Galaxy Evolution After the Big Bang: Unraveling the Metamorphosis of Galaxies

Researchers, for the first time, have managed to make direct observations of galaxy “metamorphosis” proving that galaxies have changed their shape since they were initially formed after the Big Bang.

The team has observed around 10.000 galaxies now present in the universe.

To know more about the study of morphing galaxies, read the journal Monthly Notices of the Royal Astronomical Society.

The researchers used measurements of infrared emissions from dust in galaxies taken by the Herschel telescope and combined this with data from the Galaxy and Mass Assembly spectroscopic study to determine how far away these systems are.

Professor Asantha Cooray, a co-author of the research from the College of California, stated: “This research is necessary because it establishes statistics displaying that the majority stars shaped in spiral galaxies prior to now, however a big fraction of those now seem as giant, lifeless, at this time”.

Scientists classify galaxies into two categories, those that are shaped like a disc and rotate and those that are oval-shaped, very large and littered with millions of stars. They noted that after the formation of the stars, disc-shaped galaxies tend to suffer major restructuring and evolve into egg-shaped galaxies.

A team of worldwide scientists has shown for the first time that galaxies can change their structure over the course of their lifetime.

There is another school of thought as well that proposes a rather less violent transformation wherein stars formed in a disk gradually moving to the centre of a disk and producing a central pile-up of stars. But by using the Herschel and Hubble together for the first time the extent of this transformation has been accurately measured. According to it the stars formed in a disk.

Such galactic shape-shifting had been theorised before, says the study’s lead author Steve Eales of Cardiff University.

“Galaxies are the essential constructing blocks of the Universe, so this actually does symbolize one of the vital modifications in its look and properties within the final eight billion years”. The professor explained that this study has shown to everyone that this kind of transformation is not exceptional. That happened in its appearance in the last 8 billion years.

This study revealed 83% of stars formed since the Big Bang were initially disc-shaped, but only 49% that exist in the universe today are shaped like this, including the Milky Way (pictured from the ISS).

‘This study will require us to refine the models and computer simulations that attempt to explain how galaxies formed and behaved over the last 13 billion years’.