Mira pulses like a cosmic heartbeat

The star Mira, or Omicron Ceti, is a red giant that dramatically changes brightness every 332 days, pulsing like a giant heart in space. Discovered in 1596, its light can increase 1,600 times, shifting from visible to the naked eye to needing a telescope. This happens because Mira, 400 times the size of our Sun, expands and contracts its outer layers due to internal instabilities. Studying Mira helps astronomers understand how stars age and what might happen to our Sun in billions of years. Interestingly, Mira also trails a vast tail of gas as it moves through space.