Eyeglasses made of nylon were introduced in the late 1940s. Because of brittleness and other problems, eyeglass manufacturers switched to blended nylon (polyamides, co-polyamides and gliamides). Today's blended nylon frames are both strong and lightweight.
Venus is the closest size to Earth and is sometimes called Earth's sister planet.. Its diameter is 95% of Earth's but its mass is only 81% as much.
Of these, the question of which planet is the smallest has been the subject of some controversy. Until recently, the smallest planet was considered to be Pluto. But with the 2006 IAU Resolution that put constraints on what the definition of a planet entails, that status has since passed to Mercury. So in addition to being the closest planet to the Sun, Mercury is also the smallest. Size and Mass: With a mean radius of 2440 km, Mercury is the smallest planet in our Solar System, equivalent in size to 0.38 Earths. And given that it has its experiences no flattening at the poles â like Venus, which means it is an almost perfectly spherical body â its radius is the same at the poles as it is the equator.