Understanding astronomical units to hands Conversion
An astronomical unit (au) is the average Earth-Sun distance, fixed by definition at 149,597,870,700 meters and used as the base measure for Solar-System distances. A hand (hh) is a small length equal to exactly 4 inches, or 0.1016 meters, used chiefly to measure the height of horses at the withers. Converting an au into hands relates a planetary distance to an everyday equestrian unit, a memorable demonstration of astronomical scale.
Conversion Formula
To convert astronomical units to hands, multiply by this factor:
Step-by-Step Example
Convert 25 astronomical units to hands.
How to Convert astronomical units to hands
Convert an astronomical-unit distance into hands with one step.
- Begin with au: Take your distance in astronomical units, such as 25 au.
- Multiply by the factor: Use 1,472,420,000,000 hands per au.
- Find the product: 25 x 1,472,420,000,000 gives the total in hands.
- Give the answer: 25 au equal about 3.68105 x 10¹³ hands.
astronomical units to hands conversion table
| astronomical units (au) | hands (hh) |
|---|---|
| 0 | 0 |
| 1 | 1472420000000 |
| 2 | 2944840000000 |
| 3 | 4417260000000 |
| 4 | 5889680000000 |
| 5 | 7362100000000 |
| 6 | 8834520000000 |
| 7 | 10306940000000 |
| 8 | 11779360000000 |
| 9 | 13251780000000 |
| 10 | 14724200000000 |
| 15 | 22086300000000 |
| 20 | 29448400000000 |
| 25 | 36810500000000 |
| 30 | 44172600000000 |
| 40 | 58896800000000 |
| 50 | 73621000000000 |
| 60 | 88345200000000 |
| 70 | 103069400000000 |
| 80 | 117793600000000 |
| 90 | 132517800000000 |
| 100 | 147242000000000 |
| 150 | 220863000000000 |
| 200 | 294484000000000 |
| 250 | 368105000000000 |
| 300 | 441726000000000 |
| 400 | 588968000000000 |
| 500 | 736210000000000 |
| 600 | 883452000000000 |
| 700 | 1030694000000000 |
| 800 | 1177936000000000 |
| 900 | 1325178000000000 |
| 1000 | 1472420000000000 |
| 2000 | 2944840000000000 |
| 3000 | 4417260000000000 |
| 4000 | 5889680000000000 |
| 5000 | 7362100000000000 |
| 10000 | 14724200000000000 |
| 25000 | 36810500000000000 |
| 50000 | 73621000000000000 |
| 100000 | 147242000000000000 |
| 250000 | 368105000000000000 |
| 500000 | 736210000000000000 |
| 1000000 | 1472420000000000000 |
What is the astronomical unit?
The astronomical unit (au) is a unit of length used in astronomy to express distances within the Solar System, roughly the mean distance between Earth and the Sun.
Definition
The astronomical unit is defined as exactly 149,597,870,700 metres.
Since 2012 this is a fixed conventional value adopted by the International Astronomical Union (IAU), replacing the earlier definition based on the Gaussian gravitational constant. Related astronomical units build on it: 1 light-year ≈ 63,241 au and 1 parsec ≈ 206,265 au.
Origin and History
The concept dates to antiquity as astronomers sought the Earth–Sun distance to scale the Solar System. Early estimates were crude; the 1761 and 1769 transits of Venus allowed the first reasonably accurate measurements. For most of the 20th century the au was defined dynamically via Kepler's third law and the Gaussian constant. In 2012 the IAU redefined it as a fixed number of metres to eliminate its dependence on the changing measured value of the heliocentric gravitational constant.
Law and Notable Facts
The au is accepted for use with the SI, with the symbol "au" recommended by the IAU and BIPM (older texts use "AU" or "ua"). Light travels one astronomical unit in about 499 seconds, or roughly 8.3 minutes—the reason sunlight reaching Earth is always about 8 minutes old.
