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.
The smallest planet in regards to both mass and volume is Mercuryâthis tiny world is nearly 20 times less massive than Earth, and its diameter is about times 2 Â½ smaller. In fact, Mercury is closer in size to our Moon than to Earth.