Did You Know?
The Jovian planets (gas giants) of our solar system are not the only celestial bodies with weird weather. The clouds of Venus rain sulfuric acid, while those on Saturn's moon Titan rain liquid methane. Other planets outside our solar system are also thought to have some bizarre weather, with rains of glass or molten iron.
For diamonds to form on the Earth, many different processes have to take place at the right place and the right time. For starters, carbon has to get buried at least 100 miles below the surface of the Earth's crust. Then, this carbon has to be subjected to a temperature of over 1,000°C, and also massive pressure of more than 75,000 pounds per square inch. The carbon must endure these harsh conditions for many years before it turns into a diamond. Even then, the stone will reach human hands only if it is lucky enough to be pushed back to the surface by a fast-moving flow of molten magma. As you can imagine, it is pretty rare for all of these conditions to occur on our planet together, which is why diamonds are so rare and expensive.
However, in the Jovian planets of our solar system, the formation of these gems is thought to be a very common occurrence, as diamonds may fall as rain on Saturn and Jupiter. These gems might be found in such large numbers, that they wouldn't be considered rare at all. Let us see why such a bizarre phenomenon might be possible.
Why Does it Rain Diamonds on Saturn, Jupiter, and Neptune?
There are two accepted scientific theories which can explain the potential of such a phenomenon occurring on Jovian planets:
Theory 1: The atmosphere of all the gas giants in our solar system are made up largely of hydrogen, helium, and methane. According to the first theory, whenever methane molecules are struck by lightning, carbon atoms break free from the methane molecules. These separated carbon atoms get attracted and bond with each other, eventually forming large particles of carbon soot. The particles of soot now slowly float down through the dense gaseous atmosphere towards the planet's rocky core, all the while facing ever-increasing pressures and temperatures. At some point, the heavily compressed soot turns into graphite, and consequently into diamonds, when the temperatures reach over 2,000°C. As the diamonds float lower, the temperature reaches levels of over 8,000°C, where the stones melt to form liquid diamond raindrops.
Theory 2: This theory is similar to the first in a few ways. It states that, lightning strikes on methane molecules form carbon soot. However, it also states that, rather than forming due to the soot sinking towards the core, the diamonds are formed due to even more lightning strikes on the soot particles. The lightning strikes magnetically fuse the soot together to form diamond hail. Then, as this hail falls, it reacts with hydrogen under high temperature and pressure to reform methane gas, which rises to cooler areas, eventually reforming diamonds, creating a diamond-methane cycle. The second theory has some basis in fact, as this cycle was recreated under controlled laboratory conditions. However, until we are able to build spacecraft capable of handling the extreme environment of Jupiter or Saturn, both theories will remain unconfirmed.
Saturn and Jupiter are not the only planets with the potential for this strange phenomenon. It is thought that diamonds are raining on Neptune and Uranus as well. It is important to note that, while the extreme heat of Saturn and Jupiter might melt any diamonds before it reaches its core, the same does not hold true for any occurrences in Neptune and Uranus. The cooler temperatures in the latter planets ensure that any diamonds that might form will probably remain in a stable solid state.
Implications for the Human Race
The diamonds that form on these planets could range anywhere between 1 - 10 centimeters in diameter. It is estimated that over 1,000 tons of such diamonds are raining down each year on Saturn alone. While this amount is negligible in comparison to the huge sizes of the gas giants, the combined number of diamonds in all the Jovian planets is simply mind-boggling, in Earth standards.
In the future, when humans have optimized the science of interplanetary travel, the diamonds from these planets might be collected and used for mining machinery and other industrial purposes by robot probes. However, it is highly unlikely that the stones would be brought back to Earth for jewelry, as the huge influx of these stones would hit the financial markets hard, and diamond jewelry would not have any value associated with it anymore.