6 The Mercury that we know today is thought to be the almost-exposed core of a planet. It was 4.5 times bigger before it had a collision with another proto-planet that blew away most of Mercury’s crust and mantle.

Mercury had a hit-and-run collision with a roughly Earth-sized planet 4.5 billion years ago. It indeed stripped the planet’s rocky mantle which explains why the planet is so tiny as compared to others and has a huge, iron core. 

It was in 2011 that a spacecraft sent of Mercury revealed the presence of rich volatile elements like potassium, sulfur, sodium, chlorine, and a giant iron core. 

The researchers were puzzled and were able to find a possible answer only in the collisions of planets. Using some computer simulations, a model of the collision was created that supports the idea of the presence of volatile material on the planet. 

However, the theory is only true when we assume Mercury was the impactor in the collision that hit the proto-planet with 0.85 times the mass of Earth. 

It also suggested that Mars could’ve also had the same hit-and-run history during its formation. (Source)

7 According to researchers, it may be possible for planets Neptune and Uranus to have oceans with liquid diamonds. Experiments conducted under high pressure that mimic conditions on these gas-giant planets show that pieces of diamonds can float on a sea of liquid carbon. 

The research that supports the presence of liquid diamonds on the two planets also provides the first detailed measurement of the melting point of the hardest natural material known, diamond. 

Current theories on the two planets suggest that they have solid cores surrounded by an icy mantle of water, ammonia, and methane ices. 

Scientists first conducted experiments where they blasted diamonds under high pressure using lasers. They had to expose diamonds to pressures 40 million times greater than that found at Earth’s sea level. 

Later they compared the conditions to those on Neptune and Uranus. This revealed that they were quite speculative of finding a liquid carbon core surrounded by floating diamonds or even “diamond-bergs.”

It isn’t sure in which form we are likely to find diamonds, chunks, or bergs. However, if we do find diamonds, they would be the first solid found on these planets. 

There are two ways to actually know if diamonds float on the oceans on Neptune and Uranus. Either we have to send spacecraft to the planets or we have to stimulate similar conditions. Both the methods are extremely expensive and would take years to execute. (1, 2)

8 Even if the planet Mercury is extremely hot and is closest to the Sun, it has ice on its surface. The ice could be found in permanently shadowed craters that are never exposed to sunlight. 

The speculation that ice could be present on Mercury was first based on the discovery of a red-bright material present on the north polar region of the planet. Later the spacecraft that orbits the planet. Messenger, confirmed the presence of between 100 billion to one trillion tons of water ice at both poles. 

The spacecraft team revealed that the water ice passed three challenging tests that confirm its presence. Researchers were able to measure water ice concentrations using hydrogen measurements in the radar-bright regions. 

They found that the polar deposits have a hydrogen-rich layer more than tens of centimeters thick beneath a surficial layer 10 to 12 centimeters thick that is not rich in hydrogen. 

The layer that is consistent with hydrogen contains nearly pure water ice. Moreover, the atmospheric conditions on Mercury are such that there is no chance for water to exist in the liquid state. The landform might support liquid water at some places, but the atmosphere will quickly transform it into ice or vapors. (Source)

9 In cosmical terms, the rings of Saturn are a very brief event. Currently, we have already reached halfway through the 200-million-year lifespan and are very lucky to be able to witness them. However, the planet is losing the rings at the worst-case-scenario rate. 

The conclusion that the Saturn rings would disappear stems from a phenomenon called “ring rain.” The process explains how water is pulled out of Saturn’s rings into the planet’s midlatitude regions.

The ring rain phenomenon, which is aided by a special form of hydrogen, was explained successfully in 2011. The rings are basically pulled by Saturn’s own gravity as a dusty rain of ice particles which is further disrupted by Saturn’s magnetic field. 

When studied, the rain would eat up large chunks of rings between 925 and 6,000 lbs per second. Based on these numbers, scientists predicted the life of the rings. 

If it is true that Saturn’s rings are temporary, then we surely just missed out on witnessing giant rings of other planets like Jupiter, Neptune, and Uranus. They still have ringlets today, but they are very thin. (1, 2)

10 The farthermost planet from the Sun, Neptune, is warmer than Uranus. This is because it radiates twice as much heat that it receives from the Sun. The extra heat is generated by a phenomenon called “gravitational contraction.” 

While researching we can only measure temperatures in the outermost layers of the planets. So when we compare the temperatures on Uranus and Neptune this way, we find that they’re at the same temperature. 

However, scientists say that this shouldn’t be the case since Neptune is farther from Sun than Uranus. But at the same time, if we consider the temperature of the planets in terms of heat emitted by them and not heat absorbed by the Sun, Neptune wins. 

It is important to note that Neptune is not the oddball here, but Uranus is. This is because Jupiter and Saturn, too, emit twice as much heat they absorb from the Sun. The exception is Uranus that doesn’t. 

Uranus has no internal source to produce heat whereas Neptune does. And there is no clear reason why this is the case. Gravitational contraction, the process that produces extra heat on the other three planets takes place when the planets contract gravitationally but slowly. 

The material that falls inward changes its potential energy into thermal energy that is then released upwards out of the planets. (Source)