Bahram Mobasher of the Space Telescope Science Institute, leader of the science team, explains, "We found this galaxy in Hubble's infrared images of the UDF and expected it to be young and small, like other known galaxies at similar distances. Instead, we found evidence that it is remarkably mature and much more massive. This is the surprising discovery."

"If the distance measurement to this object holds up to further scrutiny, the fact such a galaxy has already completed its star formation implies a yet earlier period of intense activity," Ellis adds.

The very high energy/matter densities of the very early universe meant that star, and galaxy formation proceeded at a much greater rate in the begginging of the universe.
All the matter and energy was present at the birth, not created as time went by.
At one point in the very early universe(ABOUT 300K YEARS AFTER tbb) the mater/energy density was so high that it put the universe under a photonic pressure of round 14psi.
thats so much light it exerted 14 pounds of pressure per square inch.

While it remains the staple of virtually all cosmological teaching, the concept of expanding space in explaining the increasing separation of galaxies has recently come under fire as a dangerous idea whose application leads to the development of confusion and the establishment of misconceptions. In this paper, we develop a notion of expanding space that is completely valid as a framework for the description of the evolution of the universe and whose application allows an intuitive understanding of the influence of universal expansion. We also demonstrate how arguments against the concept in general have failed thus far, as they imbue expanding space with physical properties not consistent with the expectations of general relativity.

Much has been written in the debate about whether the space between galaxies is "really" expanding, or whether on the other hand the motion of galaxies is a kinematic recessional motion through space. The equivalence principle strongly suggests that it is impossible to detect any observational difference between the two models, indicating that we have no reasonable alternative but to treat both as being equally valid and mathematically interchangeable.

I'll conclude by noting that while the equivalence principle suggests that 'expanding space' and 'kinetic recession' are merely different descriptions of the same thing, that doesn't mean we have sorted out all of the complexities. In particular, no complete and demonstrably valid explanation has been provided as to how the cosmological redshift and the Superluminal recession of distant galaxies can be explained by a purely kinetic model. However, the equivalence principle encourages optimism that eventually the kinematic model will be fleshed out enough to provide a fully kinematic alternative explanation of those phenomena. On the other hand, we may eventually conclude that a fully kinematic explanation would result in measurable observational differences. That remains a real possibility, despite the faith we put in the equivalence principle. In which case, we will eventually be able to know for a fact whether 'expanding space' causes particles to separate, or whether the particles are moving kinematically through space.

But it's interesting to see this very question is being debated in the physics community, and even being called "the root of all evil"

CONCLUSIONS:

At any given epoch, quasars' intrinsic Luminosities vary over roughly three orders-of-magnitude. And, quasars appear to brighten from z=3 to z=2, before steadily dimming, by about three orders-of-magnitude, from z=2 to z=0.03, after which quasars have faded from view.

Quasar numbers also follow a similar evolution, rapidly increasing in comoving density, before fading from view: