Slowing of Earth's Spin Revealed in Ancient Astronomers' Tablets

The work of ancient astronomers reveals that the Earth's spin is slowing down — though not as much as scientists believed.

Each century, the length of the solar day, or the time it takes the planet to do a full rotation, grows by 1.8 milliseconds, according to a new study using astronomical observations going back to 750 B.C. Researchers have known that the planet's rotation is slowing because of friction caused by the tides, as water that's being tugged on by the moon's gravity sloshes against the solid Earth. However, measurements of this tidal effect suggest that the planet should be slowing in its rotation by 2.3 milliseconds per century, slightly more than the new research finds.

NASA's Juno spacecraft flies by Earth, captures this incredible video

The video below, taken by NASA's Juno spacecraft as it zipped past Earth on Oct. 9, may be imperfect, but it will give you chills.

Captured with sensors designed to track faint stars rather than rocky planets, the video begins just as the Earth-and-moon system has come into Juno's view, 600,000 miles in the distance.

As Juno flies in closer, you can see the small white dot of the moon gliding silently around a fuzzy blue Earth. Closer still, and the moon moves off into the margins as our spinning planet takes up more of the field of view.



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