- Why is Earth geologically active?
The Earth is geologically active because of its internal heat. It is able to retain this heat because of its large size. The heat keeps the Earth's lithosphere thin as well as its core molten, which ensures activity.
- What processes shape Earth's surface?
There are four major processes that shape the Earth's surface. Impact cratering is caused by asteroids or comets that crash into the surface of Earth. Volcanism is the eruption of molten rock from the planet's interior onto the surface. Tectonic activity is the disruption of a planet's surface by internal stresses, such as tectonic plates. Erosion is the wearing down or building up of geological features through wind, water, ice, and other means of weather.
- How does Earth's atmosphere affect the planet?
Earth's atmosphere protects us from ultraviolet and X-ray radiation from the Sun. Visible light is able to pass through the atmosphere which provides the energy for photosynthesis as well as acts as the main source of heat for the Earth's surface. Our atmosphere also traps additional heat through the greenhouse effect.
- Was there ever geological activity on the Moon or Mercury?
There was geological activity on both the Moon and Mercury. The last activity of the moon occurred between 3 to 4 billion years ago when lava flooded into craters. Mercury's volcanoes may have died out about a billion years later than the Moon's.
- What geological features tell us that water once flowed on Mars?
There is evidence of water erosion on the surface of Mars. Channels caused by water erosion formed about 2 to 3 billion years ago, which proves that there was once rainfall as well as surface water on Mars.
- Why did Mars change?
Mars changed because its atmosphere became thinner which caused a weakened greenhouse effect. These gases also escaped due to solar winds.
- Is Venus geologically active?
Venus is geologically active today because it still retains its internal heat, much like Earth. The surface of Venus is geologically young and has few craters and lacks plate tectonics.
- Why is Venus so hot?
Venus's atmosphere has huge amounts of carbon dioxide and no water due to the greenhouse effect. This causes the high temperature.
- What unique features of Earth are important for life?
Earth is the only planet that has temperatures and pressure conditions that allow for surface water and significant amounts of oxygen in the atmosphere. Earth is the only planet to have an ozone layer. It has also the only planet with a surface shaped by tectonic plates which heavily influence its climate stability.
- How is human activity changing our planet?
Human activity is causing global warming. There has been an increase in atmospheric carbon dioxide due to the burning of fossil fuels and other human activities.