It’s a staple of scifi, and a requirement if we’re going to travel long-term in space. Will we ever develop artificial gravity?
It’s safe to say we’ve spent a significant amount of our lives consuming science fiction.
Berks, videos, movies and games.
Science fiction is great for the imagination, it’s rich in iron and calcium, and takes us to places we could never visit. It also helps us understand and predict what might happen in the future: tablet computers, cloning, telecommunication satellites, Skype, magic slidey doors, and razors with 5 blades.
These are just some of the predictions science fiction has made which have come true.
Then there are a whole bunch of predictions that have yet to happen, but still might, Fun things like the climate change apocalypse, regular robot apocalypse, the giant robot apocalypse, the alien invasion apocalypse, the apocalypse apocalypse, comet apocalypse, and the great Brawndo famine of 2506.
Not to mention things that’ll probably never happen, things that could not be, in accordance with the laws of nature. Faster-than-light travel, instantaneous teleportation, and the ability to destroy whole planets with a space station laser pointer.
But there’s one future technology, a massive violation of the laws of physics which plays a role in nearly every single book, show and movie you can mention.
I promise you, if authors, screenwriters and directors tried to adhere to the laws of physics with even a shred of accuracy, your favorite scifi would unfold very differently.
I’m talking artificial gravity.
It’s magical. Captain Kirk can actually *stand* on the bridge of the USS Enterprise, and he just stands there. He can sit in the mess and enjoy a pint of Romulan Ale not served in a plastic bag, or go just to the bathroom without a freaky-weirdo suction toilet.
I understand scifi authors are imagineering spaceships like ocean going vessels, yet in space.
That’s where they go wrong.
On Earth, you can stand on the deck of your warship, drink your Romulan Ale from an open topped non-collapsible container, and it’s all thanks to you, gravity. The Earth is pulling the ale towards its center, and it’s stopped by the glass, which is stopped by your meat and skeleton, stopped by your well polished boots, stopped by the plates on the deck of the ship, held up by the rest of a the ship, held up by buoyancy, which all work to keep everything from zipping down to the center of the planet, or at least the floor of the ocean.
Out in space, no gravity. You’ve seen the crew on board the International Space Station.
Once you’re in microgravity, you float around like a balloon. You have to drink and pee into a tube, and one of those involves a vacuum cleaner. Protip: Do not mix up those tubes.
Most importantly, once a spaceship started moving, or undertook evasive maneuvers, everyone would ping pong around like crunchy meaty bingo balls.
Will we ever develop artificial gravity?
The only way to get gravity is with mass. The more mass, the more gravity you get. Without mass, you can’t have gravity.
Before we go any further, there’s no such thing as anti-gravity.
Now that’s out of the way, there are a few ways we can fake it.
The force of gravity that we feel is actually just an acceleration towards the center of the Earth at 9.8 meters per second squared, or 1G.
As Einstein showed us, everything’s relative. If you were in a spacecraft and it was accelerating away from Earth at a rate of 1G, it would feel exactly the same if you were standing on the ground.
This is known as constant acceleration, and if you could somehow power a spacecraft with that much energy, it would be just what you needed.
Want to get to the Moon? Accelerate at 1G for an hour and a half, turn around, and decelerate for the same amount of time. Not only would you get to the Moon in under 3 hours, but you would have experienced Earth gravity the entire time.
Want to fly to Jupiter? It would only take about 80 hours of acceleration, and then 80 hours of deceleration. At the halfway point of this journey, you’re going more than 2,800 kilometers per second, which is close to 1% the speed of light.
Want to travel a light-year? Accelerate for about a year, then decelerate for a year. At the mid-point, you’ll be going the speed of light.
Uh oh. There’s the problem. As you probably know, as you approach the speed of light, it requires more and more energy. And you can’t go faster than the speed of light. So using this method only lets you travel about a light year at a time.
There’s an idea that I’m sure you Arthur C Clarke fans know, which requires way less energy: artificial gravity from centripetal force… spinning.
Take a large enough spacecraft and set it spinning.
Thanks to inertia, free floating objects within the spacecraft, like astronauts, would try to fly off into space, but the hull of the spaceship would keep them inside.
