Which Planet Has The Shortest Day?

Planet with shortest day
Which Planet Has The Shortest Day?

Each day of our life just passes by like a blip in time. We don’t even notice a single day in our lives. But, to experience just this single day of 24 hours, the Earth has to rotate a full 360 degrees on its axis at a speed of about 1674.4 km/hr. It is truly wonderful how a day in our life is possible only after the Universe does so much work. Gravitational forces need to be just right between the Sun and the planet to cause this rotation and in turn cause day and night. Wondering, what days on other planets must be like? And which planet has the shortest day? Well, the mechanics stay the same, but the speed at which planets rotate changes due to difference in gravitation and the tilt of the axis. So does the length of the day.

Which Planet Has The Shortest Day?

Jupiter has the shortest day among the planets of our Solar System. It’s even more astonishing considering Jupiter is the largest planet. Thus, it is worth pondering how fast Jupiter needs to rotate to get the shortest day.

Comparing it with our own planet, Jupiter has a diameter more than 11 times that of Earth, which essentially means that it would have to rotate 11 times faster than earth to have a day of 24 hours. But it has a day measuring to 9 hrs 55 min 26 sec which means that it has to rotate even faster. The rotational speed of Jupiter is about 43000 km/hr. The gas giant rotates at this mind-boggling speed which has all kinds of insinuations on the planet. The high rotational speed causes Jupiter to lose its spherical shape and appear flattened on the poles. The equatorial region seems more bulged than it should be.

What Does a Planet’s Day Length Insinuate?

A day in a Planet’s life is its rotation about its axis i.e. the imaginary line passing through its North and South Poles. It constitutes the inevitable day and night that a Planet experience owing to which side of the planet faces the Sun and which side is away from it. The tilt of the axis affects the area which experiences day or night at a particular time. The Earth has its axis tilted at 23.5 degrees away from vertical whereas Jupiter has its axis tilted only at 3.13 degrees. This tilt in axis also affects the seasons we experience around the year, as the tilt essentially shows the amount of heat the surface of the planet receives while revolving on its orbit around the Sun.

Why is Jupiter Different?

The interesting thing about Jupiter is that the day’s length depends on where you are on the planet’s non-existent surface. If you are at one of the poles, the day is about 5 minutes longer than that at the Equator. This phenomenon is known as differential rotation. It was difficult to calculate the actual rotational time of Jupiter as it does not have a surface or any topography, fixating on which time could have been measured. Also, it is basically a mass of gases, forever changing shape and swirling in space. Thus, the rotational speed and time were calculated based on the rotation of its magnetosphere rather than the actual surface.

Also, considering the little tilt Jupiter’s axis has, it does not have a monumental change in seasons as we experience on Earth. Also, this little tilt helps Jupiter to spin faster than any other planet in our Solar System.

Which Exoplanet Has the Shortest Day?

This was all about our Solar System, but there are countless other planets and around trillions of stars in space. The fastest spinning planet discovered so far is the Beta Pictoris b. This young exoplanet is 8-20 million years old and due to its high rotational speed of around 100,000 km/hr, it appears like a spheroid rather than a sphere. It has a day length of about 8 hours which is lesser than any other planet encountered to date.

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