A major challenge to the big bang has come from observers using the corrected optics of the Hubble Space Telescope to measure distances to other galaxies. The new data is giving the theorists fits!
Here's a magazine article about it:
Astronomer Wendy Freedman and others recently used the Hubble Space Telescope to measure the distance to a galaxy in the constellation of Virgo, and her measurement suggests that the universe is expanding faster, and therefore is younger, than previously thought. In fact, it "implies a cosmic age as little as eight billion years," reported Scientific American magazine just last June. While eight billion years sounds like a very long time, it is only about half the currently estimated age of the universe. This creates a special problem, since, as the report goes on to note, "other data indicate that certain stars are at least 14 billion years old." If Freedman's numbers hold up, those elderly stars would turn out to be older than the big bang itself!
Still another problem for the big bang has come from steadily mounting evidence of "bubbles" in the universe that are 100 million light-years in size, with galaxies on the outside and voids inside. Margaret Geller, John Huchra, and others at the Harvard-Smithsonian Center for Astrophysics have found what they call a great wall of galaxies some 500 million light-years in length across the northern sky. Another group of astronomers, who became known as the Seven Samurai, have found evidence of a different cosmic conglomeration, which they call the Great Attractor, located near the southern constellations of Hydra and Centaurus. Astronomers Marc Postman and Tod Lauer believe something even bigger must lie beyond the constellation Orion, causing hundreds of galaxies, including ours, to stream in that direction like rafts on a sort of "river in space."
Cosmologists say the blast from the big bang was extremely smooth and uniform, according to the background radiation it allegedly left behind. How could such a smooth start have led to such massive and complex structures?
Geller's three-dimensional maps of thousands of clumped, tangled, and bubbled galactic agglomerations have transformed the way scientists picture the universe. She does not pretend to understand what she sees. Gravity alone appears unable to account for her great wall. "I often feel we are missing some fundamental element in our attempts to understand this structure," she admits.
Geller enlarged on her misgivings: "We clearly do not know how to make large structure in the context of the Big Bang." Interpretations of cosmic structure on the basis of current mapping of the heavens are far from definitive—more like trying to picture the whole world from a survey of Rhode Island, U.S.A. Geller continued: "Someday we may find that we haven't been putting the pieces together in the right way, and when we do, it will seem so obvious that we'll wonder why we hadn't thought of it much sooner."
That leads to the biggest question of all: What is supposed to have caused the big bang itself? No less an authority than Andrei Linde, one of the originators of the very popular inflationary version of the big bang theory, frankly admits that the standard theory does not address this fundamental question. "The first, and main, problem is the very existence of the big bang," he says. "One may wonder, What came before? If space-time did not exist then, how could everything appear from nothing? . . . Explaining this initial singularity—where and when it all began—still remains the most intractable problem of modern cosmology."
An article in Discover magazine recently concluded that "no reasonable cosmologist would claim that the Big Bang is the ultimate theory."
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