What a stupid dweeb. The embodiment of Mr. Bean for real. He envisioned Earth blazing hot. Earth can’t change temps at will. The Sun governs Earth’s temp. It spins through a sea of COLD in its orbit. Without Sol, we’d freeze. God’s promise, to Noah after the flood, still stands. Read Genesis chapter 8, especially verse 22. One of God’s promises to Noah, to his progeny, and to us and OUR progeny.
You are right, in that the surface of the Earth would quickly turn into an iceball.
But actually, the core of the Earth isn’t warm because of the Sun. It would take a slight amount of time for the Earth to freeze. The Earth is essentially a dirty bomb; The intense heat of its core makes Uranium and other radioactive substances react hotter, which in turn keeps it hot. The interior of the planet is thousands of degrees; the slight difference between 0 degrees and 300 degrees wouldn’t make much of a factor next to the thousands of degrees the Earth heats itself up to, for a very long time. And without convection, those 300 degrees would radiate their heat very slowly indeed.