The “Gravity Probe-B” probe measured the influence of planet Earth on the curvature of space-time with the highest precision. / NASANASA
The culprit is gravity. Gravity is defined as the attractive force that a body or object with mass exerts on another object. The more massive a body is, the greater the gravitational pull it exerts.
Although it is not known whether this is actually true, it is said that the English physicist and mathematician Isaac Newton (1643-1727) had a “Eureka moment” when he saw an apple fall from a tree (another version states that that the poor apple fell into the head!). But behind this fall, whether true or not, there was a question: Why does the apple always fall vertically to the ground?
From this, Newton concluded that the Earth must exert an attractive force, calling it gravity and solidifying its definition. With this seed, he formulated the “Theory of Universal Gravitation” (1687), which accurately describes the way objects move within a gravitational field and explains not only the fall of objects to the ground, but also the movement of objects . planet and that's why he called it universal. A whole scientific revolution!
More information
These laws remained in effect until the beginning of the 20th century, when the German physicist Albert Einstein (1879-1955) published his “General Theory of Relativity,” which describes gravity as a geometric effect based on a deformation caused by the mere presence of the Space is caused by objects with mass, similar to what happens when we place a heavy ball on an elastic cloth or net. For example, if we apply this to our Solar System (SS), the deformation created in the web by the Sun (which makes up 98% of the mass of the SS) will tell the planets how to move through space. This concept of a deformable network due to the presence of massive bodies is called the space-time continuum. As the planets move, the mesh deformation changes.
What does all this nonsense have to do with the original question? We only talked about massive objects. Light has no mass, but it is an electromagnetic wave that travels precisely through spacetime, just as sound is a mechanical wave that travels through air (we couldn't hear in a vacuum). When spacetime is curved in the presence of a large mass, light propagating through it is forced to follow a path that is also curved. The German theoretical physicist John Archibald Wheeler (1911-2008) put it best: “Matter bends space and space bends material paths, so spacetime tells matter how to move; “Matter tells spacetime how to curve.”
Beatriz Agís Gonzalez She has a doctorate in astrophysics and is a researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC).
Question emailed from Ricardo Gomez Kenny
Coordination and writing:Victoria Toro
We answer is a weekly scientific consultation organized by Dr. Antoni Esteve Foundation and the L'Oréal-Unesco “For Women in Science” program and answers readers' questions about science and technology. They are scientists and technologists, members of AMIT (Association of Women Researchers and Technologists), who answer these questions. Send your questions to [email protected] or on Twitter #nosotrasrespondemos.
You can followTHEME on Facebook, X and Instagram, or sign up here to receive our weekly newsletter.