A groundbreaking discovery has been made in the field of astrobiology as researchers confirm the existence of exotic ice formations on distant planets. The phenomenon, known as plastic ice VII, exhibits traits of both solid ice and liquid water, opening up new avenues for understanding the internal architecture of other worlds.
For the first time, researchers have directly observed a strange and hybrid phase of water called plastic ice, which forms at high temperatures and pressures. This unusual ice phase exhibits traits of both solid ice and liquid water, making it an exciting discovery for scientists studying the internal architecture of other worlds in our solar system and beyond.
Plastic ice, also known as polyethylene glycol (PEG) ice, is a type of ice made from a mixture of water and PEG.
It has been used in various applications, including cooling packs for medical purposes.
Plastic ice has several advantages over traditional ice, such as being more durable and less likely to melt quickly.
However, it also has some drawbacks, like being more expensive and potentially toxic if ingested.
In 2019, a study found that plastic ice was still present in the human body after '10 days' of ingestion.
What is Plastic Ice?
Plastic ice is a type of ice that has been theorized to exist but never directly observed until now. It’s called plastic because it’s more easily molded or deformed than typical crystalline ice, exhibiting a property scientists call plasticity. Imagine something that can squeeze through a hole and come out, even if it’s still solid – this is what plastic ice is like.
The Formation of Plastic Ice
Most of the ice on Earth’s surface consists of water molecules arranged in a hexagonal lattice, known as ice Ih. However, there are at least 20 other known ice phases that form in different pressure and temperature conditions. At pressures above 20,000 bars, ice lattices compress into Ice VII, a polymorph with a dense, cubic structure. Plastic ice VII is thought to occur when the individual water molecules start to rotate freely, as if liquid, while occupying fixed positions, as in a solid.

Plastic ice VII, also known as high-density amorphous ice (HDA), is a metastable form of 'water ice.'
It was first discovered in 1994 and has since been the subject of extensive research.
This unique form of ice has a density higher than that of regular ice VI and a crystal structure that is not yet fully understood.
Plastic ice VII is created by compressing and cooling amorphous ice to extremely high pressures, typically above 1 GPa.
Its properties make it an interesting area of study for scientists investigating the behavior of 'water' under extreme conditions.
The Observation of Plastic Ice VII
To observe plastic ice VII, researchers used a relatively new tool at the Institut Laue-Langevin in Grenoble, France. They pointed a neutron beam at water samples and subjected them to temperatures up to 326° C and pressures up to 60,000 bars. Measuring the scattered neutrons’ energies allowed them to characterize the molecules’ motions and identify the phase that had formed.
The Significance of This Discovery
This discovery may help researchers better understand the internal architecture and processes of other worlds in our solar system and beyond. Plastic ice VII may have existed during the early formational stages of Europa, Titan, and other icy moons, before all the water had escaped from their high-pressure interiors. The new observations could also help determine whether the strange phase’s presence enhances the exchange of salts between exoplanet seafloors and the oceans above.
Future Research Directions
Investigating how easily plastic ice VII incorporates salts into its lattice could help determine whether the strange phase’s presence enhances the exchange of salts between exoplanet seafloors and the oceans above. This would be an important step in understanding the potential habitability of exoplanets with deep oceans.
- sciencenews.org | A weird ice that may form on alien planets has finally been observed