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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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Animals
Where Do Birds Get Their Songs?
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iStock

Birds display some of the most impressive vocal abilities in the animal kingdom. They can be heard across great distances, mimic human speech, and even sing using distinct dialects and syntax. The most complex songs take some practice to learn, but as TED-Ed explains, the urge to sing is woven into songbirds' DNA.

Like humans, baby birds learn to communicate from their parents. Adult zebra finches will even speak in the equivalent of "baby talk" when teaching chicks their songs. After hearing the same expressions repeated so many times and trying them out firsthand, the offspring are able to use the same songs as adults.

But nurture isn't the only factor driving this behavior. Even when they grow up without any parents teaching them how to vocalize, birds will start singing on their own. These innate songs are less refined than the ones that are taught, but when they're passed down through multiple generations and shaped over time, they start to sound similar to the learned songs sung by other members of their species.

This suggests that the drive to sing as well as the specific structures of the songs themselves have been ingrained in the animals' genetic code by evolution. You can watch the full story from TED-Ed below, then head over here for a sample of the diverse songs produced by birds.

[h/t TED-Ed]

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Animals
Watch the First-Ever Footage of a Baby Dumbo Octopus
NOAA, Wikimedia Commons // Public Domain
NOAA, Wikimedia Commons // Public Domain

Dumbo octopuses are named for the elephant-ear-like fins they use to navigate the deep sea, but until recently, when and how they developed those floppy appendages were a mystery. Now, for the first time, researchers have caught a newborn Dumbo octopus on tape. As reported in the journal Current Biology, they discovered that the creatures are equipped with the fins from the moment they hatch.

Study co-author Tim Shank, a researcher at the Woods Hole Oceanographic Institution in Massachusetts, spotted the octopus in 2005. During a research expedition in the North Atlantic, one of the remotely operated vehicles he was working with collected several coral branches with something strange attached to them. It looked like a bunch of sandy-colored golf balls at first, but then he realized it was an egg sac.

He and his fellow researchers eventually classified the hatchling that emerged as a member of the genus Grimpoteuthis. In other words, it was a Dumbo octopus, though they couldn't determine the exact species. But you wouldn't need a biology degree to spot its resemblance to Disney's famous elephant, as you can see in the video below.

The octopus hatched with a set of functional fins that allowed it to swim around and hunt right away, and an MRI scan revealed fully-developed internal organs and a complex nervous system. As the researchers wrote in their study, Dumbo octopuses enter the world as "competent juveniles" ready to jump straight into adult life.

Grimpoteuthis spends its life in the deep ocean, which makes it difficult to study. Scientists hope the newly-reported findings will make it easier to identify Grimpoteuthis eggs and hatchlings for future research.

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