58703
On Earth , a significant portion of the heat output from the interior of the planet , estimated at a third to half of the total , is caused by the slow collapse of planetary materials to a smaller size , generating heat .
 Earth
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 Earth