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42.1 km/s
Solar escape at 1 AU
Escape speed from the Sun’s gravity at Earth’s distance. √(2GM☉/1 AU) ≈ 42.1 km/s.
To leave the Sun from where Earth is, you need about 42.1 kilometres a second. Not a rounded light-year. A vis-viva number. Earth’s own orbital speed is about 29.8. The extra is the door out.
NASA / JPL
Printed 42s
A proton count. A catalogue seat. A scan. A model boundary. A patch that draws 4 and II. A joke a JPL scientist made in public. Different kinds. NASA printed them. That does not make them one Answer.
The metal
- Z = 42Molybdenum
Proton count. The integer was 42 before Adams.
- jokeDouglas Adams element
Russell at JPL named the metal. NASA printed the joke.
Sky and distance
- M42Orion Nebula
Catalogue seat. NASA’s Cosmic Hearth is Maya reception.
- C42Caldwell 42
Another catalogue. NGC 7006. Not a measured forty-two.
- ≈42 AUKuiper collisions
Stern 1995. A modeled boundary, not Albion’s distance.
42.1 km/sSolar escapehere
Vis-viva at 1 AU. Family 4.2, not 42.00.
Missions and tools
- 42 minMariner 2
A scan of Venus. Duration, not a law of the planet.
- 42 dApollo 12 S-IVB
Missed heliocentric burn. NASA prints the period.
- 42Expedition 42
Sequential crew number. The patch draws 4 and II.
- STS-42STS-42
Shuttle number. Discovery, IML-1.
- 42Horizons keywords
JPL’s own manual. A documentation count.
What it supports
v = √(2GM☉/r) at r = 1 AU. IAU solar GM 1.3271244×10²⁰ m³ s⁻². AU 1.495978707×10¹¹ m. Result 42.12 km/s, commonly printed 42.1. The third cosmic speed relative to the Sun at Earth’s orbit.
What it does not
Not 42.00 exactly. Not Earth’s surface escape 11.2. Not a light-year. 41.9 or 42.3 would still be physics. The hundredths follow the constants.
Calculation
√(2 × 1.3271244×10²⁰ / 1.495978707×10¹¹) = 4.212×10⁴ m/s ≈ 42.1 km/s.
Vis-viva escape at 1 AU. Constants, not a hunt for 42.
ExactnessApproximate
Form4.2
Unitkm/s
Strengthhard
Hung16 September 2026