Hence my excitement a few years back at finally locating a faint blur high in the autumn sky, that is actually the Andromeda Galaxy, twice the size of the Milky Way, and our largest galactic neighbour.
Southern skies
And I was awestruck on a visit to South Africa 4 years ago to see the southern sky dominated by two large cloudy patches that even a casual observer could not fail to miss – our galaxy's closest neighbours, the Large and Small Magellanic Clouds (LMC and SMC) - named after the sixteenth century round-the world explorer Ferdinand Magellan. This was a special and rare experience for me as these galaxies are only visible from the southern hemisphere – in this image you can see them both in the sky above the ESO's Paranal observatory in Chile.
The LMC, a satellite of our own galaxy, is thought to be a spiral galaxy like our own, but which has been been distorted by the gravity of the much bigger Milky Way. Because it is so near (a mere 170,000 light years away), and it lies away from the bright main band of the Milky Way, powerful telescopes are able to see a lot of detail in it.
Star nurseries
For example, this image, taken by the European Southern Observatory's (ESO's) Very Large Telescope in August 2013, shows two glowing clouds of hot gas in the LMC, the birthplaces of young stars. The red cloud is hydrogen, and the blue one is oxygen - both are glowing due to the radiation from the hot young stars that they contain. These young stars have been formed from the hot gasses, and now their radiation is sculpting the gas from which they were formed - note the intriguing bubble formation around the central star in the cloud on the left.
As well as fine details, telescope observations of the LMC as a whole can tell us a lot about the dynamics and movements of the galaxy. It is known that spiral galaxies generally rotate, but how fast? For more distant galaxies this can only be calculated by observing the Doppler shift in their light (the way in which the frequency of the light's wavelength changes with movement towards or away from the observer). But the LMC is near enough that individual stars can be picked out by powerful telescopes, and earlier this year, much more precise measurements of the LMCs rotation were calculated by observing the tiny movement of hundreds of these individual stars over seven years. Researchers found that that the LMC takes 250,000 years to complete one rotation, in the pattern shown in this image.
Being home to a huge number of interesting astronomical objects, with examples of stars in many different stages of their life history, as well as evidence of the huge gravitational forces that shape our universe, the LMC and its little sister the SMC are a favourite hunting grounds for astronomers. For those of you who live in the southern hemisphere they will no doubt be a familiar sight; but for any northerners who happen to venture further south, don't forget to make a point of looking out for these beautiful and tantalising glimpses of the universe beyond our home galaxy.
1.ESO/H. Dahle
2. ESO
3. NASA/ESA
More about the Large Magellenic Cloud:
http://www.nasa.gov/press/2014/february/hubble-watches-stars-clockwork-motion-in-nearby-galaxy/#.U4JGqijDt-A
http://www.astronomynow.com/news/n1308/07lmc/#.U4rwLigcYnJ
Next week: Life cycle of stars