and with the entire Earth-Moon system orbiting the Sun. In fact, all of it — the Earth spinning on its axis, the Moon revolving around Earth, the Earth revolving around the Sun, and even the Sun spinning on its own axis — spins in the same direction: counterclockwise, as viewed from looking "down" on the Earth's north pole. Is this true for all planets in all solar systems? The answer turns out to be "mostly," but there are some incredibly interesting exceptions.
71419777
submission
StartsWithABang writes:
When the electric potential difference between storm clouds in the upper atmosphere and the solid ground of the Earth becomes greater than the breakdown voltage in air, spontaneous lightning strikes occur, exchanging some 10^20 electrons per bolt. But this same phenomenon occurs, spontaneously, during volcanic eruptions, something that's been well-documented for nearly 2000 years. After decades of investigation, we're finally very close to understanding exactly how this happens.
71357109
submission
StartsWithABang writes:
If you move at the speed of light and are inside the event horizon of a black hole, you inevitably fall towards the singularity at the center. But if you were completely outside of the event horizon, you can escape. So what if you were completely outside of a large, massive black hole (with small spatial curvature at the event horizon) and then dipped just a small amount of matter inside. Could you just pull it out again? It turns out the answer is no, and that — to date — there's still no way to escape from a black hole!
71320649
submission
StartsWithABang writes:
We’re all familiar with Hubble’s law, or the notion that the Universe is expanding, and that the farther away you look, the faster you’ll see that distant galaxy moving away from you. This relation would be exact, if only the rest of the objects in the Universe didn’t exert gravitational forces on one another. They do, however, leading to distortions that aren’t really there when we try and reconstruct maps of the Universe, known as “fingers” and “pancakes” of God. Thanks to some amazing physics, however, we can understand and remove these artifacts, allowing us to map the Universe on the largest scales to unprecedented accuracy.
71289001
submission
StartsWithABang writes:
Once every 18 years, a French Abbey — Mount St.-Michel — becomes inaccessible, as the English Channel rises to such levels that the causeway that normally reaches it becomes engulfed by the surrounding waters. You might think this is due to the tides, where the Earth, Moon and Sun align, but then shouldn’t this happen twice a month, during the two Spring Tides? As it turns out, the effects are much more subtle, and involve the Moon’s elliptical orbit and the equinoxes as well, but when they all align, once every 18 years, a supertide is the result, and Mount St.-Michel becomes an island!
71259327
submission
StartsWithABang writes:
Every time we go to higher-and-higher energies with our particle accelerators, we increase the chances of finding new particles, new knowledge, and new fundamental physics. While there are also potential risks, the most commonly trotted-out one is that the LHC — set to run at 13 TeV, up from 7 TeV previously — will create an Earth-destroying black hole that will devour the planet in short order. Here's the physics of why that's impossible.
71219487
submission
StartsWithABang writes:
In 2012, Mars Science Laboratory performed the first robotically-controlled soft landing of a vehicle of such incredible mass: nearly half a tonne. A few months later, the rover, Curiosity, took the first ever billion-pixel mosaic from the Red Planet's surface, with breathtaking views of the terrain and alternate views of what the soils would look like were they here on Earth. Now in its third year on Mars, Curiosity is roving the low slopes of its ultimate destination: Mount Sharp.
71145797
submission
StartsWithABang writes:
You know the fundamental principle of special relativity: nothing can move faster than the speed of light. But space itself? That's not a "thing" in the conventional sense. Two years after coming up with special relativity, Einstein devised the equivalence principle, and thus began the development of general relativity, where space itself would have properties that changed over time, responding to changes in matter and energy. This includes the ability for it to expand, even faster than the speed of light, if the conditions are right.
71114405
submission
StartsWithABang writes:
Sure, it's easy today to look at the Sun and know it's a ball of (mostly) hydrogen, generating energy by combining those protons in a chain into helium through the process of nuclear fusion. But before we even knew that nuclear fusion was possible, we needed to figure out what the Sun was made out of, a more difficult task than you'd imagine. The credit was given to Henry Norris Russell (of Hertzsprung-Russell diagram fame), but he completely stole the work from a woman you never heard of, his student, Cecilia Payne, after discouraging her from publishing her work on the subject four years prior.
