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A Pink Stellar Nursery and a Telescopic Birthday

The views expressed are those of the author and are not necessarily those of Scientific American.

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Glowing hydrogen and a stellar birthplace 6,500 light years away (ESO/VLT)

Fifteen years ago the European Southern Observatory, a consortium of 15 member states, started scientific operations with the Very Large Telescope (VLT) on Cerro Paranal in the Chilean Atacama desert. The VLT is a beast of an observatory, to put it mildly.

The VLT in all its glory - spot the human to the extreme left (ESO/VLT)











Four 8.2 meter diameter mirrors are housed in domes that would put most single mirror observatories to shame, and they’re complemented by four 1.8 meter diameter movable telescopes that can be utilized for optical interferometry – a technique to significantly improve the resolving power of the observatory for bright objects.

Often though, visiting astronomers only make use of the individual 8.2 meter instruments – each on its own is an enormous light gathering bucket capable of detecting some of the faintest, and most distant, objects in our observable universe.

These great telescopes also have Mapuche names: Antu (The Sun), Kueyen (The Moon), Melipal (The Southern Cross), and Yepun (The evening star – Venus).

The above image of a stellar nursery was chosen to help celebrate the fifteen years of operation of the VLT observatory, and its extraordinary discoveries. The nursery has a rather dull name of IC 2944, but it’s a beautiful place. Intense light from young stars is ionizing hydrogen gas, stripping electrons from protons, and as the hydrogen ensnares new electrons it ejects photons of light with the characteristic red-pink glow that illuminates this place with the color of a spring rose.

But in among this glow are dark forms, like flocculated clumps of matter held in a watery suspension. These are usually known as Bok globules, or in this specific case they are called Thackeray’s Globules after South African astronomer David Thackerary who spotted them in IC 2944 in the 1950′s.

They’re the densest remnants of the gas and dust-rich nebula that once was. Eroded by the punishing ultraviolet light of nearby young massive stars they are being eaten away, evaporating and shrinking. Although it’s possible that these clumps might one day condense under their own weight to form new stars, there are no signs of this happening. The more probable fate is for them to be dissipated back into component atoms and molecules, adding to the surrounding rosy fog.

It may sound a little mournful, but this is all part of a cosmic cycle, one day perhaps the contents of these globules will end up helping give birth to another set of stars, and it’s a fitting image to celebrate the great VLT.

Caleb A. Scharf About the Author: Caleb Scharf is the director of Columbia University's multidisciplinary Astrobiology Center. He has worked in the fields of observational cosmology, X-ray astronomy, and more recently exoplanetary science. His books include Gravity's Engines (2012) and The Copernicus Complex (2014) (both from Scientific American / Farrar, Straus and Giroux.) Follow on Twitter @caleb_scharf.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. jtdwyer 1:17 pm 05/29/2013

    Wonderful image – looking forward to many important observations in the future!

    Images of active stellar nurseries often seem to exhibit many stars at relatively close proximity – that do not seem to be violently interacting as one might expect. Are their discrete gravitational interactions muffled by the disperse mass of molecular clouds that still envelop them?

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  2. 2. David Cummings 6:19 am 05/30/2013

    “IC 2944 is an emmision nebula in Centaurus, 5900 light years distant.” —

    Why not just tell us how far away it is. I always want to know. I mostly have to go look it up. is absolutely terrible in that regard. Almost none of their astronomy stories ever mention distances. And they don’t have a comment section.

    Please. Just mention the distance of an object if you mention the object. How hard is it? When it’s not mentioned, I spend my time searching the article for it and missing what the article is about until I go off-site, find the answer, then come back and actually read the article.

    As for the observatory. Absolutely amazing. It must be an exhilarating experience working there.

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  3. 3. Caleb A. Scharf in reply to Caleb A. Scharf 9:57 am 05/30/2013

    The distance (6,5000 light years) is right there in the figure caption.

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