Comparing Mars and Earth: Size, Gravity, and Physical Characteristics

As humans continue to explore the vast expanse of space, the question of how other planets compare to Earth becomes increasingly relevant. One such planet that has captured our attention is Mars, the fourth planet from the sun. Mars has been of particular interest to scientists due to its potential to support life and the possibility of future colonization. One of the most fundamental questions about Mars is how it compares to Earth in terms of size and physical characteristics.

While Earth and Mars share some similarities, such as the presence of water and a rocky surface, they also have significant differences. Mars is smaller than Earth, with a diameter of approximately 6,779 kilometers compared to Earth’s 12,742 kilometers.

This means that Mars has less mass and volume than Earth, resulting in lower surface gravity. Understanding these differences is crucial for scientists as they continue to explore Mars and gather information about its potential to support life.

In this article, we will explore the question of whether Mars is bigger or smaller than Earth, and how it compares to our planet in terms of gravity and other physical characteristics.

We will examine the latest research and scientific findings to provide a comprehensive understanding of the similarities and differences between these two planets. By the end of this article, readers will have a better understanding of the unique characteristics of Mars and how they compare to Earth.

Size Comparison

Mars’ Size

Mars is the fourth planet from the sun and has a diameter of approximately 6,779 km. This makes it about half the size of Earth, which has a diameter of 12,742 km.

Despite being smaller than Earth, Mars is still considered a relatively large planet in our solar system.

Another notable difference in size between Mars and Earth is their mass. Mars has a mass of 6.39 x 10^23 kg, which is only about 11% of Earth’s mass. This difference in mass has a significant impact on the gravity on each planet, which we will discuss later in this article.

Earth’s Size

As mentioned earlier, Earth is much larger than Mars, with a diameter of 12,742 km. It is the third planet from the sun and is the largest of the terrestrial planets in our solar system.

Earth’s mass is also much larger than Mars, with a mass of approximately 5.97 x 10^24 kg.

One interesting fact about Earth’s size is that it is not perfectly spherical. Due to the rotation of the planet, the equator bulges slightly, making Earth slightly wider at the equator than at the poles.

This phenomenon is known as the equatorial bulge and causes Earth’s diameter at the equator to be about 43 km larger than its diameter at the poles.

Overall, while Earth is significantly larger than Mars, both planets are still relatively large in our solar system and have unique physical characteristics that make them interesting objects to study.

Mars and Earth
Mars and Earth

Gravity Comparison

Gravity is an important physical characteristic that affects everything on a planet. The gravitational force on a planet determines the weight of objects on its surface, as well as the strength of its atmosphere. Here is a comparison of the gravity on Mars and Earth:

PlanetGravity (m/s²)

As we can see, the gravity on Mars is only about 38% of the gravity on Earth. This means that objects on Mars weigh less than they would on Earth. For example, a 100 kg object on Earth would weigh only 38 kg on Mars.

The lower gravity on Mars also affects its atmosphere. Mars has a much thinner atmosphere than Earth because its gravity is not strong enough to hold onto gases as effectively.

This means that Mars has a much weaker greenhouse effect than Earth, which makes it much colder overall.

However, the lower gravity on Mars also makes it easier for spacecraft to land and take off from its surface. It requires less fuel to escape Mars’ gravity than it does to escape Earth’s gravity, which makes Mars an attractive destination for space exploration.

Physical Characteristics Comparison

Mars and Earth are both rocky planets, but they have some noticeable differences in their physical characteristics.

PlanetSize (Radius)MassGravityAtmosphere
Earth3,959 miles5.97 x 10^24 kg9.8 m/s²Nitrogen, Oxygen, Argon, Carbon Dioxide
Mars2,106 miles6.39 x 10^23 kg3.7 m/s²Carbon Dioxide, Nitrogen, Argon

The table above shows that Mars is smaller and less massive than Earth, which means that its gravity is only about 38% of Earth’s gravity. This means that if you weigh 100 pounds on Earth, you would only weigh about 38 pounds on Mars.

Another major difference between the two planets is their atmosphere. Earth’s atmosphere is much denser and contains more oxygen, which is essential for human life.

Mars, on the other hand, has a very thin atmosphere that is mostly made up of carbon dioxide. This makes it difficult for humans to breathe on Mars without the help of special equipment.

In terms of temperature, Mars is much colder than Earth. The average temperature on Mars is about -80°F (-62°C), while the average temperature on Earth is about 59°F (15°C).

This is due in part to Mars’ distance from the sun and its thin atmosphere, which cannot retain heat as well as Earth’s atmosphere.

Overall, while Mars shares some similarities with Earth, such as its rocky composition, it also has many distinct physical characteristics that make it a unique planet in our solar system.


After comparing the physical characteristics of Earth and Mars, it is clear that the two planets have many differences that set them apart from each other.

Mars is smaller than Earth, with a diameter of 6,779 km compared to Earth’s 12,742 km. Mars also has a much thinner atmosphere, which means that its surface experiences more extreme temperatures and pressure changes than Earth.

One of the most significant differences between the two planets is their gravity. Mars has a surface gravity of 3.711 m/s², which is only 37.6% of Earth’s gravity.

This means that objects on Mars weigh much less than they do on Earth, making it easier for humans to move around and complete tasks.

Despite these differences, Mars has many similarities to Earth as well. Both planets have seasons, polar ice caps, and geological features like mountains and valleys.

Mars also has a day/night cycle that is similar to Earth’s, with a day that lasts 24 hours and 39 minutes.

Overall, while Mars may be smaller and have a weaker gravitational pull than Earth, it is still a fascinating planet with many unique characteristics that make it an exciting destination for exploration and research.