gisburnuk

Light from the car would certainly not be able to project forward! Why are most of the members saying 'yes'? Light has a velocity constancy which basically means that light has a speed limit. For instance: if I was travelling on a coach at 30 mph and I throw a ball at 5 mph towards the drivers direction, then the overall speed of the ball would equal to 35mph. Light cannot gain any extra velocity unlike the ball described earlier. On what foundation do you think time dilation is based upon?

I read a interesting article in this months issue of scientific american about the production of antiatoms, in particular the antiatom of hydrogen. The research was developed to find out whether their was any flaws in the CPT symmetry, and whether they could implement a new fuel, providing thrust via the anihilation of these antiatoms and atoms. What the particle physicists had to do was to find how to capture antiprotons and positrons seperatly via a trap to make antihydrogen. They first of all needed acess to the CERN particle collider. To produce antiproton, they needed to fire a proton into a copper wire or metal (from memory).And to produce a positron, they needed a isotope (sodium) which emits several high speed positrons. Before they could detect any defects in CPT symmetry (via the analysis of the spectra of antihydrogen) they had to find a way to slow these newly formed antiparticles. The method was to use aluminium sheets and the magnetic and electric inner shell of CERN. Another team of particle physicists also found a easier and cheaper way of producing antihydrogen by using lasers. I am interested to know whether anybody elese had found this article interesting? As far as vehicle engine technology goes, it still remains the same after 100 years! I remain optimistic to see how far the production of antiatoms goes. If particle phycisists found a cheaper and mass productive way of producing antiatoms, we would expand our lazy ideas and imagination, that I hope will one day eventually take our eyes away from fossil fuels and conventionality. Hydrogen fuel cell engines have also remained close to the headlines, but as far as development of hydrogen is concerned, it still remains inefficient and costly. Ion engines is another option, but this is still in its development stage for its use in space probes.

I'm not sure whether I am talking about the same engine here. I heard about NASA producing a engine that works when xenon atoms are ionised when electrons are forced through the xenon atoms (using the Hall effect). The consequence of this is that the xenon atoms are fired out of the exhaust producing a slow yet effiecient thrust.

This topic is controversial and has unfortunately been active in the forum for a while. Does time exist when things are in motion? Or does time exist when their is space? Let's just imagine that a rocket is travellintg at the speed of c (light). To the observor in the ship everything in the ship would remain static including his clock (time dilation). In fact if he was to throw something ahead of him that object including his arm would be exceeding the speed of light, but in reality the observor couldn't due to E=mc2. As we know light is constant and cannot gain extra velocity. So essentially to the observor in the rocket he would find himself unable to move and would be frozen in time, whether as I questioned earlier if time exists through motion?

I have talked about this subject on several occasions to a freind, he beleives that time is a increase in disorder of things or 'entropy'. Trying very hard to picture this idea of objects becoming broken and remaining broken wasn't too hard.Whether this constituded towards his belief that time does exist remained unknown. I cannot express my views on this complicated subject because like 4 dimensions it is hard to picture. Has anybody raised the subject of time dilation and the extended life of muons?

Just to correct that statement, I said the "eye", but I was meant to say the 'brain'!

I read recently that our eyes have what is called a 'colour constancy' which helps us visualise one colour even though the frequencies from that source may change. In other words it prevents us from seeing objects that evolve into a multitude of colours.

I have understood the general concept of electromagnetic waves since I was at school, and now I have delved into the harder part of physics with an extended desire to study astrophysics. I was taught at school that light is within the visible part of the electromagnetic spectrum, and so we perceive light and it's frequencies as colour through light. But what I had failed to recognise was that light doesn't really have a spectrum of colours but a spectrum of frequencies that we perceive as colours. So this had become a shock to me because now I have had to realise that colour is psychological and not physical as we would apprehend. I think schools should point this out very clearly whenever they talk about light as "the visible part of the spectrum". Visible to our mind, 'yes'! But not to an observor in reality.