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!
61131379
submission
StartsWithABang writes:
Big galaxies = big black holes, right? Our Milky Way has a central, supermassive black hole of about 4 million solar masses, while our big sister Andromeda has a significantly larger one. If we look at the entire local supercluster, the largest black hole in it can be found in the biggest galaxy: Messier 87. But what about the biggest black hole in the Universe? Is that going to be in the Universe's biggest galaxy? Quite likely, very not, as the largest black holes we know about aren't in the largest galaxies at all, for reasons we don't completely understand. Where are my next generation radio-and-X-ray telescopes to help us find out?
61088257
submission
StartsWithABang writes:
We've all been in that situation, whether we're applying for college, grad/med/law school, a scholarship, fellowship, grant, or simply a job: where you need a strong, positive recommendation to convince someone to take a chance on you. Some of us find ourselves on the other side of that as well: when we're asked to write such a letter. There's very little quality advice out there as far as who you should ask, when you should walk away, and when — as the recommendation writer — you should say no. (As well as how to do it.) A great must-read for anyone, especially young/inexperienced people, who find themselves in that position.
60988095
submission
StartsWithABang writes:
Reid Wiseman, one of the newest crewmembers aboard the International Space Station, has created the first Vine from space, a six second video constructed from 90 minutes aboard the space station, observing the Sun over an entire ISS orbit. A good explanation of how/why this happens can be found here.
60932687
submission
StartsWithABang writes:
So you look up at the sky, and you see a brilliant point of light — either in our own galaxy or in a foreign, distant one — where there was none before. It's much too bright to be a nova, so it's got to be a supernova, yes? Not so fast! Just when you thought the cosmos couldn't get any weirder, now you learn that there's such a thing as a supernova impostor, or stars that appear to fake their own death. Sometimes their actual deaths come just a couple of years later, other times many centuries pass, and still no further change. Here's what we know about what these objects are, where they come from, and what causes them.
60916167
submission
StartsWithABang writes:
In the 1800s, British astronomer John Couch Adams spent his life devoted to explaining the minor orbital deviations of the then-newly discovered planet, Uranus. But despite his best efforts to find the theoretical new planet responsible, he was scooped by the French theorist Urbain Le Verrier. To make matters worse, Adams sported one of the worst combovers in photographic history! But everyone gets a shot at redemption, and for Adams, discovering the origin of meteor showers and growing an epic beard saw him make good on both of those counts. Happy 195th birthday to one of astronomy's (and history's) forgotten heroes!
60877501
submission
StartsWithABang writes:
Earlier this week, attempts to cut NASA's budget were defeated, and it looks like the largest space agency in the world will actually be getting nearly a 2% budget increase overall. While common news outlets are touting this as a great budget victory, the reality is that this is shaping up to be just another year of pathetic funding levels, putting our greatest dreams of exploring and understanding the Universe on hold. A sobering read for anyone who hasn't realized what we could be doing.
60812047
submission
StartsWithABang writes:
If everything began with the Big Bang — from a hot, dense, expanding state — and things have been cooling, spreading out, but slowing down ever since, you might think that means that given enough time (and a powerful enough space ship), we'll eventually be able to reach any other galaxy. But thanks to dark energy, not only is that not the case at all, but most of the galaxies in our Universe are already completely unreachable by us, with more leaving our potential reach all the time. Fascinating, terrifying stuff.
60675661
submission
StartsWithABang writes:
On the one hand, galaxies are definitely redshifted, and they're redshifted more severely the farther they are; that's been indisputable since Hubble's data from the 1920s. But spacetime's expansion — the idea that photons get redshfited because expanding space stretches their wavelength — is just one possibility. Sure, it's the possibility predicted by General Relativity, but a fast-moving, receding galaxy could cause a redshift, too. How do we know what the cause is? Here's how.
60639119
submission
StartsWithABang writes:
It's hard to believe, but there are people alive today who remember a world where Newtonian gravity was the accepted theory of gravitation governing our Universe. 95 years ago today, the 1919 solar eclipse provided the data that would provide the test of the three key options for how light would respond to the presence of a gravitational field: would it not bend at all? Would it bend according to Newton's predictions if you took the "mass" of a photon to be E/c^2? Or would it bend according to the predictions of Einstein's wacky new idea? Celebrate the 95th anniversary of relativity's confirmation by reliving the story.
60596779
submission
StartsWithABang writes:
Recently, time-lapse photographer Thomas O'Brien put together his first video of the night sky, focusing on meteors and using nine years of footage to do it. But the majority of what you're seeing in that video isn't meteors at all, but presents an amazing opportunity to showcase what you actually see (and why) in the night sky. Enjoy the science behind a time lapse night sky.
