What Do We Know About the Planets in Our Solar System?
Source: Pixabay by 0fjd125gk87
The Solar system consists of our Sun, Earth, and other objects that orbit it. It was formed by the gravitational collapse of a giant interstellar molecular cloud. The Sun contains the majority of the system's mass, while the remaining mass is distributed among the other planets. The Moon, Mars, and Jupiter are some of the most prominent planets in our Solar System.
What then are these planets? What are they made of and how different are they from earth? Is there any chance that the biological life of earth could survive on any of the planets in our solar system? Let's learn about some of the most important ones.
Saturn's moon Titan
By NASA/JPL-Caltech/Space Science Institute - http://photojournal.jpl.nasa.gov/catalog/PIA14602, Public Domain, Link
Saturn's moon Titan is the largest moon in the solar system and the only body outside of Earth that has a liquid-covered surface. It was discovered by Dutch astronomer Christiaan Huygens in 1655 and was named after the Greek gods, the Titans. From Earth, Titan appears as a featureless brownish-red globe with a thick haze.
The map was compiled from 16 images obtained by the Cassini spacecraft. They range in scale from 52 to 21 miles per pixel, and cover latitudes from 80 degrees south to 35 degrees north. The images were highly detailed, and reveal features on the surface as small as 60 miles across. The images are a major improvement over the ground-based observations, which are still too poor to understand the surface of Titan.
The Cassini spacecraft passes by Titan on a regular basis and uses a radar instrument to peer through its thick atmosphere. The mission also observed the planet's climate. As a planet with seasons, Titan's climate is likely to undergo seasonal changes, and Cassini data will be helpful in evaluating its hydrologic system.
Mercury
Mercury is one of four terrestrial planets in our solar system, and its mass is about 70% metallic and 30% silicate. Because of its high core-to-shell ratio, the most widely accepted theory is that the planet was struck by an object of planetesimal mass, which had a radius of hundreds of kilometers and produced the high density of the planet.
By NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington - https://photojournal.jpl.nasa.gov/catalog/PIA11364, Public Domain, Link
Mercury has a very small atmosphere and is very close to the sun. As a result, it experiences the largest temperature range of any planet in the solar system. At its closest point to the Sun, its surface temperature is approximately 427 degrees Celsius, and at its farthest distance, it drops to -183 degrees Celsius. Scientists have also observed a magnetic field around Mercury, which they attribute to the planet's iron-bearing core.
The rotational period of Mercury was long unknown, but scientists later found that it was similar to its translation time. The planet's orbit around the sun takes 88 days, with one Mercurial day lasting almost two Earth years. This is a phenomenon known as orbital resonance.
Venus
By NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington - http://photojournal.jpl.nasa.gov/catalog/PIA10124, Public Domain, Link
Venus is our sister planet and is studied by scientists extensively. Their goal is to understand the future of Earth and the solar system. Venus is closer to Earth than Mars and more accessible and less time-consuming to travel to. However, all attempts to colonize Venus to date have failed. It is also quite similar in size with earth. So, what do we know about Venus?
By NASA - Venus,_Earth_size_comparison.jpg, Public Domain, Link
Radar studies from Earth's orbiting satellites and altimetry studies from a few landers have helped to provide the first maps of Venus' surface. The images from these spacecraft have shown that Venus has two major highland areas, one about the size of Australia and the other about the size of Africa. One of these regions is named Ishtar Terra and contains the highest mountain on Venus, Maxwell Montes.
If we were to go to Venus, we would notice a big difference in gravity. We would weigh about 26 kilograms less on Venus than on Earth. Furthermore, the pressure of Venus' atmosphere is equivalent to a deep dive into Earth's ocean. However, the human body can only tolerate this level of pressure at a depth of 500 meters.
Earth
The Sun is a star that is at the center of our Solar System. It is a nearly perfect ball of hot plasma that is heated by nuclear fusion reactions in its core. Its energy is radiated out in the form of light, ultraviolet, and infrared radiation. This energy is the most important source of energy for life on Earth.
The formation of the solar system occurred over many millions of years. During this time, the young sun blasted out raging solar winds. These solar winds carry energetic particles into the solar system and drive lighter molecules to the outer protoplanetary disk. Eventually, these objects form rocky planets.
