Jessica Sekelsky

I thought the entire presentation was very interesting and it was one of my favorite talks so far this semester. The most interesting part, in my opinion, was when we talked about how scientists only know about 5% of what everything is and that this matter is what comes from the stars. It is scary to think deeply about what the other 95% of matter is and what it can do.

 

Alicia Skaff

Before coming to class I was looking forward to this lecture because the topic of black holes interests me. Dr. Mathur was very insightful and had a strong interest for his field and the continual progression of the study. I really liked finding out about the horizon of the black hole where it is almost a point of no return. The horizon contains no energy because it is equaled out and the closer you are towards the center, the potential energy drops until there is negative energy. I did not enjoy the topic of how entering a black hole would not just kill or crush you but tear every individual part of you. It just made me think of how many people had to experience that until it was a known fact. Saying that you died from a black hole sounds like a very unique way to go but it would immensely painful and could have been prevented. I also liked Dr. Mathur’s explanation of how in science and the world, everything is sought to be explained but black holes are an exception. Energy is not created or destroyed, just transferred. Once a black hole evaporates,  information just disappears without explanation. Also, knowing we only know 5% of what is out there is more terrifying that knowing we only know about 10% of the depths of our ocean. I wonder how much more of either will be discovered before the big crunch wipes the slate and possibly reboots the world.

Myah Mahayri – Dr. Mathur

I thought it was really cool that Dr. Mathur got the opportunity to meet Dr. Stephen Hawking and worked with a college of Hawking! Fr. Mathur talked about how gravity affects a different kind of star and that a black hole is a collapsed star.

Hawking wrote a thesis on Hawking radiation in 1974. Hawking radiation is the electromagnetic radiation that is emitted by the black holes. Hawking also wrote a thesis in 1975 about a black hole information paradox; This is what made Hawking famous. Each star has different information in it and hawking questioned about what would happen when the star collapses. He said that the information in this said star is still there, but it eventually disappears in the black hole.

If we were able to back in time to look at the universe, we would see the universe as one point; only space but no time. The Hartle-Hawking wave function says that before the big bang, there was no time. Hawking and Hartle claim that the universe was a singularity before the big bang.

It was asked if the universe will keep expanding and Dr, Mathur explained that eventually, the universe will go through a “Big Crunch”, which will start a new big bang.  Dr. Mathus also talked about how previous big bangs and big crunches might have happened but since the information from the stars disappears with black holes, we could never know if we’re in a cycle.   I was surprised to find out that we know nothing about dark energy and dark matter!

Stephen Hawking work summary

Dr. Samir Mathur helped describe the work of Stephen Hawking and his black hole information loss paradox of 1925. Specifically how energy can become zero when many objects are placed near the blackhole. It was very interesting learning more about the work of this famous scientist. Before this lecture, I had never really known about Stephen Hawking’s work. Learning more about his work has given me a greater appreciation for physics.

Claire Lavoie | Dr. Samir Mathur

Stephen Hawking

Movie to watch: The Theory of Everything.

Most of his work was when he was fairly young.  What we’re most impressed with how well he continued to function with his disabilities.

Black Holes: what happens when the stuff in a star runs out? It becomes a white dwarf – no heat left.  The polyexclusion principle holds it up.  Then becomes a neutron star – super heavy but very small.  It keeps shrinking and shrinking and eventually becomes a singularity.  In physics, we couldn’t figure this out.  This smells like a paradigm shift… something that disagrees with our current understanding is making us rethink our approach.

“Anything where something goes wrong and we don’t understand it, we call it a singularity”

What is Hawking most famous for?

  1. Hawking radiation 1974
  2. Black hole information paradox 1975 – there is so much information in a star.  Every star is different.  So when a star collapses, that point still contains all the information the star had.  As it collapses, if you add stuff to it, you can get the energy to be zero, and therefore the mass is zero and all information is lost.

Since 1975 we’ve been trying to find a solution to this problem.

As you come closer to the black hole, you can use the energy to create particles (this is Hawking radiation).  Eventually the black hole evaporates, but all the information is still gone.

Thought from me -> if our universe started as a point, what if before the point existed, there was a different universe that was shrinking?  I think a current theory is that at some point the universe will get too large and collapse in on itself, so what if 1) time is not linear and 2) the universe cycles between being a point and very large, but because of the information loss paradox, it is a different universe every time.

If string theory is true, then none of the black hole stuff we just talked about can be true.

I saw a post on Twitter earlier that said the ocean is scarier than space because there is so much of the ocean we haven’t explored and there are weird creatures.  I don’t think this person truly understands how much we don’t know about space.

We can only explain 5% of everything.

Note to self: look into multiverses. String theory in 9-space dimensions.

If every singularity is surrounded by a horizon where nothing will ever come out, we (and physics) are safe.

The Black Hole Information Loss Paradox

Dr. Mathur spoke about the theory of black holes: that they are formed initially from stars (which are held up by heat), and due to gravity, it continues to shrink and gains density and becomes a white dwarf (which is held up by the Pauli Exclusion Principle). It eventually gains “infinite” density and becomes a singularity, which is the center of a black hole.

