
Pressure Law: constant volume
Convert all Temperatures to Kelvin
0°C= 273K

answer= 312Kelvin
Limestone, Sandstone, and Shale would be the answer.
1. it is difficult to search for it . Because infrared rays will never penetrate through earth atmosphere.
2. we are unaware of how it looks like and we only know it is red and will glow . A damaged star also looks like this.
3. Dust also makes is hard to detect Dyson spheres . So we will get confused between Dyson sphere and a star surrounded by dust.