To make this comfortable, you need a ring-shaped spacecraft with a radius of 250 meters. This ring would need to turn about twice a minute for astronauts within the spacecraft to experience 1 G.
Building a spacecraft like this is an engineering challenge, but it’s probably within reach of our current technology.
Something like this would help us explore the Solar System without the health risks of microgravity.
That’s right, not only is microgravity super annoying for trying to pee, but it’ll also ruin you.
Unless we discover anti-gravity, we’ll probably never have the kind of artificial gravity we see in science fiction. It’s going to be huge rotating rings for the foreseeable future, sadly.
What’s your favorite science fiction story that seems to have ignored the problem of artificial gravity? Tell us in the comments below.
There is nothing wrong with rotating donuts.
There is no air resistance in space, so aerodynamics are not a consideration.
Arthur C Clarke got it right.
On that robots apocalypse thing…. http://futureoflife.org/AI/open_letter
To the extent someday we may find gravitons we may find one particle interactions favors creating them and another favorably gobbles them up. Then we can have gravity fields. Not antigravity, just local density of gravitons we can control.
If….
I don’t think we will ever find gravitons. Gravity is a function of space itself. If we think of space as a medium through which we travel (an ether?) than we have to say space is something and not just void. Gravity is a function of the acceleration of this medium. Some particles are effected by the medium, some are not, therefore some particles have mass and others do not. Not only that mass effects the medium as well. Space is not static, it moves, it flows. Especially in the presence of mass. space flows into an object like water down the drain in your bathtub. as it approaches the mass it accelerates, the inertial effects of the space medium cause masses to clump together, their electromagnetic charge causes them to pile up, the more mass clumped together the greater acceleration causing higher gravity. All a black hole is is when enough mass has gathered in one place to where the acceleration of the space medium exceeds the speed of light, light cannot travel fast enough through the medium to escape the accelerated region. You say nothing can travel faster than light, but it is already accepted that during the great inflation shortly after the big bang, space did actually expand many times faster than the speed of light…
But what happens to the space medium when it reaches the center of the mass and gravity reaches zero? That is the question.
Does it slip through some portal into another dimension? Does it cancel itself out? and if it does, where does it go? That question assumes the fabric of space behaves like particles, or mass.
In Einsteins model you can say gravity behaves like space is curved, which would be accurate. But even there space has to be something beside H+W+D+T. There has to be a medium, a fluid. I think we are a victim of our own common sence. We automatically assume but as we can see comparing Cosmology and Quantum mechanics not everything is equal. There are obviously truths in cosmology that contradict truths that are found in Quantum Mechanics and it could very well prove to be a massive waste of time to resolve them. What is true in one realm does not have to be true in another. But where is the boundry? Where does one truth give way to another? Is there only one boundry? Quantum mechanics doesn’t seem to be affected by distance or time, but in our cosmological realm distance and time are the same thing. Quantum mechanics has no use for gravity but in our cosmological universe nothing but a soup of energized perticles exists without gravity.
SIMULATED gravity is a better term. Because it isn’t really gravity, it is something which feels pretty much like it, but with coriolis effects. And if the thingy stops rotating, you’re suddenly weightless. Crucial systems have to be designed to work in both microgravity and whatever g-force, in a simulated gravity spacecraft. Because it might stop! That can’t happen on Earth or any massive body. So there are some differences between gravity and simulated gravity, although you could walk in both, and probably suffer none of the bad health effects of long term microgravity.
Gravity/acceleration are relative. We could call it real gravity if we wanted.
Is inertia and gravity the same force? if not than what is gravity and what is inertia. Inertia is easily explained as the resistance to any change in accereration by a massive object in space.
People like to explain gravity as the attraction of mass in space, but I think that is extremely lacking? How do the mechanics of gravity work? Does on mass send out a particle and when it reaches another mass it turns around and drags it back? The people searching for gravitons would try to make you think so. Is gravity an internal force or an external force? In other words are masses drawn together or pushed together? The mainstream always uses the former as the basis for how gravity works. Like electromagnatism where anything within the magnetic field is either drawn in or repelled depending on charge. We know that gravity does not act like electromagnetism. Electromagnetism is very limited in reach. it has a boundaries. Gravity does not. Although gravity gets weaker the furthewr it gets from the mass, it does continue into infinity.
