In the Solar System, natural satellites often get the name moon. This is because they orbit a planet in a similar way as the Earth’s Moon does.
The planet Mars has two oddly shaped moons named Phobos and Deimos. They are among the smallest in our solar system.
Phobos is the larger of the two moons orbiting Mars. It’s about 16.8 miles (27 km) across and astronomers believe it was formed as an asteroid captured by the planet’s gravity.
The satellite revolves once around Mars every 7 hours and 39 minutes, making it one of the closest planetary moons to the planet. It is so close that it appears to rise in the west, move across the sky rapidly and set in the east twice each Martian day.
Its elongated shape makes it difficult for astronomers to accurately see it above the horizon from most places on Mars. It is also too light for its gravity to make it a spherical object, which is why some astronomers believe that it was once an asteroid that was captured by Mars’ gravity.
Scientists are now examining the surface of Phobos to see what it is made of. They are hoping to find clues about the early history of Mars, including whether or not it had liquid water.
This is a crucial question, because life on the Red Planet might have been impossible if there was no liquid water in its atmosphere during the first 1 billion years of its existence. The chemical imprints of such a scenario should be frozen-into the regiolith that forms the surface of Phobos.
To see what’s there, scientists will need to sample and return the material from the regiolith to Earth. They will also need to study the effects of space radiation and solar wind on the material.
The regiolith is an excellent candidate to be a repository for extinct biosignatures of Martian origin, because it should have samples from all regions and epochs on the planet. Based on simulations, the fraction of material from each era should exceed
In addition to containing evidence of past life, the regiolith should be an important tool for studying how the planet mars has changed over time. If tidal forces have sped up the planet’s rotation over the past few billion years, for example, it may have caused some of the materials deposited on the surface to be pushed back into the outermost layers of the regolith.
Deimos is the outer and smaller of the two moons orbiting the red planet Mars. It was discovered by American astronomer Asaph Hall in August 1877 and named for one of the sons of Ares, the Greek god of war.
Its cratered surface is covered with fine dust, which gives it a smoother appearance than Phobos. It is estimated to have a mean age of at least 3 billion years (Fig. 2).
Like its larger companion, Deimos is a dark object made up of materials similar to those found in asteroids in the asteroid belt. Its surface is dotted with large impact craters, including Stickney, which was first photographed by the Viking spacecraft. Its two named craters are Voltaire and Swift, each of which is 1.9 miles in diameter.
As with Phobos, Deimos has a wide range of equatorial temperatures, from -4degC (25degF) on the sunlit side to -112degC (-170degF) on the shadowed side. Its average temperature is about -40degC.
According to the most widely accepted hypothesis, the two Martian moons are captured asteroids that were pushed out of the asteroid belt by Jupiter’s gravity and snatched up by Mars’ gravity. The gravitational forces of these giants pushed the asteroids into their current orbits, where they remain today.
This theory has a few caveats: Mars, with a fraction of Earth’s mass, has a weaker gravitational pull than Jupiter, and it’s difficult to explain why it would capture an asteroids zipping by. Other possible explanations include that Mars’ atmosphere dragged the asteroids into their current orbits, or that some of them were ejected from orbit when they collided with a larger body, such as Mars itself.
In any case, scientists are hoping that future spacecraft will be able to bring samples from Deimos to Mars. There are several missions currently in development that aim to do just this. Some of them include the Phobos and Deimos and Mars Environment (PADME) mission and OSIRIS-REx 2.
Moons are small spheres of rock or ice that orbit a planet. In the Solar System, our planet Earth has one moon, while Jupiter and Saturn have four. Mars also has two moons, Phobos and Deimos.
The origin of these moons has long puzzled astronomers and scientists. They are tiny, cratered and potato-shaped, and they appear to have a composition outside of the planet’s own. This has led to a wide variety of theories. Some of them suggested that they were originally asteroids that were captured by Martian gravity. Others said that they formed in a giant collision.
A team of researchers from France, Belgium and Japan, has come up with an alternative theory for the birth of these moons. In this scenario, they would have been created as debris from a collision with a primordial planet one-third of Mars’ size, about 100 to 800 million years after the planet was formed.
This collision, the research suggests, could have thrown up a disc of debris around Mars, similar to what formed many other natural satellites in our Solar System. The impact might have left behind molten material that clumped up to form the two moons.
Another possible way for the moons to have formed is from the asteroid belt, which is a spherical collection of rock and ice that separates the orbits of Mars and Jupiter. C-type asteroids are plentiful in this belt, and some astronomers think that Phobos and Deimos might have originated there.
These theories do not account for the strange orbits of Phobos and Deimos, however. They tend to move more erratically than they should in the absence of an atmosphere. This happens because the tidal forces on Phobos are greater than those of Mars.
These tidal forces are slowing down the orbits of Phobos and Deimos, making them closer to the red planet. Eventually, they will break up into smaller pieces and crash into Mars or form a ring of debris. Depending on how fast the tidal forces are acting, this might happen within 40 to 50 million years.
The planet Mars has two moons, Phobos and Deimos, both of which are natural satellites of the red planet. Both were discovered by astronomer Asaph Hall in August 1877, and were named after the Greek mythological twins Phobos (fear and panic) and Deimos (terror and dread).
These two moons orbit Mars at very close distances, so we can’t see them from Earth even though they are only 238,855 miles away. The curvature of the planet’s surface also hides them from view, making them hard to see even with a powerful telescope.
As a result, they have never drawn much attention from astronomers. But they do have some interesting facts about them that make them more than just mere specks of rock in the sky.
First, they are among the smallest moons in the Solar System. Both of them have a mean diameter of less than 14 miles, and they’re not round because gravity hasn’t pulled them into a sphere like Earth’s moon.
Next, they are both primarily made of carbon-rich rock mixed with ice, which makes them dark and lumpy, and not very reflective. They are also very irregular in shape and have lots of craters on their surfaces, including the huge Stickney crater on Phobos.
The craters have left behind some interesting rock layers that are rich in sulfur, nitrogen, oxygen, phosphorus and carbon–the main ingredients of life on Earth. Curiosity found traces of all of these in the powder sample it drilled from the Sheepbed mudstone on ancient Mars, and scientists believe that the chemistry of Mars would have been just right for living microbes.
Finally, they have the most unusual feature of any moon in our solar system: two subsurface lakes. These lakes are thought to be filled with liquid water – and they could be a possible habitat for life.
The lakes are located in a very large crater called Stickney on the surface of Phobos, and scientists think that they were formed when the moon was hit by a meteorite or other large object. This impact triggered the formation of the crater, which is a perfect example of what scientists call “crystal-clear impact craters” – a very rare phenomenon that occurs on moons only once in a hundred million years or so.