What is the temperature at the lunar center? What is the highest temperature inside Luna?
There is an article at Spiegel Online in German.
They write about quakes on the moon during the Apollo mission. The astronauts left several sensors on the moon which were sending data to Earth from 1969 to 1977. The quality was (and still is) quite poor, but with modern methods they have been able to analyse the data that allows a glance into past.
Scientists from NASA used a method called "Double Array Stacking" to intensify the signals. It provides information about the centre of the moon:
It contains an iron sphere with a diameter of about 480km. Around that sphere there was a liquid mass out of iron and sulphur.
Over time the moon cooled down - the liquid became more viscous, but it's still not solid.
The melting point of iron is about 1.800K (~1.500°C), so let's assume that the core temperature is in a range between 1.270K and 1.800K (1.000-1.500°C).
The German site of the moon-wiki comes to the same result.
If anybody is interested in registering for an article in English from the magazine Science to share any further information I'd be grateful.