Is the nucleus of an atom a sea of quarks without clear boundaries between protons and neutrons? | AskScience Blog

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Wednesday, July 4, 2018

Is the nucleus of an atom a sea of quarks without clear boundaries between protons and neutrons?

Is the nucleus of an atom a sea of quarks without clear boundaries between protons and neutrons?


Is the nucleus of an atom a sea of quarks without clear boundaries between protons and neutrons?

Posted: 03 Jul 2018 10:39 AM PDT

I am aware of the quantum stuff that means we can't know exactly where the protons and neutrons are but that's not what I mean. Since both are made of quarks, ups and downs I think, are the quarks just all together in one big soup instead of being bonded to two others like in diagrams?

submitted by /u/DomPulse
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What does it actually mean if a quantity is an exact differential?

Posted: 04 Jul 2018 04:51 AM PDT

I came across this sentence: "since heat is not an exact differential it is not a property of the system. It is a path function."

So how can those things be inferred just by knowing that heat is not exact differential?

submitted by /u/quazarzzz
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Is there any dark matter in my room right now?

Posted: 03 Jul 2018 09:18 AM PDT

Do any non-human animals deliberately combine foods for eating simultaneously? Do any prepare meals with more than one ingredient?

Posted: 02 Jul 2018 01:08 PM PDT

How was the Apollo Command Module kept oriented so the lift force acted "upwards" with respect to the Earth?

Posted: 04 Jul 2018 12:46 AM PDT

I'd love to know how the pod was oriented correctly and stably with respect to the earth for re-entry. It had an offset center of mass and flew at an angle of attack of something like 20-26 degrees, flying a lifting re-entry. But to do that it had to be rotated the right way; if it rotated along its longditudinal axis, the lift would act sideways or downward, making it slam harder into the atmosphere.

From what I've been able to learn so far it's a "free body" in physical terms, so the offset center of mass does not naturally "fall" downward to orient the craft with the required angle.

It also seems like the crew were able to guide the pod by changing its rotation in flight, so the lift acted to divert the course left or right and in the process make the re-entry profile steeper or shallower.

Was the rotational orientation done entirely with reaction control thrusters? Or was there some inherent stability at work?

I know aerodynamic stability (center-of-mass in front of center-of-drag) keeps the heat shield pointed at the airflow, but what keeps the craft rolled the right way for a lifting re-entry?

submitted by /u/iiiinthecomputer
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UAE plans on towing icebergs from Antarctica for fresh-water supply. How feasible is this and what are the possible side effects?

Posted: 03 Jul 2018 09:34 AM PDT

Here's the link to the article.

I know the article already talks about some of the effects it will have on climate change in the UAE, but what are the other possible side effects (if any) of this, on the world, or areas around the planned route of towing. The impact it would have on Antarctica, etc. Anything that isn't mentioned on the article.

Edit: Here's a more recent article I found.

Here's the website for the project.

submitted by /u/Pmhp34ham
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Why is the speed of gravity limited to the speed of light?

Posted: 03 Jul 2018 01:53 PM PDT

I've been taught 4 things:

  1. The speed of light is the maximum speed that anything can travel through space
  2. Unlike light, gravity is not a force carried by particles traveling through space, it's caused by the distortion of spacetime itself
  3. The expansion of the universe can happen faster than the speed of light, because the maximum speed limit only applies to things moving through space, not space itself distorting
  4. Gravity/gravity waves travel at the speed of light

Number 4 doesn't seem to follow from the first three, can someone explain why gravity can't propagate faster than the speed of light? For example, I've heard it said that the earth doesn't orbit the Sun's current location, it orbits where the sun was 8 minutes ago. Why couldn't the curvature of spacetime be "updated" faster? Why can spacetime expand faster than light, but not bend faster than light?

submitted by /u/Gammapod
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Why can’t an electron’s original velocity be measured by comparing the energy loss of the photon used to detect its position with the energy loss used to detect the electron at a secondary position?

Posted: 03 Jul 2018 07:04 PM PDT

So I've been trying to delve into some more advanced physics than I had previously known and recently looked into the Heisenberg Uncertainty Principle. As I understand it, part of the problem with trying to measure an electron's position vs. its velocity is that the energy of the photon needed to measure each figure necessarily decreases the certainty of the other measure (ie. a high energy photon is more localized so the electron's position can be more accurately determined but the photon will impart so much energy that the electron's velocity will be greatly affected, and vice versa with a low energy photon).

My question is, if one were to hit the electron with a high energy (localized) photon, thereby more accurately determining its position, and then detect the photon after the collision, couldn't you measure the change in frequency to determine the energy transferred to the electron?

And then could you not attempt to measure the electron's position post-collision to determine where the electron travelled post-collision, and with what energy level, and then, taken with the energy loss from the original photon, use that to determine the original velocity of the electron prior to collision?

submitted by /u/epgenius
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Did satellite imagery help us discover anything new about the Earth's topography?

Posted: 03 Jul 2018 03:08 PM PDT

Were there any islands or ocean features we just didn't know about until we got into space or were our globes already basically accurate by that point?

submitted by /u/Ninjamin_King
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How can matter enter a black hole?

