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Why Does the Moon Sometimes Look Huge?

Have you ever seen the moon floating above the horizon of your city, and noticed that it looked oddly huge? I sure have. In fact, I've seen the effect in lots of popular media, including that one iconic shot from E.T. and other "supermoon" photos. But aside from movie magic, why does this happen in real life? If the moon gets bigger in the sky, it would have to get much closer to the Earth -- and while the moon's orbit does bring it a bit closer at times, it doesn't come close enough to account for the massively visible change in size. So how do we explain this effect?

There are several things going on here. First up, let's stipulate that our moon is really big, relative to other moons we see in our solar system -- our moon is roughly a quarter of the diameter of our planet. That's huge, and what that means from our perspective on the ground is that the moon is always quite large -- even sometimes large enough to block out the sun (in the case of solar eclipses), though the sun is of course much larger and farther away. The other major factor appears to be psychological. When the moon appears to be near other objects (as it tends to be when near the horizon), our brains register its relative hugeness and effectively inflate its size because we finally see its size relative to other objects. When the moon is all alone up in the sky, with tiny points of light around it, we have no frame of reference -- though it's still the same size it would be if by the horizon. (A related effect occurs when you can see the big ol' moon in the sky on a sunny day -- it looks weirdly big, perhaps because the sun is also up there.) Finally, there is one more odd effect relative to items approaching the horizon...but I'll leave that last one for this most excellent ASAP Science video to explain:

How you experienced the extra-huge moon? Have you tried what they suggest in this video -- looking at it upside down? I have not, though I encourage you all to try the next time the moon is near the horizon.

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science
Why a Howling Wind Sounds So Spooky, According to Science
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Halloween is swiftly approaching, meaning you'll likely soon hear creepy soundtracks—replete with screams, clanking chains, and howling winds—blaring from haunted houses and home displays. While the sound of human suffering is frightful for obvious reasons, what is it, exactly, about a brisk fall gust that sends shivers up our spines? In horror movie scenes and ghost stories, these spooky gales are always presented as blowing through dead trees. Do bare branches actually make the natural wailing noises louder, or is this detail added simply for atmospheric purposes?

As the SciShow's Hank Green explains in the video below, wind howls because it curves around obstacles like trees or buildings. When fast-moving air goes around, say, a tree, it splits up as it whips past, before coming back together on the other side. Due to factors such as natural randomness, air speed, and the tree's surface, one side's wind is going to be slightly stronger when the two currents rejoin, pushing the other side's gust out of the way. The two continue to interact back-and-forth in what could be likened to an invisible wrestling match, as high-pressure airwaves and whirlpools mix together and vibrate the air. If the wind is fast enough, this phenomenon will produce the eerie noise we've all come to recognize in horror films.

Leafy trees "will absorb some of the vibrations in the air and dull the sound, but without leaves—like if it's the middle of the winter or the entire forest is dead—the howling will travel a lot farther," Green explains. That's why a dead forest on a windy night sounds so much like the undead.

Learn more by watching SciShow's video below.

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Space
SpaceX's Landing Blooper Reel Shows That Even Rocket Scientists Make Mistakes
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SpaceX's Falcon 9 rocket launches.
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On March 30, 2017, SpaceX did something no space program had done before: They relaunched an orbital class rocket from Earth that had successfully achieved lift-off just a year earlier. It wasn't the first time Elon Musk's company broke new ground: In December 2015, it nailed the landing on a reusable rocket—the first time that had been done—and five months later landed a rocket on a droneship in the middle of the ocean, which was also unprecedented. These feats marked significant moments in the history of space travel, but they were just a few of the steps in the long, messy journey to achieve them. In SpaceX's new blooper reel, spotted by Ars Technica, you can see just some of the many failures the company has had along the way.

The video demonstrates that failure is an important part of the scientific process. Of course when the science you're working in deals with launching and landing rockets, failure can be a lot more dramatic than it is in a lab. SpaceX has filmed their rockets blowing up in the air, disintegrating in the ocean, and smashing against landing pads, often because of something small like a radar glitch or lack of propellant.

While explosions—or "rapid unscheduled disassemblies," as the video calls them—are never ideal, some are preferable to others. The Falcon 9 explosion that shook buildings for miles last year, for instance, ended up destroying the $200 million Facebook satellite onboard. But even costly hiccups such as that one are important to future successes. As Musk once said, "If things are not failing, you are not innovating enough."

You can watch the fiery compilation below.

[h/t Ars Technica]

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