EITIITERIESTIIILS III UFOS 135
lions of years, scientists can show that without a large moon, our
Earth's axis probably would have become unstable and the Earth
might have tumbled, making life impossible. French astronomer Dr.
Jacques Lasker estimates that without our moon the Earth's axis could
oscillate between 0 and 54 degrees, which would precipitate extreme
weather conditions incompatible with life. So the presence of a large
moon also has to be factored into conditions used for Drake's equations. (The fact that Mars has two tiny moons, too small to stabilize its
spin, means that Mars may have tumbled in the distant past, and may
tumble again in the future.)
Third, recent geological evidence points to the fact that many times
in the past, life on Earth was almost extinguished. About 2 billion years
ago the Earth was probably completely covered in ice; it was a "snowball Earth" that could barely support life. At other times, volcanic eruptions and meteor impacts might have come close to destroying all life
on Earth. So the creation and evolution of life is more fragile than we
originally thought.
Fourth, intelligent life was also nearly extinguished in the past.
About a hundred thousand years ago there were probably only a few
hundred to a few thousand humans, based on the latest DNA evidence.
Unlike most animals within a given species, which are separated by
large genetic differences, humans are all nearly alike genetically.
Compared to the animal kingdom, we are almost like clones of each
other. This phenomenon can only be explained if there were "bottlenecks" in our history in which most of the human race was nearly
wiped out. For example, a large volcanic eruption might have caused
the weather to suddenly get cold, nearly killing off the entire human
race.
There are still other fortuitous accidents that were necessary to
spawn life on Earth, including
• A strong magnetic field. This is necessary in order to deflect cosmic
rays and radiation that could destroy life on Earth.
• A moderate speed of planetary rotation. If the Earth rotated too
slowly, the side facing the sun would be blisteringly hot, while the
lions of years, scientists can show that without a large moon, our
Earth's axis probably would have become unstable and the Earth
might have tumbled, making life impossible. French astronomer Dr.
Jacques Lasker estimates that without our moon the Earth's axis could
oscillate between 0 and 54 degrees, which would precipitate extreme
weather conditions incompatible with life. So the presence of a large
moon also has to be factored into conditions used for Drake's equations. (The fact that Mars has two tiny moons, too small to stabilize its
spin, means that Mars may have tumbled in the distant past, and may
tumble again in the future.)
Third, recent geological evidence points to the fact that many times
in the past, life on Earth was almost extinguished. About 2 billion years
ago the Earth was probably completely covered in ice; it was a "snowball Earth" that could barely support life. At other times, volcanic eruptions and meteor impacts might have come close to destroying all life
on Earth. So the creation and evolution of life is more fragile than we
originally thought.
Fourth, intelligent life was also nearly extinguished in the past.
About a hundred thousand years ago there were probably only a few
hundred to a few thousand humans, based on the latest DNA evidence.
Unlike most animals within a given species, which are separated by
large genetic differences, humans are all nearly alike genetically.
Compared to the animal kingdom, we are almost like clones of each
other. This phenomenon can only be explained if there were "bottlenecks" in our history in which most of the human race was nearly
wiped out. For example, a large volcanic eruption might have caused
the weather to suddenly get cold, nearly killing off the entire human
race.
There are still other fortuitous accidents that were necessary to
spawn life on Earth, including
• A strong magnetic field. This is necessary in order to deflect cosmic
rays and radiation that could destroy life on Earth.
• A moderate speed of planetary rotation. If the Earth rotated too
slowly, the side facing the sun would be blisteringly hot, while the