Why Are Astronauts Weightless?
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Published 2012-05-12
I have been working with Catalyst on ABC1 to bring some Veritasium to Australian TV. In this segment I ask why astronauts in the space station are weightless. The most common answer is because there is no gravity in space. But of course there is gravity in space, especially where the space station is located (only about 400km from Earth's surface). So astronauts still experience a gravitational pull - it's just that they and the space station are in free fall so they are accelerating together towards the Earth. The space station doesn't crash into the Earth because of its orbital velocity - it's going 28,000 km/h so as it falls, the Earth curves away from it.
All Comments (21)
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The trick to flying is fall, but miss the ground.
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"It's not flying, it's falling, WITH STYLE!" -Buzz Lightyear
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"The knack of flying is learning how to throw yourself at the ground and miss." - Douglas Adams
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in the case of something orbiting, the acceleration is perpendicular to the velocity. This means it can change the direction of velocity but not its magnitude. For acceleration to cause a change in speed it must have a component in the same (or opposite) direction to velocity.
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i love knowing the answers beforehand, i feel like a genius because of it
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2) One important thing to consider is that the force of gravity cannot really be felt. The only reason we have a sense of weight is because for the most part, we are all experiencing forces that COUNTER the force of gravity. So when you stand on the ground, you are not feeling the force of gravity, you are feeling the force of the ground pushing you up (usually with an equal and opposite force of gravity). When in free fall, there are no countering forces, so you FEEL weightless. but you're not.
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Play Kerbal Space program, easiest way to understand this.
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As my physics lecturer would say "You are never weightless, you are however, normalforceless. It is this normalforcelessness that you call weightless. You cannot perceive weight"
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I enjoy your videos, thank you for explaining in simple terms. Great Job!!
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Hey, i really like ur videos, u make things easy to understand, can you post a video about cellular systems, no other video can be as helpful as yours!!
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I love the direction this show is going!! I have a feeling I'm going to be a long time subscriber!!
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Wow, love your channel, your doing a great job of explaining science to people, well done :o)
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Veritasium in simulated micro gravity is very creepy :P
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If you are on your way to the moon, you really do reach a point where the Earth's gravity is negligible. Two Earth diameters away from Earth and your weight would be 4% of its present value (and the moon is roughly 30 Earth diameters away)
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Thanks for actually explaining it, instead of doing what everyone else does and saying "It's because you're in freefall!" without giving any explanation whatsoever.
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Really awosome video!! Just perfect. I loved you practising the concept of science-teaching video and bringing it solidly into reality. That was a perfect ,complete scene showing the whole theoritical concept.(Y) APPRICIATE!!
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Such a simple concept, but did not know until I was about 50. Am 70 now. Why in the !&#* didn't one of my teachers back in the 1960s' spend just 3 minutes explaining. And this was when orbiting the earth was BIG news. Thank you Veritasium for filling some of the huge gaps.
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So, would I feel the exact same sensation here on earth if I were to, say, jump off of a building while inside some type of container? The "container" is just there so I don't feel the air resistance.
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Wah animations!!! Productions value +5. Loved it before, love it now. Keep up the great work!
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well the space station is not that much further as a proportion of orbital radius, plus the velocity is inversely proportional to the square root of r so I think the similarity makes sense.
