About "gravity" .....
Hebrews 1:1-3
1God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets, 2Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds; 3Who being the brightness of his glory, and the express image of his person, and upholding all things by the word of his power, when he had by himself purged our sins, sat down on the right hand of the Majesty on high;
Colossians 1:17-17
16For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him: 17And he is before all things, and by him all things consist.
It's the Word of God that holds everything together ... not "gravity."