Below is the online edition of *In the Beginning: Compelling Evidence for Creation and the Flood*,
by Dr. Walt Brown. Copyright © Center for Scientific Creation. All rights reserved.

Click here to order the hardbound 8th edition (2008) and other materials.

Now that the calculations are complete, before making any conclusions, it is appropriate to look at the validity of the assumptions made, and see how sensitive the final answers were to the four most significant assumptions. Those assumptions were:

1. The debris that hit the Moon was launched from the Earth’s equator.

2. The debris left the Earth with a vertical velocity of 11.35 km/sec.

3. The Earth lost 3% of its mass during the flood.

4. 1.22% of the mass ejected from the Earth hit the Moon.

First, let’s look at Equation 8, where we assumed the debris that impacted the Moon came from the equator and had an eastward velocity of 0.4584 km/sec. The debris could have come as far north (or south) as 28.58° latitude and still hit the moon. If the calculations above were repeated assuming the debris was launched from the maximum latitude of 28.58° as shown in Equation 9, the debris would have the slowest possible eastward velocity of 0.4026 km/sec when it left Earth. In this case the debris would have also been in an inclined orbit, and the final numbers would be almost exactly the same even if no other numbers were changed. For example, the synodic period of the Moon after the flood would be 29.501 days, instead of 29.504 days (found in Equation 38). So this assumption had no real impact on the final results.

It was also assumed the debris that impacted the Moon was launched from the Earth with a vertical velocity of 11.35 km/sec. To measure the sensitivity to this assumption, the calculations outlined here were duplicated with many other vertical launch velocities. Without changing any other numbers, as long as the velocity was between 11.26 km/sec (the minimum velocity sufficient to reach the Moon) and 11.88 km/sec, the Moon’s orbit always became more eccentric, and the lunar month was also shorter than before the flood. Both changes are consistent with what we see today. Also, velocities in this range from 11.26 to 11.88 km/sec are consistent with the values estimated in Table 44 on page 615. So, this assumption was reasonable, and the final results were not affected significantly by slight changes in the estimated velocity.

It was also assumed that the Earth lost about 3% of its mass at the time of the flood. This is the average of two different studies that estimated the mass of all TNOs. One study estimated that the mass of all TNOs is 2% of Earth’s mass, and the other study, using a different technique, arrived at 4%. [See Endnote 148 on page 382 and pages 360–371.]

As stated earlier, it is also assumed that 1.22% of this mass impacted the Moon. This is slightly more than the 0.7% that we would expect to hit the Moon if the debris was evenly distributed in all directions from Earth.^{9} However, there is no reason to believe the debris was evenly distributed; it probably was more concentrated near the pre-flood equator.