For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Why is Biblical creation so important? This is an excellent question because, as has already been suggested, it is the foundation upon which we can build our world view. However, in my opinion, one needs to exercise caution when discussing this question because it may become a dogmatism that can only be supported by faith. While faith is important, it often needs help by confirming facts as was demonstrated by the man who asked for Jesus to help his faith with evidence. (Mark 9:24; Romans 14:1)
To provide support for our faith in God’s creation of the heavens and earth, we can look to science. It has been said that if science and religion disagree, it is either because of bad science or bad religion. The role science plays in adding to the creation scenario is especially important for young people. When growing up in the Christian faith, they are often told simplified stories about creation which may become a source of stumbling as they are exposed to more information related to the sciences.
For instance, one simple example may involve the origin of the universe. In Genesis 1:1, we are told that God created the “heavens and earth” in the beginning. Hebrews 11:3, makes a very scientific statement by saying that “[ESV] By faith we understand that the universe was created by the word [Jesus] of God, so that what is seen was not made out of things that are visible.” In other words, the universe was created by Jesus, “ex nihilo.”
Historically, Aristotle said that the universe did not have a beginning but had always existed. This immediately caused problems for Jews, because of Genesis 1:1. For the same reason, it later became an issue for both Islamic philosophers and Christians. Nevertheless, this problem began to be resolved in 1927 by Georges Lemaitre who didn’t agree with Aristotle but instead proposed an expanding universe based upon Einstein’s equations. If the universe was expanding, then it must have had a beginning.
With the discovery of the “Cosmic Microwave Background” (CMB) radiation, the Big Bang model has become the most likely explanation for the origin of the universe. Science demonstrated that Jesus did actually create the universe “ex nihilo.” This discovery resolved the religious difficulties that Jews, Mohammedans, and Christians had with science in this regard. The discovery also vindicated Genesis 1:1 as being accurate and true much to the consternation of Biblical critics.
Since then, with the satellite surveys made by COBE and WMAP, we now can explain how the galaxies and many features of the universe were formed. In the vernacular, these “features” were called “seeds” that later developed into the universe we see and study. It is amazing that the entire universe was already mapped out before the Big Bang occurred and we have been able to prove that by scientific evidence today. In this regard, science has vindicated Genesis 1:1. This is just one simple example of such harmony between science and the Bible. Young people need to know that the Bible isn’t unscientific after all.
The Big Bang model is a possible explanation for the origin of the universe, and is widely accepted due to its prevalent in teaching and popular culture. However, it is not the only possibility, nor even the 'most likely.' Further observations of the universe have only weakened, not strengthened, the theory,
It has its own topic on eBible: Question: Did God use the Big Bang to create the universe? See Answer: http://ebible.com/answers/21153?ori=167400
(One critical thing to note is that the measuring of the CMB actually -disproved- all various proposed theories of the Big Bang of the day as it turned out the CMB had too low a temperature to make any Big Bang model viable.)
There is also no concrete proof that the universe is expanding. There is observed redshift, greater for more distant stellar objects - but this merely does not contradict the idea of an expanding universe and constitutes a possible support. This observed redshift is actually expected from the well-tested Shapiro effect.
For the expanding universe theory to work with what we actually observe from the rotation of galaxies and interactions between matter, scientists have to assume the existence of more and more dark matter and energy to keep their projected models and calculations afloat.
Going to the heart of your post though, an 'explanation,' especially one based on assumptions, is not equivalent to 'truth.' Mankind is great at coming up with explanations - many which turn out to be incorrect.
It is merely an 'explanation,' or interpretation, of the extremely small temperature fluctuations (40 µK to 70 µK) in the CMB found by COBE and WMAP represent the seeds of early galaxy formation.
And the data itself is questionable at best. Both of those microwave ansitropy maps lacked reproducibility and signal to noise. Since the signal received from our own galaxy was a thousand times stronger, WMAP took some questionable assumptions to 'discount' that signal in some places, but strangely ignoring it in others. Weighting the same data with different factors leads to vastly different 'maps,' all as 'valid' (or invalid) as WMAP's version. Then there is the problem of getting ghost images when one tries to remove a dominany signal from a far weaker one, WMAP's resolution problems, etc. COBE was at least able to measure actual temperature (unlike WMAP which could only measure difference.)
To add to this, some more recent theories call into question the CMB itself, pointing that the signal we 'read' could plausibly, even more likely, originate not in the far reaches of space, but on Earth.
It is good for scientists to observe, formulate hypotheses, test if possible, and check their hypotheses against newer observations as equipment and knowledge advances. It is bad for scientists to declare that only one theory is correct or the only 'true' scientific explanation.
