Template:Are You Sure/February 13

Position and trajectory of Voyager 1 and the positions of the planets on 14 February 1990, the day when Pale Blue Dot and Family Portrait were taken.

• ... that Pale Blue Dot is a photograph of planet Earth taken on February 14, 1990, by the Voyager 1 space probe from a record distance of about 6 billion kilometers (3.7 billion miles, 40.5 AU), as part of the Family Portrait series of images of the Solar System, and that Voyager 1, which had completed its primary mission and was leaving the Solar System, was commanded by NASA to turn its camera around and take one last photograph of Earth across a great expanse of space, at the request of astronomer and author Carl Sagan?

• ... that mathematician David Hilbert was among the first to distinguish between mathematics and metamathematics?

• ... that mathematician John Hadley laid claim to the invention of the octant, two years after Thomas Godfrey claimed the same, and that Hadley also developed ways to make precision aspheric and parabolic objective mirrors for reflecting telescopes?

• ... that physicist and radio engineer Karl Guthe Jansky discovered radio waves emanating from the Milky Way while investigating sources of static that might interfere with radio voice transmissions, and is considered one of the founding figures of radio astronomy, yet radio astronomy remained a dormant field for several years, due in part to Jansky's lack of formal training as an astronomer?