"The environment of 3C 297, appears to have the key features of a
galaxy cluster, enormous structures that usually contain hundreds or
even thousands of galaxies. Yet this galaxy stands alone.
This result made with NASA’s Chandra X-ray Observatory and the
International Gemini Observatory may push the limits for how quickly
astronomers expect galaxies to grow in the early 
Universe.
“It seems that we have a galaxy cluster that is missing almost all of
its galaxies,” said Dr. Valentina Missaglia, an astronomer at the
University of Torino.
“We expected to see at least a dozen galaxies about the size of the Milky Way, yet we see only one.”
First, the X-ray data reveals the lone galaxy is surrounded by large
quantities of gas with temperatures of tens of millions of degrees —
something normally seen in galaxy clusters.
Second, the supermassive black hole’s jet has created an intense
source of X-rays about 140,000 light-years away, implying that it has
plowed into gas surrounding the galaxy.
A third trait of galaxy clusters possessed by 3C 297, previously
reported in Karl G. Jansky Very Large Array data, is that one of the
radio jets is bent, showing that it has interacted with its
surroundings.
Despite having these important features of a galaxy cluster, the new
data from the Gemini Observatory revealed that none of the 19 galaxies
that appear close to 3C 297 in an optical image, and that have accurate
distance measurements, are actually at the same distance as the lonely
galaxy.
“The question is, what happened to all of these galaxies?” said Dr.
Juan Madrid.
The researchers think 3C 297 is no longer a galaxy cluster, but a
‘fossil group.’ This is the end stage of a galaxy pulling in and merging
with several other galaxies.
“It may be challenging to explain how the Universe can create this
system only 4.6 billion years after the Big Bang,” said Dr. Mischa
Schirmer, an astronomer at the Max Planck Institute for Astronomy.
“This doesn’t break our ideas of cosmology, but it begins to push the
limits on how quickly both galaxies and galaxy clusters must have
formed.” SciNews
It's NOT really "challenging"---if one considers they were designed & created -- at one time in the not very distant past: And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. And the evening and the morning were the fourth day.
Genesis 1:16,19