568 replies to this topic

[Incognitum]

Another question you could ask is when a car is going 55 mph and turns on the headlights, is the light now traveling the speed of light plus 55 miles per hour?

There is no speed for C+55m/h. C can be slowed by an impediment such as air, glass, or gravity, but no force in the universe can make it go faster (according to relativity, QED produces some interesting results that suggest otherwise, but only in certain specially defined circumstances)

[Incognitum]

For number 5, you convert to Fahrenheit.

Soo... 0 degrees Celsius is 32 degrees Fahrenheit.
1/2 of 32 = 16
16 degrees Fahrenheit = approximately -8.6 degrees Celsius.

Nope, that won't work. As I stated earlier:

#5 is a problem with unrigorous language. There is no measure of 'twice as cold' We measure the warmth of things, not their coldness. Just as there is no twice as thin, or three times less wealthy. Where does the thinness scale start? at 300 lb? 800lb? With no concrete and finite starting place for the scale, the increments are indefinable, and multiplication cannot occur.

Switching from Fahrenheit to kelvin solves nothing, because there is a Fahrenheit equivalent for any temperature. The question is where and when is he measuring the first drop to 0, that he can double that drop again tomorrow. Is it twice as cold as yesterday? As 6 months ago? as ten minutes ago? The scale is not defined. It's not a conversion problem. Even if you did transfer to Kelvin and subtract half, you'd be subtracting a nominal amount only since the increments are of different size. It would be a meaningless exercise.

[Cipher22]

Cipher22: you capitulated too quickly.

Are you kidding? I'm 16. Is that actually one of the theories? Besides, nobody knows for sure just what will happen at that speed, even if your spaceship is inside a 'bubble' of antigravity, which we aren't even sure exists....of course, there is the cashmir effect (probably spelled that wrong) but that's not really antigravity.

@Kingmadmushroom: lol You beat me to it. The simple Atheist answer.

Actually I don't really believe God is almighty in the sense that he can intervene in person at any time and fix whatever he wants to. Otherwise we might have world peace, clean energy, and a chicken in every pot. I think he built the world more like a mechanical watch that just needs to be wound up again every now and then. He could still beat me up on the playground after school though.

[bibek.r]

for the question

will your next word be no?

answer is "It can't be"

[bukbonzai]

# This girl goes into the past and kills her Grandmother. Since her Grandmother is dead the girl was never born, if she was never born she never killed her grandmother and she was born.

I always had this problem with Back to the Future.
If he kept his parents from getting together, then he disappeared...but since he was not born, he didnt screw with their meeting...etc etc etfc..

That would probably be the point at which time ripped apart

[nikox66]

i would just like to point out (and correct me if im wrong) that it is first of all impossible to go the speed of light. i know this has been previously mentioned but i felt like reiterating the fact. and also that the speed of light is the fastest you can go. you cant go faster then the speed of light because light has no mass and therefore is going the fastest as is possible. so therefore when you turn on the headlights while going the speed of light, which is impossible anyways, the light would not shoot out ahead of you it would simply keep pace with you. i anxiously await your rebuttal

[Incognitum]

i would just like to point out (and correct me if im wrong) that it is first of all impossible to go the speed of light. i know this has been previously mentioned but i felt like reiterating the fact. and also that the speed of light is the fastest you can go. you cant go faster then the speed of light because light has no mass and therefore is going the fastest as is possible. so therefore when you turn on the headlights while going the speed of light, which is impossible anyways, the light would not shoot out ahead of you it would simply keep pace with you. i anxiously await your rebuttal

You're wrong, that was me correcting you.


The first thing I need to point out is that there are several unique circumstances under which things (information, particles, and light) can travel faster then light, or, perhaps if we're not quite right about things, then at least they seem to. However, at at deeper level, apparently you don't quite grasp what the 'relativity' part of general relativity is all about.

When you state that it is impossible to travel at the speed of light, how do you know if you have? You presumably measure by traveling to a star, but how do you know the star isn't moving? In fact, Hubble's law states that every star in the sky has a recessional velocity. So when you reach your star and check your watch, do you know that you were moving that fast, or might the star have been moving at a rate unequal to that which you thought?

