Random Science Facts Thread!

[Camacha]

On 05/11/2017 at 2:59 AM, mikegarrison said:

Notice that they had to build something that looks entirely unlike a bicycle in order to generate their effect, and even in the article you quoted they admit normal bikes can be made unstable by reducing trail.

You're not getting the gist of the article. The effect I was talking about works on basically every bicycle. They just built a strange bicycle to show the effect being fully capable of keeping it upright without the two other effects acting upon it. The effect is not uniquely generated by their model, it's just isolated in it.

I'm not sure why you insist on mentioning trail. I just noted that an thus far unknown effect has recently been discovered, which is correct. No one was talking about trail, nor disputing it.

[magnemoe]

1 hour ago, Camacha said:

You're not getting the gist of the article. The effect I was talking about works on basically every bicycle. They just built a strange bicycle to show the effect being fully capable of keeping it upright without the two other effects acting upon it. The effect is not uniquely generated by their model, it's just isolated in it.

I'm not sure why you insist on mentioning trail. I just noted that an thus far unknown effect has recently been discovered, which is correct. No one was talking about trail, nor disputing it.

Thanks, just an side note I don't think you will cancel an gyro effect by an counter rotating wheel, I think it would double it as you now has twice the rotating mass.
On the other hand the test bicycle had too small and light wheels for any relevant gyro effects anyway. 

[Bill Phil]

1 hour ago, magnemoe said:

Thanks, just an side note I don't think you will cancel an gyro effect by an counter rotating wheel, I think it would double it as you now has twice the rotating mass.
On the other hand the test bicycle had too small and light wheels for any relevant gyro effects anyway. 

https://en.wikipedia.org/wiki/Angular_momentum#Vector_.E2.80.94_angular_momentum_in_three_dimensions

The goal is to have two vectors which then add up to zero.

[cubinator]

To protect the electronics from being fried by Jupiter's intense radiation belts, wiring in the Voyager probes was wrapped (due to extreme lack of time before launch) in kitchen-grade aluminum foil bought at a local store.

[GoSlash27]

A sphere with a radius measured in "x" km is equivalent to "x" miles cubed. ex: If Kerbin were compressed into a cube, it would be about 600 miles wide.

[Green Baron]

Hehehe. Everybody tested their calculators :-)

[p1t1o]

• There's carbon nanotubes on burnt toast.
• There are dioxins (a class of extremely toxic compounds) in burnt toast.
• If I had a 3rd fact about burnt toast it would really round-out this comment.

[Green Baron]

1 hour ago, p1t1o said:

• There's carbon nanotubes on burnt toast.
• There are dioxins (a class of extremely toxic compounds) in burnt toast.
• If I had a 3rd fact about burnt toast it would really round-out this comment.

Lemmyhelp: besides the dioxins and charcoal, if made from white industrial bread isn't that healthy at all ....

[Racescort666]

On 11/12/2017 at 9:22 AM, cubinator said:

To protect the electronics from being fried by Jupiter's intense radiation belts, wiring in the Voyager probes was wrapped (due to extreme lack of time before launch) in kitchen-grade aluminum foil bought at a local store.

I had to look this up and it was something that was mentioned in a PBS special that came out recently. http://www.businessinsider.com/voyager-kitchen-aluminum-wrap-radiation-short-circuit-2017-9

[p1t1o]

On 11/12/2017 at 2:22 PM, cubinator said:

To protect the electronics from being fried by Jupiter's intense radiation belts, wiring in the Voyager probes was wrapped (due to extreme lack of time before launch) in kitchen-grade aluminum foil bought at a local store.

 

44 minutes ago, Racescort666 said:

I had to look this up and it was something that was mentioned in a PBS special that came out recently. http://www.businessinsider.com/voyager-kitchen-aluminum-wrap-radiation-short-circuit-2017-9

Man, I hope there wasnt a queue at the checkout, can you imagine!?

Would YOU let someone ahead of you if they told you a multi-billion dollar space project might fail if they didnt get to the cashier first?

"Yeah yeah buddy, I've got the same NASA T-shirt, they sell them at the gift shop...whats all that foil for? Hats? HAHAHAHAHA!" <looks at person next to you in the queue making the "crazy" hand signal> <person in NASA t-shirt starts openly weeping>

[wumpus]

1 hour ago, p1t1o said:

Would YOU let someone ahead of you if they told you a multi-billion dollar space project might fail if they didnt get to the cashier first?

"Yeah yeah buddy, I've got the same NASA T-shirt, they sell them at the gift shop...whats all that foil for? Hats? HAHAHAHAHA!" <looks at person next to you in the queue making the "crazy" hand signal> <person in NASA t-shirt starts openly weeping>

Aluminum foil is a standard kludge to pass EMI (electro-magnetic-interference tests).  I'm sure there are many multi-billion dollar projects that have required a quick rush to the grocery store, and many more mult-million dollar projects,  if only due to the lack of higher dollar projects.

- I've never done it, but I have had to go to radio shack to pick up repair parts, and then ECO the original paperwork to include radio shack as a supplier of alternate parts...

[p1t1o]

1 hour ago, wumpus said:

Aluminum foil is a standard kludge to pass EMI (electro-magnetic-interference tests).  I'm sure there are many multi-billion dollar projects that have required a quick rush to the grocery store, and many more mult-million dollar projects,  if only due to the lack of higher dollar projects.

- I've never done it, but I have had to go to radio shack to pick up repair parts, and then ECO the original paperwork to include radio shack as a supplier of alternate parts...

 

The article posted above explains it well. At first though, I had thought that "extreme time pressure" meant that they needed to fudge it during the countdown or something!

 

 

[cubinator]

Just now, p1t1o said:

 

The article posted above explains it well. At first though, I had thought that "extreme time pressure" meant that they needed to fudge it during the countdown or something!

