Almost 85% of Mercury’s radius is represented by its enormous iron core.Another event called the Late Heavy Bombardment which ended around 3.8 billion years ago, may also be responsible for Mercury’s cratered surface. After Mercury was formed, scientists believe that it suffered heavy bombardments by comets and asteroids shortly after.Mercury formed around 4.5 billion years ago after gravity pulled swirling gases and dust together.Mercury’s changes in temperature are the most drastic in the Solar System.At night, Mercury’s surface temperatures can drop to as low as -290 degrees Fahrenheit / -180 degrees Celsius.During the day, Mercury’s average surface temperatures can reach up to 800 degrees Fahrenheit / 430 degrees Celsius.Though it is the closest planet to the Sun, temperatures on Mercury are both hot and cold.Mercury has a radius of 2.439 km / 1.516 mi and a diameter of 4.879 km / 3.032 mi.

It is the most heavily cratered planet and this means that it hasn’t been geologically active for many years.

The surface of Mercury is similar to the Moon.

Mercury does not have any satellites or ring systems.

Despite being so small, Mercury is the second-densest planet in the Solar System after Earth.

It is also the smallest planet in the Solar System.

Out of all the terrestrial planets, Mercury is the smallest.

Mercury is the closest planet to the Sun at a distance of 57 million kilometers / 35 million miles.

It probably received this name because it moves very quickly across the sky. In Greek mythology, Mercury was known as Hermes, the messenger of the gods. The high energy levels of these storm systems typically make them hazardous due to associated heavy precipitation, lightning, high wind speeds and possible tornadoes.Mercury is named after the Roman god of commerce, travel, and thievery. The image, taken while the International Space Station was located over western Africa near the Senegal-Mali border, shows a fully formed anvil cloud with numerous smaller cumulonimbus towers rising near it. The photo was taken from a viewpoint that was at an angle from the vertical, rather than looking straight down towards the Earth’s surface. The cloud tops flatten and spread into an anvil shape, as illustrated by this astronaut photograph. The tropopause halts further upward motion of the cloud mass. Beyond the tropopause, the air no longer gets colder as altitude increases. The tropopause is characterized by a strong temperature inversion. If enough moisture is present to condense and heat the cloud mass through several convective cycles, a tower can rise to altitudes of approximately 10 kilometers at high latitudes and to 20 kilometers in the tropics before encountering a region of the atmosphere known as the tropopause-the boundary between the troposphere and the stratosphere. This leads to the characteristic vertical “towers” associated with cumulonimbus clouds, an excellent example of which is visible in this astronaut photograph. This type of convection is common in tropical latitudes year-round and during the summer season at higher latitudes.Īs water in the rising air mass condenses and changes from a gas to a liquid state, it releases energy to its surroundings, further heating the surrounding air and leading to more convection and rising of the cloud mass to higher altitudes. The air mass itself also expands and cools as it rises due to decreasing atmospheric pressure, a process known as adiabatic cooling. Surface air is warmed by the sun-heated ground surface and rises if sufficient atmospheric moisture is present, water droplets will condense as the air mass encounters cooler air at higher altitudes.

Perhaps the most impressive of cloud formations, cumulonimbus (from the Latin for “pile” and “rain cloud”) clouds form due to vigorous convection (rising and overturning) of warm, moist and unstable air.

Planet quiz for kids