Astronomers Learn About Alien Galaxy's Evolution Through Images, Believe 'Something Significant Happened Not Too Long Ago'
NASA continually captures stunning pictures of various phenomena in space, which gives experts more knowledge regarding various formations in the universe. Recently, NASA's Hubble Space Telescope caught a glimpse of a particular formation in space. The pictures showcased how other galaxies necessarily do not follow the pattern of the Milky Way Galaxy. Findings regarding the several revelations made by the pictures have been published in The Astrophysical Journal.
The subject of the photos is the Andromeda galaxy, which is located 2.5 million light-years away. The pictures illuminated the existence of three dozen small satellite galaxies. Researchers made several observations regarding this galactic "ecosystem" using the data gathered by 1,000 Hubble orbits. The team also created a 3D map describing how dwarf galaxies surround Andromeda and attempted to trace how these galaxies formed over 14 billion years.
The findings indicate that the Milky Way and Andromeda Galaxy evolved differently. While the former had quite a placid journey, the latter experienced many dynamic phenomena like a major merger with another big galaxy. "Everything scattered in the Andromeda system is very asymmetric and perturbed. It does appear that something significant happened not too long ago," said principal investigator Daniel Weisz of the University of California at Berkeley, stated NASA. "There's always a tendency to use what we understand in our own galaxy to extrapolate more generally to the other galaxies in the universe. There have always been concerns about whether what we are learning about the Milky Way applies more broadly to other galaxies. Or is there more diversity among external galaxies? Do they have similar properties? Our work has shown that low-mass galaxies in other ecosystems have followed different evolutionary paths than what we know from the Milky Way satellite galaxies."
Researchers further noted that the formation of stars by these satellites depends on factors like distance and size. "We see that the duration for which the satellites can continue forming new stars really depends on how massive they are and on how close they are to the Andromeda galaxy," said lead author Alessandro Savino of the University of California at Berkeley. "It is a clear indication of how small-galaxy growth is disturbed by the influence of a massive galaxy like Andromeda." Another unique pattern that the team observed was in the alignment of these satellites. Half of them were in the same plane and all orbiting towards a particular direction. There was no variation at all. "That's weird. It was actually a total surprise to find the satellites in that configuration, and we still don't fully understand why they appear that way," said Weisz.
Experts further claimed that contrary to popular beliefs, star formation with these satellites did not stop till a few billion years ago. "Star formation really continued to much later times, which is not at all what you would expect for these dwarf galaxies," continued Savino. "This doesn't appear in computer simulations. No one knows what to make of that so far." Scientists never expected to find so many bodies inside the Andromeda galaxy. The research team is hopeful that they will get more findings from the photos so that they can have more insights into the galaxy's background. "We do find that there is a lot of diversity that needs to be explained in the Andromeda satellite system," added Weisz. "The way things come together matters a lot in understanding this galaxy's history."