How fast does gravity travel?

We don't.

What we do know is this:

1. There are ways that are inherently unable to get you to the speed of light. For example, the acceleration of an object having mass will never get you there, because the closer you get the greater your mass becomes. To get to the speed of light you need infinite energy, so getting faster would require more than infinite energy.
2. FTL inherently allows you to set up situations in which you can go back in time and change the past. This is anathema to many people, including physicists.
3. There are things faster than light. Spacetime can expand at a rate faster than light, for example.

However, we do not know for certain that FTL isn't possible for, say, that object having mass mentioned before. What we do know is that it cannot *accelerate* to such a velocity and that it could violate causality if it found another way to get to that velocity.

I thought this was the case for all fruit that grows on trees.

Does that mean it only creates clones of itself? And if it can do so, why would they keep the option of fertilisation around?

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It's the fastest thing that we know of. That's the beauty of science, we can accept new information as it becomes available but for the time engaged all the calculations indicate the light is the fastest known thing.

I recommend reading this reply and the next few in this thread. I find they explained it pretty well.

Light is one of the fastest things. In fact, there are other things that move precisely at the speed of light. These are gluons (tiny particles that hold protons and neutrons together) and potentially gravitons (the particles that would carry the gravitational force if we can merge quantum mechanics with General relativity).

The speed of light isn't actually just the speed of light. It's the speed of anything that does not have mass. Photons are the thing that we often see that doesn't have mass, so it was given the name "speed of light" rather than "speed of gluons".

But the key is that photons are massless. We cannot have things go faster than the thing with 0 mass. Because mass inherently slows things down.

So unless you can find something with negative mass. (We have no real expectation that such a thing exists), everything is moving either at the speed of 0 mass particles, or slower.

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Basically it goes like this:

Our current understanding of physics says there's a maximum speed that anything can travel. This is the speed of causality, which we call c.

One result of the equations we've discovered that gave us this information is that the more mass something has, the harder it is to accelerate, but also that that acceleration gets even harder as it gets going faster and faster. A corollary of this is that if something has no mass, it's super easy to accelerate. In fact, so easy that something without mass literally cannot be still, and it can only travel at one speed: the speed of causality, c.

So we know a) there's a maximum speed limit in the universe, b) anything without mass must always travel at that speed, and c) light has no mass. From that we conclude that light must also travel at that speed, which is why we often call it the speed of light.

We know that on the surface of the Earth, there is a maximum distance you can get from any other object. We could have confirmed this empirically by placing transmitters at points around the world and seeing how far away they were, but we instead we proved it conclusively by showing that the Earth is a sphere, and given the way that distances work, it doesn't make sense for something to be more than 20,000 km away along Earth's surface. If you try to, the object will seem to appear closer behind you, though from the outside we know it just moved across the point opposite you on the Earth's surface.

There's an analogous fact about spacetime. Minkowski space, which seems to be what we live in, does not geometrically allow for something to accelerate above the speed of light. It's not simply something we haven't observed, it's more like trying to get more than 20,000 km away on Earth's surface - the way velocities work in this geometry make that physical action kind of nonsensical. We 'proved' things can't go faster than light by experimentally confirming various effects that we would expect in a Minkowski space like length contraction and time dilation.

It may be that things can go faster than light, but if so it will require new physics, and will mean we don't really live in a Minkowski space, but something that usually behaves similarly but something is different. This is very probably the case, since we know that general relativity is an incomplete theory, but so far no extensions allow for faster-than-light travel either.

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It's more that there is a universal speed limit and light travels at it. because it has no mass.

We do, in fact, have some varieties of seedless apples. They just aren't very popular. There are two main problems:

First, even if the apple is seedless, it's still going to have a core, and people still aren't going to want to eat the core. So making it seedless isn't super profitable. (This problem is even more pronounced in cherries: it's not the seed that people object to, but rather the stone around the seed.)

Second, apples are notoriously hard to breed. The children are nothing like their parents. Basically each tree we plant is a new roll of the dice. The odds that a mutant seedless apple will also have other desirable properties like "has at least a hint of sweetness" and "is not a crabapple" are low.

I think the Romans might have had a decent seedless apple at one point, but, if so, it went the way of the silphium.

Make something heavier and it's tougher to move it.

The more mass something has, the harder it is to keep on making it go faster.

Anything with no mass moves as quickly as anything is able to move.

Light has no mass.

A third fun fact is that the Mythbusters found it plausible that pirate captains could've used eye patches to preserve some darkness sensitivity in one eye, so that they'd be able to see well both above and below deck without having to adjust to the gloom below.

Last time I had the double mono jacks was in 2016. The infotainment was very old, with a small and very low res screen. Didn’t take many long haul flights since then, but I took 4 in 2022 and all 4 planes had single stereo jacks with very good infotainment systems. I still bring the 2 jack adapter for my noise cancelling headphones though, just in case

Yup, I think it's something like 1 in 40000 seeds that will actually yield a palatable variety. Avocado is similar.

A lot of health plans will allow (maybe even encourage) you to see a nutritionist for free. Chat with your GP to see if they can recommend a virtual consultation.

Although the flow is different, the time taken to communicate between merchant, payment processor, issuer are all in the milliseconds, 1 trip increases the time by maybe 5 milliseconds, no one would really notice it.

Aren't apples grafted anyway? I've read that if you plant an apple seed, the fruit from the resulting tree will be nothing like the original apple.

Stone fruit, like cherries, would have nothing to maintain the shape and firmness of the fruit, so a seedless variant would likely not survive to be propagated.

As for apples, I’m sure that if a seedless variant were to appear, it would be propogated

So fun fact, they did just discover a variety of seedless apples very recently. Not sure if they are marketable, but it's a "thing".

The difference here is some fruit can do something called "parthenocarpy", it basically means the plant will produce flowers that aren't fertilized and will still grow into fruit. The resulting fruit, since it wasn't fertilized, will lack the reproductive seeds.

It turns out some plants do this and those are our seedless fruits mostly.

Some plants, like apple trees, don't do this, so we don't get seedless apples.

As for the signal, imagine a clock face with a hand turning very fast, drawing a circle. Divide the clock into 4 sections (like a graph). I'm going to draw a circle around the very center(origin) of the clock. If I want to send a 1, I shall make the signal stronger, and the circle will get bigger. If I to send a 0, my signal gets quieter and lets the circle shrink.

Back to the hand. I have from the time the hand passes 12 to 3 to send a 1 or 0. I send a 1, so my circle in this section is big as the hand passes. My next bit is a 0, so for 3 to 6, my circle curves toward the center. 6 to 9, another 0, so my circle stays in the center. 9 to 12, I want to send a 1, so it curves out. Each time the hand goes around, I send you 4 bits of info, by changing signal strength. (Amplitude modulation... AM)

What if we want to talk faster? Well, I could speed up the hand(clock speed), I could divide the clock into more sections so we get more bits per revolution of the hand, or many other combinations...

But the principal is the same, we agree that some change or other property of the signal means something. We could use a light bulb, a buzzer, flags... So long as we agree on the system. If we use a wire, it is an electric pulse. If we are on wifi, that pulse is from a small radio transmitter. Fiber optic uses light travelling through special cables.

Maybe they mean in the arm rests? That's not required but planes used to have them.