After the formation of the solar system and the decrease in the bombardment of E
ID: 290704 • Letter: A
Question
After the formation of the solar system and the decrease in the bombardment of Earth, comets are concentrated today in the:
Oort cloud.
asteroid belt.
solar nebula.
universe.
The oldest crustal materials on Earth are dated by zircons at _____, whereas rocks gathered on the surface of the moon during the Apollo missions date at _____.
4.6 billion years old; 4.2 billion years old
4.2 billion years old; 4.6 billion years old
4.0 billion years old; 4.2 billion years old
4.0 billion years old; 4.6 billion years old
Oort cloud.
asteroid belt.
solar nebula.
universe.
Explanation / Answer
Long period comets originate from the Oort clouds while Kuiper belt is from where we get short period comets and hence we can say that the Kuiper belt and the Oort clouds are the home of comets. As per the option given we can say that the first option that is the Oort Cloud is the place where we have the concentration of comets.
The earth itself is believed to be 4.5 billion old and the oldest crustal material’s zircon aged 4.4 billion year old and the rocks that were gathered by Apollo mission dates 4.6 billion year old and hence as per the option, second option is the most appropriate that is 4.6 billion years old and 4.6 billion years old.