Shao Yung 邵雍 was a famous and top skilled master of numerology, cosmosology, metaphysics and confucism in the ancient Song dynasty. Master Shao was the inventor of "Early Heavenly 64 hexagrams" circle and square sequence diagrams 先天六十四卦方圓圖 symbolic the heaven and earth yin yang qi movements for metaphysics, numerology, divination, feng shui applications.
 
In one of his famous books titled "Huang-Chi-Ching-Shu"皇極經世書 , he talked about the heaven qi and earth qi.Below is a small extraction:
 
Those live with heaven (sky) qi would become active and vibrant, those live with earth (ground) qi would become inactive and quiet. .........
 
For Heaven (sky) qi, the shape and form are less important than the invisible qi itselt as always actively changing and moving. For earth (ground) qi, the shape and form are important as the inactive qi would stay with and attach to the objects of different shape and form utilised for making effectiveness. Therefore, those living in the sky and those living on ground, would carry the same characters of the respective qi, as being fed and driven by the qi characteristic, so the living creatures are being developed with the qi so as long as the qi is being retained in their body and in-taking for live.
 
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<皇極經世> 所言: " 得天氣者動，得地氣者靜。..........天以氣為主，體為次。地以體為主，氣為次，在天在地者亦如之。氣則養性，性則乘氣，故氣存則性存，性動則氣動也。...."
 
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You can see, the heaven qi carries the yang characteristic whereas the earth qi carries the yin characteristic.