What Do Green Galaxies Signify?

Scientists from Durham's Institute for Computational Cosmology (ICC) used a new computer modeling of the Universe to examine the green galaxies. It reveals that these galaxies are likely to be at the critical stage in their evolution when they are quickly turning from blue to red.

The study was presented at the Royal Astronomical Society's National Astronomy Meeting in Nottingham, the UK on June 30, 2016. It is named EAGLE or Evolution and Assembly of Galaxies and their Environments. The study was funded by the Science and Technology Facilities Council (STFC) and the European Research Council (ERC), according to Science Daily. The team used computer simulations to model how the ages of stars in galaxies and what those stars are made from transform into the color of light that they create.

James Trafford, the lead researcher and Ph.D. student in the ICC at Durham University explained that galaxies emit a healthy blue glow while new planets and stars are being born. On the other hand, if the formation of stars is halted galaxies turn red as stars begin to age and die.

Trafford also said that there are many blue and red galaxies in the Universe. On the other hand, the green galaxies are rarer. He further said that the few green galaxies they catch are likely to be at a critical stage in their evolution, quickly turning from blue to red.

The team also discovered that smaller green galaxies are being violently stirred around by the gravitational pull of a massive neighbor. This causes their gas supply to be stripped away. On the other hand, the bigger green galaxies may self-destruct as immense explosions produced by super-massive black holes at their centers can blow the dense gas away. On the other hand, there was hope for green galaxies as few might take up a fresh supply of gas from their surroundings.

A galaxy is the vast collection of dust, gas and billions of stars and their solar systems. It is held together by gravity. The galaxies are categorized into the spiral, elliptical or irregular. Many galaxies have black holes at their centers. This includes the Milky Way, with central black hole known as Sagittarius A. This has a mass four million times greater than the Sun.