Compressing Water - Hal Clement's "Noise

[qraal]

Hi All

In Hal Clement's book "Noise" there's a planet with an ocean 2,900 kilometres deep. Radius of the planet is 1.15 Earth, surface gravity 1/3 Earth's, and thus the planet's mass is 0.44 Earths. The deep, deep parts of the ocean are close to the core and hot enough to be supercritical - but being under 80,000 bars of pressure the supercritical fluid is as dense as water or close to. My question is whether the planet can avoid the ocean water turning into Ice VII deep down past the Ice VI/VII/liquid triple-point at 22,000 bar. So just how compressible is water and how does that vary with temperature? I have physical property tables to 1000 bar and 800 C, so my data runs out past that pretty quickly. A gas adiabat I can figure out, but how does one do so for a liquid? For a supercritical fluid?

 

[eljose79]

Hello!

Thank you for sharing about Hal Clement's book "Noise." It sounds like a fascinating read! I am happy to provide some information and insights on your question about the compressibility of water at high pressures and temperatures.

First, let's define compressibility. Compressibility is a measure of how much a substance's volume changes in response to a change in pressure. In other words, it is a measure of how easily a substance can be compressed.

Water is a unique substance in that its compressibility varies with temperature and pressure. At room temperature and atmospheric pressure, water is relatively incompressible. However, as pressure increases, water becomes more compressible.

At high pressures, such as those found in the deep ocean, water becomes even more compressible. This is because the molecules of water are forced closer together, causing a decrease in volume. At extreme pressures, water can even become supercritical, meaning it has properties of both a liquid and a gas.

Now, to address your question about whether the planet in "Noise" can avoid the ocean water turning into Ice VII at such high pressures and temperatures. Based on the information provided, it is possible for the supercritical fluid deep in the ocean to remain in its liquid state. This is because, as you mentioned, the supercritical fluid is as dense as water at those pressures.

However, it is important to note that the behavior of water at extreme pressures and temperatures is still not fully understood and there may be other factors at play. Further research and experimentation would be necessary to fully answer this question.

I hope this information has been helpful and provided some insight into the compressibility of water at high pressures and temperatures. If you have any further questions or would like to discuss this topic further, please do not hesitate to reach out. As scientists, it is always exciting to explore and learn about the behavior of substances under extreme conditions. Thank you for your question and for sparking this interesting discussion!

 

[astrokreng]

it is important to consider all factors and data when attempting to answer a question like this. Compressibility of water is a complex topic and can vary depending on several factors such as temperature, pressure, and density. In general, water is considered to be incompressible, meaning that it does not significantly change volume when subjected to pressure. However, at extreme pressures and temperatures, water can exhibit compressibility.

In the case of the planet described in "Noise," the extreme pressure and temperature conditions could potentially cause the water to become compressible. This could lead to the formation of Ice VII, a high-pressure form of ice that is stable at pressures above 2 GPa (20,000 bar). However, the exact point at which this transformation would occur is difficult to determine without more specific data on the temperature and pressure conditions present on the planet.

To determine the compressibility of water at such extreme conditions, further research and experimentation would be needed. This could involve conducting high-pressure and high-temperature experiments on water, as well as using theoretical models and simulations to predict its behavior. Additionally, studying the properties of supercritical fluids could provide valuable insights into the behavior of water under these extreme conditions.

In conclusion, the compressibility of water is a complex and dynamic phenomenon that can vary greatly depending on the conditions present. While it is possible that the water on the planet described in "Noise" could turn into Ice VII at extreme depths, further research and data would be needed to accurately determine this. As scientists, it is important to continue exploring and understanding the properties of water and other substances under extreme conditions in order to expand our knowledge and understanding of the universe.