Cosmos Definition and 88 Threads

Sagan describes this on page 207 of his book (1995 reprint hardback edition). In the context of the page he is discussing accelerating at 1g for half the journey and decelerating the other half for trips to Barnard's Star, the center of the Milky Way and the Andromeda galaxy. Then he talks about...

How the physics and science limit our cosmos observation and link it to speed of light? I could not find any equation, study or science that can support and limit our observation parameters.

How can a single Big Bang be true if matter is disappearing into multiple holes within multiple galaxies throughout the cosmos and no matter how far back into the cosmos scientist look the galaxies are as mature as the galaxy we reside within?What matter will be left exactly to actually...

I was looking for resources on stellar nucleosynthesis, and I found the following seminar, which has been going on since 1990. The 17th Symposium will be 17-22 Sep, 2023 in Daejeon, South Korea. https://www.jinaweb.org/events/17th-international-symposium-nuclei-cosmos...

Based on the fact of observed cosmological redshift, scientists have proposed different ideas to explain. One interesting question is whether gravity does negative or positive work now: According to universe expanding in Big Bang theory (Lemaitre, 1927), obviously gravity does overall negative...

November 3, 2021 2:00 PM – 3:30 PM Online Register https://www.alcf.anl.gov/events/ai-science-atoms-cosmos https://www.anl.gov/event/ai-for-science-from-atoms-to-the-cosmos

What then can happen to the radio signal sent into space? It seems to me that after a while our signal will return to us as an echo, but the return period depends on the frequency of the signal. This corollary does not have a rigorous mathematical proof; an analogy is simply drawn with rational...

Hey everyone, I've watched some youtube videos on special and general relativity. A sentence that I heard over and over again puzzles me. "If I were in a closed space, there would be no way of distinguishing between acceleration and gravity." And there is supposed to be no way of telling how...

Does the term center of mass of universe mean anything? Why why not?

Does anyone know if the accelerating expansion of the universe was measured in more than one direction? Unlike the expansion having no obvious center, it seems like the accelerating expansion would have to point to a “center”. Our galaxy, for example, cannot be accelerating away from a...

what is the speed of Earth as it travels the cosmos,compared with the center of the universe.lets say the big bang starting point.?

Greg Bernhardt submitted a new PF Insights post This article is part of our student writer series. The writer Arman777, is an undergraduate physics student at METU A Journey Into the Cosmos - FLRW Metric and The Friedmann Equation Continue reading the Original PF Insights Post.

Greg Bernhardt submitted a new PF Insights post A Journey Into the Cosmos - The Friedmann Equation Continue reading the Original PF Insights Post.

hello folks. 1.its possible to change simple analog radio device (reciever) to cosmos radio waves reciever or just cosmos radio with relativy small price. if you know how please ilustrate it with images, thank you very much.

Hello everyone, I have been trying to learn as much physics as my little brain can handle in my off time. I have to say this forum has made a world of difference helping me do so. I would like to throw a concept out there at the risk of being told that it's nonsense and fringe science...

According to this paper there are many unanswered questions in cosmology. https://arxiv.org/pdf/1611.03505.pdf Do We Really Understand the Cosmos? T. Padmanabhan Comments: Invited Review; 28 pages; 1 figure Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic...

In Brian Greene's documentary The Fabric of the Cosmos, the thesis of the documentary is that empty space has physical properties even if there are no atoms or molecules in it. As I recall, most of the documentary shows the story of how NASA had a goal of sending a gyroscope up into space to...

In my thread titled "What does cold hydrogen gas emit at 1420 MHz?", physicsforums member blueleaf77 told me the following: "There are three main types of interaction between bound state electrons and photons: absorption, stimulated emission, and spontaneous emission. The first one involves...

The CMS or cosmological background permates the whole universe. It's mentioned so often in study halls and on documentaries that NOTHING can peak further back into the universe evolution beyond the CMS. Just want to hear all of your ideas on how YOU would solve this problem if you were on this...

I'm wondering if time and light(entire spectrum) can only coexist simotanuously. When we look out into the cosmos and see stars they can be many light years away. Because it takes time for light to travel. That may have not been relevant. But what I'm saying is... Time is manipulated by the...

Hello! My name is Brenna Bruce and I am 15 years old. This past year I have discovered my thirst for knowledge about the universe. How it works and what makes it work (to my understanding is explained by mostly physics) are concepts I want to be able to grasp. My question for anyone reading this...

Hello all... I'm a long time electronics and EMR technician... Along with doing much work in photography. The technical end as well as the 'taking pictures' end.. Which I call my major and minor of non-college, but very intensive OJT studies, experience, and diploma equivalents over...

It is said that when an observer look up the sky and observe the cosmos, the further out he looks, the further back in time he sees, allowing him to peer into the past. However, there is a catch, namely, the observation must take place at present time. In other words, a distant object 100 light...

Dark Energy is one of the primitive forces of cosmos, existing since early years after Big Bang and its noted that its still is accelerating the rate of expansion of our universe. My question is that what is the source of this mysteries force?People stay that it existed ever in the universe.So...

For this situation, we consider light as an electromagnetic field traveling in x,y and z coordinate of space (cosmos) and electromagnetic fields are produced by oscillating electric and magnetic field. So can't there be such a similar EM field as proposed by Micheal Faraday?

