How can you know about Earth composition or Earth sub layers activities that provoke earthquakes and continental drift? You can always try to go down a volvano crater like in Journey to the Center of the Earth, however satellite observation would be a much practical solution ! Measuring magnetic and gravitational fields with satellites can give much more information on our Earth that Jules Verne would have dreamt of. Check the maps and data provided by ESA missions such as SWARM for magnetic field or GOCE for the gravitational field to convince yourself.
Earth magnetic and gravitational fields were the topic of Alpbach Summerschool organized by FFG (Austrian Research Promotion Agency) and ESA in which I took part this summer. REVOLVE Fellow Florian joined 60 students from all over Europe to attend this event in the middle of the beautiful Austrian Alps. For more read his blog!