BusaDave9

If it is impossible to make the distinction, why is it so difficult to make people accept that gravity is acceleration ?

No, gravity is not acceleration. Gravity can cause acceleration but they are not the same. I am going to stop short of saying you don't understand relativity because language and expressing yourself can often get in the way and may be your problem. I'd like you hear you explain yourself more thoroughly.

Let me start off by taking a step back and talk about the theory of relativity. Lets say you are in a very powerful spaceship. You blast off and for two months you accelerate so fast you are pressed back against your seat. You finally take some measurements and determine that you are now going faster than 186,000 miles per second (300,000 kilometers per second). EUREKA, you are now going faster than the speed of light! To double check your accomplishment you measure the speed of the light coming from the Sun that you left 2 months ago. This sunlight is passing you up at 186,000 miles per second. Light is passing you up exactly as if you are standing still! How could that be?

Einstein explained this in his General Theory of Relativity. In general (not accelerating) motion is relative. Einstein said that you could consider that you were burning up all that fuel just to maintain your position in the universe. It's plausible that the Earth was the one that was always moving at an extreme speed. Now you are only standing still. After all that effort light is still passing you up as if you are standing still.

But now it looks like we have a contradiction. Back on Earth you made these same measurements and found out that light was passing up Earth as if Earth was standing still. Now you have measured your speed in the spaceship to be in EXCESS of 186,000 miles per second but yet you are still standing still! ?! ? ! How could this be?

Einstein showed in his General Theory of Relativity that speed is relative. He showed that all the dimensions (space and time) are relative. At relativistic speeds these dimensions become distorted (compared to Earth, or whatever you are measuring your 'relative' speed). The length of such a spaceship becomes shorter. Time on this spaceship runs slower. And it's mass would increase. If a spaceship were ever able to reach the speed of light, its length would become zero, time would no longer progress and its mass would then become infinite. Since these three conditions are impossible, it is not possible for any spaceship to reach the speed of light. As the mass of a spaceship increases it takes more effort to accelerate it. It would never be possible for the mass to approach infinity.

So now back to your measurements. You measured that you are moving faster than 186,000 miles per second. Because of the distortions of the dimensions that Einstein predicted you are not really going faster than 186,000 miles per second. That 186,000 miles that you measured is actually only 150,000 miles. And that second that you measured that it took you to get that far was actually almost a minute. So your spaceship is only going 150,000 miles per minute.

But wait a minute. You were accelerating so fast you were pressed against your seat for 2 months. How's that? Well, your mass also increased. It was taking more and more energy to accelerate you. And your mass was pressing harder and harder back against the seat. It was getting extremely hard for the engines to accelerate you and your spaceship.

Because of this increase in mass nothing that weighs anything (mass greater than 0) can ever reach the speed of light. But everything that weighs nothing (such as photons) always travels the speed of light.

Now back to inertia and gravity. In Einstein’s Special Theory of Relativity he said even accelerating motion is relative. If you are spinning and feel centrifugal force you could think of it as if you are standing still and the entire universe is spinning causing the force on you. Also if you are accelerating you could think of the entire universe as accelerating and causing the force on you.

This is Ernest Mach's idea from the 1880s. GR has a Machian "flavour" since Einstein was familiar with Mach's work.

Exactly. EigL gets the cupie doll. Einstein based his Special Theory of Relativity on Mach's Principal. Einstein didn't think Mach brought his principal far enough so Einstein wrote his Special Theory of Reactivity

Really really sure?

Yes, I am really, really sure.

Oh, wait, I have one more thing to say, and this may prevent you from making one more post.

I am really, really, really sure.

Are you sure?

Yes, this is true because the universe is uniform.

This is how the General Theory explains inertia as another manifestation of gravity.

Or put another way, there are gravitational waves all over the universe, going every direction, much like the background radiation. These omnipresent gravitational forces keep everything that is still from moving without an external force applied. These gravitational forces also keep everything that is moving, moving a constant speed unless an external force is applied.

As swansont pointed out, E=mc² refers to the energy within any matter with mass. It is from the Special Theory of Relativity not the General Theory.

