He̍k-chheⁿ sī chi̍t khoán thian-thé, in kho͘ Ji̍t-thâu ia̍h sī pa̍t-ê hêng-chheⁿ kiâⁿ-sóa, ka-tī bô pàng chhut la̍t-thâu (energy). Kho-ha̍k-kài ū chi̍t kóa koh khah giâm-keh ê tēng-gī, nā chiàu Kok-chè Thian-bûn-ha̍k Liân-ha̍p (International Astronomical Union) koat-tēng ê hun-lūi, chit-liōng ū kàu gia̍h chiâⁿ îⁿ-khoán ia̍h óa-kīn îⁿ-khoán, pún-sin m̄-sī ōe-chheⁿ, só͘ kiâⁿ ê kúi-tō téng-bīn bô chhun sè-lia̍p mi̍h kap chhùi-iú-á, chiah sī he̍k-chheⁿ.
Tē-kiû sī chi̍t lia̍p he̍k-chheⁿ.
Chham-chiàu
- "What Is a Planet?". SPACE.com
- "Planet" Encyclopaedia Britannica.