Astronomers were able to detail our Milky Way galaxy’s first “family tree” and it revealed that the largest collision occurred around 11 billion years ago with another galaxy that was named after a mythical sea monster.
The collision between the Milky Way and Kraken galaxies is definitely an exciting revelation for those who work in the field of astronomy because it occurred about 11 billion years ago when our galaxy was in its developmental stages and its early history has remained a mystery for so many years.
While intergalactic collisions were fairly common in ancient times, the one that occurred between Milky Way and Kraken was so massive that it actually changed our galaxy’s appearance. A few examples of ancient collisions include the “Helmi Streams” event that occurred approximately 10 billion years ago; the Sequoia event that happened about a billion years later; and the Gaia-Enceladus event that occurred a short time later around 9 billion years ago. In fact, the Gaia-Enceladus event was believed to have been the biggest ever collision with our galaxy until experts uncovered the Kraken event.
According to Dr. Diederik Kruijssen from the University of Heidelberg and who co-authored the study, since the merger with Kraken occurred 11 billion years ago when our galaxy was around four times smaller than it is today, it would make sense that the event changed its appearance.
Our galaxy is huge at about 100,000 light-years across with spiral arms and a peanut-shaped core. So in order for the experts to find out how it became so massive, they used artificial intelligence to study global clusters that contain up to a million stars.
Dr. Kruijssen as well as Dr. Joel Pfeffer from Liverpool John Moores University and a team of international researchers created computer simulations of our galaxy called E-Mosaics which allowed them to study different global clusters.
There are over 150 clusters in the Milky Way and many of them were created in other small galaxies that eventually merged with ours. Around five galaxies with over 100 million stars and approximately 15 galaxies with a minimum of 10 million stars all merged into the Milky Way, with the largest ones colliding with us between 6 and 11 billion years ago.
Their research was published in Monthly Notices of the Royal Astronomical Society where it can be read in full.