No. 9 Acquired winter 2018-spring 2019, created soon before.
I got this bookmark at the gift store of a solar observatory in Northern Italy, during a school field trip.
It's holographic on the front, and it displays the 8 planets and the Sun of the Solar system, ordered by distance from the Sun. In the background of the picture it shows the Milky Way, that shifts when viewed from different points of view, along with the names of the planets. On the back it has a chart with the avg diameter at the equator, mass, avg density, avg gravitational acceleration at the equator, length of day, synodic day, avg distance from the Sun and orbital period of the various planets of the solar system.
It's made of a layer of flexible plastic with a thin plastic coating on the back the chart is printed on. The front has shallow grooves on it, the back is smooth.
