Do you ever think about the weight of the Earth? It’s a fascinating question that sparks curiosity. To know the weight of the Earth, we must first understand what we mean by weight. Weight is the force exerted on an object due to gravity. The mass of an object determines its weight.
So, how do scientists determine the mass of the Earth?
One of the primary methods is by measuring the gravitational pull exerted by the Earth on objects around it. Through observations and calculations, scientists have estimated the Earth’s mass to be approximately 5.9722×10^24 kilogrammes (13.1 septillion pounds).
This massive figure shows the sheer scale of our planet and its gravitational influence on everything within its vicinity.
However, one must know that the journey to this calculation has been arduous. Scientists earlier leveraged Isaac Newton’s law of universal gravitation. Newton’s equation, coupled with the experiments of physicist Henry Cavendish in 1797, paved the way for understanding Earth’s mass.
Cavendish’s experiments
Cavendish’s experiments used a torsion balance to measure gravitational forces.
The setup of Cavendish’s experiment was ingeniously simple. It involved a torsion balance, a device consisting of a horizontal bar suspended from a thin wire, with two small lead spheres attached to each end.
These lead spheres were positioned near larger lead spheres. It created a gravitational attraction between them and provided a crucial value – the gravitational constant (G). This value, though subject to slight variations over time, remained a cornerstone in calculating Earth’s mass.
A physiologist at the University of California in San Diego, John West, reportedly told the Live Science media portal, “His work was very original and made a big impact at the time.”
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Stephan Schlamminger, a metrologist at the US National Institute of Standards and Technology, said, “Sometimes it’s the cracks that the universe gives us that we can apply our lever to and get more scientific understanding.”
“This may be a crack the universe is offering us, and we don’t want to let that opportunity pass,” he added.
(With inputs from agencies)