Stars, Sem's Temperature, and Sem's Placement in the Universe

To those able to find certain gnomish scholars, read their text, or somehow manage to find their own method of discovery: it becomes obvious that the heat generated by the stars would mean they'd either be so energy-dense they'd explode, or they'd take up half the universe in how big they'd need to be. This has lead astrologists to believe they are immaterial, and thus belong on the immaterial (magical) plane that parallels our own, and are either so magically potent so as to break through to the material plane, or are somehow a spell being cast by something at the center of them- though to approach this thing would likely fry whoever tries it.
As a result of this arrangement of stars, Sem would not normally have night if it were not for Nicholas' Cage, and does not have seasons, though as Sem rotates, it does get colder at night when one is facing away from the nearest stars, and hotter at day. The axis Sem rotates on means that certain areas are colder than others on average as they get exposed to less heat though. On average, the temperature of Sem would be 4 degrees Celsius lesser than real life's Earth, causing many areas to be far colder, and ice more prevalent, though strange geological heating vents under the surface of Sem's crust keep it warm with a boiling, red substance that mixes in with the ocean water.