The latest Cosmic Microwave Background (CMB) radiation measurements (WMAP) is a valid basis for determining the Big Bang origin of the universe. To show the timeliness of that assertion, I can refer you to a NASA report updated February 26, 2016 which says the following:
“WMAP has also, for the first time, discovered the polarization of light everywhere in the CMB. This is important because it helps us understand what happened during the first split second after the Big Bang.”
https://cosmictimes.gsfc.nasa.gov/online_edition/2006Cosmic/modern.html
There is a lot more about the Big Bang under its related topic: http://ebible.com/answers/21153?ori=167400
Briefly, however, here are just a few of the many problems with the WMAP measurements:
"FIRAS was unable to obtain proper nulls, despite the FIRAS team’s reports that they obtained “the most perfect blackbody spectrum ever measured”. Unable to obtain a proper null, the FIRAS team blames instrument problems and the calibrations, but never entertains the possibility that the sky....is not behaving as a blackbody as they assume..... In order to attempt to account for the data, the FIRAS team applies, ad hoc, a 4% reflectance to Ical"
http://milesmathis.com/COBE.pdf
(They made assumptions, and 'corrected' their data accordingly)
"if you try and measure the rate of expansion from two different methods -- one from the fluctuations in the CMB and one by building a cosmic distance ladder -- you get two different results that don't agree with one another."
https://www.forbes.com/sites/startswithabang/2016/04/12/the-biggest-problem-with-the-expanding-universe-might-be-trouble-for-dark-energy/#5e983a932a64
"It is therefore likely that the power spectrum, allegedly proving certain features of the Big-Bang Theory, is in fact only an artefact of the data analysis showing features of the beam profile, but has nothing to do with the CMB at all."
https://www.physicsforums.com/threads/wmap-data-analysis-flawed.7740/
Another source showing proof that the Biblical creation is true comes from the Caltech Astronomy department. In a current discussion of the CMB it states:
“One of the most important questions in cosmology is: What is the origin of all the galaxies, clusters, great walls, filaments and voids we see around us? . . . During the metamorphosis of quantum fluctuations into CMB anisotropies and then into galaxies, primordial quantum fluctuations of a scalar field get amplified and evolve to become classical seed perturbations and eventually large scale structure. Primordial quantum fluctuations are initial conditions. Like radioactive decay or quantum tunneling, they are not caused by any preceding event.”
https://ned.ipac.caltech.edu/level5/March03/Lineweaver/Lineweaver5.html
As a creationist, I welcome scientific findings like this. Note that the origin of “galaxies, clusters, great walls, filaments and voids” lead up to the comment about “seed perturbations.” Where did these seed perturbations come from? They [seed perturbations] were “not caused by any preceding event.” Here we see the direct hand of God. The entire universe was designed in eternity past and then through some highly complex process, suddenly extruded a volume of space/time filled with matter that we call the “Big Bang.”
My primary purpose in relating this is to show atheists and young people that you do not have to give up science to believe in the Bible.
Another fact that confirms the Biblical account of creation is found in NASA’s “Universe 101” site. It states:
“The FIRAS experiment measured the spectrum at 34 equally spaced points along the blackbody curve. The error bars on the data points are so small that they cannot be seen under the predicted curve in the figure! [shown on the web page] There is no alternative theory yet proposed that predicts this energy spectrum. The accurate measurement of its shape was another important test of the Big Bang theory.”
According to the Big Bang theory, the frequency spectrum of the CMB should have this blackbody form. This was indeed measured with tremendous accuracy by the FIRAS experiment on NASA's COBE satellite. Scientists always try to test their ideas in more than one way, if possible. That is why the agreement of different techniques is so important. Age estimates for the universe based on radioactive atoms observed in old stars, models of the lifetimes of stars and their aging over time, and the expansion history since the big bang all give the same answer. This web of evidence means that the assertion of a very old universe is not subject to possible problems or the limitations of any single technique.
This again shows that science proves the Bible is true when it says “In the beginning, God . . . . (Genesis 1:1)
https://map.gsfc.nasa.gov/universe/bb_tests_cmb.html
There are many confirmations of the Biblical creation account such as the Forbes article dated April 12, 2016 discussing what the universe will be like billions of years from now. It starts by saying:
“The Big Bang is one of the most successful scientific theories of all-time, detailing how the Universe came to be the way it is today over billions of years of cosmic history.”
However, with regard to interpreting the future based upon our present knowledge, it says:
“Yet that very story doesn't tell us how our Universe itself will continue to evolve into the future. The Big Bang gives us possibilities, but without additional information, it doesn't tell us the answer. . . . The problem is that, if you try and measure the rate of expansion from two different methods -- one from the fluctuations in the CMB and one by building a cosmic distance ladder -- you get two different results that don't agree with one another.”
Even with these uncertainties about the future, what do we know now? The article says:
“The bottom line, however, is that the measurements we're seeing at late times tell us that the Universe is expanding about 8% faster than we would have expected based on the early-time measurements.”
The beginning of the Universe once again is scientifically proven to be in accord with the Biblical account.
https://www.forbes.com/sites/startswithabang/2016/04/12/the-biggest-problem-with-the-expanding-universe-might-be-trouble-for-dark-energy/#6fa831a32a64