 

 

No, not quite that extreme. It was the deadlines for building the spacecraft.

[GoSlash27]

Wumpus,
 I didn't realize that "ECO" was a standard term across the industry. Never heard it before outside my own organization until just now.

 Do you folks have "red marks" and "run +holds" as well?

Best,
-Slashy

Edited November 14, 2017 by GoSlash27

[wumpus]

14 hours ago, GoSlash27 said:

Wumpus,
 I didn't realize that "ECO" was a standard term across the industry. Never heard it before outside my own organization until just now.

 Do you folks have "red marks" and "run +holds" as well?

Best,
-Slashy

I'm pretty sure it has pretty broad use, I remember reading in "Soul of a New Machine" the engineers were talking about ECOing  the deck [as in carpentry] they were building.  Drawings were "red lined", but a lot depends on how hostile Configuration Management was about the state of the drawings.  Sometimes the letters are slightly different, or perhaps Engineering Change Notice means something else.

Come to think of it, I'd have to assume that red lining has to postdate AutoCAD.  I'd assume that you would simply draw in black on hand drawn drawings (I've only pulled a drawing once and seen that it was hand drawn, and that was ages ago).  ECOing may date back to the pyramids (with appropriate language changes).

I've only dealt with small manufacturing runs on site, so never ran into "run+holds".

[mikegarrison]

3 hours ago, wumpus said:

I'm pretty sure it has pretty broad use, I remember reading in "Soul of a New Machine" the engineers were talking about ECOing  the deck [as in carpentry] they were building.  Drawings were "red lined", but a lot depends on how hostile Configuration Management was about the state of the drawings.  Sometimes the letters are slightly different, or perhaps Engineering Change Notice means something else.

Come to think of it, I'd have to assume that red lining has to postdate AutoCAD.  I'd assume that you would simply draw in black on hand drawn drawings (I've only pulled a drawing once and seen that it was hand drawn, and that was ages ago).  ECOing may date back to the pyramids (with appropriate language changes).

I've only dealt with small manufacturing runs on site, so never ran into "run+holds".

https://en.wikipedia.org/wiki/Engineering_change_order

Of course we have the same things where I work, but I've never heard the term used. We have different acronyms for such things.

[p1t1o]

On 11/12/2017 at 1:41 AM, Bill Phil said:

https://en.wikipedia.org/wiki/Angular_momentum#Vector_.E2.80.94_angular_momentum_in_three_dimensions

The goal is to have two vectors which then add up to zero.

This was baking my noodle for a while, how could two opposing wheels still have a gyroscopic effect?

Then I thought about what you said.

I was thinking "If you consider the pair of wheels, and you look at each point on one wheel and its counterpart point on the other, then all the vectors cancel out to zero, so what gives hmm?"

But if you consider the acceleration of each point of the wheels, both points in the pair are accelerating inwards, when you combine them they DOUBLE!

 

Is that a fair assessment of why two oppositely-rotating wheels still have a gyroscopic effect?

 

(then I started thinking - so how can you cancel out the constant inwards acceleration of all of the points on a wheel? Then I started trying to imagine an inverse wheel, or an inside-out wheel and my mind started to hurt so now Im going to have a bath)

[Aghanim]

TIL that scientists are working on a way to make computer that uses quantum physics and time travel to solve some hard computer science problem and break Heisenberg uncertainty principle:

https://phys.org/news/2013-12-warp-possibility-cloning-quantum.html#nRlv

https://www.nature.com/articles/npjqi20157

 

[Green Baron]

On 17.11.2017 at 3:18 AM, Aghanim said:

TIL that scientists are working on a way to make computer that uses quantum physics and time travel to solve some hard computer science problem and break Heisenberg uncertainty principle:

https://phys.org/news/2013-12-warp-possibility-cloning-quantum.html#nRlv

https://www.nature.com/articles/npjqi20157

 

I especially found this quote .... clarifying:

"Meaning that, if you kill your grandfather, you do it with only probability one-half," Wilde said. "Then, he's dead with probability one-half, and you are not born with probability one-half, but the opposite is a fair chance. You could have existed with probability one-half to go back and kill your grandfather."

 

Eh ? So, what's the sentence for one-half-probability murdering ?

 

 

The Yeti, genetically identified (that took long didn't it ?) as brown bear, black bear or one sample simply from a dog. Anybody disappointed ? :-)

http://rspb.royalsocietypublishing.org/content/284/1868/20171804

 

Edited November 29, 2017 by Green Baron

[Racescort666]

26 minutes ago, Green Baron said:

The Yeti, genetically identified (that took long didn't it ?) as brown bear, black bear or one sample simply from a dog. Anybody disappointed ? :-

I can't bear it.

[justidutch]

On 10 November, 2017 at 9:21 AM, ARS said:

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

I wonder how many letters will have been spelt by the time you spell "one thousand"

[Bill Phil]

If you were standing on Callisto, Jupiter would be more than 4 degrees wide in the sky. Or, in other words, over 8 times the angular diameter of the Moon from Earth.

[kerbiloid]

Somebody just has accidentally pressed "R" button in NASA KSP.
Voyager RCS engines have activated.

https://www.nasa.gov/feature/jpl/voyager-1-fires-up-thrusters-after-37

Edited December 3, 2017 by kerbiloid

[KSK]

Wombat poop comes out in little cubes. 

[Green Baron]

2 hours ago, KSK said:

Wombat poop comes out in little cubes. 

That one made me lol. Unfortunately the page referenced in the link cannot be found.

They say that cubic poop is better suited to mark the territory because it doesn't roll off the branches of trees. I am trying to imagine a scenario where the selective pressure leads to cubic poop production ... :-)