Imagine you are driving in your car at what you think is 55km/h. Now if we want to know how fast you are actually moving we need to know if you are driving east or west, because the earth rotates at a speed of about 1,609km/h which must be accounted for, so your speed is actually 55+/-1,609km/h. But wait, there's more! Now you must ask whether it is day or night, because the earth is flying around the sun at a rate of about 108,000km/h. So your actual speed is 55km/h +/- 1,609km/h +/- 108,000km/h. But we're not done yet, because our solar system is swinging around the galactic center, and our galaxy is speeding away from the point of the big bang. And we cannot discount the possibility of motions other then this we have no way to measure. This is the heart of relativity; there is no fixed place to measure from, so the only metric that has any use is the relative speed between two objects (like your car and the road), not the absolute speed, which is impossible to know, and difficult to guess at.

The speed of light is a constant (in vacuum) relative to all observers. Therefore, if traveling at the speed of light in your car, you and your headlights are at rest *relative to each other*. This means that when you turn your headlights on, the light must shoot out from your car at the speed of light *relative to you*. It is true that to an independent observer not traveling with you, the headlights would seem NOT to emit from the car, because relative to them you are both traveling at an equal rate.

[nikox66]

i completely understand your points and i see the reason in them. i'll also admit yes i have not studied physics and the theories that go along with physics that much, and not nearly as much as you have obviously. but thinking logically and scientifically, the thought that you can go faster then the point at which you have no mass.....it just doesnt make much sense to me. but it only doesnt make sense when i follow the mindset that everything has set rules and there are no outliers. the way you describe the headlights coming out and appearing differently to two different observers completely defies logic and makes it seem to me that rules can be bent, molded to fit the situation so to speak. which is the way i prefer to look at things. but im not sure how radical that train of thought is and how many people would understand/agree with that way of thinking. unless im just completely misunderstanding what you're saying.

[Incognitum]

i completely understand your points and i see the reason in them. i'll also admit yes i have not studied physics and the theories that go along with physics that much, and not nearly as much as you have obviously. but thinking logically and scientifically, the thought that you can go faster then the point at which you have no mass.....it just doesnt make much sense to me. but it only doesnt make sense when i follow the mindset that everything has set rules and there are no outliers. the way you describe the headlights coming out and appearing differently to two different observers completely defies logic and makes it seem to me that rules can be bent, molded to fit the situation so to speak. which is the way i prefer to look at things. but im not sure how radical that train of thought is and how many people would understand/agree with that way of thinking. unless im just completely misunderstanding what you're saying.

I am confused by the way you keep referring to the speed of light as the point at which you have no mass.... As you approach the speed of light your mass increases, it doesn't decrease. And I don't suggest that you or I can go faster then light. It is completely true that we have seen particles pop into being out of nothingness, and then travel back in time to animate themselves before they do. This doesn't mean I am advocating a workable system of either defying the law of Conservation of Mass, or that it is feasible to time travel in anything like a commercial scale. These are laboratory tricks only, but they do prove that the 'absolutes' about our universe do not always hold true. Or to be more precise, that the 'absolutes' which always hold true aren't always the ones we think they are going to be.

On a side note, if you are interested in reading up on these things, I cannot recommend highly enough 'A Short History of Nearly Everything' by Bill Bryson. It is plenty accessible for the general reader, and is I think the most informative book I have ever read, textbooks included. A little more technical, but an excellent reference book is "who's Afraid of Schrudinger's Cat', unfortunately I just moved and not all my books are to hand at the moment so I can't give you the author, also my copy is about 10 years old, so if there's no new addition it may be a little out of date, but a worthy read nonetheless. The book that got me started on this line of inquiry in the first place, 'The Physics of Star Trek' is quite an interesting read; although somewhat shallow on the physics, it is good for stirring an inquiring mind. Any of the Feynman books have great nuggets of physics in them, as well as the zany and enchanting real life antics of Nobel laurite physicist Richard P. Feynman. Although it must be said, most of this physics will be QED and not relativity. A friend of mine who is actually a physicist recommended I read ‘The Fabric of the Cosmos,’ but alas, I have not yet done.

[nikox66]

i might check into that. i say that the speed of light has no mass because i heard that from someone else, i guess he was wrong.but when you say that there are exceptions to absolutes, that confuses me. the very definition of an absolute is that it IS absolute and there are no exceptions. so if what you say about there being exceptions to certain absolutes then it would occur to me that they really arnt the absolutes we think they are, and might need to be refined somewhat. and let me say that if im alot more ignorant then i think i am i realize how frustrating a conversation with me might be and so if that is happening just say so and i'll understand