Earth and our entire Milky Way galaxy may sit inside a mysterious giant hole which makes the cosmos expand faster here than in neighbouring regions of the universe, astronomers say. Their theory is a potential solution to the 'Hubble tension' and could help confirm the true age of our universe, which is estimated to be around 13.8 billion years old. The latest research – shared at the Royal Astronomical Society’s National Astronomy Meeting (NAM) in Durham – shows that sound waves from the early universe, "essentially the sound of the Big Bang", support this idea.