Recent content by Philip7575

Marcus, et al: A few, some, many, most (take your pick) readers of this blog are non-scientists. A deep understanding of many of the questions non-professional people ask requires knowledge of the mathematics behind them. What you dismiss as "pop-sci" is, by necessity, written without any...

Scratching my head. Taking a shower (where I do some of my best thinking) after I posted my question, I realized that part of the problem is the word "observable." When we look (at light or radio waves or X-rays) out into space, we're looking back in time. I forget how far away the...

In an earlier thread--What is space?--a few people indicated that only a part of our universe is observable: Because space is expanding, photons from distant parts of the of the universe haven't had time to get here yet. So that's my next question. Is our entire universe observable? My...

Some of these comments are getting off-track, but that's the nature of any blog. To summarize (at least what's in my head): Our universe is finite but expanding. The space in our universe, for example, the distance between galaxies, is also finite but expanding. Our universe is...

Imax: "2 times infinite is still infinite." To cite Greene again, "In the case of an infinite universe, 'larger' does not refer to the overall size of space, since once infinite always infinite." This is one of the things that led to my initial question. If the universe is infinitely...

phinds: Jeez, I'm an English teacher. How could I possibly have a personal opinion about the cosmological constant or the size of the universe in cubic centimeters? I'm paraphrasing Brian Greene's The Hidden Reality, p. 138 and p. 337 n. 8 and 9. Greene is a professor of physics and...

The--or maybe I should say "our"--universe is infinite? I'm paraphrasing from the Brian Green book, but one of the things we know pretty certainly is that the expansion of the universe is speeding up. That's what Perlmutter et al just got a Nobel Prize for. Researchers have been able to...

I'm reading The Hidden Reality by Brian Greene. Here's his explanation (buried in a note at the bottom of p. 138): "If space were infinitely big, you might wonder what it means to say that the universe is larger now than it was in the past. The answer is 'larger' refers to the distances...

I'm brand-new to this site, an English teacher, certainly not a physicist, but I'd sure appreciate some (gentle) help. The short version of my question: How can the universe expand into infinite space? Are there two kinds of space? The first is the distances between galaxies in our...