Chapter 1: An Overview of Gravity in Watchmen

Having recently completed the HBO series Watchmen, I found it to be a refreshing take on the superhero genre. Now, let's delve into the scientific aspects. While the show embraces fantastical elements, such as Dr. Manhattan's omnipotence, some scientific inaccuracies warrant discussion.

To avoid spoilers, I’ll focus on a pivotal scene. In it, the character Adrian Veidt departs from Europa, one of Jupiter's moons. The narrative introduces an artificial habitat for human survival. Veidt boards a spacecraft, which is set to autopilot, and takes off.

Upon launch, the onboard system announces:

Artificial gravity: enabled.

Leaving atmosphere.

Launch successful.

This moment aims to highlight the spacecraft's cold, mechanical nature and Veidt's lack of control. However, the phrase "artificial gravity enabled" raises questions. While the concept of artificial gravity is intriguing, the necessity of activating it during launch is puzzling.

It's a common misconception that gravity ceases once one exits Earth's atmosphere, which is incorrect. This notion leads to the assumption that the rocket activates artificial gravity to counter the lack of atmosphere on Europa.

To clarify, gravity is a force that acts between any two masses. The interaction's strength depends on both the masses involved and the distance separating them. For instance, two nearby objects exert a gravitational pull on one another, a concept illustrated in the following example.

The gravitational force, while present, is relatively weak. For example, two people standing 2 meters apart experience a gravitational attraction of about (10^{-7}) Newtons, an imperceptible force. Yet, when one of the masses is significantly larger, like Earth, the gravitational pull becomes evident.

Now, onto the question of gravity in space. Yes, gravity exists beyond Earth's surface. The Earth’s orbit around the Sun is due to gravitational interaction, confirming that gravity is indeed present in space.

Considering astronauts in low Earth orbit, they are approximately 400 km above the surface. Although the gravitational force diminishes with distance, it remains at about 88% of the force experienced on the ground.

So why do astronauts appear to float inside the International Space Station (ISS)? This can be attributed to "fake forces." Imagine being in an elevator accelerating upwards; you feel heavier for a moment. In an inertial reference frame, the floor exerts a greater upward force than gravity, causing an upward acceleration.

However, in a non-inertial frame, such as inside the ISS, the apparent weightlessness occurs because the astronauts are in continuous free fall, maintaining a circular orbit around the Earth.

But what about Veidt in the accelerating spacecraft?

Is gravity present? Yes. Does the floor exert an upward force? Absolutely. Is there a fake force at play? Indeed. But does he require artificial gravity? Not at all.

To improve the spacecraft's announcement, it could simply say:

Current acceleration: 2 g's.

Leaving atmosphere.

Launch successful.

This minor adjustment enhances the script without altering its essence.

Now, let’s discuss the gravity on Europa. The moon has less mass than Earth, resulting in a weaker gravitational field. However, its smaller radius increases the gravitational force at the surface, yielding a gravity of approximately 13.4% of Earth's (1.314 N/kg).

This reduced gravitational force would make movement on Europa peculiar, and the thin atmosphere would be insufficient for human life. Dr. Manhattan must have employed some form of force field to maintain air on the moon's surface, perhaps even manipulating the moon’s mass to enhance gravity.

In conclusion, while the portrayal of artificial gravity in the rocket is unnecessary, the fascinating interplay of gravity on Europa adds depth to the narrative.

The first video titled "Prisoners of Gravity: Watchmen" provides an analysis of the show's unique take on physics and storytelling. This insightful perspective enhances the understanding of the thematic elements of gravity in the series.

The second video, "HBO Backstories: Watchmen," offers a behind-the-scenes look at the making of the series, shedding light on the creative decisions that shaped its narrative, including the depiction of scientific concepts.