StartsWithABang writes: It’s a good thing that sunlight doesn’t reach us simply from its moment of creation in the core of stars, otherwise we’d be bombarded with lethal gamma rays, rather than the life-giving UV, visible and infrared light we actually experience. But the neutrino signatures from those reactions can travel to us directly, allowing us to observe that direct sunlight indirectly, rather than from the photosphere or corona.
StartsWithABang writes: By far, one of the highlights of astronomy this year took place earlier this week: a total lunar eclipse featuring a perigee Moon. The sight of watching the Earth’s shadow consume the Moon, eventually swallowing it whole and revealing a faint, red lunar disk, and then the process reversing itself, is unlike any other visible to the naked eye. But the rest of the sky is always a treat as well. While a full Moon often ruins an otherwise pristine night sky with its light pollution, a dark sky during a lunar eclipse can be just as exciting as a new Moon sky, with a transition unlike anything else.
StartsWithABang writes: With such a low atmospheric pressure, liquid water on Mars seemed an unlikely prospect. But newly formed gullies gave us hints that something was flowing, the observation of salts showed that water must have been present, and the newest observations have taught us exactly how the combination of these salts plus water molecules can lead to liquid water under Martian surface conditions. Could these briny, crusty pools potentially house primitive, Martian life? It's not only possible, it's worth looking for.
StartsWithABang writes: When young galaxies are first formed, they’re accompanied by tremendous bursts of star formation, giving rise to billions of new stars within just a few million years. Yet how these galaxies first form in the initial stages is very much an open question. In addition, pretty much every large galaxy we find — even in the extremely young Universe — has a supermassive black hole at its center. But these black holes aren't the engines of newly formed galaxies, it's the other way around!
StartsWithABang writes: What causes those mysterious bright spots on the Solar System’s largest asteroid? Although those bright, highly-reflective features at the bottom of Occator crater on Ceres were what first jumped out at us, subsequent imaging has revealed that these features are present in many other (but not all!) locations where the surface has been eroded away by impacts. Measurements of Ceres’ density reveals that it’s not only much lighter than Earth, but also lighter than other large asteroids like Vesta, hinting at the possibility of a subsurface ocean. These features could be ice, rock, geyser or salt deposits, but are probably not volcanic in origin.
StartsWithABang writes: When you think about the frontiers of scientific knowledge — on the border between what’s known and what’s unknown — you have the phenomena that we know exist, yet that we can’t fully explain. This includes the matter-antimatter asymmetry, the inflationary origin of our Universe, dark matter and dark energy, among others. Yet two of these, inflation and dark energy, have an awful lot in common. Are they connected? There’s a whole class of models devoted to the study that they might be, but we have yet to have evidence come in, one way or the other.
StartsWithABang writes: The good news about life in the Universe is that the ingredients for it appear to be everywhere, including in interstellar space, in asteroids, comets, and a whole host of worlds other than our own. The bad news is that even if the conditions are right for life to arise, there's no guarantee that it will. Yet we might not even have to venture to another star system to find life beyond Earth; there are eight tantalizing possibilities right in our own backyard. Most excitingly, Pluto made the list!
StartsWithABang writes: We like to think that Newton was infallible until Einstein came along, with only the genius of special and then general relativity replacing Newtonian mechanics and gravitation. But when it came to the field of optics, it was the spectacular (and largely forgotten) work of François Arago that changed our conception of our world. A wonderful example of how logic, reason, and the power of your own mind is simply useless in understanding the world, unless you can confront your ideas with a physical experiment.
StartsWithABang writes: If you look at Earth from space, you’ll find that we’re a blue planet. You might chalk that up to the fact that our sky is blue, the sky is the outermost layer of our planet, and hence the planet appears blue. But then why do the continents and clouds appear to be such different colors, and why is the “blue” of the ocean such a different shade from the sky we see? It’s because the “blue” we see from space — or the blue we see from looking at the ocean — actually has nothing to do with the contents of our atmosphere! If you ever thought the ocean was blue because it reflects the sky, you’ve got to read this.
StartsWithABang writes: There are many issues associated with traveling to and landing on Mars that are both technological and financial, but going from robotic, automated spacecrafts to humans is a tremendous task! Larger payloads, softer, more precise landings, and biological considerations — including radiation, food and resupplies — are all concerns. Here are the six major issues we’ll have to overcome if we ever want to set up, create and sustain a human colony on Mars.
StartsWithABang writes: The deeper we look out into the Universe, the farther back in time we look. Our largest, deepest surveys have shown us not only galaxies in the very distant Universe, but teach us what they looked like when it was much younger, as well as how clustering — due mostly to dark matter — has evolved. The Extended Groth Strip, shown in full here, takes up just a sixth of a square degree on the sky, but contains over 50,000 galaxies, giving us a literal treasure trove of riches about the Universe.
StartsWithABang writes: In our Solar System, we have the inner, rocky worlds, an asteroid belt, the gas giants and then the Kuiper belt. Out beyond that, in theory, we have the Oort cloud, where a few of the longest-period comets come from. Due to its tremendous distance — the Kuiper belt ends at just 50 A.U. — we weren't able to find Oort cloud objects in situ for all of the 20th century. But that changed with the discovery of Sedna, and now we've got a handful of others, indicating to us at last that the Oort cloud is real!