I'm a Christian who believes the Bible is the written word of God, but not that the earth is 6000 years old or that the dinosaurs were made up. However, I do believe in a literal garden of Eden and that humans were created by God separately, rather than descending from apes.
I don't think it's wise to put a time frame on the creation narrative in Genesis. God's on His own incomprehensible time frame, as the Bible quote "one day is as a thousand years with the Lord" infers.
The way I see it is what's written in Genesis 1 and what we now know of the origins of life from scientific research don't necessarily need to be in conflict. For example:
(From the Huffington Post - edited for length)
Genesis: (First day) -- 15 billion to 4.5 billion years ago
"In the beginning God created Heaven and Earth."
Science
At some point in the history of time between, 9 and 15 billion years ago, the origins of the universe began. There was absolutely nothing but emptiness, when suddenly an infinitely hot and dense spot called the singularity appeared. From that spot there was an unimaginable gigantic explosion, called the Big Bang, and within less than a fraction of a second, the entire universe was formed. This was the start of everything that exists -- matter, energy, time and every atom that was ever created. The sun and earth itself were estimated to have been formed about 4.5 billion years ago.
Genesis: (First day)
"God said, 'Let there be light.'"
Science:
During the Big Bang, electrons caused very small packets of light making the whole universe glow.
The sun was formed 4.5 billion years ago along with the Earth.
So the start of the universe and then the start of the sun and Earth on the first day of Genesis definitely coincide with contemporary science.
Genesis: (Second day) -- 4.5 billion to 3.75 billion years ago
"God said, 'Let there be firmament in the midst of the waters and let it separate the waters from the waters.'"
Science:
Water-rich asteroids and protoplanets collided with prehistoric earth, bringing water. Later, gaseous emissions from volcanoes added additional water. This occurred approximately 4.4 billion years ago. Over the next several billion years, as the earth cooled, water vapor began to escape and condense in the earth's early atmosphere. Clouds formed and enormous amounts of water fell on the earth. The waters were separated, water on earth and water in the atmosphere. So day two fits with science and is in the correct order.
Genesis: (Third day) -- 3.75 billion years ago
"And God said, 'Let the waters under the Heaven be gathered together in one place and let the dry land appear.'"
Science:
The beginning of the oceans and the separation of the land mass areas occurred on Earth about 3.75 billion years ago. Again, it fits with science and is in the right order.
Genesis: (Third day)
"And God said, 'Let the earth put forth grass, herbs yielding seed and fruit trees bearing fruit.'"
Science:
This section of Genesis' third day is out of sequence. Plants, grass, and fruit bearing trees, did not appear until after sea creatures. Although microscopic single cell algae (bacteria or archaea microbes) are a plant and appeared at this time, it is not the advanced forms of plant life described in Genesis. Again, the appearance of flora did not take place at this time according to contemporary science.
Genesis: (Fourth day)
"And God said. 'Let there be light in the firmament of Heavens to separate the day from the night.'"
Science:
This phrase is confusing because the Sun's creation was earlier, so why is light mentioned here? There is nothing to compare here between Genesis and science. The open question is why light is repeated on day four.
There are a number of theories to explain this. One is by Dr. Gerald Schroeder, Ph.D., a professor of nuclear physics and earth and planetary sciences at MIT who spent five years on the staff of the MIT physics department. He is also a lecturer in science and spirituality. He contends that the sun, the moon, and the stars were already there but that the atmosphere was opaque. With the cooling of the Earth and the rise in atmospheric oxygen, the atmosphere became transparent, and there was light.
Another interesting theory is presented by Dr. Alan Parker, a respected evolutionary biologist and research fellow at Oxford University. He speculates that this second reference to light on day four of Genesis refers to the evolution of vision. If there was no vision, then there was, in a sense, no light. So the lights were "turned on" in the evolution of sight in animals. "To separate day from night" refers to the time before and after sight.
Genesis: (Fifth day) -- 3.5 billion years to 635 million years ago
"And God said, 'Let the waters bring forth swarms of living creatures. Be fruitful and multiply and fill the waters in the seas...'"
Science:
This is exactly what happened. Life began in the sea. The earliest fossils of life, single-celled bacteria, are found in ancient rocks deposited in the oceans 3.5 billion years ago. By 1.2 billion years ago, the first complex multicellular life had evolved. The oldest evidence of full animal life in the oceans comes from about 635 million years ago.
Genesis: (Fifth day)
"'...and let the birds fly above the earth.'"
Science:
According to contemporary science, this is out of sequence. Birds did not appear until later. However, flying insects did appear at this time, and this could be a remote but possible explanation.
Genesis: (Sixth day) -- 250 million to about 6000 years ago
"And God said, 'Let the Earth bring forth living creatures according to their kind; cattle and creeping things and beasts of the earth according to their kind.'"
Science:
This is exactly as science reports: life began in the water and then expanded onto land.
Genesis: (Sixth day)
"Then God created man in his own image...Male and female created He them...And God formed man of the dust of the ground...He took one of Adam's ribs and made a woman."
Science:
Nothing in this section resembles science at all. The only correct thing is that man was at the end of the chain of life. One coincidence that has been noted is that just as Adam's rib was used to form another person, Eve, the first life forms, single-cell organisms, divided to form other single-cell organisms. Admittedly, this is a stretch.
Genesis: (Sixth day)
"God said, 'Be fruitful and multiply and fill the Earth and subdue it and have domination over fish of the sea and over birds of the air and over every living thing that moves upon the Earth.'"
Science:
It is obvious that today, man does have domination over every fish, every bird, and every living thing that moves across the Earth. Genesis was right: man dominates the Earth.
When Genesis was written about 4000 years ago, humans were almost universally illiterate. The alphabet was being perfected, writing (not hieroglyphics) was still new, calendars were still not perfected, and books and paper didn't even exist.
But nevertheless, the writers of the Bible somehow figured out that creation occurred first with the universe, then the Earth, then light, then water, then land rising out of the water to separate land and sea, all in the proper order according to contemporary science.
Then, most amazingly of all, these ancient Hebrew scholars and Old Testament writers figured out, in accordance with modern science, that the origins of life started in the water. Scientific information on the subject was not developed until over 3500 years later.
The beginnings of earth and life as reported by Genesis correspond very closely with current scientific knowledge.