J is for Jupiter

I don’t think anyone can look at a picture of the great planet Jupiter and not feel amazed and incredibly curious. This world is so unlike our own it’s hard to imagine they meet the same definitions for planet. I remember learning about it in school and thinking it seemed like a world of extremes.

Jupiter is the fifth planet from the sun and the largest in the solar system. It is the fourth brightest object in the sky behind the Sun, the Moon and Venus. In fact if the sun is low enough in the sky, Jupiter can even be seen in the daytime. It is probably for that reason that we have know about Jupiter since ancient times.

The Babylonians were the first to record the existence of Jupiter around the 7th or 8th century BC.. For them the planet represented their god Marduk and it’s path through the constellations in the sky represented their zodiac. We got name Jupiter from the Romans, who named it after their principal god.

I have always felt the name was fitting. As Jupiter was the king of the gods, Jupiter to me is king of the planets. It is a giant planet with a mass of one-thousandth the mass of the sun and two and a half times larger than all the others combined. Despite it’s size it has the shortest day in the solar system, it turns on its axis every 9 hours and 55 minutes! It orbits the sun about every 12 Earth years.

Jupiter is so big it even helped shape the early solar system. There are even whole groups of asteroids the proceed and follow Jupiter in its orbit around the Sun.

Jupiter is a gas giant, meaning it is mostly made up of gases like hydrogen and helium. Despite it’s ginormous size it has a lower density than any of the smaller terrestrial planets. It might have a small core of ice and rock but we don’t really know. We don’t really know anything about what is going on inside Jupiter and a lot of what we think we know is based on models and simulations.

The upper atmosphere of Jupiter is divided into belts of clouds made primarily of ammonia crystals, sulfur, and mixtures of the two compounds. These bands are what give Jupiter it’s unique, banded appearance. Another unique feature of Jupiter’s atmosphere, and the reason I became interested in the planet as a kid, is its Great Red Spot.

Detail of Jupiter’s atmosphere, as imaged by Voyager 1.

Jupiter’s Great Red Spot is actually a storm that has been raging for at least 350 years. A storm that is so large 3 Earths could fit inside it! mathematical models show that the storm is actually pretty stable and may be a permanent feature of the planet. There are actually many such storms rotating in Jupiter’s atmosphere but they are either white or brown, they are also smaller and lesser known.

In 2000 scientists noticed the forming of what has been nicknamed “Red Spot Junior” when three smaller storms merged and changed in color from white to red.

Jupiter has a large amount of moons, 67 in total. 51 of those are pretty small, less than 10 kilometers in diameter and only relatively recently discovered. The four largest, Io, Europa, Ganymede, and Callisto, can be seen from Earth with binoculars on a clear night.

The orbits of Io, Europa, and Ganymede form a special pattern. For exactly every four orbits that Io makes around Jupiter, Europa makes two, and Ganymede makes one. The pattern causes the moons to pull on each others orbits and distort them into elliptical shapes but the gravity from Jupiter counter acts that and keeps them more circular.

This back and forth tugging of gravity causes the shapes of these moons to flex and change shape, which causes the interiors of these moons to heat up. This means the all have pretty active volcanic activity, especially Io which is the closest to Jupiter.

A lot of people don’t know that Jupiter also has its own rings system. The rings are faint and nothing like the ring system of Saturn but it is there. They are made of dust, not ice like Saturn’s rings are, and come from material from impacts on its moons that gets caught between the gravity of the planet and the moons.

Jupiter isn’t exactly my favorite planet but it definitely has some very interesting things going on. It has played a very important part in the formation of the solar system and may have even protected the inner planets, including Earth, from catastrophic meteor impacts. Scientists still have so much more to learn about the “king of the planets” and plan to send more probes to study it in the future.


Image: This artist’s impression shows Jupiter and its moon Europa using actual Jupiter and Europa images in visible light. The Hubble ultraviolet images showing the faint emission from the water vapour plumes have been superimposed, respecting the size but not the brightness of the plumes. Astronomers using Hubble have detected signs of water vapour being vented off this moon, creating variable plumes near its south pole — the first observational evidence of water vapour being ejected off the moon’s surface.

Water vapour plumes on Jupiter’s moon Europa (artist’s impression)” by NASA, ESA, and M. Kornmesser. Science Credit: NASA, ESA, L. Roth (Southwest Research Institute and University of Cologne, Germany), J. Saur (University of Cologne, Germany), K. Retherford (Southwest Research Institute), D. Strobel and P. Feldman (Johns Hopkins University), M. McGrath (Marshall Space Flight Center), and F. Nimmo (University of California, Santa Cruz) – http://www.spacetelescope.org/images/heic1322a/. Licensed under Public Domain via Wikimedia Commons.


4 Replies to “J is for Jupiter”

  1. Another awesome post! Scientists are pretty sure Jupiter’s immense gravitational pull has been the death of numerous planets ten times the Earth’s mass early in the solar system’s beginning.

    Stephen Tremp
    A to Z Cohost
    Twitter: @StephenTremp


  2. Love! I remember a while back the spot randomly disappeared… It turns out that’s a normal part of the weather pattern every couple hundred years or something? But when I saw the headline I thought I’d fallen into “Where in the Solar System is Carmen Sandiego” or something. :D


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