Random Science Facts Thread!

[Steel]

3 minutes ago, Grand Ship Builder said:

In the scale of the Universe, we are in the very middle. It takes just as much Planck lengths to reach the length of a human brain cell, as it takes brain cells to reach the length of the Observable Universe.

/pedantic{In that case a human brain cell is in the middle, a whole human is a few orders of magnitude larger than the middle}

[Bill Phil]

The mass ratio of the S-IC, the first stage of the Saturn V, without the other stages, adapters, payloads, etc. is about 17. It also had a wet mass of approximately 2286 tonnes, representing a vast majority of the Saturn V's launch mass.

[Streetwind]

This thread seriously needs a rule of "link your source".

Not only are some of the facts presented here interesting enough to make me want to read more about it, but some other facts are plainly unverified hearsay.

Don't be that guy. Cite your sources!  

 

On topic:

The slipperiness of stepping on a banana peel has been scientifically measured. The coefficient of friction is about 0.07. (Source)

[Green Baron]

I would give you 3 likes if i could @Streetwind, for the link, the hearsay and the banana.

 

The only complete Neanderthal skeleton, in Altamura, Italy, yet left in situ because it can't be separated without destruction from the karst it is embedded in, has recently been dated.

Source

If one day it could be retrieved, it would help answer a lot of questions.

Edited November 9, 2017 by Green Baron

[Green Baron]

What we all suspected but did not dare to admit has been proved:

Video gaming changes structures in the brain, and not to the best.

http://onlinelibrary.wiley.com/doi/10.1111/adb.12570/abstract;jsessionid=B003A4C519C369B3E431EF706F1961C6.f02t02

Okay. So be it

[p1t1o]

37 minutes ago, Green Baron said:

What we all suspected but did not dare to admit has been proved:

Video gaming changes structures in the brain, and not to the best.

http://onlinelibrary.wiley.com/doi/10.1111/adb.12570/abstract;jsessionid=B003A4C519C369B3E431EF706F1961C6.f02t02

Okay. So be it

Ha! It specifies "internet gaming" (yeah, you know, that term we all use: "Anyone up for some internet gaming?"), all my gaming is 100% offline, so I must be safe.

***

Anyhoo, random science facts.

Here's some stuff I learned when starting to work for a company that makes concrete and cement related construction products:

 

You cant dispose of a body at a building site by dumping it into wet concrete/cement. It is never (or hardly ever) poured in layers thick enough to submerge a body, usually only a few inches at a time (or a continuous process with a few inches of wet concrete). And anyway, void formation is a known and undesirable phenomenon, and the huge void caused by a decomposing body would be quickly detected by quality control procedures and would never be allowed.

There is a special recipe of concrete specifically for rocket launch pads.

There are concrete recipes that float in water.

Concrete continues to "mature" for a great many decades, and its compressive strength increases as it does so. 

Concrete and cement do not harden as it "dries", the curing reaction is started by water. Some of the water is consumed in the reaction but the concrete/cement can still be wet/damp when fully set. Concrete and cement can cure underwater.

The most produced/used/consumed material in the world, is water. The second is concrete.

[Grand Ship Builder]

2 hours ago, p1t1o said:

 

Anyhoo, random science facts.

Here's some stuff I learned when starting to work for a company that makes concrete and cement related construction products:

 

Also, I heard somewhere that concrete can rot.

[Grand Ship Builder]

On 11/9/2017 at 6:05 AM, Streetwind said:

This thread seriously needs a rule of "link your source".

Not only are some of the facts presented here interesting enough to make me want to read more about it, but some other facts are plainly unverified hearsay.

Don't be that guy. Cite your sources!  

 

I agree highly. But I don't like editing my posts after a while, and sometimes searching things up is evidence enough. But yes, sources are highly recommended.

 

Also:

On 10/26/2017 at 9:47 PM, Grand Ship Builder said:

Sources and more information:

  Reveal hidden contents

1. 

