70151059
submission
StartsWithABang writes:
On November 3rd, 2013, a total solar eclipse occurred as the Moon passed in front of the Sun, its shadow barely large enough to cover the disc of the Sun over a tiny swath of land in Africa. With camera teams in three different countries along the path of totality, Miloslav Druckmüller brrought out extraordinary details in the Sun's corona, even through the clouds, improving upon what spaceborne satellites (such as NASA’s SOHO) could observe. Due to the small shadow of the Moon at Earth's surface, he even created an image of the Moon's entire shadow as seen from Earth. Come see and learn about Druckmüller's amazing accomplishments during Earth's most recent solar eclipse.
70098561
submission
StartsWithABang writes:
Thanks to the fact that the Moon is tidally locked, we can only see 50% of it's surface on any given night. Over time, the fact that the Moon's orbit is elliptical, and that it moves faster at perigee and slower at apogee means that up to another 9% is visible over the course of many years. The observed "rocking" and growing/shrinking of the Moon over time is known as lunar libration, an incredibly interesting phenomenon. But now, for the first time, we've been able to visualize how the Earth appears to move as seen from above the far side of the Moon. A must see!
70063835
submission
StartsWithABang writes:
When you think of waves, chances are you think of some type of pressure wave moving through a medium, like sound or water waves, or you think of light, which is an electromagnetic wave that requires no medium to move through. But there’s another type of wave that exists, that no one expected before Einstein came along: gravitational waves. These are energy-carrying ripples through the fabric of space itself, explained in a beautiful analogy with light and detailing how they affect our Universe and how to detect them.
70028309
submission
StartsWithABang writes:
Our Universe is the way it is for two reasons: the initial conditions that it started off with, and the fundamental particles, interactions and laws that govern it. When it comes to the physical properties of everything that exists, we can ask ourselves how many fundamental, dimensionless constants or parameters it takes to give us a complete description of everything we observe. Surprisingly, the answer is 26 (not 42), and there are a few things that remain unexplained, even with all of them.
69996731
submission
StartsWithABang writes:
Moons in our Solar System — at least the ones that formed along with the planets — all revolve counterclockwise around their planetary parents, with roughly uniform surfaces orbiting in the same plane as their other moons and rings. Yet one of Saturn's moon's, Iapetus, is unique, with a giant equatorial ridge, an orbital plane that doesn't line up, and one half that's five times brighter than the other. While the first two are still mysteries, the last one has finally been solved!
69952749
submission
StartsWithABang writes:
When you think of dark matter, you very likely think of a halo of diffuse, unseen mass whose gravitational influence is felt by everything within our galaxy, and every galaxy or cluster out there. But what you might not consider is that this dark matter is consistently passing through Earth and every atom-and-molecule on it. Every once in a while, a lucky (or unlucky) dark matter particle strikes, say, a DNA molecule in your body, breaking its bonds and leaving an unmistakeable, destructive signature. Creatively, a new paper has the scoop on how we might use this exact phenomenon to experimentally, directly confirm the particle nature of dark matter!
69913387
submission
StartsWithABang writes:
In the early 1600s, Galileo became the first to resolve much of the Milky Way into individual stars, not yet knowing that it was also full of dust, nebulae, and star-forming regions as well. Thanks to amazing projects such as ESO’s Gigagalaxy Zoom, we can view the entire galactic plane at once, at resolutions unimaginable centuries ago.
69837339
submission
StartsWithABang writes:
Ever since quantum mechanics first came along, we’ve recognized how tenuous our perception of reality is, and how — in many ways — what we perceive is just a very small subset of what’s going on at the quantum level in our Universe. Then, along came cosmic inflation, teaching us that our observable Universe is just a tiny, tiny fraction of the matter-and-radiation filled space out there, with possibilities including Universes with different fundamental laws and constants, differing quantum outcomes existing in disconnected regions of space, and even the fantastic one of parallel Universes and alternate versions of you and me. But is that last one really admissible? The best modern evidence teaches us that even with all the Universes that inflation creates, it's still a finite number, and an insufficiently large number to contain all the possibilities that a 13.8 billion year old Universe with 10^90 particles admits.
