# How scientists calculated the weight of Mars

• Electrical
In summary, scientists used Newton's law of gravity to calculate the mass of Mars to be 6.39 × 10^23 kg.
Electrical
How scientists calculated the weight of Mars to be 6.39 × 10^23 kg?

If you google for "calculate the mass of a planet" you'll find how this is done fairly quickly. I strongly suggest that you actually try the calculation - it is way more fun than just looking up the final answer.

If you do the math (just start with Newton's law of gravity) you'll find that the behavior of an orbiting object depends on the mass of the the object being orbited but not the mass of the orbiting object. This allows us to calculate the mass of Mars from the observed orbit of its moons, just as we canculate the mass of the sun from what we know of the Earth's orbit.

vanhees71
Also, the amount how much a focal point of the elliptical orbit of Mars around Sun deviates from the centerpoint of Sun could be one quantity that can be checked for consistency (after estimating the mass of Mars from the centripetal acceleration of Phobos and Deimos).

sophiecentaur, vanhees71 and hutchphd
hilbert2 said:
Also, the amount how much a focal point of the elliptical orbit of Mars around Sun deviates from the centerpoint of Sun could be one quantity that can be checked for consistency (after estimating the mass of Mars from the centripetal acceleration of Phobos and Deimos).
Yes, good point, and that technique is essential when we don't have a convenient orbiting body - as is the case when we're trying to determine the mass of Earth's moon.

vanhees71
Nugatory said:
If you google for "calculate the mass of a planet" you'll find how this is done fairly quickly. I strongly suggest that you actually try the calculation - it is way more fun than just looking up the final answer.

If you do the math (just start with Newton's law of gravity) you'll find that the behavior of an orbiting object depends on the mass of the the object being orbited but not the mass of the orbiting object. This allows us to calculate the mass of Mars from the observed orbit of its moons, just as we canculate the mass of the sun from what we know of the Earth's orbit.
Well, not exactly. As long as the mass of the orbiting object is very small compared to the planet, you get a fairly accurate answer. But as the mass of the orbiting body increases, it becomes less accurate. For example, if you were to calculate the Earth's mass from just the Moon's orbital period and distance while ignoring the Moon's mass vs. doing so while accounting for the Moon's mass, you would get answers that differ by about 1%

vanhees71, sophiecentaur and Nugatory

## 1. How did scientists calculate the weight of Mars?

Scientists used Newton's Law of Universal Gravitation to calculate the weight of Mars. This formula takes into account the mass and distance between two objects to determine the gravitational force between them.

## 2. What data was used to calculate the weight of Mars?

Scientists used data from previous space missions, such as the Mars Global Surveyor and Mars Reconnaissance Orbiter, to determine the mass and radius of Mars. They also used data from Earth-based telescopes to measure the gravitational pull of Mars on its moons.

## 3. How accurate is the calculated weight of Mars?

The calculated weight of Mars is estimated to be accurate within a few percentage points. However, as technology advances and more data is collected, this estimate may become more precise.

## 4. Can the weight of Mars change over time?

Yes, the weight of Mars can change over time due to factors such as meteorite impacts, volcanic activity, and the movement of its moons. However, these changes are relatively small and do not significantly affect the overall weight of the planet.

## 5. Why is it important to know the weight of Mars?

Knowing the weight of Mars is important for understanding the planet's composition, structure, and evolution. It also helps scientists make accurate predictions about the planet's future and its potential for supporting life.

• Mechanics
Replies
46
Views
3K
• Mechanics
Replies
7
Views
2K
• Mechanics
Replies
1
Views
156
• Mechanics
Replies
2
Views
960
• Mechanics
Replies
4
Views
2K
• Aerospace Engineering
Replies
82
Views
5K
• Mechanics
Replies
37
Views
10K
• Mechanics
Replies
3
Views
902
• Special and General Relativity
Replies
14
Views
768
• Mechanics
Replies
202
Views
9K