Blackholes,distance and time

Is it true that nothing can actually enter a blackhole, because time completely comes to a halt, before anything can touch the blackhole ?
Does The fact that Gravitaional wells are curves mean that Gravity does not reduce proportionately as the distance from a piece of matter that is causing the gravity increases ?
What significance do the Gradients of tangents on a Graviational curve have, do they signify that distance has been shrunk or time has been dilated ?

The above are questions that have been on my mind for a while, and I just wanted to confirm the answers. I could not find the answers of these questions on google.

[edit on 16-8-2005 by siddharthsma]

We don't know.

Also, Black holes may not be gravity..... You see Stephen Hawking puts it in a way

Light Photons have no mass, gravity only affects things with mass, therefor gravity can not affect light, but it does!!!! Also a reason why gravity is a theory and not a law or whatever.

Does gravity affect light? I'm not sure. If memory serves, I think it actually bends the space that the light is travelling through. The light is still travelling in a straight line, but the space it is travelling through is being bent back into the black hole. This causes light to be redirected back into the black hole, even though the light itself never changes direction or velocity.

But a black hole is a star that explodes inwards so I do not know . But I have heard it can pull anything in it ...

Gravity does affect light, in a process called "gravitational lensing." Here's an image of this process at work. It's a larger image, hence the link.
image

You can see how the light from the more distant galaxy bends around the closer galaxy.

This effect was theorized by Einstien's Theory of General Relativity and observed soon after that theory was published. Though not by high quality images such as the one above, but by examing the light of stars as they passed behind the Sun during a solar eclipse. It wasn't until 1980 when there was an image of it in action two quasars.

It is now alos known that there are three types of gravitational lensing; strong, weak, and micro. Strong lensing is where there are visible changes in the image. Weak lensing is only detectable by scrutinizing the image for distortions. Finally, micro lensing is when no change can be seen, but the amount of light that comes through is changed.

Gravitational lensing also comes in handy because the more massive object magnifies the objects that are behind it.

Now, on to other things!

Originally posted by siddharthsma.
Is it true that nothing can actually enter a blackhole, because time completely comes to a halt, before anything can touch the blackhole ?

Time doesn't come to a halt, but it does slow down to nearly zero. I think that as soon as the matter enters the blackhole, its mass joins the blackhole's mass and can be considered to have entered/touched the black hole.

Does The fact that Gravitaional wells are curves mean that Gravity does not reduce proportionately as the distance from a piece of matter that is causing the gravity increases ?

I'm sorry, I really don't understand what you're asking. Could you try and clarify it, please?

What significance do the Gradients of tangents on a Graviational curve have, do they signify that distance has been shrunk or time has been dilated ?

I think that you're asking about gravitational lensing there, and the distance has not been shrunk. I don't believe time would be dialated either. What happens is the light is just bent, or focused, around the more massive object.

Originally posted by James the Lesser
Also, Black holes may not be gravity

Black holes are not gravity. They are an object that has mass. By having mass they also have a gravitational effect on thier surroundings. Gravity is a force.

Originally posted by James the Lesser
We don't know.

Also, Black holes may not be gravity..... You see Stephen Hawking puts it in a way

Light Photons have no mass, gravity only affects things with mass, therefor gravity can not affect light, but it does!!!! Also a reason why gravity is a theory and not a law or whatever.

Ugh, please, don't EVER confuse a theory and law again. If there's one thing you should know, it's that theories and laws are the same thing...it's just a matter of time periods when they changed the language.

Originally posted by T_Jesus
Ugh, please, don't EVER confuse a theory and law again. If there's one thing you should know, it's that theories and laws are the same thing...it's just a matter of time periods when they changed the language.

A theory is something that has a lot of evidence to prove it works, while a law is something has been proven to work every time. And, just for kicks, a hypothesis is an idea that has not been studied scientifically. Most peoples' "theories" are just hypotheses

Gravity is a theory.
Relativity is a theory.

Kepler has his laws.
Kirchoff has his laws.

JTL was right.

Hahaha, oh man.

A scientific theory is the same as a law...I'm a physicist, I think I know the scientific method pretty well...

Scientific philosophers may use different words to try to describe two different words that are actually the same thing. Laws can change if new things are observed, we can't account for every possibility.

Originally posted by T_Jesus
A scientific theory is the same as a law...I'm a physicist, I think I know the scientific method pretty well...

Scientific philosophers may use different words to try to describe two different words that are actually the same thing. Laws can change if new things are observed, we can't account for every possibility.

\

Alright, Mr. Physicist, read through these:

Scientific Laws, Hypotheses, and Theories

Scientific Hypothesis, Theories and Laws

Looks like those, which I found in about 30 seconds of Googling, are against you. Good luck finding links saying otherwise!

Um, actually, you pretty much proved what I said to be correct...