Real-World Examples and Conversions
- Earth orbits the Sun at 1 au (about 149.6 million km).
- Neptune orbits at roughly 30 au from the Sun.
- The Voyager 1 spacecraft is over 160 au away as of the 2020s.
- 1 au ≈ 92.956 million miles ≈ 499 light-seconds.
What is the Hand?
The hand is a non-SI unit of length used almost exclusively to measure the height of horses and other equines, taken from the withers (the ridge between the shoulder blades) to the ground.
Definition
One hand is defined as exactly 4 inches, or 0.1016 metre.
Heights are conventionally written with the whole number of hands, a decimal point, and the number of remaining inches (0 to 3), so "15.2 hands" means 15 hands plus 2 inches, i.e. 62 inches, not 15.2 hands in a base-ten sense. The abbreviation is often "hh" for "hands high."
Origin and History
The hand derives from the breadth of a human hand and appears among the oldest recorded units, referenced in ancient Egyptian and Babylonian metrology. In England it was standardised by statute of Henry VIII in 1541 to a fixed 4 inches, removing its dependence on the varying size of an actual hand.
Law and Notable Facts
The hand remains the legal and customary unit for equine height in English-speaking countries, including the United States, the United Kingdom, Canada, Australia, and Ireland; most of continental Europe measures horses in centimetres instead. Because a hand is exactly 4 inches, the fractional notation ".1", ".2", and ".3" represents 1, 2, and 3 inches respectively.
Real-World Examples and Conversions
- A horse must generally stand at least 14.2 hands (58 inches, 1.4732 m) to be classed as a horse rather than a pony.
- A typical Thoroughbred racehorse stands about 16 hands (64 inches, 1.6256 m).
- The tallest horses, such as the Shire breed, can exceed 18 hands (72 inches, 1.8288 m).
- 15 hands equals 60 inches, which is exactly 1.524 m.
Frequently Asked Questions
How many hands are in an astronomical unit?
One astronomical unit equals about 1.47242 x 10¹² hands, roughly 1.47 trillion hands. This comes from dividing 149,597,870,700 meters by 0.1016 meters per hand.
How do I convert au to hands?
Multiply the astronomical-unit value by 1,472,420,000,000. For example, 2 au equal about 2.94484 x 10¹² hands.
What is 25 astronomical units in hands?
25 au equal approximately 3.68105 x 10¹³ hands, about 37 trillion hands.
What is a hand used for?
A hand is an equestrian unit equal to 4 inches (0.1016 m) used to state a horse's height at the shoulder; a horse of 15.2 hands is 15 hands plus 2 inches.
Is converting au to hands meaningful?
It is a novelty conversion rather than a working one, useful mainly for illustrating just how enormous an astronomical unit is compared with a familiar small measure.
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Complete astronomical units conversion table
| Unit | Result |
|---|---|
| Nanometers (nm) | 149597900000000000000 nm |
| Micrometers (μm) | 149597900000000000 μm |
| Millimeters (mm) | 149597900000000 mm |
| Centimeters (cm) | 14959790000000 cm |
| Decimeters (dm) | 1495979000000 dm |
| Meters (m) | 149597900000 m |
| Kilometers (km) | 149597900 km |
| light-years (ly) | 0.00001581251 ly |
| parsecs (pc) | 0.000004848137 pc |
| ångströms (angstrom) | 1.495979e+21 angstrom |
| Mils (mil) | 5889680000000000 mil |
| Inches (in) | 5889680000000 in |
| Yards (yd) | 163602200000 yd |
| US Survey Feet (ft-us) | 490805700000 ft-us |
| Feet (ft) | 490806700000 ft |
| Fathoms (fathom) | 81801110000 fathom |
| Miles (mi) | 92955810 mi |
| Nautical Miles (nMi) | 80776390 nMi |
| chains (ch) | 7436465000 ch |
| rods (rd) | 29745860000 rd |
| furlongs (fur) | 743646500 fur |
| hands (hh) | 1472420000000 hh |