So what are the mechanics of gravity? The explanation given by Einstein of curved space in the presence of mass works nicely. but it lacks too. We can imagine a greater mass creating a dimple in the fabric of space and any other mass that approaches would naturally roll downhill into the depression. That works in 2 dimensions, well 3 if you include time, but how does that work in 4 dimensions? There is no up or down, only a 3 dimensional warp. That is hard to visualize… So as an object on the surface of another object being suspended there by elctromagnetism we are still traveling this arc toward the center of the larger mass. Are there gravitons that being sent outt from the center of the masses that when they reach the other turn around and drag them back? Should we consider that our own masses is still in motion accelerating toward the center of the larger mass? What is the mechanism? If I am no longer in motion I am no longer accelerating so I should be weightless… unless gravity is actually inertia, that my mass has weight on the surface of another mass because of the resistance to a change in acceleration. I am being pushed toward the center (not drawn) of the larger mass. I am given weight because the elctromagnetic bonds of the molecules of the surface of the earth would allow the electromagnetic bonds of my mass to pass through, but something is passing through and accelerating toward the center of both masses, it pushes my mass against the other mass. If I were on a more massive body the with similar density the acceleration would be greater and if massive enough I would be crushed, my body not having sufficient structure to withstand the acceleration.
So to say inertia is simulated gravity is a misnomer at best.
“Back to the future” is in many Scifi movies. Entropy appears to be the one way gate for such action. What other limitations on going back in time?
Exactly, if you were to formulate some mechanism for backward time travel you would not be traveling into the past, you would only be traveling to an alternate future. but even then the future is already there, the universe doesn’t create itself with each passing nanosecond, the entire past to future is already there, we are just traveling along it on a wave of time. Not to say this is the only wave… there could be many waves like ripples on a pond. Motion and energies are all a byproduct of time and watching as things unfold. Just like a movie, each frame already exists you just haven’t seen it yet, but each planck second is static. it exists unto itself. We ride the wave with the illusion of motion, of change but each point in time is unique unto itself. If there is a wave just ahead of us and another just behind, whoever the observers on those waves would be seeing the exact same present we are, only on a different car on the rollercoaster.
Not only do they have artificial gravity on Star Trek but they have some tech called inertial dampers as well. Otherwise every time the Enterprise goes to Warp whatever, Kirk & co would end up as a warm squishy mess on the rear wall of the bridge, right by the elevator doors. Which may be why they’re painted red.
When the ship accelerates in a certain direction, the gravity plating pulls you and everything else along in that direction. It works at the sub-Quark level so every particle in everything is countered with the same force. It’s controlled with a temporal resolution of 1 step smaller than Planck time.
How about 2 gravitational massez underneath the floor. They rotate so fast against each other that the approach c. Thus their apparant mass increases. It also serves as an enwrgy storage system since these 2 twirling masses pulsate gravity and that energy can be extracted or increased by bombarding this pair by angled burst of energy using conservation of momentum.
I am surprised this statement was made in this article … “The Earth is pulling the ale towards its center …”
No it’s not. The ale is falling along the curved space created by the mass of the Earth.
Sir Isaac Newton and Fraser offer the best explanation presently. Please post your peer reviewed papers showing how the theory of relativity (curvature of spacetime) shows how gravitational fields form. There is no such theory of gravitation. What you may be thinking of is the old fabric of spacetime analogy used by Einstein’s GR proponents who use the analogy to explain how large masses can bend the path of light in a vacuum.
To my knowledge nobody has found a graviton or demonstrated how GR can be used to explain the force of gravity..
A number of us here discussed this in Frasers artice: Is gravity faster than light.
An excellent peer reviewed paper I found discussing this can be found here:
http://metaresearch.org/cosmology/speed_of_gravity.asp
To further clarify what I posted, While Einsteins GR theory can be used in place of Newtons to describe the effect of gravity (more accurately at velocities close to light speed), it does not describe what gravity actually is. So either theory or description could be used for describing things happening on earth (until such time as a theory can explain what gravity actually is, both are approximations of effect and not proof of cause)
Einstein defines gravity as the curvature of space.
