The Birthplace of Stars

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Meet the Pillars of Creation, a photograph taken by the Hubble Telescope in 1995. These apparent “pillars” of dust and gas are what we call molecular clouds. And this region of clouds in space is aptly named: it’s where stars are created.

Technically, there are two types of molecular clouds—molecular clouds and giant molecular clouds, or GMCs—but I’ll get into that in a second.

Molecular clouds are deep within the interstellar medium. In case you don’t remember the ISM from my “recent” posts (sorry about that), it’s the stuff between the stars. It’s the galaxy’s backstage. Space is in fact not a perfect vacuum—it’s full of the ISM.

So what’s going on with molecular clouds like the Pillars of Creation? Continue reading

The Balmer Thermometer

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How hot would you say this star is? Take a wild guess.

Well…sorry, but I’m going to stop you for a moment just to make sure we’re all using Kelvins. The Kelvin scale is like the Celsius scale, except water freezes at 273 K instead of 0℃. 0 K is absolute zero, which is purely theoretical and doesn’t exist.

Now can you guess this star’s temperature?

I’ll give you another hint. This is a real photograph, so it’s impossible for this star to be any star other than our sun. How hot do you think our sun is?

Okay…I’ll tell you. It’s about 5800 K, which—for those of you unfamiliar with Kelvins—is about 5527℃. Kinda crazy, huh?

Next question. How do we know this? I mean, it’s not like we stuck a thermometer in the sun’s surface and actually measured it, right? Continue reading