74585001
submission
StartsWithABang writes:
If it's weren't for our atmosphere at all, the average temperature on Earth's surface would be a paltry 255 kelvin (-18 C / 0 F), so the greenhouse effect does plenty of good by warming us an additional 33 C (59 F) on average. But over timescales of hundreds of millions of years, the Sun's energy output increases as its core temperature — and the rate of fusion — heats up. In one-to-two billion years, the Earth's oceans will boil, ending life as we know it on our world. Perhaps we're very lucky life evolved as fast as it did on Earth; a little slower and intelligent life may never have had a chance.
74567599
submission
StartsWithABang writes:
In the solar system, everything orbits the Sun: planets, asteroids, kuiper belt objects and more. That is, unless an object is in orbit around one of those, like a moon or a satellite object. Is it possible, then, for a moon or satellite to have another level: an object that orbits it, in turn? While we presently haven't discovered any in our Solar System, it is theoretically possible, with numerous candidates already identified for where to look for such objects.
74538887
submission
StartsWithABang writes:
Our Sun, like all stars, spends most of its life burning hydrogen into helium, placing it on the main sequence. When we run out of fuel, we'll start fusing helium into carbon, a process that still takes a long time, but not nearly as long as hydrogen burning. In the most massive stars, this will be followed by phases of carbon burning, oxygen burning, silicon burning and more. Yet even as there are more phases to undergo, these phases take increasingly shorter amounts of time, and a star running out of fuel literally sees its life end in the blink of an eye.
74491345
submission
StartsWithABang writes:
When it comes to the fabric of our Universe, we live in four dimensions: three space and one time. At least, that’s what it seems like. But it’s possible that at very high energy scales — or at very small distance scales — not only might even more forces unify, but we might discover that the interactions between particles spill over into even more spatial dimensions. Through concepts like unification, duality and holography, we're starting to understand exactly what might be relevant for our Universe, and what might be forever beyond our reach.
74465967
submission
StartsWithABang writes:
Back in 2006, the International Astronomical Union officially defined the word “planet” for the first time, claiming that as long as something met all three of the following criteria:
1.) It was in hydrostatic equilibrium (pulled itself into a spherical/spheroidal shape under its own gravity),
2.) It didn’t orbit any other body larger than itself (i.e., wasn’t a moon), and
3.) Cleared its orbital path of all other major bodies,
then it got to be a planet. By that definition, Pluto was out. And yet, Pluto and all the other Pluto-like objects out there in the Kuiper belt are not only paramount to the formation of our own Solar System, these objects vastly outnumber the planets. Not only our Solar System’s planets, but the icy, lonesome Kuiper belt objects outnumber the planets galaxy-wide. With everything we’re learning about it, is it time to reinstate Pluto’s planethood?
74457383
submission
StartsWithABang writes:
The speed of light requires a little over four hours to send a signal from Pluto to Earth. With NASA's New Horizons having just completed its flyby the morning of July 14th, you might think that it's only a short matter of time before we have everything it has to offer. But in reality, when it begins data transmission, it will take a full 16 months to transfer the full suite of its data to us. Here's the science of why.
74363389
submission
StartsWithABang writes:
In our own Solar System, there are the four gas giant worlds, the four inner rocky worlds, and then a bunch of icy and rocky bodies smaller than those. But in other solar systems, there’s a whole class of worlds in between the size of Earth and Neptune, called either super-Earths or mini-Neptunes. This class not only exists, but it’s the most common type of planet in the Universe, to the best of our knowledge. Here's why we think we don't have one (now), owing to the unique, migratory history of our own planets.
74346067
submission
StartsWithABang writes:
A scientific theory needs to meet three criteria: it needs to explain all the successes of the previous leading theory, it needs to explain any failures or shortcomings that its predecessor couldn't, and it needs to make new, testable predictions that can either be falsified or verified. If the Multiverse doesn't meet that third criterion, can it be considered science? A fascinating exploration leads us to conclude that no, perhaps it isn't science after all.
74321109
submission
StartsWithABang writes:
Naming the planets in order and recognizing what they look like from their famous images might seem like an easy task. But an unfamiliar view, a focus on a single feature or a comparison with two similar images from other worlds can prove an incredibly difficult task. Take these two planet identification quizzes and see for yourself; the Solar System may be incredibly diverse, but the eight planets are often awfully hard to tell apart!
74289179
submission
StartsWithABang writes:
On Monday, xkcd asked 36 solar system questions, providing brief answers (and non-answers) to a few of them. But not only do most of them have actual, legitimate scientific answers, most of the ones that don't have had a lot of progress made on them. To the best of science's knowledge, here are the best answers to all 36 of them.
74264417
submission
StartsWithABang writes:
Back in the 1820s, Heinrich Olbers put forth his famous paradox: that if the night sky was filled uniformly and infinitely with stars, eventually the human eye should encounter one in any and all directions. Yet the darkness of the night sky clearly showed this was not the case! In modern times, the Big Bang provides a solution to this by showing that there is a finite age to the Universe, and hence a time before which there were no stars. There is a leftover glow, but it’s redshifted into the microwave region, visible as the CMB. And perhaps surprisingly, Poe — writing in 1848 — proposed a very Big Bang-like solution to Olbers’ paradox!
74132931
submission
StartsWithABang writes:
If there’s one thing you can be certain of when it comes to the fundamental, scientific truths of our Universe, it’s this: someday, in the not too distant future, those truths will be superseded by more fundamental ones. And even those, quite likely, won’t be the final truths, but just one step further along the line towards our understanding of reality. Does this mean that we’ve necessarily got it all wrong, and that we might just as well ignore the successes of our best theories so far? Does it mean that all we know about the Universe could easily be upended and replaced, leading to vastly different conclusions to questions like where everything came from? These are exceedingly unlikely, for a myriad of reasons. Instead, this is what the next major scientific revolution will probably look like.
74132477
submission
StartsWithABang writes:
There are few things as closely associated with American independence as our willingness and eagerness to celebrate with fiery explosions. I refer, of course, to the unique spectacle of fireworks, first developed nearly a millennium ago halfway across the world. But these displays don’t happen by themselves; there’s an intricate art and science required to deliver the shows we all expect. So what’s the science behind fireworks? Here's the physics (and a little chemistry) behind their height, size, shape, color and sound, just in time for July 4th!
74108169
submission
StartsWithABang writes:
From helium up through uranium continuously, every element in the periodic table can be found, created by natural processes, somewhere in the Universe. (With many trans-uranic nuclides found as well.) Yet out of all of those, only three of them aren't created in stars: lithium, beryllium and boron. Boron in particular is necessary for life as we know it, as without it, there would be no such things as plants. Here's the cosmic story of the only three heavy elements to exist that aren't made in stars.
74106027
submission
StartsWithABang writes:
When we talk about humans existing on worlds other than Earth, the first choice of a planet to do so on is usually Mars, a world that may have been extremely Earth-like for the first billion years of our Solar System or so. Perhaps, with enough ingenuity and resources, we could terraform it to be more like Earth is today. But the most Earth-like conditions in the Solar System don't occur on the surface of Mars, but rather in the high altitudes of Venus' atmosphere, some 50-65 km up. Despite its harsh conditions, this may be the best location for the first human colonies, for a myriad of good, scientific reasons.
