why do we need gravity to live
Original When I was young, I dreamed about traveling to space and enjoying the wonders of weightlessness. I wanted to eat bubbles of water and bounce off the ceiling. I planned to take a nap on the wall and then play a 360б game of leapfrog. And the back-flips!! Oh, how I dreamed of doing innumerable, flawless back-flips. You see, I have never been particularly aerobatic (falling generally comes much easier to me), but in space, well, it seemed that anything is possible there. And if IБm being honest, I still dream about floating around among the stars. Sometimes, gravity seems like such a drag. But what if it didnБt exist? What if we all woke up one day and discovered that, suddenly, there was no more gravity? Before we embark on this little thought experiment, first, a definition:
Б is a force of attraction that exists between any two masses, any two bodies, any two particles. Gravity is not just the attraction between objects and the Earth. It is an attraction that exists between all objects, everywhere in the universe. Б Let s say you are walking down the road beside a friend. Even though you may not be aware of it, there will be an incredibly slight gravitational attraction between the atoms in your body and the atoms in your friendБs. The same is obviously true for objects that are floating about in space. Really large objects that have a lot of mass (like planets) exist because matter is gravitationally attracted to other matter. In essence, gravity makes matter clump together; it forms the planets and stars and black holesБand everything else that makes life so terribly interesting. Original At the most basic level: gravity is related to mass, which is related to matter. The more matter, the higher the mass; the higher the mass, the higher the gravitational pull. Gravity on Earth never changes because the mass of the Earth never changes. Essentially, huge chunks of our planet arenБt being ripped out from under our feet (which is, I think, generally a good thing). A change in mass great enough to result in a change in gravity isn t going to happen anytime soon (thankfully, a large portion of our planet isnБt going to up and disappear). But let s ignore physics. Suppose that, one sunny day in May, the planet gives off a frightening БPOPБ and gravity. goes away.
Obviously,. You would float; that chair that you are sitting in would float; the device that you are using to read this would float; the desk or table youБre using would float everything (is what IБm getting at here), everything would float. This might sound like a bit of fun. But, unfortunately, we would lose one of our best friends: the Moon. Of course, EarthБs gravity is the only thing keeping the Moon in orbit. Without it, it would float off into space. Oh, and of course weБd all die. The most important things held to the Earth by gravity are the atmosphere and our water. Without gravity, the air in the atmosphere isnБt compelled to stick around, so it would immediately begin drifting off into space. EarthБs oceans, lakes, and rivers would also depart. I imagine that it would be horrifying (and probably a little amusing) to see fish and whales floating in bubbles of water high in the sky. But of course, weБd be drifting off the planet along with them. Fortunately, we wouldnБt have too long to be horrified because, without air and water, none of us would last very long. б But what if there was never any gravity? What if electromagnetism, the strong interaction, and the weak interaction were all exactly as we know them, but the fourth force, the one that pulled together a bunch of rocks to form Earth and keeps us all from drifting off into the cosmos, what if it never existed? Then, for all intents and purposes, there would be no universe. Or rather, the universe would be completely flat and featureless. There would be no stars or planets, no black holes to boggle the mind. No you, and definitely no me. So, as long as we have gravity we canБt fly. But we can existБand thatБs something Gravity, is on a lot of people's minds at the moment. We have all experienced the force of gravity. It is what happens to you when you jump up into the air. Disappointingly for anyone with ambitions to be Supergirl or Superman, we tend to fall right back down to the ground. But what if we could switch gravity off? Physics is adamant that this. But that has not stopped people exploring the idea.
Here, based on the collective wisdom of several experts, is our best guess at what would happen to you if gravity suddenly vanished. Jay Buckey, a physician and one-time NASA astronaut, explored how the absence of gravity affects the human body in a short. Buckey says that our bodies are adapted to an Earth-like gravitational environment. If we spend time living where gravity is different, such as on board a space station, our bodies change. It is now an established fact that astronauts lose bone mass and muscle strength during stints in space, and their sense of balance changes. An absence of gravity brings other problems, as. For reasons not entirely clear, our red blood cell count falls, bringing on a form of "space anaemia". Wounds take longer to heal and the immune system loses its strength. Even sleep is disturbed if gravity is weak or absent. That is just what happens after a short visit to space. "What if you were to grow up without gravity? " Buckey asks. "What about the systems that depend on gravity like your muscles, or your balance system, or your heart and blood vessels? " There is good reason to believe the human body would develop differently. Buckey points to an experiment in which a cat grew up with one eye permanently hidden behind an eyepatch. The cat was rendered blind in the eye as a result. The circuitry that would have connected it to the brain's vision processing regions failed to develop, because the eye was not processing any visual information: a very literal example of the old phrase "use it or lose it". Earth's atmosphere and its oceans, rivers and lakes would be one of the first things to drift away into space It seems likely that the rest of our bodies would respond similarly. If gravity was not around for our hearts, muscles and bones to respond to, our organs would almost certainly develop in different ways. That said, if gravity did get switched off we would have more pressing things to worry about than the long-term effects on human development. , an astronomer at the University of Portsmouth in the UK, has explored the immediate physical consequences of losing gravity on. The first problem is that Earth is rotating at high speed, rather like the way a weight on a string rotates if you spin it around your head. "'Switching off' gravity is analogous to letting go of the string," writes Masters. "Things not attached to the Earth in any other way would fly off into space in a straight line that would take them away from the surface of the Earth. " Anyone unfortunate enough to be outside at the time would quickly be lost.
People inside buildings would be safer, because most buildings are so firmly rooted to the ground that they would stay put even without gravity at least for a while, Masters writes. Anything else not nailed down would also float off. Earth's atmosphere and its oceans, rivers and lakes would be one of the first things to drift away into space. Eventually there would be no clumps of matter, like stars or planets, anywhere in the Universe "Oh, and of course we'd all die,". A lack of gravity would eventually take its toll on our very planet, writes Masters. "Earth itself would most likely break apart into chunks and float off into space. " A similar fate would befall the Sun,. Without the force of gravity to hold it together, the intense pressures at its core would cause it to burst open in a titanic explosion. The same thing would happen to all the other stars in the Universe. However, because they are so far away, it would be years before the light from their death throes reached you. Eventually there would be no clumps of matter, like stars or planets, anywhere in the Universe. There would just be a diffuse soup of atoms and molecules, drifting around not doing anything much. This scenario which just to repeat, could never happen illustrates just how fundamental gravity is to the workings of the Universe. Without it, nothing interesting like planets or BBC websites could ever exist. Oh, and of course we'd all die Gravity is one of four fundamental forces that govern our Universe. The other three are just as crucial. Without electromagnetism and the strong and weak nuclear forces, atoms themselves would fall apart. But gravity is the only one that is truly a household name, which is perhaps why we are so fascinated by ideas like antigravity and why is so exciting, even if it never touches any of our lives directly.
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