# Thousand Days: Concept

reference copy: Thousand Days: Concept on github.

Stewart Russell – scruss.com — 2024-03-26, at age 19999 days …

## Summary

One’s thousand day(s) celebration occurs every thousand days of a person’s life. They are meant to be a recognition of getting this far, and are celebrated at the person’s own discretion.

## Who is this for?

• Maybe your birthday’s on a day associated with an unpleasant event. Your thousand day will never coincide with your birthday.
• Maybe your birthday’s in the middle of winter, or in another part of the year that you’re not keen on. Your thousand day is every 2 years and 3 seasons, so it shifts back by a season every time it happens.

## Quantities and scale

1000 days is approximately:

• 2.738 years
• 2 years 269 days
• 2 years 8.85 months
• 2 years, 3 seasons.

4000 days is just shy of 11 years.

Compared to regular birthdays, thousand days:

• must be calculated; they’re not intuitive when they’re going to happen. But we have computers and calendar reminders for that …
• can be used to work out your actual date of birth, if someone knows that you’re going to be x000 days old on a particular day. It’s possible to know someone’s birthday, but not know their age.

## Implementations

### Web

My ancient Your 1000 Day Birthday Calculator, first published in 2002 and untouched since 2010.

### Shell

So it turns out that GNU date can handle arbitrary date maths quite well. For example:

`date --iso-8601=date --date="1996-11-09 + 10000 days"`

returns 2024-03-27.

### Other Ways

Excel or any other spreadsheet will do, too. Although not for too many years back

# People with the same thousand day as you

This is an idea for finding people who have a thousand day on the same day as you. I suggest using 1851-10-01 as a datum, because:

• nothing particularly interesting happened that day;
• it’s conveniently 43000 days before my birthday.

then calculate

```( (birth_date - 1851-10-01) mod 1000 ) + 1
```

This results in a number 1 – 1000. Everyone with the same number shares a 1000 day birthday with you.

Why not 0 – 999?

1. No-one deserves to be a zero;
2. Wouldn’t be much of a thousand day if it only went up to 999, would it?

### Incomplete list of people with day = 1

There are more, but these were found from Wikipedia’s year pages

## Licence

🅭 2024, Stewart Russell, scruss.com