69836627
submission
StartsWithABang writes:
Ever since quantum mechanics first came along, we’ve recognized how tenuous our perception of reality is, and how — in many ways — what we perceive is just a very small subset of what’s going on at the quantum level in our Universe. Then, along came cosmic inflation, teaching us that our observable Universe is just a tiny, tiny fraction of the matter-and-radiation filled space out there, with possibilities including Universes with different fundamental laws and constants, differing quantum outcomes existing in disconnected regions of space, and even the fantastic one of parallel Universes and alternate versions of you and me. But is that last one really admissible? The best modern evidence teaches us that even with all the Universes that inflation creates, it's still a finite number, and an insufficiently large number to contain all the possibilities that a 13.8 billion year old Universe with 10^90 particles admits.
69807007
submission
StartsWithABang writes:
It’s a taxing enough task to launch something off the surface of the Earth, escaping our planet’s gravity and finding our way into interplanetary space. But to reach the outer Solar System? To go beyond the gas giants and even escape from our Sun’s pull completely? We need a little help to do that. Thankfully, the biggest planet in our Solar System is always ready to lend a helping hand. Or, as it were, an assist of a very particular type: a gravity assist. Here's the story of how we made it to Pluto in a mere nine years, thanks to Jupiter.
69795671
submission
StartsWithABang writes:
Out beyond the orbit of Neptune, hundreds of thousands of large, icy bodies stably orbit our Sun, held very tenuously by our Solar System's gravity at such great distances. For the most part, these objects leave us alone, but every once in a while, a star passes close enough to our Solar System to perturb them, sending a great number into the inner Solar System and causing a (potentially life-threatening) comet storm. There's a candidate for a huge one a few hundred thousand years from now, and a certain one coming in about 1.4 million years. Comet defense, anyone?
69741743
submission
StartsWithABang writes:
If you want to map the entire sky — whether you're looking in the visible, ultraviolet, infrared or microwave, your best bet is to go to space. Only high above the Earth's atmosphere can you map out the entire sky, with your vision unobscured by anything terrestrial. But that costs hundreds of millions of dollars for the launch alone! What if you've got new technology you want to test? What if you still want to defeat most of the atmosphere? (Which you need to do, for most wavelengths of light.) And what if you want to make observations on large angular scales, something by-and-large impossible from athe ground in microwave wavelengths? You launch a balloon! The Spider telescope has just completed its data-taking operations, and is poised to take the next step — beyond Planck and BICEP2 — in understanding the polarization of the cosmic microwave background!
69700191
submission
StartsWithABang writes:
If you want to know where you are on Earth, you typically use a GPS or, barring that, other terrestrial landmarks to help determine your location. If you didn't have access to that sort of technology or knowledge, you could still use some well-known objects in the sky to determine your latitude. Longitude, however, is trickier, since it's arbitrarily defined. Perhaps surprisingly, for centuries, the best way to determine it was by using the moons of Jupiter, and watching when they enter/exit the shadow of the giant planet.
69666457
submission
StartsWithABang writes:
When stars between about 40% and 800% the mass of our Sun run out of hydrogen fuel in their cores, they expand into a red giant phase, burning helium in their center. The intense stellar winds produced blow off the star’s outer layers, and when the core runs out of helium to burn, the central region contracts to a white dwarf, producing intense ultraviolet light that lights up the expelled gas and ions, often found in extremely rare ionization states: a planetary nebula. Here's the story of the Cat's Eye Nebula, one of the closest, most detailed planetary nebulae of all, as told (mostly) through pictures.
69639537
submission
StartsWithABang writes:
With his incomparable superpowers such as strength, speed, and vision, Superman might seem like a model for the greatest athlete of all-time. What if he didn't fly, use his super-breath or eye lasers, but decided to play baseball using only standard equipment? How far would he be able to hit a baseball, limited by the environment of Earth and the laws of physics? A great analysis suggests five-to-six times farther than anyone has ever hit one, but no farther.
