Early Universe Had Numerous Elliptical Galaxies

Just 200 million years after the Big Bang, the Universe may have already seen the formation of the first elliptical galaxies. In a new study, astronomers propose that much more such galaxies existed in the early Cosmos than was previously estimated.

Until recently, experts were convinced that the first stars appeared some 300 million years after the Universe was rapidly inflated into being, whereas the earliest galaxies appeared some 500 million years later. In fact, that appears to have not been the case.

The investigation that led to these conclusions is essentially forcing the international scientific community to revise its most basic models that try to explain what goes on in the Universe.

According to the new work, it could be that the reason why we can't seen all of those distant galaxies is because they are tremendously old, which means that their light has redshifted a lot. At the same time, the light signature they produce is tremendously faint, on account of the distances involved.

The elliptical galaxy whose discovery led to this whole investigation was discovered to contain stars that formed 13.5 billion years ago, whereas the Universe is about 13.75 billion years old.

“It seems probable that there are in fact far more galaxies out there in the early Universe than we previously estimated – it's just that many galaxies are older and fainter, like the one we have just discovered,” explains Jean-Paul Kneib.

The expert, who holds an appointment at the Marseilles, France-based Space Astronomy Laboratory, is also a coauthor of the new research paper. The work indicates the the oldest known galaxy before the last one was found to have developed some 480 million years after the Big Bang.

“This [discovery] challenges theories of how soon galaxies formed and evolved in the first years of the Universe. It could even help solve the mystery of how the hydrogen fog that filled the early Universe was cleared,” adds Lyon Observatory expert and lead study author Johan Richard.

“If this unseen army of faint, elderly galaxies is indeed out there, they could provide the missing radiation that made the Universe transparent to ultraviolet light,” the investigator goes on to add.

Astronomers believe that these objects are elliptical galaxies because these objects are generally a lot older than spiral galaxies such as our own Milky Way, Daily Galaxy reports.

“What our observations show is that alongside these compact galaxies were other ellipticals that were anything up to 100 times less dense and between two and five times larger – essentially fully grown – and much more like the ellipticals we see in the local Universe around us,” adds Michele Cappellari.

“The mystery is how these two different extremes, ‘grown up’ and seemingly ‘immature’ ellipticals, co-existed so early on in the evolution of the Universe,” concludes Cappellari, who is based at the Oxford University Department of Physics.