Have you ever wondered what seasons are like on other planets? Do you ever get tired of having to switch out your heavy coats for swim trunks? Well, if you are tired of dealing with Earth's ever-changing seasons, there are many planets in our Universe that present you with other options.
For example, astronomers are pondering over a planet in the sky named Kepler 413b, which they think might have unprecedented seasons.
Yes, much like the Star Wars concept of planet Eadu, it has seasons of wildly varying lengths - moving from Summer to Winter seemingly without warning, which from a wardrobe perspective, sounds like a huge hassle. But how do scientists even know what seasons are like there?
The answer comes down to a trait that varies from planet to planet all across the universe. Planets get their seasons, if they have them, from their axial tilt – aka, the little angle at which the poles tilt relative to the orbital plane.
Earth, for example, sits at 23.5 degrees as it orbits the sun. This tilt, or obliquity, means that for part of our 365-day orbit, sunlight strikes the Northern Hemisphere more directly, creating Summer, while it’s Winter in the Southern Hemisphere.
And as we move through our orbit, the whole thing gets reversed, until the Sun reaches the Northern Hemisphere. The result of the entire cycle is four roughly equal seasons, each lasting about 90 days.
So imagine the alternatives to this scenario - like if a planet had a tilt that changes over time, or a huge tilt, or no tilt at all. As it happens, you can find examples of these extremes within our own Solar System.
Mercury, Venus, and Jupiter, for example, have zero or very little tilt and thus no seasons. Mars, Saturn, and Neptune meanwhile have tilts like ours, plus or minus a few degrees, creating even seasons from year to year.
And don’t get me started on Uranus - it’s tilted a full 98 degrees, basically lying on its side and rolling around the sun. This means that one pole is pointed directly at the sun, and gradually reverses over the course of a Uranian year.
This is why it's interesting to consider Kepler 413b: it's axial tilt actually wobbles, or precesses, like a spinning top, varying by as much as 30 degrees over the years.
This means that the seasons there change fast, furiously, and unreliably from year to year. You’d hardly know whether to reach into your closet for a windbreaker or a bikini.
Our planet also undergoes this kind of precession, but much more gradually. Our tilt changes 23.5 degrees every 26,000 years - that's one degree every 1,106 years.
There are probably lots of other planets like 413b out there, with their own weird axial tilt oddities just waiting to be discovered. But so far, astronomers haven’t found many other examples with such extreme variations of seasons. It just goes to show that anything we can imagine in science-fiction may actually be out there in our weird, amazing Universe.
Unfortunately, until we have the technology that would make us able to travel 2,300 light years into space, the closest we will ever get to a planet as sporadic as 413b will only be through the movies.
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Sources: This story was originally published on SciShow Space. I am republishing a lightly edited version on SkyFeed in light of interest in the subject. Riemers, Ried. “What Are Seasons Like on Other Planets.” SciShow Space, YouTube. 6 April 2014. Web video.
Citation: Rovira, Lia N. "What are Seasons Like on Other Planets?" SkyFeed. 17 Jan, 2018. Web article.