August 25

1835 – The first "Great Moon Hoax" article is published in The New York Sun, announcing the discovery of life and civilization on the Moon.
1981 – NASA's Voyager 2 spacecraft makes its closest approach to Saturn. Photographs taken by the probe show thousands of rings around the planet, as well as a number of moons.
1989 – The Voyager 2 spacecraft makes its closest approach to Neptune, later passing close to its moon, Titan.
2003 – NASA successfully launches the Spitzer Space Telescope into space. The infrared telescope took many pictures of Earth's "backyard," and became one of the first telescopes to directly capture light from exoplanets.
2012 – Voyager 1 enters interstellar space, becoming the first [hu]man-made object to do so.