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This Is The Biggest Myth About Outer Space, According To A NASA Flight Controller

What is the biggest myth about outer space? That there is no gravity in space. People do not have a good understanding of what weightlessness is. They see astronauts floating around inside and outside a spacecraft and reach the conclusion that there is no gravity.

According To A NASA Flight Controller

Anywhere mass and space exist, gravity exists. Gravity is the curvature of spacetime due to the presence of mass. The gravitational influence from the Sun that keeps the Earth in orbit around the Sun is felt equally by the astronauts in space. The gravitational influence from the Earth that keeps the Moon and the ISS in Earth orbit is also felt by the astronauts floating inside and outside the spacecraft. If these influences were not felt, the astronauts would not stay in orbit.

At the altitude the astronauts in the ISS inhabit, the gravitational influence from the Earth is 8.75 m/s^2. That is only about 11% less than the 9.81 m/s^2 felt by you and me, on the Earth’s surface.

They are weightless and appear to float because they are in freefall. A spacecraft in Earth orbit is falling towards the Earth (because of gravity) but also moving forward at a speed high enough that the path traveled isn’t straight down, but instead a curve that circles the Earth.[1] The astronaut is falling and so is their spacecraft. If both are falling, there is no force of one against the other and thus no sensation of weight. We can emulate this freefall here on Earth, in a tall chamber that is pumped to vacuum.

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10 thoughts on “This Is The Biggest Myth About Outer Space, According To A NASA Flight Controller

  1. Astronauts are not feeling the gravitational forces, they are experiencing the influence of gravitational forces.

  2. That’s actually not true. The astronauts and space station are not “falling”. The reason the experience weightlessness is because at the altitude where they are orbiting the earth, the centripital acceleration (acceleration caused by circular motion, and directed away from the center of the circle) is equal to the acceleration cause by gravity. This is a state know as Dynamic Equilibrium. Dynamic because they are in motion, but still equilibrium because the sum of all forces/accelerations is zero.

    1. When I fire a rifle so that the bullet initially travels parallel to ground, it falls to the ground. Falling is a response to the gravitational force. If the bullet velocity were experimentally increased in successive firings, eventually it would be able to orbit. Gravity will make the travel path curve in every case. Seems like falling to me.

  3. Thank you Einstein. I’ve missed the guy at college who always sat in the front row and would take it upon himself to explain the concepts described by the professor to us lesser beings who sat in the back because we had already figured it all out !

  4. Where to start? So many errors! They are falling. The forces on the astronought are not balanced. Centripetal force is always into the centre. Start with Newton’s first law. A car going around a corner that hits black ice will go straight ahead at a constant speed. This requires NO force. On the other hand, to deviate from this straight path to go in a circle (like an orbiting astronought) requires a force towards the centre of the circle (the CENTRipetal force.). This is an unbalanced force that causes the continual free fall acceleration. It is not in dynamic equilibrium. So yes, the astronoughts are comtinually falling from the straight line path they would otherwise take.

  5. Both these comments are wrong. They absolutely are experience gravity. At this point in my our understanding of it, gravity is the warping of spacetime around a mass. If the earth suddenly disappeared, spacetime would flatten back out at the speed of light and after that, the astronauts would continue at their current velocity in a straight line, being no longer in curved spacetime.

  6. So technically does that mean the universe is falling ? So when they say the universe is expanding we are technically moving in a direction that makes it so we can never go back to a point we once were in that path of falling? Are we held in place in our galaxy by a black hole at the center of our universe? If it’s a black hole in the center of our universe, why is it depicted as always being so bright? Now, in the grand scale of things, I imagine the earth and our solar system is like the ISS , and we are floating/falling, in relation to the center of the galaxy milky way ( which would be paralleled to earth ) and that’s why we stay where we are in the milky way? It makes sense but I dont know how to word my question lol.

  7. That is true. Anything in orbit is falling forward what it is orbiting. But because their is forward momentum they keep missing and keep falling over and over.

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