Tuesday, November 28, 2017

Shopped out yet? Then thank your lucky stars for *this*

Okay, not stars exactly, lucky or otherwise. But nonetheless astronomy news to take your mind off the post-Thanksgiving rat race ....

(Wait. What? You say you're not yet shopped out? Then see "Buy-a-Book Saturday redux." No need to be too literal here.)

Let's start with "An interstellar rock gets a name." The very first known interstellar interloper will henceforth be known -- never mind that it will soon have receded forever beyond our sight -- as Oumuamua. ("This is a Hawaiian name, meaning, roughly, 'very first scout.' ") Or, more formally, as 1I/2017 U1.

Oumuamua (an artists' conception)

We've even gained an inkling about the appearance of Oumuamua. See "ESO Observations Show First Interstellar Asteroid is Like Nothing Seen Before: VLT reveals dark, reddish and highly-elongated object." (ESO is the European Southern Observatory. VLT is ESO's Very Large Telescope.)

You've likely encountered reports that surface flows of water have been detected on Mars. Not so fast. Once geologists from the US Geological Survey reviewed the satellite observations, they reached a different conclusion: that "The case for flowing water on Mars is drying up." More specifically, the geologists interpreted:

... the “streaks” didn't behave like flowing water. For one thing, they existed only at the tops of very steep slopes. For another, the streaks all seemed to end when their slopes matched the dynamic  “angle of repose” — the steepest angle at which a given material can be piled without slumping.

If you've ever tried to build a sand castle, you're familiar with this concept. It's why dry sand -- which has a very shallow angle of repose -- tends to slide out of shape, but wet sand -- with a steeper angle of repose -- can be piled into towers and turrets.

Something sure whacked Phobos
And speaking of Mars, and in the news-in-the-making category, I was delighted to see that "NASA Joins Japanese Mission to Martian Moons: NASA is developing a key instrument for a daring mission to the Martian moons, Phobos and Deimos, including a sample return from Phobos."

Alas, the Mars Moons eXploration (MMX) mission is also an await-awhile-for-the-news story:

Set for launch in 2024, MMX will explore the tiny Martian moons Phobos and Deimos close up, then touch down on Phobos for a sample collection for return to Earth. The sample return capsule will then arrive back on Earth with its precious cargo in 2029.

But -- assuming all works as planned -- imagine how cool that will be. The primary mission goal: an answer to the longstanding mystery about those moons' origin(s). Are they captured asteroids? Were they ejected by some ancient impact upon Mars (in line with how our own Moon is believed to have formed)? Or maybe one of each?

Now that you've had a mental break from holiday shopping, it's still not to late to go buy a book ;-)

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