The world of arbuscular mycorrhizal fungi (AM fungi) runs deep. They live symbiotically with around 70 percent of Earth’s ...

Astronomers have spent more than a century searching for a hidden world beyond Neptune, first called Planet X and now often ...

Mercury is due to join Venus and Jupiter in the night sky for an uncommon celestial event commonly known as a planet parade.

Astronomers have spent years searching for a possible hidden giant planet far beyond Neptune. Unusual orbits among distant ...

Earth, our home planet, is a world unlike any other. The third planet from the sun, Earth is the only place in the known universe confirmed to host life. With a radius of 3,959 miles, Earth is the ...

Mars is the fourth planet from the sun and has a distinct rusty red appearance and two unusual moons. The Red Planet is a ...

The rusty world is full of mysteries—and some of the solar system's most extreme geology. Learn more about Earth's smaller, colder neighbor.