Here are some possibilities:
In the traditional sense of biological decay (breaking down due to microorganisms):
* Diamond: Diamonds are made of pure carbon, which is incredibly stable.
* Gold: Gold is a very unreactive metal, meaning it doesn't readily combine with other elements. It's resistant to oxidation and corrosion.
* Platinum: Similar to gold, platinum is extremely resistant to decay.
In a broader sense of change over time:
* Light: While light can be absorbed or reflected, it doesn't technically "decay" in the same way as matter.
* Information: While data can be lost or corrupted, the underlying information itself doesn't decay.
* Fundamental constants: Values like the speed of light or the gravitational constant are thought to be unchanging over time.
However, even the most stable things can be affected by extreme conditions:
* Diamonds: Extremely high temperatures or pressure can break down even diamonds.
* Gold and Platinum: While very resistant, they can be dissolved by certain acids.
It's important to remember that everything in the universe is constantly changing, even if it takes billions of years for those changes to be noticeable.
Let me know if you'd like to explore any of these ideas further!
