Mars, the Red Planet, is a fascinating object in the night sky. It is one of the brightest objects in the sky and is easily spotted with the naked eye, a telescope or binoculars.
Mars orbits the Sun in an elliptical path, completing one orbit every 687 days. The planet goes into opposition, when it is precisely opposite the Sun in the sky, once every 2.1 years.
The Red Planet
Mars is the fourth planet from the Sun, and it’s often referred to as the “Red Planet” because of its red color. Its rusty red appearance is due to iron oxide that’s found on its surface.
The planet is about 228 million miles (401 million kilometers) from the Sun, half as far as Earth. This means that the Martian atmosphere is very thin, and the planet’s nights are very cold.
A team of planetary scientists has discovered evidence that the interior of Mars is being pushed upward by a plume from beneath. This plume, called a mantle plume, may be similar to what’s happening underneath Earth.
These findings were published in Nature Astronomy in 2018. The research shows that the Martian surface shows signs of a giant, hot tower of material moving up in the planet’s mantle. The resulting pressure is cracking the surface, and triggering tectonic activity.
As a result, the planet’s crust has stretched and twisted. The region known as Elysium Planitia displays compression features, like wrinkle ridges, while Cerberus Fossae is a bulge that appears to have stretched and twisted as well.
Scientists are still unsure how these features formed. They may have formed in the past as part of a massive impact or they could be remnants of an ancient flood, like those on Earth.
There are also signs that the planet once had liquid water on its surface. Images from the Viking 1 spacecraft suggest that there are channels, valleys and gullies across Mars that might have held liquid water for long periods of time in the past.
But the most exciting news is that Curiosity, a car-sized rover, has discovered that Mars once had a lake-and-stream system. The rover has also found complex organic molecules that indicate that Mars was once a planet with conditions favorable to life, and seasonal changes in methane concentrations have shown how the Martian climate can change over time.
All of this has led to many theories about what might have once happened on the Red Planet. And with the upcoming missions to Mars, we have much more to learn about this planet and its potential for life.
The Moon
The Moon is the second largest body in our solar system, and it’s the closest to Earth. The Moon orbits around the planet in a tidal relationship that varies with the Earth’s rotation. Its rotation causes the Moon to rotate at a slower pace than Mars, which means that the two bodies appear to move apart from each other when seen from Earth.
Despite its proximity to Earth, the Moon is very bright and easy to spot. To make the best of this celestial display, you’ll need a clear sky and a pair of binoculars or telescope.
On Wednesday, December 7-8, 2022, the full Moon will come into contact with Mars, which means that the two objects will appear close together for most of North America and Europe. This is called a lunar occultation and is an exceptionally rare sight in the sky.
The moon, which is more than 200 times closer to Earth than Mars, will pass in front of the red planet as it reaches opposition on this night, and that will cause it to temporarily obscure Mars’ light. If you live in the occultation zone — which includes much of North America, Greenland and Europe — you’ll be able to see the Moon pass behind Mars, then pop back up into view after about 30 minutes.
This will be the first time that the moon and Mars have been in this position since January 2025, and astronomers are excited to see what they can learn about the planetary pair. In fact, the opposition of Mars is one of the most significant celestial events of the year.
It’s also a good time to see the Red Planet’s two moons, Phobos and Deimos. These moons are lumpy, heavily cratered and covered in dust and rock debris. They are thought to be made of carbon-rich rock mixed with ice.
The moons are undergoing a process that will eventually cause them to fall into the planet’s atmosphere, forming a debris ring that may become visible on the Martian surface. Scientists haven’t been able to determine how long that will take, but they believe that it will happen in about 10 – 40 million years.
The Sun
Mars is the fourth planet from the Sun, at an average distance of 141 million miles (255 million kilometers). The rocky red planet orbits the Sun every 687 Earth days, taking about 1.88 Earth years to complete one full revolution around the Sun.
Its closest approach to the Sun occurs when it is near perihelion, the point where it is summer in the southern hemisphere and winter in the northern hemisphere. During these seasons, it can be as warm as 30 K (54 degC) warmer in the southern hemisphere than it is in the northern hemisphere.
Despite its distance from the Sun, Mars is bright enough to be visible at night. Its surface is a rusty-red color due to iron oxide particles in the dust that covers its surface.
The surface of Mars is rocky and has no atmosphere. However, water may have once flowed across the Martian surface in rivers and lakes that are no longer there.
Scientists have been able to study the surface of Mars using a combination of images from spacecraft and observations by rovers on the Martian surface. They’ve found that the surface is made of a mix of sand, rocks and gravel with some silica. They’ve also discovered that the surface has been shaped by impactors that impacted Mars before it was formed.
When viewed from the ground, the sun appears to set and rise in an oval shape on Mars. This is because of atmospheric refraction, which bends the light from the sun as it travels through much thicker air. Once it’s higher in the sky, refraction diminishes.
Another reason why the sunset on Mars looks bluish is because of the fine dust that extends throughout the planet’s atmosphere and scatters blue light from the sun. This makes the sunset on Mars look more bluish than it would on Earth, even though it’s still quite a bit ruddy when seen from Earth.
The sun is also known to produce long twilight glows on Mars, which are similar to Earth’s. This glow lasts for about two hours before sunrise or after sunset.
The Atmosphere
Mars’ atmosphere is primarily composed of carbon dioxide and nitrogen gases, with trace amounts of oxygen, argon, and water. Oxygized dust particles kicked up from the Martian surface fill the thin air, turning Mars’ skies a rusty tan color.
Like Earth, the Martian atmosphere is constantly changing and circulating, resulting in seasonal weather patterns. During the southern polar winter, up to a third of the mass in the atmosphere condenses into ice caps at the planet’s poles. This results in a deep drop in air pressure on Mars.
The atmosphere also consists of large dust storms that can cover the entire planet for months at a time. These are the largest in the solar system and are often visible from Earth.
Giant dust devils routinely kick up oxidized iron dust from the planet’s surface and are a permanent part of the Martian weather system. These storms can be observed from Earth, and can sometimes be a threat to the operation of rovers on the surface.
Another regular feature of the Martian weather system is snowfall. Frozen CO2 particles, instead of water ice, make up the snowflakes that fall on Mars.
There are some signs that Mars once had a more moist atmosphere, but this was buried under the surface by the formation of polar ice caps. Scientists have found evidence that liquid water once flowed down hillsides and craters.
But even today, the Martian atmosphere is far thinner than that of Earth. This is due to pressure from the Sun, which stripped the lighter molecules from the Martian atmosphere over millions of years.
Because the Martian atmosphere is so thin, it’s not protected from ultraviolet radiation by an ozone layer similar to the one on Earth. This means that any organic compounds exposed to the Sun’s rays would quickly break down.
Methane is a major gas in the Martian atmosphere, but it is chemically unstable. The Curiosity rover has detected a cyclical seasonal variation in methane in the Martian atmosphere.