A couple weeks ago Laurie Miller shot me another quick email with a burning question. There's a YouTube video making the rounds purporting to show a large circular cloud formation above Jerusalem accompanied by a deep, continuous trumpet-like sound. Laurie's question: according to online articles, NASA says it's a natural thing, so what's going on?

I (painfully) read a bunch of the articles describing the video, and one amusingly ended with the rhetorical question "Is this caused by God or ET?" Well, let me toss in two more possibilities: nature, and a computer.

Regarding nature, none of the NASA quotes were attributed to a human being with a name. Just "a source at NASA", or "a NASA associate". A couple articles just quote "NASA", as if it were an entity capable of thought and commentary. Anyway, nature does make funny sounds sometimes, but I don't think that's the culprit here.

I'd also like to point out that we live in a age where almost every person on the planet carries with them a high-definition camera, and judging by Facebook and Twitter, enjoy sharing every single picture taken with those cameras. Jerusalem hosts around 800,000 such people, and this one dude was the only one to capture this strange event?

Did I mention that the dude who posted the video is a digital effects artist, whose YouTube channel features many other blends of the real and the virtual?

The irrepressible Chris Hurtubise, apparently satisfied with my response to her query on the color of the sky but hungry for more science, continued undaunted with a new question written on my board: what about the ocean? Sometimes it's blue, and sometimes it's brown or green. What gives?

Just like air, water is also a blue thing. And also just like air, it is only slightly blue. A glass of clean water appears almost perfectly transparent, but a waist-deep pool takes on a characteristic blueish tint. Although air gets its blue color from scattering of different wavelengths of light, water molecules simply absorb reds, yellows, and greens while reflecting blue.

This is most apparent when scuba diving, where colors are visibly muted. For example, if you accidentally cut yourself the wound appears mud-brown instead of vibrantly red. Photos of spectacular coral reefs are usually taken at night (when the corals are active) and using super-high-powered lights.

But there's more to water than water. Almost all of the oceans are deserts, both in the sense of meteorology (no rain) and biology (no life). A blue ocean is a dead ocean, but currents can dredge nutrients and minerals from the deeps, and where there's food there's life. Brown sediments and green and red algae can overwhelm the natural color palette of water. A murky ocean is a lively ocean.

Speaking of corals, those creatures require shallow, clear water so their symbiotic algae can get sunlight. Normally these regions would be devoid of life, but the reef system provides the base of a complex ecosystem - to the delight of divers worldwide.

During my keynote at the COSI All-Team meeting recently, I spoke about our decades-long fascination with the erstwhile planet Pluto, culminating in the recent New Horizons mission to the outer solar system. I showed off some images beamed back from the spacecraft that truly inspire and amaze me, featuring nitrogen plains, mountains of water ice, and more.

Later that day Laurie Mille, Manager of Living Collections, shot me a quick followup email, asking how New Horizons can transit images across the vast reaches of empty interplanetary space - over 3 billion miles, in fact - but she can't get decent cell reception in the mountains of Vermont.

NASA and the New Horizons team have a few things going for them that Laurie's cell phone doesn't. Like, 700 million things. Sending probes to the furthest reaches of the solar system ain't cheap, and some of that money is devoted to making sure that "NH phone home".

Second, Laurie's phone doesn't tap into the NASA Deep Space Network, a collection of gigantic radio dishes and antennas dotted across the world. Those are some pretty sensitive ears, capable of hearing even the faintest echoes of our far-flung spacecraft.

Lastly, while the distances are impressive, the obstacles are not. Here's NASA's problem:

Earth...........*3 billion miles of absolutely nothing*.......New Horizons

And here's Laurie's problem:

phone....../\.../\../\.../\/\/\.../\/\/\.....*a bunch more mountains*....cell tower

Mountains aren't the best of friends to radio waves, so that presents a unique challenge that's hard to engineer around. But even with all that money, all that gear, and all that empty space, it still took over a year for New Horizons to beam back the data from the brief Pluto flyby.