"The Fabric Of The Cosmos," a four-hour series based on the book by renowned physicist and author Brian Greene, takes us to the frontiers of physics to see how scientists are piecing together the most complete picture yet of space, time, and the universe. With each step, audiences will discover...

Hello, Watching this show for the first time. Just saw episode ten, The Persistence of Memory. When walking through his library of the mind, Carl opens a book that looks like Russell and Whitehead's Principia Mathematica at around 32:45, when talking about hidden logical machinery behind...

The final episode of Cosmos: A Space-time Odyssey, "Unafraid of the Dark", was released today. This marks the completion of the series. Which episode did you like best?

Will the cosmos expand forever or the expansion will stop and then the whole universe collapses to that point of spacetime from which the big bang started? Carroll (2004) shows that this will become clear in a formula that shows the fate of the cosmos: Ω0a^3+(1- ΩM0- Ω)a+ ΩM0=0 This simple...

Looks like the new Cosmos TV series is about to start. We'd like to keep discussions about the series in a single thread, so feel free to post your thoughts and reactions and questions in this thread. I really enjoyed the original Cosmos TV series with Carl Sagan. It was a bit over-done at...

Anyone that has paid attention to my numerous posts, know that I am a self taught, wannabe cosmologist. I've studied numerous cosmology related articles including, high energy particle physics, perfect fluid and quantum metrics related to Cosmology in the form of the FLRW metrics. As a self...

I'm sure many of you remember the original series hosted by Carl Sagan that aired on PBS during the 1980s, and how well it was done. I'm really looking forward to this new version: Cosmos: A Space-Time Odyssey - Wikipedia, the free encyclopedia I have come to respect Dr. Tyson for his deep...

Spacetime 'loaf' according to "Fabric of the Cosmos" From what I learned watching Brian Greene's "Fabric of the Cosmos" episode on Nova, if you look at spacetime like a loaf of bread, then each 'slice' depends on your relative speed compared to another point in the loaf. This I have no problem...

If the universe is a 3 dimensional (plus time) space expanding into something, what is that something? Am I correct in stating that the universe is an infinite eternal space in which the Big Bang happened 13.5 billion years ago, and that the observable cosmos is expanding into this space...

Anyone seen the series Cosmos with Carl Sagan, just finished all of it, what a mind bending experience! Good stuff all the way! Neil degrasse tyson is coming out with a show called cosmos in 2013, perhaps in updated version of the old school show.

this is the music from the trailer of the new Cosmos series : love it Have you got any song of this type? Here's the trailer if you've not watched yet:

Hello everyone. First of all, I'd like to apologize if this isn't the right place to open a new thread. I would like to buy a book or watch a film about the cosmos. I watched Cosmos by Carl Sagan it was really worth watching. However, since I'm going on a vocation in a month, I'd like to order a...

So, I posted this on a philosophy forum... I was in a psychology class and I thought of something while reading "Why does the Earth exist?"... Bear with me here: We know that ... 0=1-1 or also shown as 0= 1 + (-1) In the latter, we know that 0=nothing. So, essentially, one and...

Do electromagnetic waves expand as they travel across the cosmos? e.g. Do the wavelengths of emitted light, from distant galaxies, have longer wavelengths when they reach Earth than they did when they were emitted?

Some astronomers detected flashes of x-ray in the cosmos. They say it can only be possible because matters temperature increases to million degrees to radiate into x-rays, and only objects entering into black hole could radiate x-rays in whole cosmos. How can you detected x-ray radiation from...

As an analogy think about telling someone the story of your childhood and growing up and organizing it in episodes that depend either on how old you were or how big you were, when whatever it was happened---your family moved to a different town, you made some new friends, you started doing...

My cosmology friend and I were watching an episode of NOVA called "The Fabric of the Cosmos" hosted by Brian Greene. I asked if he could further explain the reference to the "fabric of the cosmos". He said, "Space-time has a geometry much like a piece of fabric. Picture our universe being...

http://www.wired.com/underwire/2012/07/pl_macfarlaneqa/ This should be good

In the fabric of the Cosmos by Brian Greene there is an experiment using the example of Mulder and Scully and boxes. It is an analogy to Bell's experiment determining whether articles have definite spin before you measure them. It shows that if they have definite spin before you measure them two...

Question about Brian Greene's wormhole illustration in "Fabirc of the Cosmos" I'm currently watching this show on NOVA narrated by Brian Greene called "The Fabric of the Cosmos". In the first episode, he talks about space and the fact that it has properties. In the second episode, he talks...

If the universe is mathematically based - which it looks increasingly like it is the case - than it would be self consistent to view what we believe are physical objects as actually made from a mathematical structure rather than 'indivisible matter'. That would apply to space itself. Then the...

I want to watch Cosmos again but I worry about its age -- what should I keep in mind when watching?

Homework Statement I am taking a course from the Teaching Company called the "Physics of History". Two statements by the teacher seem in conflict to me as an amateur. 1. The average temperature of the cosmos is about 3 degrees K. 2. Most of the material in the cosmos is in the form of...

On page 56 last paragraph Brian give example of a train paradox where two person have clock and there is two observer on on the train the other outside. They agree to set there clock at 12:00 when they see the light open witch is placed between them. From there perspective each clock will be...

The basic number you hear all the time is that the Hubble expansion rate is 71 km/s per megaparsec So get the google calculator to tell you want actual percentage growth rate that turns out to be. Say over a billion year span of time. Past this blue thing verbatim into the google window...