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 closest planet to Earth varies, depending on where each planet is in its orbit around the Sun, but Venus is generally closer (on average) than Mars is. Sometimes, when botâ¦h Mars and Venus are on the far side of the Sun, Mercury will be the closest planet.