Khong-kan chiàu bu̍t-lí ê koan-liām sī 3 chhù-goân ê liân-sio̍k thé-hē, só͘-ū bu̍t-chit só͘ tī leh ê só͘-chāi.
Kó͘-tián-sek (Newton sek) ê khài-liām tang-tiong khong-kan sī choa̍t-tùi, bû-hān, bô piàn-hòa ê chōng-hóng, kap bu̍t-chit iā sî-kan bô kau-chhap.
Nā chiàu kīn-tāi bu̍t-lí (Einstein it-poaⁿ siong-tùi-sèng lí-lūn), khong-kan kap sî-kan saⁿ kat, sī 4 chhù-goân, la̍t-thâu (energy) kap chit-liōng (mass) tī lāi-té chè-chō piàn-tōng.