On about december 21 the hemisphere is tilted directly towars the sun

On about December 21 the Southern hemisphere is tilted directly towards the sun

Explanation:

On December 21st, the Southern Hemisphere is tilted towards the Sun receiving the most direct sunlight of the year during the longest day. The Northern Hemisphere is having its winter solistice, tipped away from the Sun, producing the shortest day of the year and a low Sun angle.

the transfer of energy between two molecules spaced just nanometers apart plays a key role in many technologies, including photovoltaics, quantum information systems, lighting, and sensors, as well as in biophysics to measure nanometer distances and in photosynthesis. but an open question in this area is what effect, if any, the surrounding photonic environment has on this nanoscale energy transfer. by designing and performing a carefully controlled experiment to answer this question, scientists have settled the debate and found clues to improving the efficiency of many of the technologies that rely on this process.

explanation: