LETTER of the MONTH
Thank you for your question, Tegan. The expanding universe is a tricky one to envisage because it’s occurring on such a grand scale that we will never see it happening. Ever since the universe came into existence following the Big Bang, it has been expanding. Most other galaxies are moving away from ours, the Milky Way, all the time. This is because the Big Bang is effectively spreading the contents of the universe outwards as it expands, assisted by dark energy, which is actually speeding up the expansion.