What will the Orion Nebula look like after all the gas is used up?
After the gas dissipates, you will be left with a cluster of stars a bit smaller than the Pleiades but consisting of O-type rather than mainly B-type stars. In about 50 – 100 million years these blue-white massive stars will evolve into red giants and their brightness will grow by many magnitudes to become a very pretty cluster of bright red stars about the size of the full moon. Orion’s Sword will have stabbed Orion and leaving a blood-red wound behind! And after a few million years they will star to erupt into supernova, just the way Betelgeuse did long before.
