The inner core of Mercury is made up of mainly Iron with very little else. This core is much larger than most other planets and it hints that Mercury had a bit of a chaotic formation.
Mercury being the closest planet to the sun has the quickest orbit taking only 88 Earth days to complete 1 revolution around the sun
Mercury has the thinnest of all of the planets' atmospheres. Mercury s atmosphere is comprised of mostly from particles blown from the Sun's solar flares on account of how close it is to the Sun.
Mercury is mainly comprised of heavy metals and rock, it's gravity is 38% of earths gravity, variety of craters, ridges, and terrains ranging from heavily cratered to nearly crater free.
Mercury Name Origin
Named Mercurius after the Roman god Mercury on account of how swift it moves around in the sky.
Venus has a core much too similar to Mercury in which it too is a primarily Iron core with little to nothing else in it. Unlike Mercury Venus' core isn't as large in scale compared to mercury.
Venus being the second closest planet to the sun has the second fastest speed of 225 Earth days to complete is revolution around the sun.
Venus has a very thick atmosphere that is about 90 times more massive than Earth's, it also has a thick layer of sulfuric acid clouds.
Venus has 10% difference in Gravity compared to earth someone that weighs 100 pounds would weigh 90 pounds on Venus, the surface is rather smooth in many places but we have found evidence of volcanoes, canyons and mountains similar to earth.
Venus Name Origin
Venus the Roman goddess of love is where the inspiration for this planet's name came from on account of this planets beauty and due to how bright it is.
There have been no volcanic eruptions for millions of years, but the mantle that lies beneath the crust is still largely dormant. Mars' mantle is made out of silicon, oxygen, iron, and magnesium. The core of Mars is made out of iron, nickel, and sulfur.
Being the fourth and furthest terrestrial planet from the sun Mars has the longest revolution time of 687 Earth days just to complete one trip around the sun.
Mars has less than 1% the amount of atmosphere that Earth has, so little that it does not protect the planet from the Sun's radiation nor does it do much to retain heat at the surface resulting in lower temperatures.
Mars has a 62% difference in gravity compared to Earth and 100 kg here is 38 kg on Mars. Mars is a dry, barren wasteland marked by old volcanoes and impact craters. A single hotspot could dump molten rock on the surface for at least a million years due to the lack of plate tectonics.
Mars Name Origin
Mars named after the Roman god of war because of its blood like coloring of the surface. Many other cultures also took this factor into account when they named it in their respective languages.