2.

Edit: Dang it, I didn't crop out a single letter, and OCD's killing me. Now this has to be edited 

Edit #2: Lots of trouble over deleting a single letter!!! 

Edited November 10, 2017 by Grand Ship Builder

[p1t1o]

10 minutes ago, Grand Ship Builder said:

Also, I heard somewhere that concrete can rot.

There's a great many things that can degrade concrete, collectively called "rot", I imagine there are even some biological pathways, so literal rot - although a properly formulated concrete for your use should be treated against the major risks. The most obvious is corrosion of the steel reinforcement rebar, as rust takes up more space than the original metal, it expands inside the concrete, causing spallation. One of our major products is a corrosion inhibitor for just this reason.

[ARS]

If you spell every letters when counting numbers starting from 1, you will encounter your first letter "A" in number 1000

[mikegarrison]

5 hours ago, p1t1o said:

There's a great many things that can degrade concrete, collectively called "rot", I imagine there are even some biological pathways, so literal rot - although a properly formulated concrete for your use should be treated against the major risks. The most obvious is corrosion of the steel reinforcement rebar, as rust takes up more space than the original metal, it expands inside the concrete, causing spallation. One of our major products is a corrosion inhibitor for just this reason.

Cathodic protection works pretty well too. But it's not just rust. Hydrogen embrittlement of the rebar can be a problem even if the steel isn't oxidizing.

[Racescort666]

6 hours ago, p1t1o said:

There's a great many things that can degrade concrete, collectively called "rot", I imagine there are even some biological pathways, so literal rot - although a properly formulated concrete for your use should be treated against the major risks. The most obvious is corrosion of the steel reinforcement rebar, as rust takes up more space than the original metal, it expands inside the concrete, causing spallation. One of our major products is a corrosion inhibitor for just this reason.

Kind of related to concrete/cement/steel rebar: carbon fiber composites are extremely susceptible to galvanic corrosion. Without protection, aluminum inserts degrade very quickly. 

Quote

For example, graphite fibers, which are used to reinforce some plastic structure, present a particularly challenging galvanic corrosion combination. The fibers are good electrical conductors and they produce a large galvanic potential with the aluminum alloys used in airplane structure. The only practical, effective method of preventing corrosion is to keep moisture from simultaneously contacting aluminum structure and carbon fibers by finishing, sealing, using durable isolating materials such as fiberglass, and providing drainage. Figure 14 shows the 777 carbon fiber-reinforced plastic (CFRP) floor beam design and corrosion-protection methods. An aluminum splice channel is used to avoid attaching the floor beam directly to the primary structural frame.

 http://www.boeing.com/commercial/aeromagazine/aero_07/corrosn.html

[GoSlash27]

On 10/27/2017 at 7:24 AM, PB666 said:

The Methuselah star has an estimated age older than the Universe.

 This was so baffling, I had to look it up myself. It's true, but what's even more confusing is that it's not even from the first generation of stars.
 Either cosmologists suck at estimating the age of stars that aren't really far away, or they suck at estimating the age of the universe.

Best,
-Slashy

[Green Baron]

5 hours ago, GoSlash27 said:

 Either cosmologists suck at estimating the age of stars that aren't really far away, or they suck at estimating the age of the universe.

 

Well, the measurement uncertainties put the star well within current theories.

From the nasa site about the star:

"Hubble data and improved theoretical calculations were used to recalculate the star's age and lower the estimate to 14.5 billion years, within a measurement uncertainty of plus or minus 800 million years. This places the star within a comfortable range to be younger than the universe."

http://hubblesite.org/news_release/news/2013-08/56-hubble-telescope

The universe can stop scratching its head, its children are all younger than itself :-)

Edited November 11, 2017 by Green Baron

[GoSlash27]

3 minutes ago, Green Baron said:

"Hubble data and improved theoretical calculations were used to recalculate the star's age and lower the estimate to 14.5 billion years, within a measurement uncertainty of plus or minus 800 million years. This places the star within a comfortable range to be younger than the universe."

