Why are there volcanoes in the world and on Io? How many miles is Io from earth?
Ashley
Fleischhacker,
Justin Dube,
Julie Smith,
Brenda Jacobs
Hi Ashley, Justin, Julie, Brenda:
There are volcanoes on Earth because magma is produced in the
Earth's upper mantle (about 100 km below the surface), and it is buoyant and
wants to rise to the surface. If it comes out then you have a volcano. If it
continues to come out from the same place over a long period of time then you
have a big volcano. You might then ask why the magma is produced. Well, the
interior of the Earth is kept hot by the decay or radioactive elements. We
think that this heating causes convection to occur. Convection is like in a
boiling pot of water where the hot water at the bottom rises up to the surface
and cold water has to flow down to take up the space. In the Earth, some of the
mantle material that is rising up melts, and this is the magma that will
eventually rise up to erupt from a volcano.
I don't know much about Io. It is a much smaller planetary body than the Earth
so presumably much of its radioactivity has been used up. It should therfore be
pretty cold. However, at least some people think that because Io is so close to
giant Jupiter, the squishing and stretching due to Jupiter's gravity causes
enough friction within Io to generate magma. This magma rises to the surface
and erupts to form volcanoes.
It is 1 astronomical unit (AU) from the sun
to the Earth, and about 5 AU from the sun to Jupiter. Therfore it is about 4 AU
from Earth to Jupiter (at the closest approach). 1 AU = 93,000,000 miles so the
distance from Earth to Io must be about 372,000,000 miles!!
I hope this helps answer your question a little bit.
Sincerely,
Scott Rowland, University of Hawaii
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