I stand by what I've previously said, as I am schooled enough, and worked enough, to know the difference very well.

I thought a theory wasn't proved, like the big bang and evolution (why is that still a theory?) due to huge debate.

Meanwhile on the part of black holes, I saw a program about it and the experts said they don't know too much about black holes as our physics isn't advanced enough. Considering we haven't sent anyone into one we can't say for sure. Isn't a black hole a dead star which has imploded (or exploded) which has a certain type of gravity field. Isn't it just a hueg gravity field which has some other special characteristics?


MOD EDIT: Removing offensive content

[edit on 8/16/2005 by cmdrkeenkid]

Originally posted by T_Jesus
Um, actually, you pretty much proved what I said to be correct...

Maybe if you had read through the links you would have seen it actually proved you wrong. I guess this just goes to show those eggheads at NAYSAY are just stuck in a rut!

Scientific Laws, Hypotheses, and Theories
A law governs a single action, whereas a theory explains a whole series of related phenomena.

An analogy can be made using a slingshot and an automobile.

A scientific law is like a slingshot. A slingshot has but one moving part--the rubber band. If you put a rock in it and draw it back, the rock will fly out at a predictable speed, depending upon the distance the band is drawn back.

An automobile has many moving parts, all working in unison to perform the chore of transporting someone from one point to another point. An automobile is a complex piece of machinery. Sometimes, improvements are made to one or more component parts. A new set of spark plugs that are composed of a better alloy that can withstand heat better, for example, might replace the existing set. But the function of the automobile as a whole remains unchanged.

A theory is like the automobile. Components of it can be changed or improved upon, without changing the overall truth of the theory as a whole.

You can figure out how the second one proves you wrong by reading it for yourself.

Okay,

A scientist follows the scientific method. Read what the scientific method is, and what the outcome of the scientific method is. You will realize though scientific philosophers enjoy saying there are differences between the two, there really is none by the scientific method.

I know the common thought is that a law is a fundamental expression of nature in a concise equation, but there are plenty of theories that do the same. When was the last time something was stated to be a law? You will see my point is proven - if a law is defined by some as this fundamental expression of nature, then there are theories now that should be reconsidered and named laws because the outcome is short, concise, and proven equations.

That is why it is just a matter of language, basically.

I will sum it up briefly:

If you follow the scientific method, you will always reach the same outcome (which is called a "theory"). You cannot argue that; it's the basis for how we work.

There is one primary difference. Theories may be modified as new information is gained. Laws are not expected to change. The first law of motion, though discovered so long ago, has not been revampted or changed since it became law. On the other hand, the theory of evolution is its self evolving as we gain more information, better dating tools, more fossils by which to study, etc. As more information becomes available, the theory is expected to change. A law is not.

Originally posted by T_Jesus
I will sum it up briefly:

If you follow the scientific method, you will always reach the same outcome (which is called a "theory"). You cannot argue that; it's the basis for how we work.

Let's hope not! That's how we get so much junk science! Failability must have a place in the scientific method, or the whole process is for naught.

Laws aren't expected to change because of the name, theories are expected to change because of the name. Laws have been modified in the past, it's not something new. I stated this before, how long has it been since something (in physics anyhow) has been named a law? A long time...and like I continue to say, it's just a matter of language.

If you follow the scientific method, you will get a theory. Getting to theory status is not easy, that's why there are prior steps...that's why if you ask most astrophysicists, they will say things such as black holes are not science.

What do you consider "junk?"

Hey JJ thanks for backing the science community!

I like the explanation of the light not being effected byt the space it is in. But this leads to the question of if nothing is faster then light then uh, how to put it so it is understandable...

Ok, I think I know. Light photon moving east, gravity affects the space it is in and pulls it north. But how is the gravity able to affect the light? Imagine a car going mach 2, you are going to try and effect it by kicking it, only problem is you can't catch it for it is faster then you. So is gravity "faster" then light? But they say nothing can be faster then light....

Why I love science, so many questions, so few answers, and when you do get an answer it brings about dozens of questions.

But how is the gravity able to affect the light?

Because Light follows the topography of the membrane of space/time. When a gravity well distorts this membrane light which is stuck to this membrane follows the gravity distorted contours in the fabric of space.

For instance imagine you put a bowling ball on your bed, and your mattress is the fabric of Space/Time. It makes an indent. Now take some marbles which represent photons and roll them across the bed, what happens? That the best explanation I've got, so I hope you understand.

Do you read Stephen Hawking? He said the same thing except he used rubber mat instead of mattress. Of course that is a 2d situation, life is 3d.

Take said mattress with bowling ball at one end and marble at other. Drop the marble on the other side of the bed away from the bowling ball, what happenes? The marble isn't pulled towards it, and even when it lands it may not roll if it is far enough away.

Edit:Explained it better when I took a few minutes to think about it.

[edit on 16-8-2005 by James the Lesser]