Green Baron,

 I wouldn't exactly call it "comfortable". The low end of the estimate is 13.7Gy, which is only 100My after the currently accepted age of the universe. Cosmologists place the first stars at 300My after this one, and this is a second generation star.

I think they still got some 'splainin' to do.

Best,
-Slashy

 

[Green Baron]

Uncertainties are no strict limits. They describe were the probability curve gets so flat that it looses significance. The probability curve is computed based on the current knowledge and estimations of the figures that contribute to it. Apparently overlap allows for the above interpretation.

But sure, many theories need refinement and corrections, including measurement of star's magnitudes, colours and relative speeds. And not all processes inside a star are understood in detail, which allows for speculations about their dimming for example, or the rate with which they burn their material.

I surely don't always believe all that Nasa says, but in this case i'd say that the star can still get younger (it was guestimated 16by before) and the universe can get older (even cosmological constants have shown a rate of change in the past ...). I'd rather bet on the star having some leeway for younger dates. *shrug*

Edited November 11, 2017 by Green Baron

[GoSlash27]

3 minutes ago, Green Baron said:

the star can still get younger (it was guestimated 16by before) and the universe can get older (even cosmological constants have shown a rate of change in the past ...). I'd rather bet on the star having some leeway for younger dates. *shrug*

Green Baron,
 FWIW I'm inclined to agree with you. But at the moment, I wouldn't call this disparity "comfortable" (I know, not your words). At *best*, I'd call it "an oddity explainable by error and/ or false assumptions". Either the universe is older than they assume or this star is younger than they assume. Possibly both. But whatever the cause of the discrepancy, they've still got work to do.

Best,
-Slashy

[mikegarrison]

A billion years here, a billion years there, and pretty soon it starts adding up to serious amounts of time.

[Green Baron]

Geology professor in one of the introductory lectures on earth's internal dynamics. The guy was a few months before his retirement and didn't take everything too serious any more. 3 short sentences = 60 million years.

"... the oceanic crust draws from the middle oceanic ridge towards the continent, cooling and getting denser until it is heavy enough to rip off from the continental crust and dive into the mantle. Because it cooler and denser than the surrounding mantle it tears ever more oceanic crust after it, thus closing the ocean, until it gets so heavy that a slab rips off. The overlying continental crust, held down by all the weight, suddenly springs up and there ... you have a mountain range like the Alps."

Edited November 11, 2017 by Green Baron

[Diche Bach]

If it can't be grown, then it must be mined <--sticker on one of my geology profs doors back in the Paleolithic . . .

[kerbiloid]

Spoiler

2 hours ago, mikegarrison said:

A billion years here, a billion years there

How fast time goes...

 

[Brotoro]

I was disappointed to learn that the Higgs mechanism is NOT responsible for neutrinos having mass. And that we don't actually have any explanation for why neutrinos have mass in the Standard Model.

[Steel]

4 hours ago, Brotoro said:

I was disappointed to learn that the Higgs mechanism is NOT responsible for neutrinos having mass. And that we don't actually have any explanation for why neutrinos have mass in the Standard Model.

In fact the Higgs mechanism only really explains why a certain group of bosons have non-zero mass (and some other more subtle, but still important, particle physics things).

EDIT: I'm wrong here, see below

Edited November 11, 2017 by Steel

[Brotoro]

What? The Higgs Mechanism doesn’t give electrons and quarks mass, too? (Not ALL of their mass, of course)

Edited November 11, 2017 by Brotoro

[Steel]

8 minutes ago, Brotoro said:

What? The Higgs Mechanism doesn’t give electrons and quarks mass, too? (Not ALL of their mass, of course)

You're quite right, I was mis-remembering my particle physics! The Higgs mechanism is responsible for some fermion masses too, however the interaction with the Higgs field that results in mass is different for fermions and bosons.