{"id":727,"date":"2026-03-23T05:47:21","date_gmt":"2026-03-23T11:47:21","guid":{"rendered":"https:\/\/talesofmanythings.com\/blog\/?p=727"},"modified":"2026-03-23T11:23:57","modified_gmt":"2026-03-23T17:23:57","slug":"falling-forever-why-200-miles-up-feels-like-zero-gravity","status":"publish","type":"post","link":"https:\/\/talesofmanythings.com\/blog\/2026\/03\/23\/falling-forever-why-200-miles-up-feels-like-zero-gravity\/","title":{"rendered":"Falling Forever: Why 200 Miles Up Feels Like Zero Gravity"},"content":{"rendered":"

After I wrote about losing gravity<\/a>, I was asked a great follow-up question: if the Earth is a massive object warping the fabric of spacetime and pulling everything toward it, why do astronauts appear like they\u2019re floating in a giant expensive fish tank?<\/p>\n

If the curvature of space is still there, shouldn’t they just … \u201cthud\u201d?<\/p>\n

The answer is surprisingly simple and a little counterintuitive.<\/p>\n

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The Perpetual Miss<\/strong><\/p>\n

The secret to weightlessness in Low Earth Orbit isn\u2019t that gravity has \u201crun out\u201d. Objects in Low Earth Orbit aren\u2019t free from gravity at all. In fact, gravity at the altitude of the International Space Station is still about 90% as strong as it is on the ground.<\/p>\n

What\u2019s really happening is that the spacecraft, the astronauts and everything inside the space station are in a perpetual state of freefall.<\/p>\n

Imagine throwing a baseball. It travels in a curved path and eventually hits the ground. Now imagine throwing it faster. It travels farther before hitting the ground. If you could throw it fast enough, about 17,500 miles per hour, the curve of the ball\u2019s fall would match the curve of the Earth beneath it. It would keep falling, but never hit the ground. That\u2019s orbit.<\/p>\n

The International Space Station isn\u2019t \u201cdefying\u201d gravity. It is falling toward the center of the Earth at a terrifying speed, but it\u2019s moving forward so quickly that the surface of the planet curves away beneath it at the same rate that gravity pulls it down. The result is a continuous fall around the planet. In effect, the space station is moving forward so fast that it consistently misses the planet.<\/p>\n

And because everything inside the station is falling at exactly the same rate, the \u201cweight\u201d disappears. It\u2019s the ultimate \u201cglitch\u201d in the system: weightlessness is just the feeling of falling without ever hitting the floor. This is a critically important element in understanding how orbital mechanics work.<\/p>\n

It is also important to stress that while you may be weightless in space, you are not massless and your mass still influences things in your immediate vicinity. Think of it this way: the Earth is effectively weightless as it orbits the Sun. It is in a perpetual freefall towards the sun, but moving quickly enough to keep missing it.\u00a0 At the same time, Earth\u2019s mass is not being negated. Even while \u201cweightless\u201d in its fall around the Sun, the Earth still exerts gravity on you as you walk across its surface.<\/p>\n

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Straight Lines in a Crooked Universe<\/strong><\/p>\n

From a relativity perspective, this is even more elegant. In curved spacetime, objects in freefall are actually following the straightest possible path available to them, what physicists call a geodesic<\/em>. So paradoxically, an orbiting spacecraft isn\u2019t being \u201cforced\u201d into a curved path. It\u2019s following the natural geometry of spacetime shaped by Earth\u2019s mass.<\/p>\n

When you are on the space station, you aren\u2019t \u201cturning\u201d in a circle because of a \u201cpull\u201d. You are traveling in the straightest possible path through a universe that has been bent into a curve. To the astronaut, they are flying straight. To the universe, they are circling the drain of Earth\u2019s gravity well. That\u2019s a perspective through the lens of relativity.<\/p>\n

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Faking It: The Vomit Comet<\/strong><\/p>\n

Of course, while we can\u2019t turn gravity off, we\u2019ve gotten pretty good at faking its absence and its presence. You don\u2019t have to go to space to experience this \u201cglitch\u201d.<\/p>\n

NASA\u2019s famous KC-135A aircraft, affectionately known as the \u201cVomit Comet\u201d, creates brief periods of weightlessness by flying in a carefully controlled arc. The plane climbs steeply, then noses over into a downward trajectory that matches the acceleration of gravity. For about 20 to 30 seconds at a time, everyone inside is in freefall together, just like in orbit. For those few seconds, you have successfully faked the absence of gravity. Loose objects hover, water forms floating spheres and your inner ear starts filing complaints.<\/p>\n

At least until the plane pulls up, at which point gravity introduces itself again with twice the normal force as you enter the next arc. And thus the name \u201cVomit Comet\u201d.<\/p>\n

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Do It Yourself: The Spin Cycle<\/strong><\/p>\n

On the flip side, if we can \u201cfake\u201d a loss of gravity, we can also \u201cfake\u201d its presence. We do this through centrifugal force using acceleration, particularly through rotation.<\/p>\n