# Light-years to Thou (ly to thou)

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

**1 ly = 3.7246970364491E+20 thou**

One light-year equals approximately 3.725 x 1020 thou (about 372 quintillion mils). The light-year measures cosmic distances; the thou (0.001 inches / 25.4 micrometers) measures paint thickness and wire gauges. About 21 orders of magnitude separate them.

## Formula

Convert Light-years to Thou

## Conversion Table

| Light-years (ly) | Thou (thou) |
|---|---|
| 1.0E-20 ly | 3.7246970364491 thou |
| 1.0E-19 ly | 37.246970364491 thou |
| 1.0E-18 ly | 372.46970364491 thou |
| 1.0E-17 ly | 3724.6970364491 thou |
| 1.0E-16 ly | 37246.970364491 thou |
| 1.0E-15 ly | 372469.70364491 thou |
| 1.0E-14 ly | 3724697.0364491 thou |
| 1.0E-13 ly | 37246970.364491 thou |
| 1.0E-12 ly | 372469703.64491 thou |
| 1.0E-11 ly | 3724697036.4491 thou |
| 1.0E-10 ly | 37246970364.491 thou |

## 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.

### Thou (thou)

One thousandth of an inch (0.0254 mm). Also called a mil in the US. Used in engineering, manufacturing, and for measuring thin materials like plastic film.

## Background

A thou is 2.685 x 10-21 light-years. A coat of paint (3 thou) is about 8 x 10-21 light-years thick. These units have never met in any practical context and never will.

## Good to Know

The thou was invented by American engineers to avoid going metric. The light-year was invented by astronomers to make cosmic distances comprehensible. One is a stubbornly imperial precision unit; the other is a poetically named cosmic unit. Both are useful. Neither is going away.

## FAQ

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

One light-year contains approximately 3.725 x 1020 thou (about 372 quintillion).

### How many light-years is 1 thou?

One thou equals approximately 2.685 x 10-21 light-years.

### Is this conversion ever used?

Never. Paint coatings and stellar distances occupy different measurement universes separated by 21 orders of magnitude.

## Non-Frequently Asked Questions

### How many coats of paint span 1 light-year?

At 3 thou per coat, about 1.24 x 1020 coats (124 quintillion). At 1 hour drying time per coat, painting 1 light-year takes 14.2 trillion years. The universe is 13.8 billion years old. You need 1,029 universe lifetimes of paint drying. The watched paint does not dry.

### If every thou of wire ever manufactured were connected, would it reach a star?

A thou of wire is 0.001 inches = 0.0254 mm. Even connecting a billion kilometers of wire (the approximate total of global copper production) gives about 39.4 trillion thou = 10-8 light-years. Not even close to 1 light-year. Humanity has not wired enough of the universe.

### How thick is the universe in thou?

The observable universe is about 93 billion light-years across = about 3.46 x 1031 thou. That number has 32 digits. If each digit were 1 thou high, the number itself would be 0.8 mm tall. Even the size of the universe in thou fits in less than a millimeter of text.

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## See Also

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