Earth, Our Home Planet
Of all the beautiful images humans and robotic spacecraft have captured while exploring our solar system,
perhaps none are more powerful than pictures of Earth. It can be profound and humbling to see our planet
from deep space, as Planetary Society co-founder Carl Sagan eloquently explained in his 1994 book “Pale Blue
Dot.”
Astronauts who travel to space experience what is known as the “overview effect” upon seeing Earth from
afar. They often return home feeling a deep responsibility to preserve and cherish our planet. We know of no
other habitable worlds like Earth, nor do we currently have the technology to terraform a world like Mars to
make it Earth-like.
Earth sits in our Sun’s habitable zone, the not-too-hot, not-too-cold region around a star where liquid
water can exist on a planet’s surface. Our planet’s churning liquid-metal core generates a magnetic field
that shields us from most of the Sun’s harmful radiation. A dense, oxygen-rich atmosphere provides a blend
of gas that animals and plants use to grow and reproduce.
Earth is the only planet known to support life. It offers liquid water, an oxygen-rich atmosphere, and protection from the Sun’s harmful radiation.
By exploring the cosmos, we learn more about Earth and how life evolved here.
Asteroids occasionally impact Earth and cause widespread damage. With proper planning, we can prevent this natural disaster from happening.