According to Einstein, gravity is not a force. To Newton, it was a force. (although not correctly attributed to electrostatics)
According to Einstein’s theory and equations, the Casimir Effect should not exist and would cause an infinite curvature of space. (which obviously is not observed and has never been validated in any experiment or observation).
Even so called gravitational lensing is explained by Plasma Cosmology. http://www.physicsmyths.org.uk/#gravlens
Nikola Tesla on Space Curvature:
“On a body as large as the sun, it would be impossible to project a disturbance of this kind [e.g., radio broadcasts] to any considerable distance except along the surface. It might be inferred that I am alluding to the curvature of space supposed to exist according to the teachings of relativity, but nothing could be further from my mind. I hold that space cannot be curved, for the simple reason that it can have no properties. It might as well be said that God has properties. He has not, but only attributes and these are of our own making. Of properties we can only speak when dealing with matter filling the space. To say that in the presence of large bodies space becomes curved, is equivalent to stating that something can act upon nothing. I for one, refuse to subscribe to such a view.”
– Nikola Tesla
By 1916, Einstein had replaced the old ether in his theory of General Relativity with “curved space-time” itself. Only, this new ‘ether’ is no longer a medium in three-dimensional Euclidean space, but in four-dimensional non-Euclidean (curved) space-time.” It was this idea that was completely unacceptable to Tesla, and he criticized Einstein in the 1930s because of it.
To Tesla, “The Theory of Relativity is just a mass of error and deceptive ideas violently opposed to the teachings of great men of science of the past and even to common sense. The theory wraps all these errors and fallacies and clothes them in magnificent mathematical garb which fascinates, dazzles and makes people blind to the underlying error. The theory is like a beggar clothed in purple whom ignorant people take for a king. Its exponents are very brilliant men, but they are metaphysicists rather than scientists.”
Writing a decade before the explosion of the atom bomb, and ignoring the space curvature data from the 1919 eclipse which supported Einstein’s idea that space was curved around large bodies such as stars, Tesla suggested that the existence of a force field would account for the same mathematical results. Thus, Tesla brazenly concluded, “Not a single one of the relativity propositions has been proved.”
“Supposing that the bodies act upon the surrounding space causing curving of the same, it appears to my simple mind that the curved spaces must react on the bodies, and producing the opposite effects, straightening out the curves. Since action and reaction are coexistent, it follows that the supposed curvature of space is entirely impossible. But, even if it existed it would not explain the motions of the bodies as observed. Only the existence of a field of force can account for the motions of the bodies as observed, and its assumption dispenses with space curvature. All literature on this subject is futile and destined to oblivion. So are all attempts to explain the workings of the universe without recognizing the existence of the ether and the indispensable function it plays in the phenomena.
My second discovery was of a physical truth of the greatest importance. As I have searched the entire scientific records in more than a half dozen languages for a long time without finding the least anticipation, I consider myself the original discoverer of this truth, which can be expressed by the statement: There is no energy in matter other than that received from the environment.”
— Nikola Tesla
“Today’s scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality.”
— Nikola Tesla
Space is not curved, although it is understandable why physicists think that it is.
Remember the “Einstein elevator” example? I’ll modify it a bit. Suppose you are in a large room in remote outer space and free of all significant gravitational influences. A garden hose squirts water out of a wall; the water goes straight across the room. Now lite the rocket engine under the room. The room accelerates. But the water does not. Once it leaves the accelerating garden hose, it is in free space, and is not being acted on by any forces. The room (i.e., the reference system) is still accelerating. Its vertical velocity is changing, and no longer matches the (zero) vertical speed of the water. The water APPEARS to be moving on a curved path, at least to an observer in the accelerating room. If the observer is unaware of the effects of an accelerated reference system, he might say the space is curved.
When I was a kid, we used to play ‘catch’ on a rotating merry-go-’round. The ball would be thrown straight across the center of the merry-go-’round. The path of the ball was actually straight (relative to the ground) but to us, its path was strongly curved, and was very difficult to catch. Of course, the modern explanation of this is equivalent to “space is curved in the vicinity of rotating merry-go-rounds”.
