query: Why is there ice at the Earth's poles?
positive_passages.docid: 143720
positive_passages.text: Why is there a temperature gradient on Earth?
negative_passages.docid: 36381
negative_passages.text: earth; the earth
negative_passages.docid: 52116
negative_passages.text: How much heating does Earth inner core provide to the surface?
negative_passages.docid: 35534
negative_passages.text: Magnetic field lines
negative_passages.docid: 51988
negative_passages.text: What made us think that Earth moves around the Sun?
negative_passages.docid: 74923
negative_passages.text: Why did the Earth cool down?
negative_passages.docid: 156570
negative_passages.text: Variations of earth's magnetic field strength
negative_passages.docid: 123094
negative_passages.text: Lead in ice block
negative_passages.docid: 72421
negative_passages.text: Why geologist do not consider molten iron in the magma to be the source of Earth's magnetic field?
negative_passages.docid: 89194
negative_passages.text: Potential at Center of Earth
negative_passages.docid: 102752
negative_passages.text: Is Earth really a magnet?
negative_passages.docid: 137850
negative_passages.text: Friction at zero temperature?
negative_passages.docid: 13143
negative_passages.text: Why doesn't planet Earth expand if I accelerate upwards when standing on its surface?
negative_passages.docid: 128817
negative_passages.text: What is the source of Earth's magnetic field?
negative_passages.docid: 18257
negative_passages.text: How can interstellar space have a temperature of 2-3K?
negative_passages.docid: 124661
negative_passages.text: Effect on length of day as the polar ice caps melt
negative_passages.docid: 91679
negative_passages.text: Why does soda fizz when it meets ice?