82846
The specific energy of an object such as a meteoroid falling on the earth from outside the earth 's gravitational well is at least one half the square of the escape velocity of 11.2 " km / s .
 meteoroid
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:
 meteoroid