The earth we live on is a special planet in the solar system with water and air and where living things thrive. But is it really different from other planets in the solar system?
Let’s explore the earth from the perspective of the solar system by comparing it with other celestial bodies.
Beginning of the Journey
On this journey, what kind of celestial bodies will we encounter?
The Earth contains various environments. There are variations in water, air, and temperature both in the ocean and on land. Because of these points, the Earth is said to be special, even considering the other celestial bodies that make up the solar system (source: Miraikan).
However, is the Earth really special? Are there no similarities to other planets that were born at the same time — about 4.6 billion years ago?
Many studies are exploring the mystery by collecting evidence using many methods such as the telescope, spacecraft and landed probes. As a result, we have found several celestial bodies with conditions similar to the Earth.
In this tour, we are going to explore the Earth compared with other objects in the solar system. The Earth, which we’ve thought to be special, is the same as the fellow planets of the solar system — let’s go on a journey to find the similarities and the stories they can tell.
Mercury Caloris Basin / Barringer Crater, Traces Where a Celestial Object Collided
One of the topographies many celestial bodies have in common is the crater, which is the trace of where an object that collided with the planet.
On the Earth, craters gradually disappear with weathering and erosion. However, on celestial bodies without air and water, they remain as they were long ago — especially, the Caloris Basin on Mercury. It is one of the largest craters in our solar system with a diameter of over 1,500 km.
Even on the Earth, craters in dry desert areas leave the appearance of the crash relatively clean. The Barringer crater in Arizona, U.S. is about 1.2 km wide and 180 meters deep and was made about 50,000 years ago.
Mars Olympus Mons vs Mauna Kea, A Mountain that Exceeds 10,000 Meters
Everest, at 8,800 meters, is the highest mountain on the Earth.However, if you include the height as measured from the bottom of the ocean, Mauna Kea on the Island of Hawaii is over 10,000 meters and is the highest point.
The mantle deep underground supplied a large amount of magma to the Earth’s surface and created such a high mountain.
On the other hand, Olympus Mons on Mars, the highest mountain in the solar system, is about 27,000 meters tall and its base spreads to more than 550 km. There are actively moving plates on the Earth, but there is no such movement on Mars.
Therefore, it is thought the abundance of magma on Mars continued to erupt in the same place until exhausted which in turn formed that huge mountain.
Venus Maat Mons vs Mt. Aso’s caldera, A Large Indentation Created by a Volcano
One of the topographies volcanos create is the caldera. It is a large indentation in the terrain that is formed by a collapse and accompanied by a massive eruption.
Many volcanoes and calderas are found on Venus. Especially at the summit of Maat Mons, the highest volcano on Venus, there is a gigantic caldera about 30 km in diameter. It is thought it was made by small repeating collapses.
There are many calderas on the Earth but Mt. Aso, in particular, is quite distinctive. The caldera isn’t just the depression of the summit, but also the huge round hill that spreads around Mt. Aso. It was formed by frequent eruptions that occurred in the past. People built a city and now live in the caldera that extends 18 km east to west, and 25 km north to south.
Saturn II Enceladus vs The Rodriguez Triple Junction, Ocean Spreading Under Ice
In celestial bodies far from the sun, it was thought that all the water was frozen. However, on Jupiter and Saturn, we have found that there are moons where melted ice forms a vast ocean because of heat from inside the satellites.
Through space probe investigations, studying the component of steam that emanates from the crack of the ice, it was discovered there is potentially a hot water outlet at the bottom of the sea.
Life may also exist in the vicinity of the outlet of hot water which is thought to be at the bottom of Saturn’s moon, Enceladus.
A similar outlet is also found on the bottom of the Earth. There are unique ecosystems, and it is one of the places where life was born on Earth. A lot of hot water outlets have been found on the Rodrigues Triple Junction, where three plates meet.
Jupiter Polar Ice Cap vs Auroral Oval, Aurora Shining at the Pole
Just like Earth, Jupiter is one of the planets with an Aurora, which forms when a plasma wind from the sun flows into the gap of the planet’s magnetic field and collides with the atmosphere.
However, the magnetic field on Jupiter is far stronger than on Earth. And there is also the energy of the volcanic gas of Jupiter’s moon Io. As a result, the aurora on Jupiter is 100 times brighter and more intense than the Earth’s and so huge it could cover the entire Earth.
The color of the aurora varies with the atmospheric components of the planet. On Jupiter, whose atmosphere is mainly composed of hydrogen, it shines bright pink as seen with the naked eye.
Mars Polar Regions vs Tundra Area, Cracked Earth of the Permafrost
The tundra is an area near the Arctic Ocean where the permafrost land spreads even in summer. One of the typical topographies found here is the ice-wedge polygon.
This terrain, where the ground is divided into several polygons, creates permanently frozen soil. After the frozen ground cracks, the melted surface water accumulates in the cracks and freezes as it is. By repeating this process, polygon patterns are engraved in the ground.
A landscape very similar to this polygonal terrain also has been found in the Arctic region of Mars. Research continues to elucidate how this topography is made.
Saturn VI Titan vs Primitive Earth, The Star of Water and the Star of Methane
There is abundant water on the Earth. Many species have bred in the water that circulates through rains, rivers and seas, evaporation and ends in the clouds.
This circulation is also found in Titan, one of Saturn’s moons. However, the liquid is not water but methane. Because of its moderate distance from the sun, the environment enabled methane to become liquid and gaseous.
Looking at the surface of Titan, there are rivers and lakes reminiscent of the Earth, and clouds that drop rain are also form. Perhaps there is unknown life being born as well.
What was it like to compare the Earth to the other planets in the solar system?
This time we looked at only a small part. There are plenty of similar topographies and interesting environments on other planets and moons nearby. There will be discoveries as the exploration progresses in the future.
Exploring the solar system’s celestial bodies leads toward unraveling the secrets of the formation and growth of the Earth and the birth of life. It also leads us to find out how we can live better on Earth. The view of the Earth, life and the universe obtained through exploring the frontiers create our future.