A Quizzer's Guide to the Galaxy

Answer: The Milky Way

The name "Milky Way" comes from the Latin "Via Lactea". Many cultures have legends about the origin of the bright band in the sky which is what we see as we look at our own galaxy from the inside, and many of them have to do with milk! The best known is the legend of how Zeus gave the infant Heracles to suckle at the breast of his wife, the goddess Hera, while she was sleeping.

She woke, realised the boy wasn't hers and pushed him away. The spilled milk became the Milky Way.

Answer: barred spiral galaxy

A barred spiral galaxy has a central bar-shaped bulge of stars. For some years astronomers using radio telescopes suggested our galaxy was barred, and in 2005, observations by the Spitzer Space Telescope proved it. If you want to see what our galaxy looks like, look for Hubble space telescope images of NGC 1300 or of the Sculptor Galaxy.

Answer: a fried egg

Our galaxy is about 100,000 light years in diameter, and about 1000 light years thick on average, but in the middle it bulges out to a thickness of over 12,000 light years. Astronomers estimate the Milky Way contains at least 200 billion stars.

Answer: a supermassive black hole

Astronomers believe that most galaxies have supermassive black holes at their centre. A supermassive black hole has a mass of at least ten thousand times the mass of the Sun. They think the one at the centre of the Milky Way has a mass of four million times the mass of our Sun!

Answer: Pulsars

Pulsars are rapidly rotating neutron stars that shoot out beams of radiation as they spin. Each pulsar is distinctive in the pattern, frequency and timing of their pulses, so they're like natural lighthouses, each flashing their individual signature to the Universe!

Answer: Sagittarius

The actual centre is the supermassive black hole astronomers call 'Sagittarius A*'. We can't actually see it, but it's responsible for a massive radio source, created as dust, gas and whole star systems falling into the black hole.

Answer: Orion Arm

Astronomers call the Orion Arm a minor arm, because it's basically a spur sticking out of the Sagittarius Arm. That said, it still manages to be some 3,500 light years across and around 10,000 light years long!

Answer: globular clusters

Globular clusters are spherical clumps of older stars. They look a bit like somebody sprayed a blob of white paint on a black canvas. One of the best examples is Omega Centauri, which is visible to the naked eye, and can be resolved as a fuzzy blob with binoculars.

Answer: Magellanic Clouds

The Magellanic Clouds are named for the Ferdinand Magellan, who observed them during his voyage in 1519. They're easy to see with the naked eye from the southern hemisphere, but below the horizon for people in northern parts. They are irregular dwarf galaxies, orbiting the Milky Way.

Answer: Andromeda Galaxy

Astronomers aren't entirely sure whether this will be a hit or miss affair, but the result would most likely be that the two galaxies would merge. Unless the solar system is near the centre of the mess, it's likely to emerge unharmed.