2013. július 17.
What do you think is old? Your parents? Your grandparents? Well, in astronomical terms, humans never get old. Our Sun has been around for 4.6 billion years, and it's only halfway through its life! Because of the much longer lifespan of cosmic bodies, it can seem to us that nothing much changes in space. It's not very often that we get to see a star end its life in a fantastic supernova explosion. Or see an unlucky object stumble too close to a black hole and get sucked inside. But wait...that's exactly what astronomers are seeing at this moment! And it's not just any black hole that is ‘feeding’, but the supermassive black hole sitting at the centre of our very own Galaxy!
It's believed that almost every galaxy has a supermassive black hole at its heart. Ours is called Sagittarius A*, (pronounced ‘saj-it-air-ee-us A-star’). This is because when we look for it in the night sky, we have to look towards the constellation ‘Sagittarius’, which you can see in image 2 (link). But don't expect to see Sagittarius A. Black holes are named for their colour, or rather, their lack of colour. Against the dark background of space, black holes are invisible—until they begin feeding.
Now, a giant gas cloud floated too close to the black hole in the centre of our Galaxy, and for the first time ever, we're lucky enough to see it in action! This picture shows the cloud (in red), which has been stretched so much by the black hole's gravity, that it resembles spaghetti! This is actually called 'Spaghettification' or 'the Noodle Effect'. The funky blue lines criss-crossing across the picture are an artist's representation of the orbits each of the stars in this picture follow.
Cool fact: Before astronomers new that Sagittarius A* existed, they were very confused about some strange behaviour at the centre of our galaxy. About a dozen stars seemed to be dancing in circles around nothing! And whereas our Sun moves through space at around 220 kilometres per hour, these guys were zooming along at around 5,000 kilometres every second!