On these evenings, around 10 p.m., depending on how far the hills you encounter on the horizon, you will see a somewhat bright, yellowish, star-like object in the southeast.
This object is the planet Saturn. It is the sixth planet that emerges from the sun (and we live in the third planet), and it has been described as the most beautiful object in the solar system.
If you have binoculars, or better yet, a small telescope, it’s worth a look.
The planets Mercury, Venus, Mars, Jupiter and Saturn have been known almost since our ancestors began searching for them. They were distinguished from the stars because while the stars remained in fixed or very slowly changing patterns, star-like objects moved against the starry background from one night to the next.
They were called “plantae”, which is Greek for “wanderers”. Until the invention of the telescope and Galileo’s decision to use it to look at the sky, nothing was known about them.
When Galileo pointed his telescope at the sky in the early 17th century, he knew about the planets, so he went to them early. He saw Jupiter as a beige disk and discovered its four largest moons, now Io, Europa, Ganymede and Callisto.
In his honor, they are also referred to as the Galilean moons. He saw the moon covered with mountains, craters, and lava flows, which he thought were seas, and were named on this basis. However, his big shock came when he pointed his telescope at Saturn. It seemed oblong to him, and at times seemed to have handles. This planet was different.
A few years ago, in one of our observatory’s open houses, we had a replica of Galileo’s telescope. It was interesting to see how much telescopes have improved since the time of Galileo.
By modern standards, using Galileo’s telescope was a challenge. The field of view was small, so pointing the telescope in the right direction and keeping it pointed must have been a challenge. When looking at bright objects against a dark background, false-colored edges appear. What Galileo saw as much as he did is a monument to his perseverance and patience.
Christiaan Huygens was an astronomer and manufacturer of telescopes, and in 1655 he sent a home-made telescope, which was much better than Galileo’s, to Saturn. He stated that Saturn was surrounded by a large ring that did not touch the surface of the planet anywhere.
He also discovered Titan, Saturn’s largest moon. Soon after, in 1675, Giovanni Domenico Cassini noticed that the ring around Saturn consisted of multiple rings, all in the same plane. He also discovered four of Saturn’s moons: Iapetus, Rhea, Tethys and Dione.
That is why the last spacecraft sent to Saturn was called Cassini, and the lander that carried it to Titan was named Huygens. The rings attracted a lot of attention, and it soon became clear that they could not be solid.
Now, thanks to spacecraft, including Cassini, we’ve got a good, up-close look at those rings.
It appears to be composed almost entirely of tiny particles of ice, meters in size and smaller, down to millionths of a metre. There are many concentric rings, less than a kilometer thick. This complex structure is maintained in part by the pull of the nearby moons, with some embedded in the gaps between the rings (the sponsor moons).
However, although we know what the rings are made of, and can make computer models of how they function, we still don’t know for sure how or when they formed. Some believe they are long-lived, possibly dating back to the formation of the planet. Others point out that it is no more than a few million years old.
Take a look at them now. We don’t know for sure how long they will last.
Saturn will rise around 9 pm and Jupiter around 11 pm and in mountainous places they will appear later.
Meanwhile, the moon will be full on August 30.
Ken Tapping is an astronomer at the National Research Council’s Dominion Radio Astrophysical Observatory near Penticton.
This article was written by or on behalf of an outside columnist and does not necessarily reflect Castanet’s views.