Posted: 03 Jul 2018 06:26 PM PDT

It's surely a stupid question because most of what I've learned is only vulgarised theory from YouTube videos.

So from what I've understood :

If we drop a clock in a black hole and observe it from distance, the time shown on the clock would slow down until it reaches the horizon, where it would freeze. So from the clock's perspective, the whole time of the external universe(?) would pass before it enters that black hole. I already have problems picturing that, because it would mean that no black hole could grow like we know they do. And if I add to it the fact that black holes aren't eternal (Hawking radiation..?) it seems that everything that would enter a black hole wouldn't do it before the hole actually evaporates.

Now I get that it is the relative time of the external universe that is being "sped up" but I picture the black hole as a part of the external universe as long as it is able to evaporate relatively to that reference. So what am I missing?

Edit : similiar question on stackexchange with no definitive answers so far : https://physics.stackexchange.com/questions/21319/how-can-anything-ever-fall-into-a-black-hole-as-seen-from-an-outside-observer

submitted by /u/iuopkizt
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Is there any research about mass distribution inside a black hole?

Posted: 03 Jul 2018 05:27 PM PDT

The simplistic view is that all mass is in the singularity at its center but this seems to me is in conflict with another view that says crossing the event horizon is imperceptible (for large black holes) AND an observer would be able to "see", just before they're turned into spaghetti, a highly accelerated history of the Universe unfolding above him, due to experiencing severe time acceleration as they approach the singularity.

Thus, mass within the black hole is not all in its center and there might even not be any singularity to speak of. It's just an immense bunch of stuff slowly travelling (as seen by an observer outside the horizon) towards a common center but only reaching it at the end of time (again, as seen by an outside observer).

So I'm wondering if anyone thought about an experiment to determine mass distribution inside the event horizon, as difficult as that may be.

submitted by /u/entmus
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How do the "small, rocky cores" of the gas giant planets maintain such huge atmospheres?

Posted: 03 Jul 2018 05:26 PM PDT

If I'm not mistaken, most of these cores are smaller than Earth and are made out of ice and rock? Why doesn't the Earth have such a huge atmosphere?

submitted by /u/_imhigh_
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What is life the scientists are finding?

Posted: 03 Jul 2018 08:34 PM PDT

We often hear, that, there may be 'life' on Europa, no 'life' in Venus or probably 'life' existed in Mars. What actually the scientists recognise as 'life' and how do they determine it? What are the parameters with which they filter 'organic' activity from any random chemical reaction?

submitted by /u/SVIKC
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Do electrons take up enough space to “bump” into eachother when sufficiently congested, or does the electromagnetic force keep them apart?

Posted: 03 Jul 2018 03:05 PM PDT

I've heard quite often around here that electrons are points, as in they are not a sphere or some classical image of that, and this is why it's hard to talk about their spin angular momentum in an intuitive way. But they can't be points right? (Since they have a mass and take up space). In the flow of electricity, I'm wondering if the electrons physically move eachother or if their electromagnetic interactions guide the flow. Thank you!

submitted by /u/liamguy165
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What specifically would an electromagnetic pulse break?

Posted: 03 Jul 2018 06:23 PM PDT

Whenever I search about EMPs, results fall in to a few categories. *tin foil hat preper folks *people who make money on Add revenue *people who watch too much TV

But never an actual engineer or physicist, and enough of those folks hang out here, thought I'd create a new search result on the subject.

What I can never find, is what specifically "frys" when exposed to an EMP? Do capacitors explode? Resistors melt? I'd imagine at the very basic level, the copper will not stop being copper, and mosy software could be restarted.

Wouldn't surge protectors, breakers sheilding and fuses do a lot of good in protecting electronics in most cases?

submitted by /u/Khakikadet
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Does Mercury experience any significant tidal forces from Sun?

Posted: 03 Jul 2018 10:51 AM PDT

Relativity: Speed vs Gravity?

Posted: 03 Jul 2018 01:07 PM PDT

Speed slows time to an observer. And lesser gravity speeds time to an observer. At what point does one effect overtake the other? In other words, GPS satellites must account for these: the speed of the satellite (slower time), and the lesser gravity due to being away from the surface of Earth (faster time). How do these compare in magnitude with a satellite's speed and position above Earth? And at what point does one overtake the other?

I wonder this with respect to geosynchronous satellites that are high above Earth; they move at a high speed with relation to the center of Earth but are akin in certain aspects to a tall building where higher floors have a faster flow of time to observers on the surface of Earth.

Can anyone explain how this works in geosynchronous, and nearby GPS satellites?

submitted by /u/ScoobyDoobyToo
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How are today's telescopes so powerful?

Posted: 03 Jul 2018 07:14 PM PDT

Electric and magnetic fields exist, and allow for photons. Gravitational and Gravitomagnetic fields exist. Do graviphotons (?) exist? Why/why not?

Posted: 03 Jul 2018 01:54 PM PDT

I just discovered maxwell's equation analogues for gravity, it's pretty cool

submitted by /u/FragmentOfBrilliance
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How is it possible for an isotope to increase in atomic number when it goes through beta-minus decay?

Posted: 03 Jul 2018 10:53 AM PDT

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