Saturday, 5 August 2017

M8: The Blue Lagoon

No, this post isn't about alcohol or eighties erotic cult movies, although there is some eroticism in what I'm about to write. Today I'd like to take you to one of the biggest baby star factories in our galaxy: M8 or the Lagoon Nebula. This gigantic gas cloud extends over 100 by 50 light-years across and is probably as deep as it is large, making it at least fifteen to twenty times the size of the mighty Orion Nebula. The latter looks bigger and brighter from our point of view but you have to bear in mind that the Lagoon Nebula lies four times further away from us, at a distance of 5,000 light-years. Yet, it still covers an area as large as three times the full Moon in our sky. Unfortunately northern viewers are eating their heart out because the Lagoon resides in Sagittarius, very low in the sky. Even from my observing spot in Northern Italy I had to point my telescope into the horizon glow in order to make this drawing. I can only dream about how this nebula would splendour from more southern latitudes.

As I said, this nebula is an enormous baby factory and the bright star cluster that illuminates its left half has only just emerged from it. With "only just" I mean two to three million years, the time when our first ancestors emerged from the African plains. A lane of foreground dust seems to cut the nebula in half and on its right-hand side we find the so-called "Hourglass Nebula", the brightest and most active region, heated up by the small but very hot star just next to it. Several nodules have been discovered here; clumps of contracting gas that will soon light up and become stars. 

To put things in perspective, the bright star halfway between the "hourglass" and the dark lane is 23,000 times brighter than our Sun in visual wavelengths and maybe 200,000 times brighter if we add Ultraviolet radiation!

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