Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Rabbit Holes Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource You started discussion on universe expansion and gravity as spacetime curvature. Discussion covered effects of earth's rotation on weight, yielding slight weight change. Final question asked why rockets launch with earth's spin, not against it. Description An account of the resource ---are you aware that everything is moving in the universe including space itself?--- I am! It’s a pretty mind-bending reality. Not only is every planet, star, and galaxy in constant motion, but the "fabric" of space-time itself is stretching. Since the Big Bang, the universe has been expanding, meaning galaxies aren't just moving through space—the distance between them is actually growing. It’s a bit like dots on an inflating balloon; the dots stay put, but the surface between them gets bigger. Are you more interested in the physics of why this happens or the dark energy that’s pushing it all apart? You might be sitting still right now - but in reality, you're hurtling through space at unbelievable speeds. Here's what that looks like: Earth's Rotation: You're spinning at around 1,670 km/h (1,040 mph) - just by standing still. Orbit Around the Sun: Our planet zips around the Sun at 107,000 km/h (67,000 mph). Across the Galaxy: And get this - our solar system is racing through the Milky Way at 720,000 km/h (450,000 mph). So next time someone calls you lazy, remind them - you're already on a nonstop cosmic journey. #SpaceFacts #MindBlown #SpaceScience #Universe #Astrophile #Astrophysics ---are you aware that so called gravity is the effect we feel because of earths acceleration on a curved path at a near constant velocity--- That’s a fascinating way to frame it! You’re essentially describing the Equivalence Principle, which was Einstein’s "happiest thought" and the foundation of General Relativity. The Physics of the UniverseThe Physics of the Universe According to Einstein, gravity isn't a "pulling" force like magnetism. Instead: Spacetime is Curved: Mass (like the Earth) warps the fabric of space and time around it. Straight Paths in Curved Space: Objects naturally want to follow "straight" paths through this warped spacetime, called geodesics. The Ground Pushes Back: When you stand on the Earth, you feel "gravity," but what you’re actually feeling is the ground accelerating you upward, pushing you off your natural "straight" path through spacetime. Is it a "Curved Path"? In a way, yes. While the Earth moves in a nearly circular orbit around the Sun, the "acceleration" you feel while standing still on the surface is an upward proper acceleration of 9.8 m/s². Center for Experimental Nuclear Physics and AstrophysicsCenter for Experimental Nuclear Physics and Astrophysics +1 If the ground weren't there, you would be in "free fall"—which Einstein realized is actually the most "natural" state where you feel zero acceleration, even though you appear to be speeding up toward the Earth. The Physics of the UniverseThe Physics of the Universe +1 Does this mean you view the Earth's surface as a sort of "accelerating floor" in a giant elevator? Explain with an Image Visualize gravity as acceleration Create visual Are you interested in how this warping actually slows down time (time dilation) closer to the Earth? ---that would mean everything is under the effect of this including down to the molecular level?--- Exactly. It applies to every single atom and subatomic particle. In General Relativity, gravity isn't a "selective" force; it is the shape of the environment everything exists in. Since every molecule in your body occupies the same warped spacetime, they are all being "pushed" by the earth's surface to stay off their natural, free-fall paths. This leads to some wild consequences: Atomic Clocks: Because gravity (acceleration) is stronger closer to the Earth's center, molecules at your feet actually age a tiny bit slower than molecules in your head. Molecular Bonds: Even the electromagnetic forces holding your molecules together have to work against this constant upward "push" from the ground to keep you from falling toward the center of the Earth. Light Itself: Even though photons have no mass, they still follow the "curve" of space. If you shine a laser horizontally, the beam actually "falls" (curves) toward the Earth at the same rate you would if you jumped off a ledge. Everything—from a grain of sand to a DNA strand—is "accelerating" upward just by sitting still on the ground. Does this make you wonder if weight is just the resistance of your molecules being forced to move against the curve of space? would an object spinning at an equal or greater velocity on earths surface counter to the earths rotation have an effect on this Yes, moving or spinning against the Earth's rotation absolutely changes the "acceleration" you feel, though the effect is surprisingly small at everyday speeds In the "accelerating floor" model, your weight is the measurement of how much the ground has to push you to keep you from falling through it. The Earth’s rotation already "helps" you a little bit by flinging you slightly outward, reducing the amount the floor has to push. Moving Counter to Rotation (Westward) If you move or spin westward (opposite to the Earth's eastward rotation), you are effectively slowing down your speed relative to the center of the Earth. Effect: You would feel a tiny bit heavier. Why: By canceling out the Earth's spin, you lose that "outward fling" (centrifugal force). The ground now has to push you with more force to keep you on its surface. Moving With Rotation (Eastward) If you move eastward at a high enough velocity, you are adding to the Earth's spin. Effect: You would feel lighter. Extreme Case (Orbit): If you reached a velocity of about 7,900 m/s (approx. 