You are sitting on an accelerated reference system (the Earth) when you read this. The Sun is likewise engaged in accelerated motion. The acceleration moves us to a new WHEN rather that a new WHERE. Consequently, this accelerated motion is easy to ignore. Gravitation is moving us “towards” all locations (occupied or not). But we think of the Earth as a fixed reference system, certainly not something that is moving in all directions simultaneously. When starlight passes the Sun, the Sun is moving “towards” the star light, but from our perspective, the starlight is being “deflected inward”.
With radio interferometry “deflections” of MICRO seconds of arc can be detected, even when a radio object, like a quasar, is as much as 90 degrees away from the Sun. The Shapiro time delay is also easily detected. All of this is attributed to space being warped by a massive object.
But it is just a reference system effect. Space is NOT warped at all.
I hate to ruin everyone’s party but spinning a spaceship to create artificial gravity that will be useful DOES NOT work like you think it does. You’re only looking at part of the problem and the second part kills the whole concept.
It only works if you stand still and you don’t move around inside your spinning space wheel. Since you’ll probably want to go somewhere inside your 250 meter spinning wheel, that’s where spinning-for-gravity comes apart.
Think of the way you walk on Earth. Gravity is so weak, every step you take breaks the pull of gravity just enough so you can bring your trailing foot forward. After you bring your trailing foot forward you are relying on the mass of the Earth to pull you back down so you can take your next step. Walking has been described as a controlled fall.
In a spinning wheel the 1-g induced by the angular momentum is no stronger at pulling on your body than the mass of the Earth is. So, when you go to take a step in your spinning wheel the energy in your muscles exceeds the energy of the angular momentum — just like what occurs when you take a step on Earth — except there’s no mass to pull you back down. You’ve nullified your angular momentum, the only thing holding you to the inner surface of your spinning wheel, so you’ll bounce around the inside like a pea in a baby’s rattle.
The only gravity that will work in space is accelerative gravity. Accelerating at 1-g (like in a rocket ship) is identical in every way to inertial gravity (like standing on a mass like the Earth) as stated by Einstein’s Equivalence Principle from 1907 (https://en.wikipedia.org/wiki/Equivalence_principle).
Interesting! However I dont believe the crew would fly around like ping ping balls in random directions from spinning simulated gravity. I believe the opposition of angular momentum you describe would induce an odd lateral direction (the crews mass shifting opposite the angle of momentum)…
Perhaps if a spacecraft could accelerate at 1g for a substantial part of the journey, then decelerate past halfway at 1g and move the crew from the back to the front of the craft then problem solved?
What holds you “down” is your “forward” momentum, tangent to the floor. Like various amusement park rides. You wouldn’t bounce around.
That’s right. The forward or backward momentum of you would cause you to meet up with the curvature of the floor again.
To jump up and remain motionless you’d need to nullify it by running in the opposite direction as fast as the wheel spins. Like an inside-out orbit. Disregarding air friction of course. Then you could float to the center hub area.
I was thinking about this as well. Center of the hub would be effectively ‘weightless’ – in the wheel you’d feel pseudo-gravitation. BUT if the wheel is accelerated along the axis, during that acceleration you’d feel the effects there as well, so you might find yourself with a net pseudo-gravity effect leaning at a 445 degree angle from the ‘floor’ as you perceive it (assuming 1G net from rotation + 1G acceleration along the axis). That’d be pretty tricky to navigate. Either you’d need to engineer the torus to rotate (sectionally) along with the axis acceleration (plausible) or you’d need to strap everyone/thing down during axis acceleration and only permit movement during free flight – which pretty much kills the ‘accel til midpoint, flip and decel’ idea.
Oh, what nonsense. Of course astronauts wouldn’t bounce around. You’re misunderstanding what keeps objects attached to the floor in centrifugal gravity. It’s basically this: if you have a circle and a point inside the circle, all straight lines through that point intersect the circle.
In this case the circle is the curved floor of the spinning space station, the point is an astronaut, and the straight line is the constant velocity trajectory the astronaut would have if they were no longer in contact with the floor.
You can test that centrifugal gravity really does work yourself. Next time you go a fair or carnival, go on the Gravitron ride, take a tennis ball with you and lob it into the air. It will come back down. This is actually how I convinced myself that centrifugal artificial gravity works, when I was a kid and couldn’t quite wrap my head around motion in a rotating reference frame.