The ESS curriculum consists of three major components. The first module is called Earth's Place in the Universe. This module introduces students to the universe's vast scale. Students learn about the composition of the universe and the history of its development.
Mars
By Justin Cowart - Tharsis and Valles Marineris - Mars Orbiter Mission, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=71790570
The planet Mars is one of the most intriguing bodies in the solar system. Scientists are fascinated by its similarities to Earth and the possibility of human colonization in the future. They are exploring various technologies and methods for making the planet habitable. Terraforming is one of those technologies. It involves the process of converting Mars into a habitable planet.
The next planet beyond Mars is Jupiter, which is a gas giant and not habitable for life. However, it has icy moons, which can be studied with the help of space probes. Nasa's Galileo mission, which orbited Jupiter in 1995, was the first to study the moons of Jupiter. This mission collected images of the planet and its moons. During its mission, the spacecraft passed through the moon Europa 12 times.
Throughout history, visual observers have made many discoveries about Mars. Early astronomers were perplexed by its motion, thinking that it was retrograde, prograde or both. However, in 1609, Johannes Kepler used Tycho Brahe's observations of Mars to empirically deduce the laws of motion, which were a key part of the modern gravitational theory of the solar system. Using this information, Kepler was able to explain how planets move and how their distance from the sun affects the planets' orbits.
Jupiter
By NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute - National Aeronautics and Space Administration, Public Domain, Link
Jupiter is one of the most fascinating planets in the solar system and it has four major satellites. Scientists believe that Europa may contain oceans that could sustain primitive life. However, it is impossible for a spacecraft to land on Jupiter due to its extreme pressures and extreme temperatures. Despite this, Europa is one of the most likely places in the solar system to find life. It has evidence that a vast liquid ocean may exist underneath the icy crust.
Scientists do not know exactly what makes up Jupiter's rocky core. They believe that it is made of heavier elements. Its shape is an oblate spheroid with a bulge around the equator. The planet's size is also unknown. While most planets have a solid surface, Jupiter does not have one.
Observations of Jupiter are important for understanding the planet's atmosphere. There are four major moons orbiting Jupiter. Jupiter also has many smaller moons. Several of them have been named by the International Astronomical Union.
Saturn
Saturn's composition is difficult to pin down exactly, but it appears to be mostly hydrogen and helium with some silicates mixed in. Models suggest that the interior is composed of a dense core. There is some uncertainty about how it formed. However, the current observational constraints are inadequate to answer this question.
By Kelvinsong - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=32219154
The best time to observe Saturn is during its opposition, which takes place about once every four years. During this time, Saturn is visible almost all night long because it rises as the sun sets. According to the Institute of Celestial Mechanics and Ephemeris Calculations, Saturn will be in opposition again on August 27, 2023.
The two planets were one-tenth of a degree apart in the sky or 6.1 arc minutes. One degree is the size of a pinky finger. So, if they had formed simultaneously, they would have been just one degree apart!
Uranus
By NASA (image modified by Jcpag2012) - Images found in NASA, Public Domain, Link
The outermost planet in the solar system is Uranus. This ice giant has an ice-like atmosphere and is slightly larger in diameter than its sister planet, Neptune. Because of its larger size and further distance from the sun, Uranus receives less heat from the sun than other planets. It also has a very thick methane cloud.
Uranus is surrounded by four outer rings and nine inner rings, each measuring approximately nine kilometers in diameter. These rings are made of dark material and are not visible when the sun shines directly on them. They are centered around the planet's equator and surround the planet's surface. The rings are filled with rocky material and were formed by the collision of two moons.
The orbit of Uranus deviates little from its perfect circular orbit, but it has a small inclination to the ecliptic, which is the plane in which the planets move in relation to Earth. The orbital eccentricity of Uranus is low compared to other planets in the solar system, including Mercury and Pluto. This low eccentricity is the result of gaseous drag which sucked the energy out of the orbits of planets during their formation.
By Tomruen - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=68424883
There is a vast and endless continuum in space made up of countless solar systems and just understanding our single tiny solar system would take ages. It makes us realize how really small we are in the fabric of the universe. This has been one of the major drivers of my interest in the universe and astronomy. So, you'll definitely be seeing more posts like this from me soon. Make sure to follow to learn more.
Written by @gamsam
All images used are copyright free
