How does gravity work? | The scientists reply | Science | EUROtoday

Get real time updates directly on you device, subscribe now.

The pressure of gravity is the weakest interplay of people who exist in nature and is what makes two our bodies appeal to with one another. We have all skilled many occasions to launch an object that you’ve got in your hand. What occurs then is that it falls and collides with the bottom. Surely you’ve got heard of Isaac Newton’s apple, which is instructed in regards to the English physicist who was sitting below a tree and noticed how an apple fell to the grass. It is alleged that then he thought why the apple fell, however the moon didn’t. And from there he started his analysis on gravity.

What we knew, what Newton and Galileo recognized is that gravity causes acceleration. The object that was initially nonetheless in your hand falls with acceleration while you cease holding it. As I stated in the beginning, the pressure of gravity is what makes two objects appeal to with one another. And that attraction, or that pressure, relies on two issues: on this case, the mass that has the earth and the mass that has the thing that your hand releases.

It is vital to know that acceleration is impartial of the mass of the physique that falls. If I wish to speed up one thing that could be very huge I’ve to do numerous power, if I’ve to speed up one thing that’s smaller I’ve to make much less power, however the acceleration is identical. This is what Galileo demonstrated when he climbed into the tower of Pisa and threw metallic balls with completely different plenty to show that the descent time is impartial of the mass of the thing that falls as a result of the acceleration attributable to the pressure of gravity is identical. If you marvel why you didn’t drop feathers or tree leaves, the reason is that you simply didn’t have to fret along with the friction impact.

Actually, when one thing falls, the 2 strikes, the earth strikes and the thing that’s falling is moved. What occurs is that the gravity exerted by the small object that falls out of your hand over the immense land could be very small, so we don’t admire it.

The factor modifications once we evaluate two issues with comparable plenty, such because the moon orbiting across the earth. Why would not the moon fall? The clarification is that when it was shaped within the Solar System, the Moon was not nonetheless, it was turning with a pace. That flip is the one that stops it from falling. But it’s the pressure of gravity that’s turning it. It is just like the loop of a cowboy within the rodeo, when it turns it, the loop doesn’t fall. The severity of the Earth on the Moon has the same impact.

What I’ve defined up to now is the physics that Galileo and Newton found. But when Einstein seems on stage, issues change. Einstein’s severity additionally modifies time as a result of, in response to his concept, gravity is an impact of the curvature of space-time. As he demonstrated, when the gravitational area could be very intense, the time passes extra slowly.

If we consider an object that falls out of your hand while you launch it, it appears that evidently it falls in a straight line, however in actuality it isn’t. If we had been in a position to see the small modifications within the values ​​of gravity, we might see that coinciding with them there are small deviations. Although we expect they’re straight strains, in a curved space-time like ours, they don’t seem to be precisely. They are straight tailored to that geometry, similar to while you draw a line on a sphere or on a cylinder.

And one other subject that will curiosity you is the connection between gravity and weight. Your weight is strictly the pressure with which the earth attracts you. If you had been on the moon, your weight could be decrease as a result of as our satellite tv for pc has a a lot smaller mass than our planet, so is the pressure of gravity it exerts. And subsequently, astronauts who’ve the identical mass all over the place, weigh much less on the moon than on earth, as a result of the 2 celestial our bodies do have completely different plenty. You can think about that the particles that kind each our bodies pull the mass of the astronaut, appeal to it, there are much less particles exercising that attraction than on earth, so the pressure of gravity is decrease.

Ruth Lazkoz She is a physician in Physics, Professor on the University of the Basque Country.

Coordination and writing: Victoria Toro.

Question despatched by way of e mail by Francisco Gómez.

We reply It is a weekly scientific workplace, sponsored by this system L’Oréal-Unesco ‘For Women in Science’and by Bristol Myers Squibbwho solutions readers’ doubts about science and expertise. They are scientists and technologists, members of AMIT (Association of Women Researchers and Technologies), those that reply these doubts. Send your inquiries tonosotrasrespondemos@gmail.comor by x #nos we reply.

https://elpais.com/ciencia/las-cientificas-responden/2025-06-14/como-funciona-la-gravedad.html