Elen sila lumenn omentielvo!

Sunday, February 17, 2013

Sunday Burst of Weird and Awesome

Oddities and Awesome abound!

:: What Single Girls Do on Valentine's Day. As you might expect, I love the ending here....


(seen on Tumblr)

:: In the "Science rules!" department, the other night, a friend commented on Facebook how bright and clear the stars were that night, and I responded with my observation that I like the winter sky in the northern hemisphere a lot more than I like the summer one, because it always seems so much brighter and clearer and it has my favorite constellation in it (Orion the Hunter). He asked if this was because it's just generally less hazy and humid in winter, and I have figured for years that this was the case, but then I decided to actually look it up. And you know what? The actual reason why the winter sky is clearer than the summer sky turns out, as is so often the case with science, to be even more interesting than the original supposition!

As seen during Northern Hemisphere winter (or Southern Hemisphere summer), the stars seem brighter. Why? It’s partly because – on December, January and February evenings – the part of Earth you’re standing on is facing into the spiral arm of the galaxy to which our sun belongs.

Consider the sky at the opposite time of year. In June, July and August, the evening sky seen from the entire Earth is facing toward the center of the Milky Way galaxy. The galaxy is about 100,000 light-years across, and its center is some 25,000 to 28,000 light-years away. We don’t see into the exact center of the Milky Way, because it’s obscured by galactic dust. But during those Northern Hemisphere summer months (Southern Hemisphere winter months), as we peer edgewise into the galaxy’s disk, we’re gazing across some 75,000 light-years of star-packed space (the distance between us and the center, plus the distance beyond the center to the other side of the galaxy).

Read the whole thing. Amazing! I love science.

More next week!

1 comment:

Roger Owen Green said...

So THAT'S why you like the Valentine's Day video...