QUESTION:
What is the temperature at the center of Mars?

ANSWER from Bruce Jakosky on November 20, 1997:
We don't know what the temperature at the center of Mars is.  We expect it
to be much hotter than the surface, but have no way yet of determining
whether the center is hot enough to be molten, for example.

Mars does have a core, and it probably is similar in composition to the
Earth's core.  The outer portion of the Earth's core is molten, and the
inner portion is solid.  Thus, we can estimate its temperature as being near
5000 degrees.  We do not have similar data for Mars, but could obtain it if
we ever fly a bunch of seismometers that can detect the passage of seismic
waves through the center.