The existence of large-scale structures posed difficulties for Big Bang. But it still rested solidly on its two other pillars of helium abundance and microwave background ratiationat least, as far as the general perception went. We've already seen that the wide-spread acceptance of the background radiation was a peculiar business, since it had been predicted more accurately without any Big Bang assumptions at all. More recently conducted work showed that it wasn't necessary to account for the helium abundance either.
The larger a star, the hotter its core gets, and the faster it burns up its nuclear fuel. If the largest stars, many times heavier than the Sun, tended to form in the earlier stages of the formation of our galaxy, they would long ago have gone through their burning phase, producing large amounts of helium, and then exploded as supernovas. Both in Lerner's theoretical models and Peratt's simulations, the stars forming along the spiral arms as they swept through the plasma medium would become smaller as the density of the medium increased. As the galaxy contracted, larger stars would form first, and smaller, longer-lived ones later. The smaller, more sedate starsfour to ten times larger than the Sunwould collapse less catastrophically at the end of the burning phase, blowing off the outer layers where the helium had been formed initially, but not the deeper layers where heavier elements would be trapped. Hence the general abundance of helium would be augmented to a larger degree than of the elements following it; there is no need for a Big Bang to have produced all the helium in a primordial binge.
Critics have argued that this wouldn't account for the presence of light elements beyond helium such as lithium and boron, which would be consumed in the stellar reactions. But it seems stars aren't needed for this anyway. In June 2000, a team of astronomers from the Universities of Austin, Texas, and Toledo, Ohio, using the Hubble Space Telescope and the McDonald Observatory, described a process they termed "cosmic-ray spallation," in which energetic cosmic rays consisting mainly of protons traveling near the speed of light break apart nuclei of elements like carbon in interstellar space. The team believed this to be the most important source of the lighter elements. 55