# The Secret of the Ninth Planet

By Donald A. Wollheim.

"The Secret of the Ninth Planet" by Donald A. Wollheim is a science-fiction novel published in 1959. When the Sun's light mysteriously begins to dim across Earth, threatening a new ice age, young Burl Denning discovers alien machinery in the Peruvian Andes. As calculations reveal the Sun may explode within years, Burl joins a desperate expedition aboard an experimental antigravity spaceship to hunt down similar installations throughout the solar system and confront an alien force from Pluto. (Summary by Project Gutenberg, written by machine.)

- Language: English
- Subjects: Science fiction; Pluto (Dwarf planet) -- Fiction

[Read it](https://invisiblenetwork.ai/books/gutenberg/33644/read)
[Plain text](https://invisiblenetwork.ai/api/books/gutenberg/33644/text)

## Audiobooks of it

- [Secret of the Ninth Planet](https://invisiblenetwork.ai/books/librivox/6711) by Donald Wollheim (5 h 23 min, English)
- [Secret of the Ninth Planet (Version 2)](https://invisiblenetwork.ai/books/librivox/8051) by Donald Wollheim (4 h 42 min, English)

From Project Gutenberg. Public domain in the United States.