Mars is about half the diameter of Earth, its volume is about 15 per cent and its density about 70 per cent when compared to Earth. Mars’ climate is much cooler. The average temperature is about -63°C, which is in part down its greater distance from the Sun and its thin, carbon-dioxide-rich atmosphere. Martian weather is dominated by dust storms. These storms can grow to encompass the whole planet and raise the temperature.
About two-thirds of Earth’s surface is covered by oceans, whereas the surface of Mars has no liquid water. However, scientists think that the climate on Mars 3.5 billion years ago was similar to that of early Earth, i.e. warmer and wetter. We can see evidence of a Mars’ wetter climate in the form of drainage channels, delta features and former lakes.
Both Earth and Mars have experienced many impacts from meteorites over the years. However, Mars’ impact craters are far better preserved due to the slower rates of weathering and erosion, due to the lack of precipitation. Small meteorites burn up in Earth’s atmosphere, never making it to the ground, but small meteorites produce craters on Mars because the planet has a much thinner atmosphere.
By studying the seismology of Mars, through ‘marsquakes’ and meteorite impacts, we can ‘see’ inside Mars to map its internal structure.
Download Earth vs Mars 'facts'.
Meteorites are sources of seismic signals on Mars, but there are a number of other of 'space rocks' that are outlined in the image below.
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Contact Paul Denton, MarsQuake project leader, for further information.