Water, the elixir of life, is one of Earth’s most precious resources. The origins of this vital substance have long fascinated scientists, leading to the development of intriguing theories regarding its source – the basis of many is that water must have been delivered to Earth. 

To comprehend the theory of water delivery from asteroids and comets, we must delve into the early history of our planet. Earth, formed approximately 4.5 billion years ago, was a hot and volatile sphere, devoid of the life-sustaining liquid that now covers about 71% of its surface. The prevailing conditions were inhospitable for water to exist in its liquid state.

Enter the celestial messengers—comets and asteroids. Comets, icy bodies composed of water, ammonia, methane, and other volatile compounds, orbit the Sun in the outer reaches of the solar system. Asteroids, rocky remnants from the early solar system, also house water ice. The collision of these space wanderers with the fledgling Earth potential brought the cosmic gift of all gifts —water.

Water has a much lower condensation temperature than other materials that compose the terrestrial planets in the Solar System, such as iron and silicates. The region of the protoplanetary disk closest to the Sun was very hot early in the history of the Solar System, and it is not feasible that oceans of water condensed with the Earth as it formed. Further from the young Sun where temperatures were lower, water could condense and form icy planetesimals. The boundary of the region where ice could form in the early Solar System is known as the frost line (or snow line), and is located in the modern asteroid belt, between about 2.7 and 3.1 astronomical units (AU) from the Sun.[23][24] It is therefore necessary that objects forming beyond the frost line–such as comets, trans-Neptunian objects, and water-rich meteoroids (protoplanets)–delivered water to Earth. However, the timing of this delivery is still in question.

As comets and asteroids collided with the early Earth, they released their payload of water in the form of ice. The intense heat generated during these impacts caused the ice to melt, contributing to the formation of oceans. This delivery mechanism, known as the “late heavy bombardment (approximately 4 billion years ago) is a crucial period that shaped Earth’s surface and potentially kick-started the emergence of life.

This hypothesis claims that Earth accreted (gradually grew by accumulation of) icy planetesimals about 4.5 billion years ago, when it was 60 to 90% of its current size.[21] In this scenario, Earth was able to retain water in some form throughout accretion and major impact events. This hypothesis is supported by similarities in the abundance and the isotope ratios of water between the oldest known carbonaceous chondrite meteorites and meteorites from Vesta, both of which originate from the Solar System’s asteroid belt.[25][26] It is also supported by studies of osmium isotope ratios, which suggest that a sizeable quantity of water was contained in the material that Earth accreted early on.[27][28] Measurements of the chemical composition of lunar samples collected by the Apollo 15 and 17 missions further support this, and indicate that water was already present on Earth before the Moon was formed.[29]

The theory that water on Earth originated from asteroids and comets provides a captivating narrative of our planet’s cosmic past. It illustrates the interconnectedness of celestial bodies and the profound influence of these space wanderers on shaping the conditions necessary for life. As we continue to explore the mysteries of the universe, the story of water delivery from space serves as a reminder of the dynamic and intricate processes that have sculpted the Earth into a haven for life.

Modern research has helped shape this theory – the Quran nearly 1400 years ago – states that water itself came from heavens. In Surah Al Muminoon (The Believers): Ayat 18 (Quran 23:18) – The word “Sama'” in Arabic can mean heaven or sky and the term “Ma’a” in arabic refers to water itself (note this is not the Arabic word “matar” meaning rain) – this generally refers to water above the clouds (not rain) that was then made to dwell (or made to settle) on the earth.  Furthermore – in Surah An Noor (The Light): Ayat 24 (Quran 24:43) – 

Allah says that he sends down from the heaven (above the clouds) mountains with ice (hail) inside them that can strike wherever he commands and also avert wherever he commands! Like comets and asteroids delivering the water payload to the planet –  Simply amazing detail of what science has only recently stumbled upon! There are signs everywhere for those willing to ponder!