The illusion of true gravity isn’t perfect, of course. If you launch yourself off the floor with a mighty leap, so that your velocity changes appreciably from the velocity of the floor, then you won’t land quite where you planned to and you’ll come down at an angle, but you won’t go bouncing around the room out of control. And the bigger the rotating spaceship, the better the illusion.
What happens if you jump so hard you pass by the center axis and crash into the other part of the wheel 180 on the opposite side? Do you skid and get road rash? Not if you roll 180 and start running!
Thank you, now I don’t need to try to explain what you explained. Ball games might get interesting, but movements along the tangent of rotation gives no noticeable difference from real gravity, given long enough (certainly 250 meter!) radius.
Try going for a walk or run in your spinning wheel. In one direction it will feel like you’re going uphill – the faster you walk the more uphill it will feel. Go the other way and it feels downhill. Go fast enough and it will be hard to keep your balance like running down a mountain. Don’t trip or you’ll bounce around a lot before you stop. If you don’t feel like a walk, simply drop a ball towards your feet – does it drop “straight” down – nope. Not quite the same experience as a “normal” gravitational field…
We would not have to simulate it or build big spinning rings if we could somehow get a chunk of really dense matter from say a neutron star. Probably about a 5 gallon bucket would be enough to produce 1 g. Problem then becomes trying to contain that.
That’s an interesting idea, which I have never come across before, although I have been interested in simulated gravity as a casual online connoisseur. Of course containment seems impossible. A bucket of it would be worse than a big fusion bomb as the matter “undegenerates” without the gravity pull of the rest of its star remnant. But compact matter could maybe do the trick in the far future (although reengineering of human biology seems simpler, relatively speaking).
Except that the energy needed to accelerate that mass makes space travel pretty tough to accomplish. And if you get it going, then stopping it…
Of course, if we could develop a way to CREATE that mass density en route, then reduce it at the other end…
Yeah that’s a conceptual problem. But given a certain mass, one would get more surface gravity out of it by compressing it, because the distance to the center of mass decreases. But it’d be alot of luggage for the traveler anyway.
I suppose a spacecraft could get one H of a gravity assist from going close to one of them neutron star remnants. Even more from a halo high speed one. And best of all, an extremely short orbital period binary neutron star (I think crazy astronomers have found with only 12 minutes “yearly” orbit…) If one can deal with very hard X-rays and a magnetic field strong enough to eliminate chemistry and relativistic effects and who knows what else.
“To my knowledge nobody has found a graviton” is correct, but.
A positron (Antimatter electron) does not contain an antigraviton or a graviton.
This is why the antigravity research project at CERN is using antiprotons.
The results of this project will be interesting.
Just wanted to thank all the posters here – UT can have some great articles (thanks Fraser and crew) and pretty epic discussions to get the brain juices flowing… I wouldn’t be half the armchair cosmologist I am today without this site 😉
So, my novel Idea for generating artificial gravity.
Superdense material, say, uranium. Make a ball of it about 20 feet in diameter. Suspend said ball in an electromagnetic field. Pulse said field until the ball rotates at several thousand times earth rotational speed(say around 20k MPH). Boom. Gravitational field.
Obviously, I am just using guestimates on size, density and speed(I aint no science/math guy).
I could be completely off basis, I just feel it could worl.
Artificial or simulated gravity varies from normal gravity in second order effects. In a rotational environment a sideways light beam appears to bend down one way and up the other. In an accelerated elevator (with a constant force driving the acceleration) the “force” of gravity (your weight) appears the same no matter what height you choose (not a function of radius between the centers of mass) from the floor of the elevator. So contrary to theory, one CAN measure and tell the difference between simulated gravities (a force field) and the real thing.
