Will they really disappear by 2025?

SaturnThe ‘Q’ rings, visible now, appear to disappear in 2025 due to a regular astronomical phenomenon but will reappear after that. The current period is ideal for watching episodes before their next major appearance in 2027 or 2028.

If you can get your hands on a telescope, there are few more spectacular views than the magnificent ringed planet – Saturn.

Currently, Saturn is Clearly visible in the evening sky, at its highest levels immediately after sunset. It’s the perfect time to use a telescope or binoculars to get a good view of the sixth planet in the solar system and its famous rings.

This was Cassini’s view from orbit around Saturn on January 2, 2010. Source: ASA/JPL-Caltech/Space Science Institute Source: ASA/JPL-Caltech/Space Science Institute

Misinformation on social media sites

Recently, several articles have spread like wildfire across social media. Saturn’s rings, these articles claim, They disappear quickly – It will disappear by 2025!

So what’s the story? Could the next few months, before Saturn disappears from view in the evening sky, be our last chance to see its great rings?

The short answer is no. While it is true that the rings will become almost invisible from Earth in 2025, this is neither surprising nor a reason for panic. The rings will “appear” again shortly thereafter. this is the reason.

Overturning and tilting of the Earth

To understand why our view of Saturn changes, let’s start by looking at Earth on its continuing journey around the sun. This journey takes us through the seasons – from winter to spring, summer and fall, and back again.

What causes the seasons? Simply put, the Earth tilts to one side, as viewed from the Sun. Our equator is tilted about 23.5 degrees from the plane of our orbit.

The Earth has seasons because its axis is tilted. The axis always points in the same direction as our planet’s rotation around the Sun. Credit: Australian Bureau of Meteorology

Results? As we move around the Sun, we alternately tilt one hemisphere and then the other toward our star. When your hemisphere is tilted more toward the sun, you get longer days than nights and enjoy spring and summer. When you lean away, you get shorter days and longer nights, and you experience fall and winter.

From the Sun’s perspective, the Earth appears to “wiggle” up and down, showing alternating hemispheres as it moves around our star. Now let’s move on to Saturn.

Saturn, a giant tilted world

Just like Earth, Saturn has seasons, but they are 29 times longer than ours. The Earth’s equator is inclined by 23.5 degrees, while Saturn’s equator is inclined by 26.7 degrees. Results? As Saturn moves through its 29.4-year orbit around our star, it also appears to move up and down as seen from Earth and the Sun.

What about Saturn’s rings? The planet’s massive ring system, made up of chunks of ice, dust and rock, spreads over a great distance – Just over 280 thousand kilometers from the planet. But they are very thin – in most places, they are only tens of meters thick. The rings orbit directly above Saturn’s equator, and are therefore also tilted to the plane of Saturn’s orbit.

A mosaic of images from NASA’s Cassini mission in 2016, highlighting Saturn’s axial tilt during the Northern Hemisphere summer. Image source: NASA/JPL-Caltech/SSIS. Composite by Jason Major via Flickr, CC BY-NC-SA

Why do Saturn’s rings disappear?

The rings are so thin that they appear to disappear when viewed from a distance. You can easily visualize this by grabbing a sheet of paper and rotating it until it’s on the edge of the edge – the sheet almost disappears from view.

As Saturn moves around the Sun, our view changes. As for the semi-orbit, the northern hemisphere is tilted towards us and the north face of the planet’s rings is tilted towards us.

When Saturn is on the other side of the Sun, its southern hemisphere is directed toward us. For the same reason, we see the southern face of the planet’s rings tilted in our direction.

This simulation shows Saturn’s orbital period of 29.5 years, as seen from Earth. The ring system lies directly above Saturn’s equator, so both sides of its disk can be seen from Earth within one Saturnian year. Image credit: Tdadamemd/Wikimedia Commons, CC BY-SA

The best way to illustrate this is to take the paper, and hold it horizontally – parallel to the floor – at eye level. Now, move the paper down towards the ground a few inches. what do you see? The top side of the leaf is shown. Move the paper back up, across your eye line, to hold it above you and you can see the underside of the paper. But when it passes through eye level, the paper will disappear completely.

This is what we see with Saturn’s rings. As Saturn’s seasons progress, we move from a south-side tilt of the rings to a north-side view. The planet then turns back to reveal its southern side again.

Twice a Saturnian year, we see the rings on edge and they all disappear from view.

This is what will happen in 2025 – the reason Saturn’s rings will apparently “disappear” is because we will be looking at them from afar.

This happens regularly. The last time was in 2009, and the rings gradually became visible again, over the course of a few months. The rings will be on the rim again in March 2025. They will then gradually return to view as seen through large telescopes, before slipping out of view again in November 2025.

After that, the rings will gradually become clearer, reappearing first in front of the largest telescopes in the following months. Nothing to worry about.

If you want to see Saturn’s rings clearly, now is your best chance, at least until 2027 or 2028!

Written by Jonty Horner, Professor (Astrophysics), University of Southern Queensland.

Adapted from an article originally published in Conversation.