Mercury, like the other planets in the solar system, formed some 4.5 billion years ago when it condensed from the spinning ring of dust and gas left over from the sun's creation. Mercury evolved into a terrestrial planet, complete with a dense metallic core, a rocky mantle, and a solid crust. The only evidence that it started out as a gaseous planet are traces of oxygen found in its atmosphere.
How does Earth's climate affect life on Mars? On Earth, our planet's climate is affected by the presence of water and land masses. Areas of strong tectonics (such as those on Earth's mantle) can generate hot spots where rock melts and convection cells form that release large amounts of carbon dioxide from deep within the ground. This carbon dioxide then enters into the atmosphere, changing both the amount and type of radiation that reaches Mars. The presence of water may have had an impact on Martian biology as well, since it has been suggested that low-level water activity could be necessary to allow for the survival of simple organisms such as bacteria.
Why are stars more luminous than planets? Stars are more luminous than planets because they contain much more mass per unit volume.
The planet has steadily chilled over billions of years since its creation at the genesis of the solar system, a process that all planets suffer from if they lack an internal source of heat replenishment. Mercury's total volume diminishes when the liquid iron core freezes and cools. The amount of shrinkage increases as you go deeper into the planet because ice is less dense than metal.
Mercury's interior is still cooling today, so it must have cooled very rapidly after forming in order to prevent additional melting. The only place on Earth where ice can persist this long is in a deep underground reservoir called the ice cap or glacier. Scientists think that perhaps explosions of gas built up inside Mercury were reflected back toward the sun instead of being radiated away, helping to melt more ice and further decrease the planet's temperature.
As Mercury cooled below the critical point of water (170 degrees Fahrenheit), any water present would have frozen into solid form rather than becoming a gas. This is why there is no evidence for water on Mercury today; if it ever existed, it did so only as a thin veneer over a molten core.
The same process that causes glaciers to grow and ice caps to form also helps explain how Mercury's ocean may have originated.
Mercury is our solar system's smallest planet. It's only slightly larger than Earth's moon. A year on Mercury flies by. Because it is the nearest planet to the sun, it doesn't take long to complete its orbit. This makes it the fastest-spinning planet in our solar system.
Mercury has very thin air that gets heated by the sun and spreads out over most of the surface. The pressure from this thick atmosphere is so great that it must be crumpled up like a ball to contain itself.
The core of Mercury is believed to be solid iron with some nickel and phosphorus compounds. It is surrounded by a liquid metal shell about as dense as water. This is why Mercury appears to rotate around its axis every 58 days.
Although less than half the size of Venus, Mercury's surface area is much greater because it is more spherical. Using this fact combined with its mass, scientists have estimated that there is more hydrogen per square meter on Mercury than on any other planet except Earth.
This may explain why they get such strong winds on Mercury!
The average temperature on Mercury is 450 degrees Fahrenheit (230 degrees Celsius).