17,700 mph), the "outward fling" would perfectly match the downward pull of gravity. At this point, the ground doesn't have to push you at all—you would be in orbit right at the surface, feeling completely weightless. The Scale of the Effect At the equator, the Earth's spin only reduces your weight by about 0.35%. If you weigh 200 lbs, you would gain about 0.7 lbs just by standing still at the North Pole (where there is no spin) compared to the equator. Would you like to see the math on how fast the Earth would need to spin for us to actually fly off the surface? ---Would it be possible to 'cancel out' the gravity on earth, by rotating in ...--- Apr 18, 2019 — If we could speed up the Earth's rotation then yes, that would indeed happen... Right now, the Earth's spin reduces our weight by [physics] If the earth wasn't spinning would we feel the gravity more ... Sep 9, 2016 — If earth was spinning faster, people closer to the equator would feel lighter and no matter what, people closer to poles would be Effect of the Earth's rotation on measurements of g Mar 1, 2021 — The Earth's rotation affects the measured value of g, the acceleration due to gravity. Scales two forces cause centripetal acceler... completing countering earths rotation would still keep you at the same spot? If you mean staying in one spot relative to the stars while the Earth spins beneath you, then no—you wouldn't stay in the same spot relative to the ground. Think of it like a treadmill: The Ground: Moving East at about 1,000 mph (at the equator). You: Moving West at exactly 1,000 mph. To a person standing on the moon, you would look like you're hovering in one fixed point in space. But to someone on Earth, you would be racing across the landscape at supersonic speeds. You’d see the continents, oceans, and cities zip past you "backward" as the Earth rotates away. The Physics of "Weight" in this Scenario: If you achieved this "counter-rotation" (staying still relative to the center of the Earth while the surface slides under you): You'd feel heavier: You would lose the "centrifugal lift" provided by Earth's spin. You'd weigh about 0.35% more than you do now. No more "free ride": On the ground, the Earth's atmosphere and surface carry you along. To counter it, you'd need a massive amount of constant thrust (like a jet engine) to fight the air resistance pushing you East. In short, you’d be "stationary" in the universe's frame, but on Earth, you’d be the fastest traveler on the planet. Do you want to know what would happen to the atmosphere if the Earth suddenly stopped spinning but you kept moving? would u leave the earth with this counter acceleration? No, countering the Earth's rotation would actually make you "stick" to the ground a little harder. To leave the Earth, you need to move with the rotation, not against it—and you have to go much, much faster. Here is why countering the rotation keeps you down: The "Flung" Effect: Because the Earth spins, it's constantly trying to fling you off into space (centrifugal force). This makes you feel about 0.3% lighter than you actually are. Canceling the Spin: If you accelerate westward to perfectly cancel the Earth's eastward spin, you lose that "lift." You are now stationary relative to the Earth's center, so you feel the full pull of gravity without any centrifugal help. You’d effectively gain a tiny bit of weight. To actually "leave" the Earth: You need to achieve Orbit or Escape Velocity. Orbit: You have to move eastward (with the rotation) at about 17,500 mph. At this speed, your "outward fling" perfectly matches the downward pull of gravity. You aren't "leaving" gravity; you're just falling around the Earth forever. Escape: To truly leave the Earth's neighborhood, you need to hit 25,000 mph. By simply countering the Earth's 1,000 mph spin, you're actually moving slower in the grand scheme of things, which just lets gravity hold onto you more firmly. Would you like to see how much faster a plane has to go to "outrun" the Earth's rotation and keep the sun in the same spot in the sky? so countering earths rotation would still leave you on the surface Yes, you’d still be firmly planted on the ground. In fact, you would be more stuck to the surface than you are now. Because you’ve canceled out the "fling" (centrifugal force) of the Earth’s spin, the ground actually has to push up against you with a tiny bit more force to hold you up. To actually leave the Earth, you don't need to counter the rotation; you need to outrun the curve of the Earth. You’d have to accelerate to about 17,500 mph (orbital velocity) so that as you "fall" toward the ground, the Earth curves away beneath you at the exact same rate. At the 1,000 mph needed to counter the rotation, you’re just a very fast traveler staying perfectly still relative to the stars while the Earth's crust slides under your feet. Do you want to know why NASA always launches rockets in the same direction as the Earth's spin instead of against it? ---why not orbit out from the very top or bottom of earth at the poles--- Launching from the poles is actually the least efficient way to get into most orbits because you lose the Earth's "free" rotational boost. Here is why we stick to lower latitudes (closer to the equator) for most missions: The 1,000 MPH "Slingshot": At the equator, the Earth is spinning at about 1,037 mph. When a rocket launches East from there, it "inherits" that speed. At the North or South Pole, the rotational speed is essentially zero. Launching from a pole means you have to provide that extra ~1,000 mph of velocity yourself using more fuel. Orbital Flexibility: From the equator, you can launch into any orbit—equatorial, tilted, or polar—with minimal fuel. However, if you start at a pole, you are physically restricted to orbits that pass over the poles. Changing your "tilt" (inclination) once you're in space is incredibly fuel-intensive, often called the most "expensive" maneuver in orbital mechanics. Logistics and Safety: Building and maintaining a high-tech spaceport in the Arctic or Antarctica is a nightmare. You also need a clear "launch corridor" over the ocean so that falling rocket stages don't land on populated areas.