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Milky Way

July 29, 2016

The glowing band of the Milky Way arches high across the sky on these mid-summer nights. At nightfall, it stretches from almost due north, high across the east, to almost due south. And it stands high overhead by midnight. But you need to get away from the glow of city lights to see it.

The Milky Way is the combined glow of millions of stars in the disk of our home galaxy. The galaxy’s busy core is in the teapot-shaped constellation Sagittarius, which is low in the southern sky at nightfall. We can’t see anything in the core because it’s hidden behind clouds of dust, which form dark lanes within the Milky Way.

Astronomers use special instruments to peer through this dust. These instruments reveal some remarkable sights, including clusters of some of the hottest, brightest stars in the entire galaxy.

Two of these clusters are known as the Arches and the Quintuplet. They probably formed just a few million years ago, when big clouds of gas and dust rammed together, triggering an intense bout of starbirth.

Many of the stars in these clusters are among the most massive in the galaxy. The heaviest is called the Pistol Star, and it’s probably more than a hundred times the mass of the Sun.

These massive stars are also extremely hot, so they burn through their nuclear fuel in a hurry. Within just a few million years, they’ll blast themselves to bits in titanic explosions. Even so, they’ll likely remain hidden from human eyes behind the cosmic haze.

Script by Damond Benningfield

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