If you're brave enough to venture outside on a chilly Canberra night, you might just see one of the smallest galaxies in the universe.
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We normally think of galaxies as giants, full of billions to trillions of stars. Indeed, our Milky Way is one of these mammoths, a spiral galaxy made up of 400-or-so billion stars.
Yet there are some galaxies, called dwarf galaxies, that can harbour as few as only a hundred suns.
Apart from occasionally being eaten, these fossil galaxies have not changed much since their birth at the beginning of the universe.
Dwarf galaxies are often companions of larger galaxies, much like bees humming around a hive.
When a dwarf galaxy strays too close to the big galaxy, its stars can be torn out by gravity, and shredded into huge loops that swoop in and out of orbit of the big galaxy.
Astronomers have found such loops around our Milky Way, where in the past two billion years, a dwarf galaxy called Sagittarius has twice blasted through our galaxy, forming the Sagittarius Stream.
The stars in this stream will eventually become part of the Milky Way, as it shreds and "eats" this dwarf galaxy - galaxies form by swallowing other galaxies.
There are dozens of dwarf galaxy remnants just outside our Milky Way, most of which no longer make new stars.
Apart from occasionally being eaten, these fossil galaxies have not changed much since their birth at the beginning of the universe. Beyond our Milky Way's cannibalistic tendencies, we know of at least 50 intact dwarf galaxies happily buzzing around our galaxy.
Combined with our much bigger neighbour, the Andromeda galaxy, which hosts its own entourage of satellites, we have discovered over 100 dwarf galaxies in this so-called Local Group.
Over the past decade, the number of known dwarf galaxies has grown dramatically, and as our telescopes improve, even fainter and more distant dwarf galaxies are being discovered.
Understanding the populations and motions of these dwarf galaxies will help answer fundamental questions about dark matter and how galaxies form, as well as unlocking secrets about our cosmic history.
Living in the bush, we have incredible access to the night sky. Here in Canberra, a short drive from the glow of Civic, say to Mount Stromlo Observatory or the township of Tharwa, delivers unbelievably dark skies.
MORE SUNDAY SPACE:
And living in the Southern Hemisphere grants us front row seats to the brilliant light-show in the bustling centre of our Milky Way.
Think of it as viewing an expansive panorama of a city skyline from the suburbs.
Near the main attraction, you might spot what look like small, faint bits of the Milky Way that have broken off.
These are actually a pair of dwarf irregular galaxies, called the Magellanic Clouds, thought to be disrupted spiral galaxies.
Evidence of this battle with the Milky Way has been observed in the form of a long stream of hydrogen gas, which spans the 180,000 light years between the dwarf galaxies and the Milky Way.
So if you're willing to put on an extra layer of thermals and pack a flask of hot chocolate, you might be able to spot a dwarf galaxy or two. For most of Australia, they are also visible during summer, and will remain so for several more billions of years, waiting for you to gaze upon their starlight - so you have time!
- Markus Dirnberger is a postgraduate astronomy student at the Australian National University in Canberra.
