This article was first published in the January 2007 ABR Electronic Newsletter.
In terms of the age of the cosmos, the prevailing theory among astronomers is that the universe is billions of years old, with stars and galaxies forming at extremely slow rates. Those who maintain the theory of a younger universe contend that the oldest galaxies possess only the appearance of great age, rather than actual great age. The old-universe theory, with its slow-forming galaxies, has recently been called into question. In an article subtitled “Galaxy-formation theory is in peril,” the October 8, 2005, issue of the journal Science News reported that astronomers have
looked deep into space and thus back to a time when newborn galaxies filled the cosmos. Some of these babies have turned out to be nearly as massive as the Milky Way and other galactic geezers that have [theoretically] taken billions of years to form. Despite being only about 800 million years old, some of the infants are chock-full of old stars.
These chunky babies may be pointing to a cosmic crisis. They don’t seem to fit the leading theory of galaxy formation, which cosmologists have relied on for more than 2 decades to explain an assortment of puzzling features of the universe.
The theory posits that a pervasive, slow-moving, invisible type of matter vastly outweights the observable matter in the universe. Under the gravitational influence of this unseen material, known as cold dark matter, galaxies start out as small, starry fragments that merge to become much bigger objects. That’s usually a gradual process, according to the theory.
The new findings raise the question: Did the universe have enough time during its first 800 million years for infant galaxies to have merged into mature-looking behemoths?” (Cowen 2005: 235).
The article goes on to report that, “over the past 18 months, several teams have found so many massive galaxies from this early epoch that the theory is being stretched to its breaking point, several astronomers say” (Ibid.). According to astronomer Michael Rowan-Robinson of the Imperial College of Science, Technology and Medicine in London, “Our expectation is that [under the current theory] when you look back in time, it should be hard to see very massive structures because most galaxies at that early time in the universe are expected to be small. It would be worrying if this kind of [massive] galaxy is common” at early times (Ibid.).
(When Prof. Rowan-Robinson mentions “looking back in time,” he is referring to the fact that extremely distant galaxies are so far from earth that the light from them, observable right now on earth, was emitted from them a long time ago, and is only now arriving at earth. A closer example would be our sun: its light takes 8 minutes to reach us, so if the sun exploded, we wouldn’t observe the explosion until 8 minutes after it occurred.)
If astronomers find too many early, massive galaxies, “we might not have the right galaxy-formation scenario,” stated Bahram Mobasher of the Space Telescope Science Institute in Baltimore (Ibid.). The reason is that the existence of such massive galaxies so early in the universe’s history challenges the theory that the first galaxies formed slowly. According to Science News, “the new observations of big galaxies in the most ancient of times have important implications. The findings suggest that the earliest galaxies formed stars in a great hurry, much more rapidly than galaxies that were born even a billion years later did” (Ibid.).
These new discoveries bolster the position of those scientists who have maintained that the gargantuan age of the universe is in fact only the appearance of age. Indeed, the Science News article referred to the new finds as “old-looking young galaxies,” further stating, “The observations indicate that some of the youngest galaxies in the universe are prematurely old” (Ibid. 236).
Recommended Resources for Further Study
Cowen, R. 2005. “Crisis in the Cosmos?” Science News, vol. 168, no. 15.