Skyler4856

For Questions That Don't Merit Their Own Thread

963 posts in this topic

On 2/11/2017 at 7:58 AM, Toonu said:

I'm not sure what is a negative mass or how in the predictions and concepts can someone make it. Is it somewhat connected to anti-matter mass? I m now talking about negative mass and Alcubierre warp drive. 

Thanks for reply! Ave! Toonu

Im not sure, and possibly nobody is sure, what properties "negative-mass" would have. However, I can tell you that anti-matter has positive (ie:normal) mass and behave exactly like regular matter in terms of gravity. Although it should be noted that only very small quantities of anti-matter have ever been experimented with (making measurements of the effects of gravity very difficult) and there are some schools of thought which posit that anti-matter may have different properties in a gravity field, or that it exerts a non-standard field itself, although the main-stream is currently that its mass is "normal" and wouldn't.

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So i poured some hot water into a cup and it started rotating. Then, on the side of the cup I observed a shadow on the side of the cup that had several, outstretched arms and looked like a galaxy. It was also rotating. Why was there a shadow when the water was rotating?

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On 23.12.2016 at 5:38 AM, shynung said:

What are the biggest hurdles in designing a working fusion power reactor today, in ELI5 terms?

Plasma cloud quickly (less than in a second) gets unstable and unhomogeneous.

To solve this problem they use such monstrosities (see the pictures and maybe links).

P.S.
Probably, the Rey's bread will be one more mysterious meal after the "The Good, the Bad and the Ugly" scene where they eat something (soup or something) unrecognized by the internet dwellers (I took a search once).

Spoiler

 

Also the bread color is like in Zardoz

Spoiler

zardoz-bread-oven.jpg

 

Edited by kerbiloid

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13 hours ago, munlander1 said:

Why was there a shadow when the water was rotating?

A change in the density of the water?  Refraction caused the light to be less?

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23 hours ago, munlander1 said:

So i poured some hot water into a cup and it started rotating. Then, on the side of the cup I observed a shadow on the side of the cup that had several, outstretched arms and looked like a galaxy. It was also rotating. Why was there a shadow when the water was rotating?

Rotating water generates all sorts of forces that distort the surface of the water away from perfect flatness. Curved surface of water acts as lens, concentrating light on parts of the inner mug surface, and directing light away from other parts, hence, "shadows".

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Why doesn't Space X use 1 big engine rather than 9 of the small Merlin engines on the Falcon 9?:/

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I'd guess many different reasons. I can think of two:

  1. Engines aren't made for a single rocket. The Falcon 1 uses the Merlin, too, and a single one. They could have made a bigger engine for the F9, or use 9 of the existing ones and spend their time upgrading it instead.
  2. During landing, it throttles its thrust down. However, that's not as easy engineering-wise as KSP will lead you to believe. It does so by firing in short (and FAST) bursts rather than full-on. Also, it lands on a single engine rather than all nine. That would be a lot harder to achieve with a single big engine.
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^ That. Also, developing a bigger, new engine would take up valuable time. 

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2 hours ago, Spyflare said:

Why doesn't Space X use 1 big engine rather than 9 of the small Merlin engines on the Falcon 9?

Because the Merlin was developed for Falcon 1.  When Falcon 1 failed to gain headway in the marketplace, there wasn't money or time to develop a new engine *and* a new booster before they were bankrupt.  Even so, it was a close run thing - the CRS contract arrived at the 11th hour.

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What is this effect called?  I've also seen it on t-shirts and such.  Really bugs out my eyes... yet I cannot look away!

3XPLAnR.jpg

 

I don't see it on Wikipedia's List of Optical Illusions, and googling the subject just comes up with clickbait articles.

 

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