Hydrogen formed along with helium within minutes of the big bang; together, the two elements account for 98 percent of the universe's visible matter. Oxygen and the other heavy elements formed inside of stars through fusion, a process that joins the nuclei of lighter elements into heavier ones and releases a whole lot of energy.
If volcanoes keep erupting, will Earth run out of magma?
Answered by Jennifer Horton and Discovery Channel
Can geothermal power plants essentially provide free energy?
Answered by Elizabeth Blackwell and Discovery Channel
Could substances other than water support life?
Answered by Planet Green