The lowest heaven (al-sama’ al-dunya’) encompasses the earth and is high above it. Wherever a person goes on earth, the heaven is above him.
Shaykh al-Islam Ibn Taymiyah said:
It is well known from a rational point of view that the air is above the earth, and the heaven is above the earth. This was known before it was known that the heaven encompasses the earth. Being above something does not necessarily mean encompassing, even though encompassing does not contradict it. Hence the people knew that the heaven is above the earth, and the clouds above the earth, before it ever occurred to them that it encompasses the earth.
Dar’ al-Ta’aarud, 6/336, 337
Ibn al-Qayyim said in al-Sawaa’iq al-Mursalah, 4/1308, that the view that the heaven does not encompass the earth and is only above it, is a view that goes against scholarly consensus and that which is indicated by reason and tangible evidence.
Ibn Hazm said:
Based on this evidence, the earth is a place that is beneath the heaven, hence the heaven is above the earth… and with regard to the son of Adam, his head points towards the heavens and his feet towards the earth.
Al-Fasl bayna al-Milal wa’l-Nahl, 2/243
And Allaah knows best.