Wikipedia:Reference desk/Archives/Science/2019 February 7

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

February 7

What happens when you fall asleep in a dream?

Like would you have a dream in a dream? Persononthinternet (talk) 17:49, 7 February 2019 (UTC)

Welcome to the Science Reference Desk. We're here to help you find scientific research resources, but we don't conduct general commentary and discussion here. If you're looking for a place to start, here's a giant list of scientific journals on the topic of sleep psychology and physiology.

From PubMed, I found three interesting review articles, which are usually a good place for a non-expert to start learning about the subject:

• Dream experiences and the neural correlates of perceptual consciousness and cognitive access (2018)
• Cognitive and emotional processes during dreaming: a neuroimaging view (2011)
• Insights into the neural basis of dreaming (2017)

Nimur (talk) 18:25, 7 February 2019 (UTC)

For what a single observer's experience is worth, I myself have on a number of occasions thought that I had awoken from a dream but then realised that I was in fact still dreaming. The horror novel Dreamside by Graham Joyce deals with complications of such situations at length – warning, some might find it disturbing.

I do not remember ever dreaming that, within a dream, I fell asleep and dreamed, but it seems to me quite likely that I have done so but not remembered the double-dream.

The OP, if not already familiar with the concept, might like to read the article Lucid dreaming which has some relevence. {The poster formerly known as 87.81.230.195} 90.217.251.247 (talk) 23:41, 7 February 2019 (UTC)

The experience of waking up is one that we are aware of in our normal conscious thought. Whereas the experiences of falling asleep and dreaming are not. Since dreams usually replay and juxtapose disparate events from waking like, it's quite possible that the dream experience either side of the "waking up episode" is actually the same sort of dreaming, but just about different stuff. It seems quite fair for you to rationalise that it's "quite likely that you have done so but not remembered the double-dream" but, as you admit, it may not be based on your actual experience. But dreams within dreams may happen to many people. As E.J. Mahon (2002) reminds us: "Freud (1900) emphasized that the function of placing a piece of reality in a dream within a dream is an attempt to rob it of its significance and obliterate it." [1]. See The Interpretation of Dreams (1900). Martinevans123 (talk) 09:02, 9 February 2019 (UTC) p.s. maybe we need a new article on "Dream with a dream"?

Here's a 1983 paper by Austin Silber, considering the phenomenon in the context of Freudian psychology in the Journal of the American Psychoanalytic Association you might find interesting: [2]. Martinevans123 (talk) 23:49, 7 February 2019 (UTC)

That article is about as clear as mud. Do you think you could summarize its premise in 25 words or less? ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:21, 8 February 2019 (UTC)

In your dreams, Bugs. {The poster formerly known as 87.81.230.195} 2.122.1.40 (talk) 21:13, 8 February 2019 (UTC)

Sorry, you'd need to book 25 sessions or more. "... a guy walks into a psychiatrist's office and says, hey doc, my brother's crazy! He thinks he's a chicken. Then the doc says, why don't you turn him in? Then the guy says, I would but I need the eggs." - Alvy Singer. Martinevans123 (talk) 21:23, 8 February 2019 (UTC) p.s. maybe it's easier if we just stick with Edgar Allan Poe: [3].

Try this if you want to hear Poe's poem delivered with Germanic existential angst - and a guitar solo?!! PaleCloudedWhite (talk) 23:09, 8 February 2019 (UTC)

I'm tempted to throw out some pure speculation/introspection just for consideration ... bear in mind I have no proof it's true. My feeling is that when you're asleep, you think and feel differently, so you can dream you're asleep or waking up or going to sleep in recognition of that, because it's a straightforward way to interpret the data. Or you can dream that you've had a stroke, or are drunk, or are being digested by parasitic alien algae etc., based on the same data. I think it is fairly common to speak of dreams that incorporate and try to explain external stimuli; this would just be incorporating an internal stimulus? Wnt (talk) 03:50, 11 February 2019 (UTC)

Shattering window in space

I've seen several movies in which shooting or throwing something on the window in space producing a small shatter then spreads and whole window breaks caused by air rapidly escaping into space. I know this happens in fiction. I like to ask: can this also happen in real life? PlanetStar 23:08, 7 February 2019 (UTC)

From STS-113 Space Shuttle Question and Answer Board:

Q: What are the windows in the space shuttle made out of?

A: The windows on the space shuttle are actually made out of aluminum silicate glass and fused silica glass. The orbiter windows are actually three different panes, there's an interior pressure pane because the pressure inside the orbiter is a lot higher than it is in the vacuum of space. We also have an optical pane that's installed in the middle that's about three and a half inches thick and on the outside, there's a thermal pane that protects the inside of the cockpit from the high heats of ascent and reentry.

Aluminum silicate glass is basically the same stuff as Gorilla glass. Not exactly the same, but similar.

If you want to learn a lot more on this topic, read Apollo experience report - spacecraft structural windows]. --Guy Macon (talk) 01:40, 8 February 2019 (UTC)

So the window will not break even when cracked, contrary to the movie? PlanetStar 02:51, 8 February 2019 (UTC)

You might be able to break it with a sledgehammer, and it might take several blows. A large caliber handgun bullet might shatter the inner glass. A .50 caliber rifle[4] would likely go through all three panes. Anything thrown would almost certainly bounce off.

In general, movies about space are about as technically accurate as Road Runner cartoons. --Guy Macon (talk) 03:35, 8 February 2019 (UTC)

Yes. The OP should avoid using "Acme" brand armor-piercing bullets. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:38, 8 February 2019 (UTC)

Thé force on a window isn't actually all that high; the air pressure results in around 1kg per square centimeter so around 5 tonnes spread evenly over the biggest of the ISS windows.

The real problem is that when crysralline glasses lose a little bit of structural integrity, they tend to lose it all. — Preceding unsigned comment added by 2A01:E34:EF5E:4640:40F3:4B31:BBF8:D430 (talk) 07:19, 8 February 2019 (UTC)

No, high-strength glass (and Gorilla glass is the obvious example) works by finding a way to avoid that. Andy Dingley (talk) 11:30, 8 February 2019 (UTC)

Gorilla glass is more resistant to an initial fracture but, due to loss of structural integrity, still suffers from rapid and catastrophic propagation of fractures once they form. — Preceding unsigned comment added by 2a01:e34:ef5e:4640:40f3:4b31:bbf8:d430 (talk • contribs) 17:31, 8 February 2019 (UTC)

For a good explanation of the "hard to break, falls apart when it does break" effect, see Prince Rupert's drop. --Guy Macon (talk) 17:39, 8 February 2019 (UTC)