it`s already crazy hot in here…but if we`re having a blast let me try another device. Let`s consider time travel. Consider the space kraft is in fact a time travel machine that only can do is to slow (crete a difference of time) the back part of the ship against the front one. Considering the Universe is expanding fast it means we`re already traveling, so a delta-time between back and front of a ship will create 2 things : one is gravity, and we can use that to drink our wine. But second and most important, we will acquire warp drive, which would be exactly like warping space before the ship and traveling on the wave, but only much cheaper, can be done with zillion times less energy. It will be done simply by using many frequency generators (along the ship) affecting all the atoms of the ship, that will be synced or out of sync so smooth that it will create that very small time shift thowards the front of the ship. Warping space infront of a ship would need a black hole`s energy to be used, wich we all know it`s imposible to obtain…controlling those frequency generators must be very precise, orelse it could tear up the ship (we all know how a spaceship elongates when it enters warp drive)…
Is inertia and gravity the same force? if not than what is gravity and what is inertia. Inertia is easily explained as the resistance to any change in acceleration by a mass in space.
People like to explain gravity as the mutual attraction of masses, but I think that is extremely lacking? How do the mechanics of gravity work? Does one mass send out a particle and when it reaches another mass it turns around and drags it back? The people searching for gravitons would try to make you think so.
Is gravity an internal force or an external force? In other words are masses drawn together or pushed together? The mainstream always uses the former as the basis to gravity. Like electromagnatism where anything within the magnetic field is either drawn in or repelled depending on charge. We know that gravity does not act like electromagnetism. There is no energized field of particles related to gravity. Electromagnetism is very limited in reach but many times stronger than gravity within its field. It has a boundaries. Gravity does not; although gravity gets weaker the further it gets from its host, it continues on into infinity.
So what are the mechanics of gravity?
The explanation given by Einstein of curved space in the presence of mass works nicely, but it lacks too.
We can imagine a greater mass creating a dimple in the fabric of space and any other mass that approaches would naturally roll downhill into the depression. That works in 2 dimensions, well 3 if you include time, but how does that work in 4 dimensions? There is no up or down, only a 3 dimensional warp. That is hard to visualize…
So as an object on the surface of another object being suspended there by elctromagnetism you could say we are still traveling this arc accelerating toward the center of the larger mass. Are there gravitons that being sent out from the center of the masses and when they reach the other, turn around and drag them back? Should we consider that our own masses is still in motion accelerating toward the center of the larger mass? What is the mechanism? If I am no longer in motion I am no longer accelerating so I should be weightless… unless gravity is actually inertia, that my mass has weight on the surface of another mass because of the resistance to a change in acceleration. I am being pushed toward the center (not drawn) of the larger mass. I am given weight because the elctromagnetic bonds of the molecules of the surface of the earth will not allow the electromagnetic bonds of my mass to pass through, but something is passing through and accelerating toward the center of the mass, it pushes my mass against the other mass.
If I were on a more massive body the with similar density the acceleration would be greater and if massive enough I would be crushed, my body not having sufficient structure to withstand the acceleration.
So to say inertia is simulated gravity is a misnomer at best.
But is it a planet?
“To make this comfortable, you need a ring-shaped spacecraft with a radius of 250 meters.”
That would work, but it requires a very big spacecraft! And a lot of design constraints too. If you want to go even bigger, it would work really well with a large cylinder like an O’Neil colony. Sadly, we don’t have that sort of budget right now. 🙁
But there’s a much cheaper way to do it. You can connect 2 small spacecraft with a 500m tether and set them rotating twice per minute about their common center of gravity. This method would be so easy and cheap that we probably ought to use it for the first human Mars missions.
On a return trip from Mars, one might start at 1/3g and gradually ramp it up to 1g during the trip. That way the astronauts would be able to walk on arrival. 😀
LapsedPasifist 2 This would work and I know it could be done its cheap and simple but it looks good on paper and 2 small thrusters would keep it spinning all the way to and from Mars…
Yes, like a bola. Or it could be just one spacecraft at one end of the tether, and an approximately equal mass of fuel & gear at the other end. For travel, you design your ship to split in two.
A rotating bola-style ship (or space station) could have any diameter, so you could have a comfy 1g acceleration with no Coriolis problems, without the need for a large, heavy, expensive ring structure. It would work for tiny spacecraft, or enormous ones, you just need a string.
Dude, know your analogies… Romulan ale was illegal in the Federation. Kirk and friends did enjoy a belt or two anyway, but in the privacy of someone’s quarters, not in the mess.