Brian Cox visits the world's biggest vacuum | Human Universe - BBC

Summary

The world's largest vacuum chamber at NASA's space power facility in Cleveland, Ohio, simulates outer space conditions to test spacecraft. Originally a nuclear test facility built in the 1960s, it features a concrete skin for radiation shielding and external pressure resistance. The script describes an experiment akin to Galileo's, where a bowling ball and feather are dropped in a vacuum to demonstrate the true nature of gravity, free from air resistance. It takes three hours to achieve a near-perfect vacuum, after which both objects fall at the same rate, illustrating Newton's concept of gravity and Einstein's perspective that in the absence of other forces, there is no sensation of falling.

Takeaways

• 🚀 Nasa's space power facility near Cleveland, Ohio, is home to the world's largest vacuum chamber.
• 🌌 This chamber simulates outer space conditions by reducing air pressure to near-vacuum levels.
• 🏗️ Originally built in the 1960s, the facility was initially designed as a nuclear test site.
• 🛠️ The chamber's construction uses aluminum for radiation shielding and concrete for external pressure resistance.
• 📚 Galileo's experiment demonstrated that in the absence of air resistance, all objects fall at the same rate due to gravity.
• ⏱️ It takes three hours to evacuate the chamber of its 800,000 cubic feet of air.
• 🎥 The script describes a demonstration where a bowling ball and a feather are dropped in a vacuum to illustrate Galileo's principle.
• 📉 Air resistance is shown to be a significant factor in the rate at which objects fall in Earth's atmosphere.
• 🌍 Newton's theory of gravity is referenced, stating that a force pulls objects down towards the Earth.
• 🤔 Einstein's perspective on gravity is contrasted, suggesting that objects in free fall are not falling but are in a state of weightlessness.
• 📖 The script concludes by emphasizing that without the influence of gravity, there would be no way to detect the acceleration of objects towards Earth.

Q & A

What is the primary purpose of NASA's space power facility near Cleveland, Ohio?

The primary purpose of NASA's space power facility is to test spacecraft in conditions that simulate outer space.

How does the facility achieve a near-outer space environment?

The facility achieves a near-outer space environment by pumping out the air in the chamber until only about 2 grams remain out of the original 30 tons.

What was the original purpose of the facility when it was built in the 1960s?

The facility was originally built in the 1960s as a nuclear test facility to test nuclear propulsion systems.

Why was the facility constructed with a concrete skin?

The facility was constructed with a concrete skin to provide radiation shielding and to serve as an external pressure vessel to withstand the force present on the outside when the chamber is pumped out to simulate outer space conditions.

What is the significance of Galileo's experiment mentioned in the script?

Galileo's experiment is significant as it demonstrated the principle of gravity, showing that in the absence of air resistance, all objects fall at the same rate regardless of their mass.

Why did the feathers fall slower than the bowling ball in Galileo's experiment?

The feathers fell slower than the bowling ball due to air resistance, which affected their rate of descent.

How long does it take to create a near-perfect vacuum inside the chamber?

It takes three hours to pump out the 800 thousand cubic feet of air from the chamber to create a near-perfect vacuum.

What is the significance of the phrase 'We drop the millet in the last 30 minutes'?

The phrase indicates that the final preparations for the vacuum test occur in the last 30 minutes before the actual drop test, ensuring the vacuum is complete.

What does the term '6104 Manual 10 percent Orbit Station One go for Drive PCB' refer to in the script?

This term refers to a series of commands or procedures being executed to prepare for the drop test, indicating that the system is ready to proceed with the experiment.

What does the pressure set point at 240 PSI signify?

The pressure set point at 240 PSI signifies the target pressure that the chamber should reach before the drop test can commence.

How do Newton's and Einstein's views on gravity differ as described in the script?

Newton believed that gravity was a force pulling objects down, while Einstein imagined that in the absence of other forces, objects in free fall are in a state of weightlessness and are not accelerating towards the Earth.