Early galaxies differed from current ones in ways scientists never thought of, revealed a study published on the Monthly Notices of the Royal Astronomical Society.
Aided by the ESO's Very Large Telescope (VLT) and the Hubble Space Telescope, astronomers has been able to put together a comprehensive picture of the structure of galaxies as far back in time as 11 billion years ago.
By studying galaxies located in front of a quasar - a space body brighter than a galaxy - scientists analyzed the galaxies' size, mass, content of elements and how quickly it creates new stars. The technique made it possible that many of the outer regions of the galaxy remained illuminated, which allowed scientists a chance to see into it. Moreover, researchers also counted with the active star formation within the galaxy which lit up the gas around it, allowing scientists to observe it directly.
Using Hubble Space Telescope, researchers could not only observe the recently formed stars in the galaxy, but they also could calculate how many stars there were in relation to the total mass, which is comprised of both stars and gas.
With the data, scientists determined that the relative proportion of heavier elements was the same in the center of the galaxy as in the outer parts, showing that the stars that were formed earlier in the center of the galaxy enrich the stars in the outer parts with heavier elements.
Johan Fynbo of the University of Copenhagen and Jens-Kristian Krogager of the Niels Bohr Institute explained the study techniques in the following terms: "By combining the observations from both methods - absorption and emission - we have discovered that the stars have an oxygen content equivalent to approximately one-third of the Sun's oxygen content.
This means that earlier generations of stars in the galaxy had already built up elements that made it possible to form planets like Earth 11 billion years ago," she said.
