Follow Slashdot stories on Twitter


Forgot your password?

Slashdot videos: Now with more Slashdot!

  • View

  • Discuss

  • Share

We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).


+ - The origin of the first light in the Universe

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Before there were planets, galaxies, or even stars in the Universe, there really was light. We see that light, left over today, in the form of the Cosmic Microwave Background, or the remnant glow from the Big Bang. But these photons outnumber the matter in our Universe by more than a-billion-to-one, and are the most numerous thing around. So where did they first come from? Science has the answer."

+ - Is the Universe fine-tuned for us?

Submitted by StartsWithABang
StartsWithABang (3485481) writes "It’s pretty obvious that the Universe exists in such a way that it admits the possibility of intelligent life arising. After all, we’re here, we’re intelligent life, and we’re in this Universe. So at minimum, the Universe must exist in such a way that it’s physically possible for us to have arisen. But are there physically interesting things we can learn about the Universe from this line of reasoning alone? As it turns out, the answer is yes, but the things we can learn are extremely limited both in terms of scientific and philosophical significance."

+ - Dark Matter May Not Be Completely Dark

Submitted by StartsWithABang
StartsWithABang (3485481) writes "If you take two clusters, groups, or individual galaxies and collide them together, you'd expect the stars to pass through unperturbed, the gas to experience friction, slowing down and heating up, while the dark matter, if it's truly collisionless, will do the same thing as the stars. But if there's a tiny frictional force at work on dark matter, it, too, will slow down a little bit. A team looking at 72 groups and clusters saw no effect of slowing down, but then on the 73rd one, they saw a separation between the mass reconstruction and the stars. Is this the first sign of dark matter's interactions, or is it simply an astrophysical effect, or maybe even a fluke? A good recap and rundown of what we're looking at to the best of our knowledge."

+ - Dark energy measured better than supernovae with new technique

Submitted by StartsWithABang
StartsWithABang (3485481) writes "When it comes to measuring the expansion history of the Universe, the concept is simple enough: take something you know about an object, like a mass, a size, or a brightness, then measure what the mass, size or brightness appears to be, and suddenly, you know how far away that object has to be. Add in a measurement of the object’s redshift, and you can figure out not only what the expansion rate of the Universe is today, you can figure out the entire expansion history, and therefore what makes the Universe up. For practically all of the 20th century, we used brightness — or standard candles — exclusively. But new developments in both galactic surveys (like SDSS) and our understanding of dark matter and inflation has enabled us to use a new technique: baryon acoustic oscillations, or a standard ruler, which now gives us the best constraints ever on what dark energy is."

+ - That time Einstein and Schrödinger squandered the last 30+ years of their l

Submitted by StartsWithABang
StartsWithABang (3485481) writes "You've heard the saying, "God does not play dice with the Universe," and quite likely, of Schrödinger's cat as well. The idea that the Universe is random and — in many ways — unpredictable and indeterministic, is unsettling, to say the least. Yet it seems to be a fact inherent to our quantum Universe, a fact that neither Einstein nor Schrödinger could ever accept. Paul Halpern dives in deep to these issues in his newest book, as astrophysicist Ethan Siegel dishes in his review."

+ - The brightest galaxy beyond our local group is really unusual

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Of course the closest galaxies to us are going to be the brightest, with Andromeda, the Magellanic Clouds and the Triangulum Galaxy all visible to the naked eye. But beyond our local group? The next brightest galaxy is an oddity: 29 million light-years away, half the diameter of our Milky Way, and containing properties of both spiral and elliptical galaxies. In unparalleled views, come take a look at the sombrero galaxy, and learn what makes it so phenomenal."

+ - Supernovae may not be standard candles; is dark energy all wrong?

Submitted by StartsWithABang
StartsWithABang (3485481) writes "The accelerated expansion of the Universe — and hence, dark energy — was discovered by taking the well-understood phenomenon of type Ia supernovae and measuring them out to great distances. The results indicated that they were fainter than expected, and hence more distant, and hence the Universe's expansion must be accelerating. But new results have just come out, showing that supernovae may not be standard after all. Does this mean dark energy may not be real, or that it may just be slightly weaker than we previously thought?"

+ - Why NASA thinks the first signs of alien life are coming soon

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Earlier this week, NASA's chief scientist held a press conference, announcing that we should detect alien life by 2030, if both the Universe and the progression of telescope technology is as we expect. The technique is actually incredibly simple: examine what makes up the atmosphere of potentially inhabited exoplanets, and then you'll have your answer!"

+ - Mystery of how black holes get so big, so fast is solved

Submitted by StartsWithABang
StartsWithABang (3485481) writes "When we look at the centers of galaxies, it’s no surprise that there are large black holes there, millions or even billions of times the mass of the Sun. As we look farther and farther away, and hence farther back in time, we’d expect these masses to be much smaller. But what we find is that we have supermassive black holes at the centers of quasars many billions of times the Sun’s mass all the way back to when the Universe was just a few hundred million years old: less than 5% its current age. Does this mean our ideas about how the Universe formed all need to be thrown out? Hardly: here’s the solution to the mystery of how such massive black holes were formed so early on."

+ - The first rule of teaching science

Submitted by StartsWithABang
StartsWithABang (3485481) writes "The Universe is absolutely fascinating as-is, and perhaps the most remarkable fact about it is that it can be understood, scientifically, at all. But all too often, the most popular pieces of information that get widely disseminated are complete misinformation. If you're at all interested in teaching or communicating science, there's only one rule you need to follow, and everything flows from that."

+ - The LHC made simple

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Last week, CERN's Large Hadron Collider restarted, poised to set the all-time collider energy record at 13 TeV. But how does it work, what is it attempting to find, and if there is new physics out there, how are we going to find out? In five easy steps, physicist Ethan Siegel walks us through exactly what's happening at the world's most powerful machine."

+ - Solar eclipses are slowly disappearing

Submitted by StartsWithABang
StartsWithABang (3485481) writes "Of the solar eclipses where the Moon, Earth and Sun are perfectly aligned, about 50% of them are total, while the other half are annular. But this wasn't always the case, as the Moon has been spiraling out from Earth since it was first formed! As the Earth slows in its rotation, the Moon continues to move farther away to compensate. And about 650 million years from now, we'll experience our last total solar eclipse, and then we'll have to travel beyond Earth's surface to experience the phenomenon."

+ - The largest star in the known Universe

Submitted by StartsWithABang
StartsWithABang (3485481) 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."

+ - Why the planets all orbit in the same plane

Submitted by StartsWithABang
StartsWithABang (3485481) 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."

+ - The most astounding fact about the Universe

Submitted by StartsWithABang
StartsWithABang (3485481) 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."

"A car is just a big purse on wheels." -- Johanna Reynolds