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The Mount Wilson Observatory has allowed astronomers to gaze at the heavens for more than a century from a peak in the San Gabriel Mountains, just northeast of Los Angeles, but the devastating conflagration known as the Station Fire that ripped through the Angeles National Forest over the past week had stargazers wondering if the historic facility was about to go up in smoke. The flames got so close at one point that firefighters abandoned the facility, but now L.A. County Deputy Fire Chief Jim Powers has assured astronomers that he foresees “another hundred years for Mount Wilson Observatory.” This is the story of how firefighters saved the birthplace of modern astronomy as well as a virtual forest of communication towers that serve the region [AP].

On Monday night, the scene was grim. The observatory had been hastily evacuated that day, and only two-dozen firefighters stood overnight sentry, positioned along the gloomy perimeters of the observatory and towers. A greater number might have been deployed, but there were more pressing priorities in the urban elevations — the protection of hillside homes [Los Angeles Times]. By daybreak, fire chiefs made the call to retreat from the mountaintop, where firefighters could easily be trapped by the oncoming flames. “It’s not worth dying for,” said Los Angeles County Fire Department Battalion Chief Steve Martin [Los Angeles Times].

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It’s a galaxy-eat-galaxy world out there. A new study of the Andromeda galaxy, the closest neighbor to our own Milky Way at 2.5 million light years away, has mapped Andromeda in unprecedented detail and found evidence that it grew through devouring smaller galaxies. Stars and dwarf galaxies that got too close to Andromeda were ripped from their usual surroundings. “What we’re seeing right now are the signs of cannibalism,” said study lead author Alan McConnachie…. “We’re finding things that have been destroyed … partly digested remains” [AP].

Astronomers had already posited the “hierarchical model” in which small galaxies combine to form large ones, but the new study shows the model in action. The map shows stars in bright streams and clumps that were also likely ripped from dwarf galaxies that once orbited Andromeda [New Scientist]. Researchers say the clumps of stars around the edge of Andromeda couldn’t have formed there, because there wouldn’t have been enough gas to give birth to them.

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Astronomers have determined beyond all reasonable doubt that the heart of the Milky Way is a supermassive black hole, two research teams say. Astronomers have inferred the existence of a gravitational monster in the center of our galaxy for years, but the new results are “the best empirical evidence that super-massive black holes do really exist” [CNN], said researcher Reinhard Genzel.

Similar supermassive black holes are thought to form the center of many spiral and elliptical galaxies, and astronomer Robert Massey says the results suggest that galaxies form around giant black holes in the way that a pearl forms around grit. Dr Massey said: “Although we think of black holes as somehow threatening, in the sense that if you get too close to one you are in trouble, they may have had a role in helping galaxies to form – not just our own, but all galaxies” [BBC News]. Massey explains that if a black holes brings enough matter together in a dense cluster, it creates ripe conditions for the formations of stars and galaxies.

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