Izay Ayesha talks about an interesting subject
Origin of water – In one of the startling discoveries it has been pointed out that water did not actually originate on Earth but was brought down to it by meteorites. It is a stunning discovery belying almost all factors concerned with water, the vital prerequisite for life on Earth. Its presence on earth was a given as it was considered one of the aftereffects of the Ice Age. It was considered an essential ingredient of the growth of life on Earth without which life may not have originated. This discovery has proved the earlier assumption wrong but it also opened up many new avenues for research that may open up many other possibilities.
The new study reveals that water was actually brought to the Earth two million years after its formation by angrites in the early years of the formation of the Solar System. Angrites are known to be a rare group of water-rich basaltic meteorites found in outer regions of the universe. A fresh look at the rare basaltic angrites suggests that volatiles which are elements with relatively low boiling points such as water, could have been brought to our planet by meteorites during the first two million years of the Solar System.
The research behind this discovery is part of wider research conducted about terrestrial geochemistry, meteoriticsand planetary geochemistry. Such research has specified that composition of water on Earth and the composition of water in the angrites match perfectly. It indicates that water on the asteroid and the water on Earth came from the same source. The research implies that water arrived on Earth even before it was fully formed when it was likely to have been only 20% of its current size. This is an interestingly development and may bring about many allied discoveries in this regard.
It was pointed out that it is a fairly simple assumption to say that Earth’s water at least started accreting to Earth extremely early before the planet was even fully formed. This means that when the planet cooled enough so that liquid water could be stable at the surface, there was already water here. This is a justifiable assumption and may have some reality in it but it is not very difficult to doubt it keeping in view the results brought forward by the research in question.
This research is a corollary to the already established findings about the Earth describes that mentions that it was fully formed about 4.5 billion years ago and by this time Mars already had a 20-million-year head start with a stable mass and water and other chemicals on its surface, like carbon, fluorine and chlorine. On the other hand, Earth, as an inner planet had to go through a long phase of being hot and dry before it was fully formed with a stabilised mass.
The scientists believe that at this stage of planetary evolution, Earth was nothing more than a proto-planet with a molten surface of magma. They are of the opinion that faced with extremely high temperatures water was not able to sustain itself as even carbon with a melting point of 4,800 degrees Celsius was considered to be volatile and unable for sustenance. This is a well-argued point and is very credible to justify.
The researchers carried out measurement of olivine, a common mineral in basaltic meteorites, for volatile elements hydrogen, carbon, fluorine and chlorine to find out their “melt composition” because basalt is formed when molten igneous rocks cool. The researchers opined that once they found out the melt composition only then they were able to calculate the content of the water content of the planetary body. Resultantly it was discovered that parent angrite asteroids likely had about 20% of Earth’s current water levels. While this amount is not considered decisive at the moment but 4.5 billion years ago, when the Solar System was still hot, it actually constituted quite an abundant amount of water.
The researching team was also involved in estimating how big this angrite parent body could have been by means of using water and carbon levels found in them. The researchers considered this approach appropriate because both water and carbon content are dependent on pressure, so by estimating pressure, the team was able to calculate size of the angrites. Their calculation is that the angrite asteroid that came filled with water to Earth was about the size of asteroid Vesta which is roughly 525 kilometers in diameter. It may be noted that Earth is about 25 times larger in diameter than Vesta.This important discovery has opened up the possibility of further finding out the nature of angrites and efforts then may be afoot to create them and transport them to other planets for procuring water. The Weekender