# Light-years to Furlongs (ly to fur)

Source: https://www.unitconvertercalculator.com/length/light-years-to-furlongs/

**1 ly = 47029002985469 fur**

One light-year equals approximately 4.703 x 1013 furlongs (about 47 trillion). The light-year measures stellar distances; the furlong (220 yards) measures horse races. The two most specialized distance units in English convert at a factor of 47 trillion.

## Formula

Convert Light-years to Furlongs

## Conversion Table

| Light-years (ly) | Furlongs (fur) |
|---|---|
| 1.0E-13 ly | 4.7029002985469 fur |
| 1.0E-12 ly | 47.029002985469 fur |
| 1.0E-11 ly | 470.29002985469 fur |
| 1.0E-10 ly | 4702.9002985469 fur |
| 1.0E-9 ly | 47029.002985469 fur |
| 1.0E-8 ly | 470290.02985469 fur |
| 1.0E-7 ly | 4702900.2985469 fur |
| 1.0E-6 ly | 47029002.985469 fur |
| 1.0E-5 ly | 470290029.85469 fur |
| 0.0001 ly | 4702900298.5469 fur |
| 0.001 ly | 47029002985.469 fur |
| 0.01 ly | 470290029854.69 fur |
| 0.1 ly | 4702900298546.9 fur |
| 1 ly | 47029002985469 fur |
| 4.24 ly | 1.9940297265839E+14 fur |

## Units

### Light-year (ly)

The distance light travels in one Julian year (365.25 days) in vacuum. Exactly 9,460,730,472,580,800 meters. Used for interstellar distances.

### Furlong (fur)

Exactly 660 feet or one-eighth of a mile (201.168 m). Originally the length of a plowed furrow. Still used in horse racing.

## Background

A furlong is 2.126 x 10-14 light-years. The Kentucky Derby (10 furlongs) covers 2.126 x 10-13 light-years. Light covers about 1 furlong in 0.67 microseconds. A racehorse covers it in 12 seconds. Light is faster.

## Good to Know

The 'furlong per fortnight' is a famous joke unit in physics, used to illustrate that any consistent unit system works mathematically. Light-speed in furlongs per fortnight is about 1.803 x 1012. The joke proves that physics does not care about unit elegance.

## FAQ

### How many furlongs are in 1 light-year?

One light-year contains approximately 4.703 x 1013 furlongs (about 47 trillion).

### How fast does light travel in furlongs?

Light travels approximately 1.49 million furlongs per second, or about 149,000 Kentucky Derbys per second.

### Is this conversion used?

Never. But expressing light-speed in furlongs per second is a popular physics joke.

## Non-Frequently Asked Questions

### How many Kentucky Derbys does light run per second?

Light travels about 1.49 million furlongs per second. The Derby is 10 furlongs. So light runs about 149,000 Kentucky Derbys per second. Secretariat's record time of 1:59.4 looks a bit slow in comparison.

### Could a horse outrun light in any unit system?

No. Light travels 983 million feet per second. A horse gallops at about 88 feet per second. Light is 11.2 million times faster. No unit conversion, dimensional trick, or creative accounting makes a horse faster than light. Physics wins.

### How many horse races long is the Milky Way?

The Milky Way is about 100,000 light-years across = 4.7 x 1018 furlongs = 4.7 x 1017 Kentucky Derbys. Even if every star in the galaxy hosted a Derby simultaneously, they could not fill the galaxy with races.

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## See Also

- [Furlongs to Light-years](https://www.unitconvertercalculator.com/length/furlongs-to-light-years/)