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.
Although Mercury and Venus are the two closest planets on average, their orbits are not synchronous, so they can be on opposite sides of the sun from each other. At times, the Earth is actually closer to Venus than Mercury. Beyond Earth's orbit, the distance between planets increases dramatically. Mars is almost 49 million miles from Earth, Jupiter is another 338 million miles from Mars and Saturn another 400 million miles beyond that.