Backyard Astronomy for Whovians: The Magellanic Clouds

Alas, today’s entry is invisible to those in the Northern Hemisphere, but it’s the spectacular highlight of the night sky for those in the Southern Hemisphere: the Milky Way’s two largest satellite* galaxies, the Small and Large Magellanic Clouds.  Named for the European explorer, Ferdinand Magellan, these two irregular** galaxies are home to young stars and dramatic nebulae, and in 1987, the Large Magellanic Cloud was even home to one of the best-observed supernovae in history.

*Well, maybe satellites.  More on that later….

**Conventionally, they’re described as irregular, but that also might not be accurate.  Read on.

Magellanic Mining Conglomerate

The Whoniverse is not particularly known for a richly interconnected and consistent continuity, but once in a while something gets name-dropped more than once.  The Magellanic Mining Conglomerate, which presumably operates out of the Magellanic Clouds, showed up first in The Ribos Operation.  It owns title to the primitive planet Ribos, which it is not allowed to actually exploit due to the planet’s level five (pre-spaceflight) civilization.  Posing as representatives of Magellanic Mining, a pair of con-artists, Garron and Unstoff, have conspired to sell a fake deed to the planet to the disgraced Graff Vynda-K, after first planting the idea in his head that the planet was rich in the rare mineral jethrik (which, of course, it really isn’t).  Their con falls apart after the Doctor and Romana arrive, of course.

unstoffgarrondoctor

It was another seven years before Magellanic Mining would get another screen reference, in the dark dystopia of Vengeance on Varos.  A penal colony had been established on the planet of Varos, rich in the rare mineral Zeiton-7, and the prisoners are used to provide free labor extracting it.  Zeiton-7 is essential to the function of time machines, so when the TARDIS breaks down, that’s where the Doctor and Peri have to go.  By the time they arrive, the colony is no longer populated by prisoners but by their descendants, who continue to manage it much like a prison, with brutality and a harsh system of public punishments which are televised and recorded for sale in other markets.  Despite being a unique source of Zeiton-7 ore, the population is unaware of the true market value of the product, having been kept so by the Galatron Mining Corporation which has managed to maintain its position as sole buyer thanks to some well-placed bribes among the guards.  Their chief competitor is the Magellanic Mining Conglomerate, which to this point has been unable to even get to the bargaining table, allowing Galatron to remain the galaxy’s sole supplier of the ore.

sil

The Magellanic Clouds

As obvious to southern viewers as the Milky Way is to northern viewers, the Magellanic Clouds have clearly been known since antiquity.  Though named for him, Magellan was certainly not the first person to see them nor even the first to write about them.  The Persian astronomer Al Sufi made the oldest surviving record of the clouds in 964, noting that they were only visible from the southernmost extent of Arabia.  The two small galaxies are visible to anyone in the Southern Hemisphere, though they may be observed (with some difficulty, very low in the sky, presuming an unobstructed horizon) as much as 20 degrees North latitude.

magellaniccoulds

They’ve long been considered irregular galaxies that orbit the Milky Way, although measurements of their motion show that they have not always been as near as they are now, and some studies suggest a barred shape near their cores, making each a sort of mini spiral galaxy.  Perhaps they only appear irregular because of the torturous interactions with our own galaxy’s tremendous gravity; each is associated with long streams of gas and stars torn away by interactions with the Milky Way, and they have in return distorted the outer edges of our own galaxy.  And recent studies using Hubble suggest they may not even be gravitationally bound to the Milky Way after all; they seem to be moving too quickly.

The clouds are home to a lot of beautiful nebulae, and the most famous is undoubtedly the LMC’s Tarantula Nebula.  It’s not visible to the naked eye, but telescopes and long exposures bring out a very complex entity.  It’s much brighter than the Northern Hemisphere’s Orion Nebula; if the Tarantula were as close to Earth as Orion is, it would cast shadows.

Tarantula_Nebula_TRAPPIST

In 1987, the Large Magellanic Cloud got even more exciting, when a blue supergiant near the Tarantula designated Sanduleak -69° 202 reached the end of its life cycle and collapsed.  The resulting supernova, designated SN 1987A, gradually brightened to magnitude 3, easily visible to the naked eye, and then slowly faded.  Its light-echoes continue to be studied, as it is the closest core-collapse supernova in recent years and an ideal candidate for better understanding these violent processes.  Here’s what it looks like today, in a composite of images from the Hubble Space Telescope and the ALMA radio observatory.

Composite_image_of_Supernova_1987A

I’ve never seen the Magellanic Clouds, but I hope someday to see them.  It’s probably my first priority if I ever get to the Southern Hemisphere — get a clear night and look up.  😉  And I’ll bring binoculars to enhance these lovely naked-eye targets.

 

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