Paul is speaking of the eternal kingdom in the following verse:
"Who hath delivered us from the power of darkness, and hath translated us into the kingdom of his dear Son" (Col.1:13).
The word "translated" comes from the Greek word
methistemi, which means
"to transpose, transfer, remove from one place to another" (
Thayer's Greek English Lexicon).
If the kingdom of the Son was on the earth when Paul wrote those words then there would be no need to "translate" the believer to the kingdom of the Son. In what way is the Christian "translated" into this kingdom?:
"If ye then be risen with Christ, seek those things which are above, where Christ sitteth on the right hand of God...For ye are dead, and your life is hid with Christ in God" (Col.3:1,3).
"Even when we were dead in sins, hath quickened us together with Christ...And hath raised us up together, and made us sit together in heavenly places in Christ Jesus" (Eph.2:5-6).
Once the sinner believes the gospel he is completely identified with the Lord Jesus, from His death and His life (Ro.6:3) as He is now sitting at the right hand of the Father in the eternal kingdom.
This also speaks of the eternal or heavenly kingdom:
"And as we have borne the image of the earthy, we shall also bear the image of the heavenly. Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption" (1 Cor.15:49-50).