The number of moons a planet has is a key topic of discussion in astronomy. There are many theories as to why a planet may have only one or two natural satellites, or even no moons at all!
Many astronomers believe that when a large and dense body like a planet passes close to another large and dense body like an orb-weaving mother satellite, it can impact the size and shape of these orbiting bodies.
This is called plate tectic movement, and it is believed to occur when planets form in the early stages of solar system development.
There are several theories about whether there are other small natural satellites around Mars, but none have been confirmed yet.
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Phobos
Phobos is the smallest of the four major moons of Mars. It’s also one of the youngest, with an average age of only about 6,000 years.
Phobos is 57 miles across at its widest point and has a length of about 1,200 miles. Its diameter is just under one mile!
Its name comes from the Greek word for “apendre” or “marker” for something. In this case, it refers to Phoebus, or yellow star, an important astronomical landmark.
Phobos was once a large asteroid that broke into two parts: one part became Phobos and one part became Deimos. Both orbits are tilted slightly apart, so they always see Earth from separate angles.
Because they are so small and unstable, both Phobos and Deimos have changed shape over time.
Deimos
Deimos is the smaller of the two Greek gods of terror. He’s usually described as a 6-foot-1, 200-pound man with sharp features.
He’s usually portrayed with a scythe or long weapon, like a baseball bat. This is because he’s the god of terror and death.
His counterpart is Cronos, the god of time and destruction. Like Deimos, he’s mostly known for his demeanor rather than a specific object.
His wife is Phoebe, the goddess of companionship and love. She helpsguide people through difficult times by appearing to them in dreams and on social media. She also helps people face her fears so they can live life to its fullest.
They are tiny compared to Earth’s moon
While the size of the average planet in our solar system is fairly large, the sizes of some of the smaller celestial bodies are tiny.
The smallest known planet is Ganymede, which is only about one third the size of Earth and has a diameter of 1/20th that of ours.
Similarly, Epsom Salt Mars has a diameter just slightly larger than that of our saltine bread.
The largest body in our solar system is Mars, and while it is smaller than Epsom Salt Mars it still stands out.
As mentioned before, Mars has two moons called Hellas and Phobos. Hellas is about as small as an object can be without being a continent. Phobos is about as small as a human or animal can get without being tiny.
Both moons are roughly half the diameter of Mars and have average heights between 5 and 7 miles above its surface.
Masses and diameters
There are several dimensions to Mars, including length, width, depth, and height. These dimensions include length and width in how far apart two points are from one another.
Length is how far a point is from another point. For example, Mars is close to the Earth in length.
Width is how wide a point is. For example, Mars is long in width.
Depth is how deep a point is. For example, Mars is tall in depth.
Phobos
The smallest of the four planets in the Solar System, Phobos has the distinction of being the only moon outside of Earth.
Phobos is 93 miles (150 kilometers) across and has a highly elliptical orbit that puts it in a constant state of opposition with Earth. This makes it always visible to the naked eye, though not every viewer will see it.
Phobis is named for this planet because its shape resembles that of a phobia – a strong, irrational fear. It is also one of the few names with an apostrophe stuck in, making itauthorendingsthat Apostroian University does not use as an initialism.
Because it is so small and dark, little is known about Phobos and what makes it exist. Some believe it may have water or liquid water, which may have helped form an atmosphere and/or life as we know it today.
Smallest of all the moons in the Solar System
While the average size of all the other moons in the Solar System is around 1 mile in diameter, Mars has a little less than an inch for its largest moon. This makes it the smallest of all the moons in the Solar System.
According to NASA, Tharsis is about five miles long, two miles wide, and one to three thousand feet high. It takes about six months for it to orbit Mars. During this time, it moves from south to north as it rotates on its own.
When it does move across the planet, look for a line of white spots where it passes by. These are snowscapes that form when water evaporates on the surface during a year-round cycle.
These snowbanks are called albedos and they can be as much as ten thousand feet high. When they pass over Mars, they reflect sunlight back into space which causes them to disappear and reappear over and over again.
Close proximity to Mars
Having close proximity to Mars means that Earth and Mars are almost directly aligned. This is a rare occurrance, as you’ll learn in this article, and it results in a full-on space invasion.
This happens when two objects are roughly the same distance from each other, as in when Mars and Earth are aligned. This alignment occurs approximately every time we pass through the orbit of Mars and every time we enter northern summer.
The effect is that we are repeatedly hit with bursts of radiation from the red planet, which floods our bodies with some of its chemicals. These include iron-rich dust that orbits Mars, water contained within those chemicals that escaped into space, and energy that fluctuates between being very high (from Mars itself) and very low (from us).
We experience this as winters on Earth are covered with snow during summer solstices, and when people feel compelled to celebrate such important events at the same time.
Likely captured by Mars
Despite being one of the most well-known satellites in our solar system, Europa does not have very many features that astronomers can see.
Yet, this doesn’t mean that we can’t know it’s there.
Europa is a giant ice island in Jupiter’s orbit. It is around eight times larger than Earth and six times taller. It sits close to Jupiter, making them very similar sizes.
Like Earth, Europa has a core, crust, and layers. However, it does not have a molten core like Earth does but instead has icy rings that surround a frozen surface. These appear to be liquid water flowing on!
It also has volcanoes which are known to erupt and send water and dust into the atmosphere which scientists believe is responsible for features like craters.