Cosmology and our View of the World
Nature of Time & Black Holes
Lead: Tom Ash & Heather Noyes
Summary by Tavus Begenjova:
“ Why don’t you stay here, and I’ll movie through time.”
As presenters Tom Ash and Heather Noyes started their presentations, it was clear that the goal of the class should be to understand ‘time’ and its meaning to us, human beings. Tom presented different definitions of ‘time’:
• Augustine believes that ‘time’ exists only in human’s
memory as past, present and future.
• Psychological time –brain regulates time
• Time is in clocks; it needs batteries
• Atomic clock – a second created by a vibration in the Universe
Tom then posed the question: What does it mean to lose a second? And he continued by talking about different explanations of ‘time.’ For Newton’s understanding ‘time’ is independent of anythingeverything. It keeps passing no matter what happens on Earth. Others argue that ‘time’ is interdependent with everything. There is always change in everything, and time is dependent on these changes. If all changes stop (brain activities, work, school, etc) then time will stop too.
The presentation continued with diagrams about different understanding of time. These diagrams explained that ‘time’ passes with one speed despite the fact that different people are moving in different speeds. We also learned that ‘time’ does not stop everywhere at the same time, it stops in one galaxy at a time. The diagrams also showed us that even if some countries time zones are different like Europe is a few hours ahead of us while Hawaii is a few hours behind that; however this does not mean that Europe is in the future or that Hawaii is in the past. We can pick up a phone and call someone in Europe at this time. So, there are different time zones relative to the sun, but nothing like future or past. his diagram led to the Tense Time Theory, which is that ‘time’, is expressed through events that happen in the past, present, and future. However, Tense less Time Theory argues that past, present, and future is real, and therefore ‘time’ is the fourth dimension.
Then Heather continued the discussion by talking about the study of genesis, which has three paradoxes:
1. No event can happen without a cause, therefore the universe must have started with a cause, which poses a question about God causing creation. If causes happens all the time, is it possible for God to be creating them all the time?
2. Concept of gravity to explain how universe starts. Our universe might be at a 0 energy. When two planets are infinitely far away from each other gravitation energy is 0. When the planets come closer then the energy is negative, which makes it available for positive energy. So there is negative and positive energy out there, which cancel each other. So no additional energy might be needed to might have started the universe.
3. Time is infinitely divisible, so there is are different time eras that were shorter and shorter, or alternatively time may gets have been slower as it comes closer to the big bang.
The last paradox led to explanation a discussion of Black Holes, and eventually to the final statement that says ‘time’ and space might not represent what we think what it is. Time is not going anywhere.
The first statement was made by Prof. Mobius that ‘time’ to us may be whatever we think experience of time, and this depends on the state of the observer., therefore In reference to the universe time only started when we think it didwith the universe, i.e. with the Big Bang. Then there were many questions and discussions as follows:
Q: What happens to a space ship in a Black Hole? --- A: It crashes!
Q: What happens if we move as fast as the speed of light? – A: Einstein thought about it when he was 16 and wondered how light wave looks like when you move the same speed as the speed of light. It turns out that you are in a steady structure, when you move with the speed of light, so time stops. For a better understanding, the analysis of a surfer was used. A surfer moves with the speed of the wave so to the surfer the surf of the water is steady while for the audience it’s moving. Therefore, everything stops in the Black Hole. One would fall into the Black Hole at the speed of light.
Then the discussion went on about history of different words that are used in scientific discussions, such as: dimension, which is a geometrical size, but used for different explanations many times.
Then the class discussed about what happens to twin boys when one stays on earth and the other goes off to the Universe, but when he returns he finds that his twin brother is much older than he is. Did the twin who went off to the Universe stop time? – No, he did not stop the time. As he gets closer to the speed of light for him seems normal, but when he compares his clock to someone’s clock on earth, he realizes that time for him is slowing down. So it is possible to measure the different flow of time, and this has been tested. , but this is only a theory. However, iIt is impossible to accelerate close to speed of light, because you need as much mass as energy.
So, the class ended in agreeing that time is connected to any change. However, it was clear that different people, even just the people in one single classroom, view ‘time’ differently. Therefore, ‘time’, most of the time, is what we human beings believe what it is.