Mercury has the smallest and least massive planet in the solar system due to gravity. Mercury, on the other hand, has a surface gravity of 3.7 m/s2, which is the equivalent of 0.38 g due to its high density—a robust 5.427 g/cm3, which is just slightly lower than Earth's 5.514 g/cm3. This means that you could lift a weight with 1 oz (28 g) of mercury at 1 meter above the ground.
Although it has only half the mass of Earth, Mercury still creates enough gravity to be considered a major planet. It orbits the Sun every 88 days, but because it is so close to the Sun, it completes one orbit in almost exactly 12 hours. As a result, it travels around the Solar System in a highly elliptical path with an eccentricity of 0.20. This means that it spends more time closer in toward the Sun and less time farther out.
Due to this unusual trajectory, much research has been done on how gravity affects Mercury. The results of these studies have helped scientists understand how gravity works across vast distances in addition to how it varies between bodies with different compositions.
Gravity is the force that causes objects with mass to attract each other. The stronger the gravity, the faster two objects will approach one another. In our case, the force of gravity between Mercury and Earth is strong enough to hold them together as a single planet, but not strong enough to cause any significant damage to either body.
Mercury is the solar system's smallest terrestrial planet, measuring around one-third the size of Earth. It has a thin atmosphere, which allows temperatures to fluctuate between scorching and freezing. Mercury, like Earth, is a dense planet made largely of iron and nickel, with an iron core. However it is not as well protected by ice caps or other forms of surface water as Earth does, so most of its surface is very arid or even vacuum.
The key difference between Earth and Mercury is their orbits: While Earth's is nearly circular, Mercury's is almost exactly aligned with the sun's orbit, so it always faces towards us from just inside the Sun. This is why we can never see far enough back on Mercury to glimpse any part of its past or future: If it were in another part of its orbit, it would appear in different locations each time around the sun.
This unusual configuration results in many peculiar effects. For example, the amount of sunlight that reaches the surface varies throughout the month. During Mercury's summer, when it is closest to the Sun, it receives about 30 times more energy than it does during its winter months, when it is furthest away. This causes seasonal changes on the planet: The northern half experiences spring when it returns from its winter darkness, only to be followed by summer when it again moves into darkness.
Mercury, as you might expect given its speed, is the planet nearest to the sun and hence the most influenced by its gravity as it zooms around and about. At an average distance of 40 million km (25 million miles), even Venus, which is closer than Mercury, cannot outrun the speed of light when it comes time for it to leave Earth and head towards the sun.
However, because it spins on its axis so quickly, one day on Mercury is equivalent to nearly two days on Earth. This means that although it isn't visited by meteorites or satellites, some things get done on Mercury that wouldn't be possible otherwise. For example, since it's impossible to land a spacecraft on the planet, scientists have used images from orbit to learn more about its surface features. They've also used measurements from orbiting telescopes to study how much radiation hits the planet's atmosphere, which is important for understanding how much impact it experiences from solar flares.
It takes Mercury 72 days to rotate around the sun, which is almost twice as long as it takes Earth. Because of this, there are two different sides to Mercury that experience very different temperatures. The side that faces the sun always shows up as bright in photos from space, while the other half is always dark.
Mercury meanings from science (2 of 2) Mercury. The smallest and nearest planet to the Sun in the solar system. Mercury is a terrestrial or inner planet, second only to Earth in density, with a craggy, extensively cratered surface akin to Earth's Moon. It orbits the Sun every 88 days at an average distance of 40 million km (25 million miles).
Mercury was first seen by the English astronomer William Herschel on March 4, 1789, just two days before its greatest elongation from the Sun. On this occasion, it appeared as a small black spot against the Sun's bright surface.
The name Mercury comes from the Greek word for Hermes, the messenger god who was known for his tireless activity and ability to travel quickly between heaven and earth. In Roman mythology, Mercury was one of the gods born from Jupiter's head when he raped Juno, goddess of marriage. Their shared mother was Minerva (Roman for wisdom).
Hermes and Mercury have similar roles in many cultures. They are both psychopomps, or guides to the afterlife; Mercury brings learning, poetry, and music to the dead, while Hermes delivers dreams, messages, and travelers' gifts.
In addition to their common role as psychopomps, they also share other attributes.