The Cosmos A to Z was an astronomy book written by Laura Danly. The front cover featured an image of the Arachnid Nebula. An edition of the book stated that the nebula is 6.5 billion kilometers in diameter.
The cover of the book further stated:
- Your complete guide to the heavens
- Stars - Planets - Nebulae - Galaxies
- Including the Terra Nova expedition
and the back cover of the book proclaimed:
- "The essential guide to space, the final frontier! Now you can explore strange new worlds, seek out new life and new civilizations, boldly go where no one has gone before!"
On his eighth birthday in 2120, Jonathan Archer was given a copy of the book by his father, Henry Archer. Jonathan spent hours staring at the front cover of The Cosmos A to Z, his first astronomy book.
By 2151, Archer had become the captain of the Starfleet vessel Enterprise NX-01 and had the opportunity to see the Arachnid Nebula for himself. Ensign Travis Mayweather, Enterprise's helmsman, reported that the nebula was more than eight billion kilometers in diameter, not 6.5 billion. Ensign Hoshi Sato, the starship's communications officer, suggested sending the correction to the publishers of The Cosmos A to Z so that they could release a revised edition of the book. (ENT: "Fusion")