Uranus and Neptune might not be what they seem.

"Researchers have uncovered evidence that Uranus and Neptune could be far rockier on the inside than anyone expected. Their unusual magnetic fields and uncertain internal makeup show why new missions are needed to reveal what these planets are really like. Credit: Shutterstock" (ScitechDaily, New Findings Suggest Uranus and Neptune Are Not What They Seem)

“The Solar System is usually grouped into three main types of planets based on what they are made of: the four rocky terrestrial worlds (Mercury, Venus, Earth, and Mars), the two massive gas giants (Jupiter and Saturn), and the pair of ice giants (Uranus and Neptune). (ScitechDaily, New Findings Suggest Uranus and Neptune Are Not What They Seem)

“New research from a scientific team at the University of Zurich (UZH) suggests that Uranus and Neptune may not fit neatly into that final category. Their findings indicate that both planets could contain much more rock than previously assumed. The study does not argue that the two worlds must be water-rich or rock-rich; instead, it challenges the long-standing belief that an ice-heavy composition is the only viable explanation. This perspective is also supported by the discovery that the dwarf planet Pluto is primarily made of rock.”(ScitechDaily, New Findings Suggest Uranus and Neptune Are Not What They Seem)

New information suggests that Uranus and Neptune are rocky planets. This would be one of the most incredible findings in modern astronomy. The fact is that. Gravity doesn’t tell everything. About. The size of the planets.“Silicon is the eighth most common element in the universe by mass, but it very rarely occurs in its pure form in the Earth's crust. It is widely distributed throughout space in cosmic dust, planetoids, and planets in various forms of silicon dioxide (silica) or silicates. More than 90% of the Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust (about 28% by mass), after oxygen.” (Wikipedia, Silicon). 

This means that if there is mainly silicon and lighter solid elements. Even. If the planet is large. 

It’s possible. It still has quite a weak gravity. Compared to its size. The massive rocky planets called “super earths” and “hot neptunes” are giving a tip that. Maybe there are misunderstandings about those two planets. The mass of Uranus is 14.536 times that of Earth, but that includes its massive atmosphere. The gravity on that planet’s surface is 0.886g. The mass of Neptune is 17.147 times that of Earth. Surface gravity of Neptune is 1.149g.  

As in the case of Uranus. Neptune's massive atmosphere. Raises that planet’s mass. So, are Uranus and Neptune gas planets? The gas giants are not always gas. They are probably quite small planets with a large atmosphere. But all of those planets have a point where solid layers begin. The gas giant formation begins. When. A quite small rocky point acts as the gravitational center. Then that gravitational center starts to collect gas and dust around it. 

The environment must be so stable that the solar wind doesn’t blow those gas and dust layers off, while the planet is forming. This means that planets like hot Jupiters. Or ultra-hot gas giants must form far from their suns.  The ultra-hot rocky planet can be closer to its star. And in some cases, those planets are made of melted iron. In cases like hot Jupiters, the massive gravity of those planets keeps them in form. If. Planet formation starts in interstellar space. That planet will turn. 

Into an extremely large. Interstellar traveller. This requires that the planet formation begins in an interstellar nebula, with no light elements. Those nebulae are supernova remnants and nova remnants. If. There are lots of heavy elements. Those elements cannot start fusion. There is another theoretical possibility. That the small star could turn into a planet. The idea is that the supernova near a small star or brown dwarf can push so much material away from that star that its fusion ends. 

https://scitechdaily.com/new-findings-suggest-uranus-and-neptune-are-not-what-they-seem/

https://en.wikipedia.org/wiki/Neptune

https://en.wikipedia.org/wiki/Silicon

https://en.wikipedia.org/wiki/Uranus