Earth's Defenses against alien threats

An hyper ultra advanced futuristic upgraded military force

Earth's nuclear weapons arsenel

Hyper advanced hi tech laser energy based weapons

An Planetary Defense System

Hi tech moon bases all over the moon, that also has a hyper advanced defense system (Earth's first line of defense, against extraterrestrial threats)

NOTE: If all the above fails to stop the particular alien threat, then humanity is destroyed!


Honorable Mention:

Solar System's Military Defenses

Stellar Defense System (similar to the Planetary Defense System, but encompasses the entire solar system and in all the planets, moons, the sun, and the asteroid belt instead, possibly the entire oort cloud has a hi tech hyper advance defense system, all filled with hyper advanced weapons systems to protect the solar system from alien threats)

NOTE; If all this fails, then the solar system will be wiped out by the alien threat!