Universe Guide

Io, Moon of Jupiter

Io is a Moon that orbits round the planet Jupiter. Its mass is estimated/calculated at being 89,319,379,731,108,900,000,000 kg. Its density has been calculated at being 3.528. Its volume is 25319064907.

It was discovered in the year 1610 by Galileo Galilei.

The orbital period, i.e. the period it takes to complete an orbit round Jupiter is 1.76914 days. The figure is also known as the sidereel period. The figure comes from N.A.S.A..

The Equatorial Radius of the object is 1822km. The value is the radius in km of the said object at the Equator.

The Escape Velocity of the object is 8,552 km/h. The Escape Velocity is the speed an object needs to be travelling in order to break free from the objects gravity. The larger an object is, the more velocity (speed) is needed to break free from the object.The Semi-Major Axis of the orbit is 421.8, which is the furthest point from the centre to the edge of an elliptical point.

The atmospheric gases within the atmosphere of the object are Sulfur dioxide.

The equatorial circumference of Io is 11445.5 km. The surface area of Io is 41,698,064.74. The surface gravity of the said item is 1.796. The Mean orbit velocity, that is the speed at which it orbits is 62423.10 km/h. The is the average distance in km of the object is from its parent 421800.00.

The orbital inclination, the angle at which Io orbits in relation to the orbital plane is 0.04 degrees. The orbital eccentricity is 0.0041, it is the degree at which Io orbits close to a circular (0) orbit as opposed to an elliptical (1) orbit.

It is the closest to the planet of all the Galilean moons with Callisto being the furthest. the moon is easy to recognise due to its colours which is a sickly mix of yellow and green which doesn't look too nice. Sulfur is the predominant gas on the moon, making up the majority of its atmosphere and responsible for the molten sulphuric lava on the planet.

Io receives more than 1000 x the amount of radiation that is needed to kill a person. The chances of finding life on the surface would next to zero. Humanity would best be looking elsewhere to colonise rather than this moon.

The moon is tidally locked to the planet, only ever showing one side of its face to the planet at anyone time. The moon is only slightly larger than our Moon and is the fourth largest moon in the Solar system. The largest moon in the solar system is Ganymede.

Most Geologically Active of any Object in our Solar System

It is one of the most geologically active moons of any planet in the system owing in part to its location being closest. The planet is being pulled in directions by the gravitational influence of both Jupiter and the other Galilean moons. The planet has over 400 active volcanoes. The volcanoes can spout plumes as high as 300 km into the air. Some of the volcanoes and mountains are higher than Everest which is the highest mountain on our planet, the Earth. The plumes have been viewed with large telescopes from Earth.

Io's Mythological Legend

Io was originally named Jupiter I being the closest to the planet. It was not until after the death of Galileo that the name changed to the more familiar Io that we know today. Legend has it that Io was a mortal woman who Zeus took interest in. During courting between Io and Zeus, Hera caught them and to hide Io, Io was turned into a Heifer, a cow that has not had offspring or just one.

As a cow, Hera took interest in the cow and demanded that she should have it. The cow was placed up under lock and key with a 100 eyed monster guarding it. Zeus sent a warrior to slay the monster. When Hera heard of the intervention, she inflicted the cow with a Gadfly causing the cow to travel on its own for miles. When Zeus eventually found the cow, the cow was returned to Io's human form who would then give birth.

Clash of the Titans

Io appeared as a character in the re-imagined version Clash of the Titans (2010) played by Gemma Arterton. The character was inserted to increase the number of female characters and does not figure in the original Grecian legend.

Further Reading

Galilean Moons Moon Group

Galilean Moons are the four largest moons that orbit Jupiter. All four were discovered by Galileo Galilei when he looked up at Jupiter. Galileo is the Italian Astronomer who is credited with inventing the telescope.

List of Members in Galilean Moons Group

Image of the Jupiter moon of Io

Image of the Jupiter moon of Io

Io Facts

Mass (kg)89,319,379,731,108,900,000,000
Density (g/cm^3)3.528
Volume (km^3)25319064907
Orbital DirectionPrograde, same as the parents direction
Year of Discovery1610
DiscovererGalileo Galilei
Orbital Period (days)1.76914
Equatorial Radius (km)1822
Escape Velocity (km/h)8,552
Semi-Major Axis (10^3 km)421.8
Atmosphere GassesSulfur dioxide
Equatorial Circumference (km)11445.5
Surface Area (km^2)41,698,064.74
Surface Gravity (m/s^2)1.796
Mean Orbit Velocity (km/h)62423.10
Average Orbit Distance (km)421800.00
Orbital Inclination (degrees)0.04
Orbital Eccentricity0.0041

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