Using the Hubble Space Telescope, astronomers have looked 11 billion years back in time to make sense of the origins of modern galaxies.

The Hubble Sequence groups galaxies based on their morphology and star-creating activity, placing them into a vast circus of spiral, elliptical, and irregular shapes with spinning arms, fuzzy halos and shining central bulges. The two primary types of galaxy pinpointed in this sequence are elliptical and spiral. A third type, known as a lenticular galaxy, is positioned somewhere between the elliptical and spiral types.

The Hubble Sequence poses the following questions: 1) is there any general regularity or symmetry to the galaxy, 2) is the light focused in the center, 3) is there a disk, and 4) are there any spiral arms.

However, there is a fifth question that must be asked: how does galaxy morphology alter as astronomers peer further back in time, to when the Universe was just an infant.

According to lead author BoMee Lee of the University of Massachusetts, this is an extremely important question. To answer this question, however, astronomers have to look back at far-away galaxies and stack them up against their closer relatives, to determine if they can also be defined in the same manner.

Although astronomers are well aware that the Hubble Sequence is valid as far back as approximately eight billion years ago, this new information moves an additional 2.5 billion years back in time, incorporating 80 percent of the Universe’s history. Previous studies had also looked into this time to examine lower-mass galaxies, but none had definitively also studied large galaxies like the Milky Way.

The astronomers discovered that the new information affirms that all galaxies 11 billion years back in time  match the various classifications of the Hubble Sequence.

According to co-author Arjen van der Wel of the Max Planck Institute for Astronomy, the galaxies appear exceptionally mature, which is not suggested by galaxy formation models to be the situation that far back in time.

The news release from the ESA’s Hubble Information Centre notes that the galaxies that far back in time seem to be divided between blue star-developing galaxies with an intricate structure and massive red galaxies that are no longer star producers.

Studies, such as this one, that accurately describe the characteristics of mature galaxies are difficult to conduct because galaxies as massive as the Milky Way are rare in the young Universe. However, a systematic set of observations from Hubble’s CANDELS survey gave astronomers the chance to examine a greater number of these galaxies consistently, and in detail.

According to Lee, the CANDELS dataset was a valuable asset for astronomers. Plus, the resolution and sensitivity of Hubble’s WFC3 is top notch in the infrared wavelengths required to conduct this study.

The Hubble Space Telescope took off from our planet on April 24, 1990, nestled securely in the bay of the Space Shuttle Discovery. On April 25, Hubble was released into space, prepared to explore the vast unknown of the cosmos, giving humans a window to examine the distant regions of our Universe yet to be explained.