Do we really like limits, believe in them or can we prove that anything in this universe has its limits . What if we think what we know is the limit ? Limits get pushed sometimes when we know better. Knowledge is supposed to be above opinion. But exactly how far ? Any thing above a collective opinion that is proven or agreed to be proven is knowledge or common knowledge. But today's knowledge becomes tomorrow's opinion if proved otherwise. History , cosmology and biology are victims of such constant imrovements. History can only get more ancient. Biology gets discovered more and we hope to live healthier and longer . The generally accepted limit is cosmology is the speed of light. I think it is the ultimate limit of human perception. What we hear is a opinion , need not be the truth. What we see is perception and need not be the fact. Einstein has shown signs of cracking up as certain anomalies have been observed in relative velocities between clusters. Gravitational lensing is another topic for debate. In swingers or out swingers can get faster . A velocitiy faster than light need not mean that we can revisit the past or go back to the future. Our limit as of now is light. But when we stretch the limits , it is just that the a new limit has been achieved with more one way possibilities. Whether you are a skeptic who thinks time travel is not possible or whether you are an undying optimist trying to make Speilberg come true, the acceptance or rejection springs from an understanding of a bench mark and the possible operations around it. It is squint eyed in my opinion. It is like two mythical neighbours fighting over a compound wall , one disciplined and with in the wall and the other one accepting the same wall but violating . A violation is a violation. If time travel were possible where are the tourists from the future ? I agree with Stephen Hawkings. If you prove that some thing exists above the velocity of light ,like what ECG Sudarshan predicted , you simply stretch your levels of knowledge and exploitation. The neighbour gets into your wall . He is you and you are him and there is no dispute. He couldn't violate with the old barrier for he stands invited and he is you with a stretched boundary. The point is Einstein can get stretched, ECG Sudarshan can be right about Tachyons and Stephen Hawkings cannot visit us from future. He wouldn't care either for he doesn't believe in it. Einstein would still be applicable at and with in the limits of velocitiy of light . We would simply have more . Faster travels, more energy, more cosmology , more technology and more tools . But , history can get deeper as would know more ancient things faster even with out digging . Where there is great future there is ancient history. Outer space is where altitudes determine attitudes. Back home it is attitudes that determine altitudes. When we adopt a counter current philosophy of looking at things from two perceived extremes, truth and fact get better as more precise outcomes since our perception and opinion would have improved. I dont like to look at the ceiling fan when I can look at the sky.