How Heavy Is Halley's Comet?
Halley's Comet is estimated at
302,000,000,000 t (332,000,000,000 US tons)
Typical range: 101,000,000,000,000 kg – 755,000,000,000,000 kg.
Computed value (volume × density); the inputs are cited under Sources below.
Using a log scale so small objects stay visible — the numbers stay real.
- Halley's comet (nucleus)302,000,000,000,000 kg
solid nucleus treated as a 15 × 8 × 8 km ellipsoid; mass = volume × density (0.6 g/cm³, Sagdeev et al. 1988); order-of-magnitude scientific estimate
- the Eiffel Tower10,100,000 kg
official figures published by the tower operator: 7,300 t of metal frame, 10,100 t total including the lifts, shops and antennae (French metric tonnes)
- a blue whale150,000 kg
adult; females larger than males; Antarctic subspecies up to 330,000 lb (149,685 kg), North Atlantic/North Pacific over 100,000 lb (45,359 kg)
- an African elephant4,500 kg
adult male 4,500–6,100 kg; adult female 2,000–3,500 kg
- You
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Put it in perspective
- About 30,000,000× the Eiffel Tower
- About 2,000,000,000× a blue whale
- About 66,999,999,999.99999× an African elephant
Why weights differ
No mission has measured Halley's mass directly; the Giotto flyby data led Sagdeev et al. (1988) to estimate the nucleus density. NASA publishes only two nucleus dimensions (15 × 8 km), so this estimate assumes the third axis equals 8 km and treats the nucleus as an ellipsoid: volume ≈ 5.0 × 10¹⁴ L × 0.6 kg/L ≈ 3 × 10¹⁴ kg (about 300 billion tonnes). The real value could easily be several times smaller or larger.
Sources
[1] NASA (Science Mission Directorate)
1P/Halley — NASA Science: Solar System ExplorationGovernment agency
“Halley's dimensions are about 9.3 by 5 miles (15 kilometers by 8 kilometers).”
Value as published: about 9.3 by 5 miles (15 km by 8 km) · accessed 2026-11-11.
[2] Nature (Sagdeev, Elyasberg & Moroz)
Is the nucleus of comet Halley a low density body? (Nature 331, 240–242)Peer-reviewed paper
“In this paper we estimate ρ to be 0.6 +0.9-0.4 g cm -3”
Value as published: ρ ≈ 0.6 (+0.9/−0.4) g cm⁻³ · accessed 2026-11-11.
How this value was computed
- volume-l: 502650000000000 L — 来源 [1] (source [1])
- density-kg-per-l: 0.6 kg/L — 来源 [2] (source [2])
Last updated 2026-11-11.Report a correction (please include a source link).
Related objects
Frequently asked questions
How much does Halley's comet (nucleus) weigh?
Halley's Comet is estimated at 302,000,000,000 t (332,000,000,000 US tons) — solid nucleus treated as a 15 × 8 × 8 km ellipsoid; mass = volume × density (0.6 g/cm³, Sagdeev et al. 1988); order-of-magnitude scientific estimate.
How much is Halley's comet (nucleus) in pounds and ounces?
665,000,000,000,000 lb, which is 1.06 × 10^16 oz. In metric terms: 302,000,000,000,000 kg.
Is Halley's comet (nucleus) heavier than the Eiffel Tower?
Yes. Halley's Comet is estimated at 302,000,000,000 t (332,000,000,000 US tons), while the Eiffel Tower is about 10,100 t (11,100 US tons) — roughly 30,000,000×.
Why do sources give different weights?
No mission has measured Halley's mass directly; the Giotto flyby data led Sagdeev et al. (1988) to estimate the nucleus density. NASA publishes only two nucleus dimensions (15 × 8 km), so this estimate assumes the third axis equals 8 km and treats the nucleus as an ellipsoid: volume ≈ 5.0 × 10¹⁴ L × 0.6 kg/L ≈ 3 × 10¹⁴ kg (about 300 billion tonnes). The real value could easily be several times smaller or larger.
Where does this number come from?
Every source is listed at the bottom of this page with publisher, link, access date and a verbatim quote. Numbers are only published when a qualifying source can be verified.