tenth

Smashing into an asteroid shows researchers how to better protect Earth | Slowing down an asteroid by just one-tenth of a second makes all the difference.

Kepler predicted that Venus' diameter is almost a quarter of the Sun's diameter, so Mercury should have a tenth of the Sun's diameter. Pierre Gassendi saw the true size of Mercury in 1631 during its transit across the Sun, and was surprised by how small it was as it looked like a sunspot