In 1974 Stephen Hawking came up with Hawking Radiation and then in 1975 he formulated the black hole information paradox.In this paradox, all of the information about a star  lies in its singularity. If you put a body close to a black hole, you are taking energy out of the black hole, and thus you are decreasing the mass (E=MC^2); eventually, all of the mass of the hole is gone–if this happens, where does all of the information go? According to the Black Hole Paradox, the information is lost. If an electron is placed very close a black hole, the electron will have negative energy. From the energy particles are made, and these particles are known as Hawking Radiation.

I really liked how Dr. Mathur connected Hawking’s black hole theory to the Bing Bang Theory. The earth starting from a singularity is the Bing Bang Theory, and the idea that the earth eventually begins to shrink again into a singularity, is known as the Bing Crunch. Dr. Mathur proposed the question of whether or not the earth actually formed from a black hole? How do we know what we initially started with for anything? The earth starting from a singularity was the Bing Bang, and the idea that the earth eventually begins to shrink again into a singularity, is known as the Bing Crunch.

Theresa Petronzio- Hawking

Dr. Mathur came in to talk to us about Stephen Hawking. He began to tell us a little about black holes, a star will burn and begin to shrink, until it becomes a white dwarf, which is somewhat stable. He also talked about a runaway collapse, which will just become more dense as it shrinks and have more gravity. Then all the mass comes to a single point that is known as a black hole. Singularity kinda means that that thing is infinite, and we don’t really know how to deal with it. Hawking found something called Hawking radiation that lead to a disastrous problem called the black hole information loss paradox, which is what made him famous. Hawking basically discovered that if you put an electron very close to a black hole, its total energy is negative. The particles leaving the black hole are known as hawking radiation. If you make a black hole you basically defy all laws of physics. If you go beyond the horizon of the black hole, this is where you can never come back.  Dr. Mathurs style of presentation kept it pretty interesting. His drawings made it a little easier to understand because I am a visual learner. I also liked that he gave the opportunity for us to ask questions if we had any during the lecture because it broke up the lecture a bit and kept it interesting.

Olivia Wolfe – Dr. Samir Mathur

Dr. Samir Mathur spoke with us in class today about Stephen Hawking and the physics behind his discoveries and black holes. He informed us that Hawking had two main ideas: Hawking radiation, and black hole information paradox. I found it interesting when he talked about the horizon of the black hole and how if something crosses the horizon, it can’t cross back. In addition, another point in particular that raised my curiosity was when he mentioned that the universe eventually came from an infinite point and there was a set starting point for the universe. I feel like there are so many theories about how the universe came about, I find it hard to believe that there can be a set point to start. I feel this might be true, but finding it seems nearly impossible because it’s hard to tell when something starts, most of the time it’s a long time before its actually noticeable. Overall, I liked how he gave us a science presentation and tried explaining it to us instead of just lecturing about the history of the people. I appreciated it, but didn’t like how he spent a long time explaining the big bang theory, then told us it counteracts with string theory and could be all wrong. This lecture left me very confused with all the theories possible.

Emily Bopp’s Commentary on Dr. Mathur

From the start, I enjoyed the topic of discussion for this presentation.  I am fascinated by the works completed by Stephen Hawking.  He was a brilliant individual that showed genuine character despite his health hardships.  His story grasped my attention with the film, The Theory of Everything, which made me sob in a theater more than any other film has.  I am grateful that the film was created though, because it provided me with a greater understanding and appreciation of Hawking’s life and accomplishments.

Going into this lecture I had very little knowledge on the concepts of black holes.  I appreciated that Dr. Mathur took his time and clearly explained some of the basic concepts behind black holes.  He made the concepts much easier to grasp compared to attempting to read articles on the subject matter or even compared to the physics professors that I had at OSU.  I found it really interested that in a time not too long ago, in the 1960s and 1970s, the existence of black holes was heavily debated and only a young concept relatively speaking.  It is fascinating that Hawking was able to bring about a major debate within physics, called the black hole information paradox.  I have great respect for individuals capable of original thought, particularly within science; I doubt that I will ever be able to create a new scientific theory, but I hope that I may live through new discoveries.  I appreciate having a greater understanding of black hole horizons, Hawking radiation, the Big Bang Theory, singularities, etc.  It is interesting that the radiation of particles culminates in the loss of information.  But, what was most intriguing was that Hawking continued to work with science and make it popular in culture, and that he continued to participate in scientific functions until his death.  I believe that that makes him a true scientist.  The one thing that is clear is that at the end of the day we know so little.  I liked Dr. Mathur’s comment that the more we learn, the more confusing the picture becomes.  I agree with this comment.

Olivia Wolfe – Matt Goldish

Matt Goldish spoke with us about history in science, scientists, and their connection with the church. This was interesting to hear because it gave us a different perspective that started with the church being behind some of the scientist’s research. At least this was the case for Nicolaus Copernicus, who discovered that the world revolved around the sun, not the Earth. Even though the church had Copernicus research the calendar, the theories he discovered did not revolt as much against previous ideas with god, whereas Darwin’s theory of evolution, went completely against the church in two ways. Not only was the church not behind the research to begin with, but it also changed what the church was preaching and most of the church’s views. It’s interesting how the different approaches changed how scientists were view and treated.