Inner Planets

All About Planets

By Madison Nef

There are currently 9 (if you count Pluto still, which I do) planets in our solar system. In this paper, I’d like to lightly touch on the planets of the Inner Solar System. The inner system is composed of four planets, the four that revolve closest to the sun. Below, I have given some information about each of them.

Mercury

Mercury is a relatively small planet. It is known for being the closest planet to the sun as of right now- even so; it is still roughly 18 million miles away from the sun. In accompaniment to being very hot, it features a barren, crater covered surface which bares resemblance to the Earth’s moon.

Due to it being so close to the sun, Mercury is EXTREMELY hot. In fact, its average daytime temperature is usually above 400 degrees Celsius. At night, however, the temperature is quite the opposite- with no atmosphere to hold the heat from the daylight in, the temperatures completely plummet; getting down as far as -180 degrees Celsius.

Due to its low gravity, there is no water OR air to be found on Mercury- however, there is speculation to the fact that there may be air and water vapor clouds beneath its dry surface.

Venus

Venus is the second closest planet to the sun and is quite fascinating due to the fact that it is similar in size to Earth. While the size is almost the same, the two planets are still quite different due to climate, atmosphere, AND surface conditions. Its thick clouds lock in the heat while the surface rages with active volcanoes.

Meanwhile, the atmosphere of Venus is made up entirely of carbon dioxide. It’s also surrounded by clouds consisting of mercury, ferric chloride hydrocarbons and sulfuric acid. These clouds are the cause of the most corrosive acid rain found anywhere in our solar system.

These clouds are so thick that barely any light can even reach the surface of Venus. The light that DOES make its way through the clouds is converted automatically to heat and can’t escape the atmosphere… making Venus the hottest known planet at over 500 degrees Celsius.

Here is where I would have written about Earth, but to be honest there’s SO much known about it that it’s rather pointless. On to Mars.

Mars

“The Red Planet”, otherwise known as Mars, has a dusty, rocky surface and a thin atmosphere. Its relatively calm conditions and close proximity to earth make it the most likely destination for future planet exploration by humans. Mars has already been visited by man Mars Rovers in many successful robotic missions. These rovers collect many samples and record a lot of important scientific data that scientists back on Earth study to learn more about the planet.

Mars earned its nickname due to the fact that it is covered in a red, rust-like dust. Even the atmosphere in and of itself is a pinkish red; colored by small particles of dust thrown up from the surface of the planet. It tends to experience extremely violent dust storms… these storms continually change the texture and the surface of the planet.

So, that covers the inner solar system! The above planets, including Earth, are the four closest to the sun.

Along with being close to the sun, these four planets (Earth, Mercury, Mars and Venus) also have other large differences that make them unique from other planets in the universe. To begin with, these planets are all of rocky terrain; being composed of mainly metals and silicates. The outer planets are all gas giants.

Also, the inner planets are much closer together than the outer planets… so much so that you could fit the radius of the entire region between the orbits of Jupiter and Saturn and still have plenty of room. The planets are also within the frost line- an area a little less than 700 million km from the sun. The line signifies the point where solids can turn to liquid. Some scientists will refer to the line as the ‘Goldilocks Zone’- an area where life in the future may be ‘just right’.

Well- there you have it. I hope you enjoyed this paper and learned something about the planets. I know I did.

Maddie