# Angstroms to Astronomical Units (A to au)

Source: https://www.unitconvertercalculator.com/length/angstroms-to-astronomical-units/

**1 A = 6.6845871222684E-22 au**

One ångström equals approximately 6.685 × 10-22 astronomical units - an almost incomprehensibly small fraction. This conversion spans the widest gap in length measurement: from the scale of atomic bonds (ångströms) to the scale of planetary orbits (astronomical units). It appears only in theoretical physics and astrophysics education.

## Formula

Convert Angstroms to Astronomical Units

## Conversion Table

| Angstroms (A) | Astronomical Units (au) |
|---|---|
| 1000000000000000000 A | 0.00066845871222684 au |
| 5000000000000000000 A | 0.0033422935611342 au |
| 10000000000000000000 A | 0.0066845871222684 au |
| 50000000000000000000 A | 0.033422935611342 au |
| 100000000000000000000 A | 0.066845871222684 au |
| 500000000000000000000 A | 0.33422935611342 au |
| 1000000000000000000000 A | 0.66845871222684 au |
| 5000000000000000000000 A | 3.3422935611342 au |
| 10000000000000000000000 A | 6.6845871222684 au |

## Units

### Angstrom (A)

One ten-billionth of a meter (0.1 nanometers). Named after Anders Jonas Angstrom. Used in crystallography, spectroscopy, and atomic physics.

### Astronomical Unit (au)

Exactly 149,597,870,700 meters by IAU 2012 definition. Roughly the average distance from the Earth to the Sun. Used for distances within our solar system.

## Background

A carbon-carbon bond at 1.54 Å is roughly 10-21 AU - a number so small it has no practical meaning outside of demonstrating scale differences. The contrast is striking: one AU (Earth-Sun distance) contains about 1.496 × 1021 ångströms. This conversion exists primarily as a mathematical exercise showing how atomic and astronomical scales relate.

## Good to Know

This conversion spans from the realm of quantum chemistry to solar system astronomy - two fields that rarely need to communicate in the same units. It exists as a testament to the incredible range of scales in the physical universe.

## FAQ

### How many astronomical units is 1 ångström?

One ångström equals approximately 6.685 × 10-22 AU. This number is so small that the conversion has no practical application - it exists only to illustrate the vast difference between atomic and solar system scales.

### Why would anyone convert ångströms to astronomical units?

This conversion is used in physics education to demonstrate scale differences. The ratio between an ångström and an AU spans about 21 orders of magnitude, making it one of the most extreme unit conversions in length measurement.

### How many ångströms fit in 1 AU?

Approximately 1.496 × 1021 ångströms fit in one astronomical unit. That's about 1.5 sextillion ångströms - a number that illustrates why different units exist for different scales.

## Non-Frequently Asked Questions

### Could an atom hitchhike to the Sun?

An atom is about 1-3 angstroms. The Sun is 1 AU away. That is roughly 1021 atoms end-to-end. Even if atoms had thumbs, no car is making that trip.

### If I lined up atoms from here to the Sun, how many would I need?

About 1.5 x 1021 atoms end-to-end (roughly 1.5 sextillion). Your body contains about 7 x 1027 atoms, so you actually have enough atoms to reach the Sun and back about 2.3 million times. You are surprisingly well-stocked for interplanetary atomic bridge construction.

### Is the angstrom the opposite of the AU?

In spirit, yes. The angstrom is the smallest unit in common scientific use. The AU is among the largest units with a tangible real-world anchor (the Earth-Sun distance). They are measurement bookends.

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## See Also

- [Astronomical Units to Angstroms](https://www.unitconvertercalculator.com/length/astronomical-units-to-angstroms/)