Einstein showed us inertia and gravity are two manifestations of the same force. If I am standing still there are billions of stars in front of me. Almost all of them are so far away that each on of them has an infinitesimal affect on my. But since there are billions of them they add up to a strong gravitational force in front of me. But they don't pull me forward because there is just as many stars behind me pulling me backwards. These gravitational forces keep me in my place unless I apply a force to move. Once I start moving I am passing by some matter in the universe but as long as I am going a constant speed there are just as many stars in front of me as behind. For that reason their gravitational force keep me moving the same speed. I just explained inertia as if it was gravity. That's the General Theory of Relativity.

No one is saying masturbation is murder. Out of the people that have replied to this thread, no one is even saying any abortion after conception is murder. What you, iNow, seem to be saying is that defining life is too hard and we shouldn't even have this discussion. Lawmakers look to science to determine laws about abortion. If scientist won't even address the issue of when a fetus is a human life then our laws will be chaotic.

I agree that laws about euthanasia and assisted suicide should not be decided by people that don't even have a voice in the matter. If someones life is dragging on in agony the only ones that should be involved in any decision on assisted suicide should be the immediate family. Not Washington lawmakers. I don't know if we should take the same stance on abortion. Abortion into the 9th month as long as the mother and rest of the family agrees?

The only straight biological answer we can provide is that every freaking cell is alive. And that is quite silly to base policies on. And even that is not quite clear as there is no clear-cut definition for life, either.

But we MUST create policies and laws on when a fetus becomes a human.

People say abortion is murder. We all agree murder is wrong. So when is abortion murder? Anytime after conception? When the fetus is viable? Is abortion always murder? ... never murder?

From a scientific point of view, sounds like everyone is in agreement, the building of a human is gradual process. There is no sudden event that the embryo becomes a human.

For the religious, the gradual building of a human doesn't make any sense. They need a miraculous event that God says "let there be life". Conception makes sense. That's the time they believe that God infuses the fetus with a soul (whatever that is)

Some people believe life begins at conception. It actually begins before that. Every egg cell, sperm cell and blood cell in our bodies are alive. The much more important question in the abortion debate is when does that life become human? Science and federal law say it is a human life when the baby is viable to live outside the mother.

It is true that at conception the egg cell has a complete set of genes but it is not yet a human life. If I were to hire an architect to design a million dollar home but then someone were to destroy those plans, I could not sue for a million dollars. It is not yet a home although the plans show just what the final house would look like.

Albert Einstein NEVER said Time is a dimension!!

Spacetime is 4D.

Uhm . . Yes, he did say time is the 4th dimension. That's his General Theory of Relativity. Time is the 4th dimension. He is the one that coined the word "spacetime" to encompass all 4 dimensions.

You say spacetime is 4D

Space is 3 dimensional and time is the 4th dimension. Together they make up the 4 dimensional spacetime continuum. I don't understand your position and I'm not sure you do either.

Well, what's everyone think?

I think I may come across as an alarmist but I really do think the biggest problems facing planet Earth are all caused by human overpopulation. Problems such as pollution, feeding the humans, global warming, animal environment and extinction, etc. I think the human population has more impact on Earth than all other animals put together. On the other hand, some say humans are the most important animal on Earth and to a certain degree I have to agree.

Don't get all hung up about the gravitational waves. Older theories on gravity can explain the gravitational forces. Even Newton's equations on gravity are still used to put a satellite in orbit. So when you ask about large objects throwing smaller objects out of orbit, yes, even Newton and Kepler knew how this could happen.

You talk about these gravitational waves having an effect far from the source of that gravity. Yes this happens. As a matter of fact Einstein showed, in his General Theory of Relativity, that inertia is actually another form of gravity. Let me explain. If I am standing still there are billions of stars in front of me. Almost all of them are so far away that each on of them has an infinitesimal affect on my. But since there are billions of them they add up to a strong gravitational force in front of me. But they don't pull me forward because there is just as many stars behind me pulling me backwards. These gravitational forces keep me in my place unless I apply a force to move. Once I start moving I am passing by some matter in the universe but as long as I am going a constant speed there are just as many stars in front of me as behind. For that reason their gravitational force keep me moving the same speed. I just explained inertia as if it was gravity.

That's Einstein. Inertia IS gravity.

So what I am saying is I think gravitational waves are confusing your understanding of gravity.

Run for your lives?

Vote now.

