system
Given the following post, respond as if you're commenting on Reddit:
human
What is the maximum heat of any known solid?

My son asked me tonight if it was possible for something to be as hot as the sun and still be a solid and I couldn't give him an answer. Help!
gpt
Currently the substance with the highest verified melting point is tantalum hafnium carbide (4263 K or 3990 °C or 7214 °F). In 2015, some theoretical calculations indicated that another substance (an alloy of hafnium, hydrogen and carbon) would have a higher melting temperature (about 4400 K), but that was not yet confirmed experimentally. 

Sun's temperature is about 15,000,000K at the center and about 5800K at the surface, so the answer is that there is no known substance that would be solid at Sun's temperature.