Yú Sǒng 虞聳 (fl. later 3rd – early 4th century), zì Shìlóng 世龍, a Wú–Western-Jìn astronomer-cosmologist of the eminent Yú 虞 lineage of Yúyáo 餘姚 in Kuàijī 會稽 (modern Zhèjiāng). He was the sixth son of the great SūnWú classicist 虞翻 (Yú Fān, 164–233), brother to Yú Sì 虞汜, Yú Zhōng 虞忠, and Yú Bǐng 虞昺. Under Wú he served at the Yuèqí xiàowèi 越騎校尉 (Colonel of the Yue Cavalry) and rose to Tíngwèi 廷尉 (Director of the Court of Judicial Review). After the Jìn 晉 conquest of Wú in 280 he served the Western Jìn court as Héjiān xiāng 河間相 (Chancellor of the Princely State of Héjiān) under Sīmǎ Yóng 司馬顒 (Prince of Héjiān, d. 306), who is recorded as having held him in particular esteem. The Héjiān xiāng office is the title under which his clan-grandson Yú Xǐ 虞喜 虞喜 cites him in the Āntiān lùn 安天論 (KR3f0063) — “yòu dǔ zúzǔ Héjiānlì Sǒng lì Qióngtiān mó” 又覩族祖河聞[間]立穹天模 — and which the Jìn shū tiānwén zhì 晉書·天文志 confirms as his title at the composition of the Qióngtiān lùn 穹天論. He was also known for a qīngdàn 清淡 (detached) temperament and for promoting men of un-prominent family into office, against the Jìn-period clan-prestige convention.
His exact lifedates are not preserved; given that Yú Xǐ (281–356) refers to him as zúzǔ 族祖 (“clan-elder of the grandfather generation”), and that Yú Fān is his confirmed father, Yú Sǒng is most plausibly placed c. 240–310, making him a contemporary of Yáo Xìn 姚信 姚信 and a slightly older contemporary of Yú Xǐ.
He is known for a single surviving work: the Qióngtiān lùn 穹天論 (KR3f0062), a short cosmological treatise advancing the qióngtiān (“vaulted heaven”) model — a fourth model alongside the orthodox húntiān 渾天 (spherical heaven), gàitiān 蓋天 (umbrella heaven), and xuānyè 宣夜 (effulgent night) — that became one of the canonical post-Hàn alternative cosmologies. The Jìn shū tiānwén zhì’s historiographical account of post-Hàn cosmology preserves the qióngtiān model alongside Yáo Xìn’s xīntiān 昕天 and Yú Xǐ’s āntiān 安天 as the three serious post-Hàn rivals to the orthodox synthesis.
He has no CBDB id (CBDB coverage of pre-Táng figures is patchy and the Yúyáo Yú lineage other than Yú Xǐ is largely absent from the current dump).