10 Need-to-Know Things About Mercury - NASA Solar System …
Mercury is the smallest planet in our solar system – only slightly larger than Earth's Moon.
Mercury By the Numbers – NASA Solar System Exploration
2024年12月19日 · Mercury is the closest planet to the Sun, and the smallest planet in our solar system - only slightly larger than Earth's Moon.
In Depth | Mercury – NASA Solar System Exploration
The smallest planet in our solar system and nearest to the Sun, Mercury is only slightly larger than Earth's Moon. From the surface of Mercury, the Sun would appear more than three times as large as it does when viewed from Earth, and the sunlight would be as much as seven times brighter.
Planet Compare - NASA Solar System Exploration
2024年12月19日 · NASA’s real-time science encyclopedia of deep space exploration. Our scientists and far-ranging robots explore the wild frontiers of our solar system.
In Depth | Pluto – NASA Solar System Exploration
At that small size, Pluto is only about half the width of the United States. It's about 3.6 billion miles away from the Sun, and it has a thin atmosphere composed mostly of nitrogen, methane, and carbon monoxide.
Mars By the Numbers – NASA Solar System Exploration
2024年12月19日 · Mars is the fourth planet from the Sun, and the seventh largest. It’s the only planet we know of inhabited entirely by robots.
Pluto By the Numbers – NASA Solar System Exploration
2024年12月19日 · Pluto was once our solar system's ninth planet, but has been reclassified as a dwarf planet. It's located in the Kuiper Belt.
Overview | Mars – NASA Solar System Exploration
Mars is one of the most explored bodies in our solar system, and it's the only planet where we've sent rovers to roam the alien landscape. NASA currently has two rovers ( Curiosity and Perseverance ), one lander ( InSight ), and one helicopter ( Ingenuity ) exploring the surface of …
The Sun By the Numbers – NASA Solar System Exploration
2024年12月19日 · The Sun is the star at the heart of our solar system. Its gravity holds the solar system together, keeping everything – from the biggest planets to the smallest bits of debris – in its orbit.
What is a Planet? | Planets – NASA Solar System Exploration
A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.