The Death Of Galaxies From The Inside Out

With advancing imaging technology comes, surprise, better images. The largest and most advanced telescope in the world, the European South Observatory’s Very Large Telescope, has been used to take a few snapshots of some of the oldest known galaxies in the universe. With a recently released study, the finding of a group of researchers from the ETF Zurich, Switzerland has shown an interesting pattern in the biggest galaxies: they are all dying from the inside out. With additional imaging from the Hubble Space Telescope, the group began looking into the end-of-life cycles of these star systems to study the death of galaxies.

These are not your average sized galaxies. They boast masses that can reach up to one hundred times the size of the Milky Way, but the ages of their stars are not uniform. Those stars on the outside are often the youngest (as is the case with the Sun!) while the stars on the inside are quite a bit older – estimated to have formed six billion years ago. The study went looking at twenty two galaxies, and the oldest ones all showed that they were rotting at the core. Sandro Tacchella, head of the team, says that they are not sure why these galaxies are failing to form new stars at the center. The biggest galaxies are called “red and dead” due to the reddish hue they give off. Younger galaxies, composed of a larger number of youthful stars, give off a bluish hue.

The Death Of Galaxies Caused By Massive Black Holes?

Previously, astronomers thought that a larger galaxy will gain more stars, at any rate those on the outside, by colliding and then merging with a smaller galaxy. This is the case with medium-large sized galaxies. But the biggest galaxies seem to have formed from what are called compact cores. These are older galaxies that have recently stopped producing stars at an accelerated rate, but are not nearly as spread out as the biggest galaxies under question. It’s believed that a galaxy may begin small and compact, produce a great quantity of stars, and as the number of stars produced begins to decline, the galaxy will slowly spread out. The team thinks that the creation of a massive black hole at the center of these galaxies may be what stops them from producing more stars at the center. You can read the report on the death of galaxies in the latest edition of Science.

Perhaps one day, we all can ascend into space, maybe even to witness the death of galaxies. In the meantime, achieving flight is the next best experience, as depicted here: