Meteorites as a Source of Water on Planet Earth

In recent years, scientists discovered an amazing fact that provides us with new insights into the origins of water on Earth.

Many of us have seen what is commonly called a "shooting star" - a fast-moving, streak of light in the night sky.  As we know, this is a small particle of matter, hurtling towards earth from outer space at a terrific speed. As it enters our atmosphere, friction generates extremely high temperatures and the particle burns up in an incandescent flash before it can strike the Earth.

Every 24-hour period, approximately 30,000 particles with a total weight of some 600,000 tons penetrate the Earth's atmosphere.  Even though on the average, a particle penetrates the atmosphere every three seconds, the vast majority are never seen.

In 1986, Professor Louis Frank, an astrophysicist at the University of Iowa, set off an academic bombshell among his colleagues by asking a simple question: Why can't we see all of these meteorites entering the atmosphere each night?  His own surprising answer was the result of many years of work analyzing photographs sent back from the Dynamics Explorer 1 spacecraft: Most meteorites are the disintegrated remains of comets; therefore, they are mainly comprised of ice, which melts as the particle enters the upper atmosphere, and eventually falls to earth as rain.

At the annual conference of the American Geophysical Union a few years later, Professor Frank and his research colleague, Dr. John Sigwarth, presented a new series of photographs taken by the Polar spacecraft launched in 1996.  Frank and Sigwarth claimed that these photographs provided a clear view of meteorites moving in a trajectory towards Earth, entering the atmosphere, melting and turning into rain.  To their minds, the photographs proved that the Earth's water supply is not solely based on the evaporation and precipitation cycles of the great oceans, but rather, is constantly being replenished from outer space.

As far as the Sages of Torah were concerned, this was old news, for they knew of this process from their study of scripture. The Talmud" states that water on Earth comes from two sources.  The first is referred to in Genesis (2:6): "And a mist went up from the earth, and watered the whole face of the ground."  This alludes to the evaporation cycle.  The Talmud then lists another source:

"Rabbi Joshua said: The whole world drinks from the water above the firmament..  as it says: 'But the land ... drinks water from the rain of heaven' (Deuteronomy 11: 11)."

The verse does not state that the earth is watered by rain falling from clouds, but by that which falls from the heavens above the clouds. In other words, much of our water falls from a source beyond the Earth's atmosphere.

Until only a few years ago, these statements of the Sages were a mystery.  Now, scientists can display photographs of frozen meteors hurtling down onto our world each day.  As we explained above, the Sages' knowledge and understanding of the Torah is rooted in their certainty that it was written by the Creator of the universe, who imbued every word with precise meaning.  Their great sensitivity to the implications of each verse granted them scientific understanding which modern researchers are arriving upon only now, using the most advanced tools of their fields.

Further along these lines, it is thus worth citing an ancient Midrash, Pirkei d'Rabbi Eliezer, which discusses two types of precipitation: one originating in the oceans, which provides the majority of our rain, and a second, higher quality rain that falls from heaven:

"When G-d wants to bless the Earth with growth, He opens the treasure houses in the heavens and lets rain fall to the earth, which gives forth its blessed seed, as the Torah states: G-d will open His good treasury in heaven to give your land rain and to bless everything you do (Deuteronomy 28:12).

In other words, rain from outer space ("the heavens") is of higher quality and has greater benefits to vegetation and crops than that which comes from the evaporation cycle.

Pirkei d'Rabbi Eliezer was composed over 2,000 years ago, yet it comments on phenomena still indiscernible to modern scientists, but which provides a fascinating direction for future research.