Fan-made tools to convert between Earth and Eridian base-6 numbers and time, create dual-format countdowns, and find when 40 Eridani A is visible from your location.
Convert decimal (base 10) to Eridian (base 6), including the Eridian symbol notation.
Convert Earth time (days, hours, minutes, seconds) to Eridian time (days, Eridian seconds).
Create an Earth and Eridian countdown to any date and time you choose.
Compare two timestamps and see the difference in Earth time and Eridian time.
See azimuth and altitude of the real star 40 Eridani A for your location and selected time.
Learn about base 6, Eridian timekeeping, and quick reference for Eridian notation.
Train your memory like an Eridian — match pairs of musical chords in this card game.
The Eridians are an alien species from Andy Weir's novel Project Hail Mary. They come from a planet orbiting 40 Eridani A, called Erid by the main character Ryland Grace. They have no eyes and communicate through musical tones, but still managed to build spaceships.
Eridians count in base 6, likely because they have six fingers on the two hands they use for counting. Their day is about 5.11 Earth hours (18,397 seconds), split into 10,000 base-6 units (7,776 in decimal).
Project Hail Mary is a 2021 science fiction novel by Andy Weir. It follows Ryland Grace on a desperate mission involving lots of problem-solving, real science, and friendship.
The story includes first contact between Grace and Rocky, an Eridian engineer from the Erid planet. The book was praised for its realistic science and won several awards.
The movie adaptation is directed by Phil Lord and Christopher Miller, with Ryan Gosling and Sandra Huller starring.
Eridian time is based on the day length of the planet Erid, which orbits 40 Eridani A. One Eridian day is approximately 5.11 Earth hours (18,397 seconds). Eridians divide their day into 10,000 units in base-6 notation, which equals 7,776 Eridian seconds in decimal. Each Eridian second is about 2.366 Earth seconds.
Eridians count in base 6 (senary), using only digits 0 to 5. This probably matches their six-fingered biology. For example, 10 in base 6 equals 6 in decimal, and 100 in base 6 equals 36 in decimal. Our converter shows both the numeric value and the Eridian symbols.
Yes! 40 Eridani A (also called Omicron2 Eridani A or Keid) is a real star about 16.3 light-years from Earth in the constellation Eridanus. It is an orange-red dwarf star you can see with the naked eye in good conditions. Our tool calculates its exact position in your sky.
