Of course, the logical rebuttal to this is that that would be about the stupidest of all possible ways to create a flood, like intentional absurdity. God doesn't need to move water around from one planet to another; he can simply make water materialize on-site any one of a thousand different ways. If you are going to posit God as the source of the flood, reason (i.e. Occam's Razor) strongly suggests that God would do it just about any way EXCEPT borrowing water from Mars and dumping it in the Earth's oceans. Only a human (or alien perhaps) would be required to go through such an idiotic feat of rote engineering. Sheesh.
The Flood was part and parcel of a solar-system-wide calamity.
The seven days of intense light just prior to the flood are mentioned twice within a short space in Genesis:
Gen. 7:4 "For yet seven days, and I will cause it to rain upon the earth forty days and forty nights;...
Gen. 7:10 "And it came to pass after seven days, that the waters of the flood were upon the earth."
These were seven days of intense light, generated by some major cosmic event within our system.
In Isaiah 30:26, we read:
"...Moreover, the light of the moon shall be as the light of the sun, and the light of the sun shall be sevenfold, as the light of seven days..."
Most interpret this as meaning cramming seven days worth of light into one day. That is wrong; the reference is to the seven days prior to the flood. The reference apparently got translated out of a language which doesn't use articles.
It turns out, that the bible claims that Methuselah died in the year of the flood. It may not say so directly (if it does, I don't know where), but the ages given in Genesis 5 along with the note that the flood began in the 600'th year of Noah's life (Genesis 7:11) add up that way:
Gen. 5:25 ->"And Methuselah lived an hundred eighty and seven years and begat Lamech. And Methuselah lived after he begat Lamech seven hundred eighty and two years, and begat sons and daughters. And all the days of Methuselah were nine hundred sixty and nine years.
<i.e. he lived 969 - 187 = 782 years after Lamech's birth>
And Lamech lived an hundred eighty and two years and begat a son. And he called his name Noah...
<182 + 600 = 782 also...>
Thus we have Methusaleh dying in the year of the flood; actually seven days prior to the flood...
Again, Louis Ginzburg's seven-volume "Legends of the Jews", the largest body of Midrashim ever translated into German and English to my knowledge, expands upon the laconic tales of the OT. Midrashim (the full body of rabbinical literature) draw upon ancient sources, passed down from grey antiquity. The work is seven volumes, and about a foot thick counting all volumes.
From Ginzburg's Legends of the Jews, Vol V, page 175:
...however, Lekah, Gen. 7.4) BR 3.6 (in the week of mourning for Methuselah, God caused the primordial light to shine).... God did not wish Methuselah to die at the same time as the sinners...
The reference is, again, to Gen. 7.4, which reads:
"For yet seven days, and I shall cause it to rain upon the earth forty days and forty nights..."
The week of "God causing the primordial lights to shine" was the week of intense light before the flood.
The ancient (but historical) world knew a number of seven-day light festivals, Hanukkah, the Roman Saturnalia etc. Velikovsky claimed that all were ultimately derived from the memory of the seven days prior to the flood.
If this entire deal is a made-up story, then here is a case of the storyteller making extra work for himself with no possible benefit, the detail of the seven days of light being supposedly known amongst the population, and never included in the OT story directly.
Somehow, that doesn't figure. The seven days of intense light noted in ancient literature indicates some sort of a stellar blowout in or near our own system at the time.