I think that religious people are more likely to believe the whole world is for humans. That human life is good and the more people, the better. But I think that is a very anthropocentric position.

I believe the world is very much overpopulated with people. If you fly over the northeastern US, from Boston to New York and beyond you see dense cities that then give way to suburbs but no wilderness, then more dense cities. Flying over the Midwest you see a grid-like pattern of farmlands. All the fertile land is used to feed humans. In the west there is more rocky terrain that can't be farmed. While we can't farm mountainous, rocky terrain we can farm dry areas by piping in water from far away. Farms here look like many circular fields because of the round coverage of the irrigation systems.

Let's compare us to the white tail deer we have here in the US. What if white tail deer were to populate every continent. What if most of them lived in herds of hundreds of thousands, or even over a million deer. They would never be able to find food within such large herds so the deer would take over all the fertile land to grow food. Herds of more than a million would even populate the most desolate deserts (think Phoenix AZ). Populating these deserts would entail bringing water down from the mountains or other places with water. Who in their right mind would say that is not overpopulation? Anyone saying those deer are not overpopulated must believe that deer are so special that there could never be too many.

Broadly speaking we need other life to provide us with novel genetic variations.

So your stance is that the whole world with all it's wildlife are only here for our enjoyment. It any animal does not bring us enjoyment or food it has no purpose?

WOW

I don't know what to say. Hard to believe there are people like Dekan that think any animal that doesn't benifit mankind should be exterminated? ! ? !

One big city over the world? Animals only in parks if they are harmless like ducks in a pond?

That would be hell. I live in Colorado. I love getting out into the mountains and into the "wilderness". There really isn't much wilderness left. I hope to see lots of wild animals when I'm out. Animals such as bear, wolfs and if I'm lucky mountain lions. There is very little danger. No animal hunts down humans for prey.

We humans have overpopulated this world. Earth needs more wilderness.

It doesn't take any faith to believe science. Any detail in science can be challenged and this is how science evolves. Evolution is a fact. Scientist only debate the details now. The issue is you must understand the current scientific theories to debate them. A collage graduate questioning the origin of life doesn't have much credibility. The scientists that are shaping the modern understanding of the origins of life have been studying this for years and they get thier information from the other scientists that have spent thier lives studying this. Then you get a layman saying “how did evolution begin? In our best experiments, we can barely produce a fraction of a protein” You can't expect a scientist to mix up some mud in a test tube and have a single cell crawl out. Look at the timeline of evolution. It takes one million years for a new species to develop. Such as a new finch. The first life was nothing nearly as complex as a cell. It was a self replicating molecule. If it broke, similar atoms could combine to make it whole again. The part that broke off could do the same. It took 2 billion years before a cell developed. It took another billion years for multicellular life to form. As life became more complex it could evolve faster but keep in mind nothing can evolve in the short timeframes we humans are used to. This is why people doubt evolution. They want to see it with their own eyes. We have proof.

Once multi cell organisms evolved evolution was faster (now we are talking 100's of millions of years). Five and six hundred million years ago were the first plants and the simplest animals. That's how far back you have to go to see the connection between plants and animals. 300 million years ago were the first reptiles.

The first and biggest problem that people have that doubt evolution is they fail to understand the timeline.

 

Since theories don't becomes truths, I don't see how they can move beyond belief.

Is gravity a law of nature or "just" a theory?

A law of nature is how reality exists outside of human understanding. A theory is our (human) understanding of reality. When a theory is proven it doesn't become a law of nature.

Gravity is a law of nature. Then Newton came up with his theories on gravity. Later Einstein came up with his (General Theory of Relativity). Did that mean Newton was wrong? No, Newton's equations are till used to put a satellite in orbit.

I like doG's post and I will quote him often. Religion is based on faith. Science is based on facts. That's not to say religions are wrong. The best way to accept both is to say God only works through the laws of nature.

What is the soul?

I don't think it exists. Religion invented the soul. It's supposed to be yourself independent from your body. The soul was invented for the sake of the afterlife. There is no way you could prove the existance of the soul but I'd like to hear a good explanation of what the soul is.

imatfaal, you say the soul "works through molecular activity rates" That's far from the conventional view that your soul can go on to heaven. Your explanatin sounds more like an explanation of the mind. I think the mind is nothing more than the thought processes of the brain.