User talk:Aseyhe

Although some prefer welcoming newcomers with cookies, I find fruit to be a healthier alternative.

Hello, Aseyhe, and welcome to Wikipedia! Thank you for your contributions. I hope you like this place and decide to stay.

• Please sign your name on talk pages, by using four tildes (~~~~). This will automatically produce your username and the date, and helps to identify who said what and when. Please do not sign any edit that is not on a talk page.
• Check out some of these pages:
  • Contributing to Wikipedia
  • Introduction to Wikipedia
  • How to create your first article (using the Article Wizard if you wish)
  • The five pillars of Wikipedia | Cheatsheet of WikiCode

• If you have a question that is not one of the frequently asked questions below, check out the Teahouse, ask me on my talk page, or click the button below. Happy editing and again, welcome! Rasnaboy (talk) 03:57, 29 August 2023 (UTC)[reply]

Why can't I edit some particular pages?

Some pages that have been vandalized repeatedly are semi-protected, meaning that editing by new or unregistered users is prohibited through technical measures. If you have an account that is four days old and has made at least 10 edits, then you can bypass semi-protection and edit any semi-protected page. Some pages, such as highly visible templates, are fully-protected, meaning that only administrators can edit them. If this is not the case, you may have been blocked or your IP address caught up in a range block.

Where can I experiment with editing Wikipedia?

Use the main sandbox or create your own personal sandbox to experiment.

How do I create an article?

See how to create your first article, then use the Article Wizard to create one, and add references to the article as explained below.

How do I create citations?

1. Do a search on Google or your preferred search engine for the subject of the Wikipedia article that you want to create a citation for.
2. Find a website that supports the claim you are trying to find a citation for.
3. In a new tab/window, go to the citation generator, click on the 'An arbitrary website' bubble, and fill out as many fields as you can about the website you just found.
4. Click the 'Get reference wiki text' button.
5. Highlight, and then copy (Ctrl+C or Apple+C), the resulting text (it will be something like <ref> {{cite web | .... }}</ref>, copy the whole thing).
6. In the Wikipedia article, after the claim you found a citation for, paste (Ctrl+V or Apple+V) the text you copied.
7. If the article does not have a References or Notes section (or the like), add this to the bottom of the page, but above the External Links section and the categories:

==References==
{{Reflist}}

What is a WikiProject, and how do I join one?

A WikiProject is a group of editors that are interested in improving the coverage of certain topics on Wikipedia. (See this page for a complete list of WikiProjects.) If you would like to help, add your username to the list that is on the bottom of the WikiProject page.

Expansion of the universe

Very astute word choice in changing "expansion-induced motion" to "expansion-associated motion"! That's a completely safe way of expressing it. And yet...I'm tempted to change it back. Though I didn't labor over that phrase when I added it, this point nags at me: Denying that this motion is expansion-induced seems to imply that it must be intrinsic to the objects that are receding from each other. How then could it be a "valid choice of coordinates" (as stated in the article lead) to describe the Hubble flow as an expansion of space? — HelpMyUnbelief (talk) 04:50, 5 June 2024 (UTC)[reply]

Hi! The key thing to realize is that *expansion of space* is not a physical phenomenon. That's what it means to be a coordinate choice. Suggesting that expansion of space causes things to move apart is like suggesting that if you run north from the south pole, the diverging meridian lines cause your body to be pulled apart.

Physically, cosmic expansion just means that the contents of the universe are moving apart. For convenience, we may choose to describe the positions of those contents with an expanding coordinate system -- but that's a choice we (and not the universe) make. Aseyhe (talk) 01:56, 6 June 2024 (UTC)[reply]

Effect of Expansion on Light

I'm thinking about changing the Expansion of the Universe page to correct the misconception among some physicists that "E=hf" means light loses energy when the universe expands. In reality the "hf" term is only the Power of the light (the per-second energy), not the Total Energy. So while light does lose Power in the expansion of the universe, it does not lose energy. The giants of inflationary cosmology back me up on this. See my short paper with references to Prof Guth (MIT) and Prof Susskind (Stanford) and which includes an example textbook study problem for this:
Physicists Confused by their Own Mathematical Constructs

I wanted to run this past you first before changing it though, since you made a lot of edits to that page. Basically this means that light's energy density drops in the same proportion as matter (${\displaystyle \rho \propto a^{-3}}$). So I was going to fix the section about energy density, and remove the part about ${\displaystyle \rho \propto a^{-3(1+w)}.}$

What do you think? Does my paper (and Prof Guth and Prof Susskind) convince you? Or do you still think that light loses energy in the expansion of the universe?
- Jerry Huth (talk) 17:01, 12 October 2025 (UTC)[reply]

The scaling ${\displaystyle \rho \propto a^{-3(1+w)}}$ is correct. The usual derivation uses general relativity. You can also derive it just using thermodynamic principles. Note that none of the derivations (that I know of) involve E=hf. In any event, this scaling is in accordance with established physics, and if you were to change it, you would be going against established physics -- which is not the purpose of this site. Aseyhe (talk) 17:17, 12 October 2025 (UTC)[reply]

Ok, thanks for looking at this. Do you have a textbook reference for this statement on that page: "For ultrarelativistic particles ("radiation"), the energy density drops more sharply, as ${\displaystyle \rho \propto a^{-4}}$"? Or do you know what kind of textbook would have it, what subject matter or section it would be in, etc? (I live near this university library: https://library.du.edu/)

Thanks,

Jerry Huth (talk) 20:50, 12 October 2025 (UTC)[reply]

For example, Dodelson & Schmidt (2nd ed.) section 2.3. I'd guess most cosmology textbooks should have it though. Aseyhe (talk) 00:04, 13 October 2025 (UTC)[reply]