It sounds fairly alarming - but a scientist claims that our galaxy may not just be in the process of dying, but already be dead.
Kevin Schawinski of the Swiss Federal Institute of Technology, Zurich, explains that galaxies ‘die’ when they stop forming new stars from gas.
And it’s quite possible that our Milky Way is already dead.
Writing on The Conversation Schawinski says, ‘It’s entirely possible that the Milky Way galaxy is a zombie, having died a billion years ago.’
‘The crossroads of galaxy evolution is a place called the ‘green valley.’
‘This may sound scenic, but refers to the population between the blue star-forming galaxies (the 'blue cloud’) and the red, passively evolving galaxies (the 'red sequence’).
‘Galaxies with 'green’ or intermediate colors should be those galaxies in which star formation is in the process of turning off, but which still have some ongoing star formation – indicating the process only shut down a short while ago, perhaps a few hundred million years.
‘The glacial slowness of using up the remaining gas reservoir means that by the time we realize that a galaxy is in terminal decline, the 'trigger moment’ occurred billions of years ago.
‘The Andromeda galaxy, our nearest massive spiral galaxy, is in the green valley and likely began its decline eons ago: it is a zombie galaxy, according to our latest research.
‘It’s dead, but keeps on moving, still producing stars, but at a diminished rate compared to what it should if it were still a normal star-forming galaxy.
‘Working out whether the Milky Way is in the green valley – in the process of shutting down – is much more challenging, as we are in the Milky Way and cannot easily measure its integrated properties the way we can for distant galaxies.
‘Even with the more uncertain data, it looks like the Milky Way is just at the edge, ready to tumble into the green valley.