How do magnets get their magnetic fields? How do electrons get their electric fields? How do these even get their force fields in the first place? | AskScience Blog

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Tuesday, April 16, 2019

How do magnets get their magnetic fields? How do electrons get their electric fields? How do these even get their force fields in the first place?

How do magnets get their magnetic fields? How do electrons get their electric fields? How do these even get their force fields in the first place?


How do magnets get their magnetic fields? How do electrons get their electric fields? How do these even get their force fields in the first place?

Posted: 16 Apr 2019 02:35 AM PDT

AskScience AMA Series: We're Nick Magliocca and Kendra McSweeney and our computer model shows how the War on Drugs spreads and strengthens drug trafficking networks in Central America, Ask Us Anything!

Posted: 16 Apr 2019 04:00 AM PDT

Our findings published on April 1, 2019, in the Proceedings of the National Academy of Sciences demonstrate that cocaine trafficking, or 'narco-trafficking, through Central America to the United States is as widespread and difficult to eradicate as it is because of interdiction, and increased interdiction will continue to spread narco-traffickers to new areas in their pursuit of moving drugs north.

We developed a simulation model, called NarcoLogic, that found the result of the 'cat-and-mouse' game of narco-trafficking and counterdrug interdiction strategies is a larger geographic area for trafficking with little success in stopping the drug from reaching the United States. In reality, narco-traffickers respond to interdiction by adpating their routes and modes of transit, adjusting their networks to exploit new locations. The space drug traffickers use, known as the 'transit zone', has spread from roughly 2 million square miles in 1996 to 7 million square miles in 2017. As a result, efforts by the United States to curtail illegal narcotics from getting into the country by smuggling routes through Central America over the past decades have been costly and ineffective.

The model provides a unique virtual laboratory for exploring alternative interdiction strategies and scenarios to understand the unintended consequences over space and time.

Our paper describes the model, its performance against historically observed data, and important implications for U.S. drug policy: https://www.pnas.org/content/early/2019/03/26/1812459116.

Between the two of us, we'll be available between 1:30 - 3:30 pm ET (17:30-19:30 UT). Ask us anything!

submitted by /u/AskScienceModerator
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Are 2FA codes random or is there an algorithm in place to make the digits more human-friendly?

Posted: 16 Apr 2019 12:32 AM PDT

Hey,

At my work, as in most tech companies, we use the security tokens to log into certain systems as a 2-FA.

For those who don't know, it's a little device that displays a 6-digit code that changes every 30 seconds and you use it to log into work-related systems. Some sites use your phone for this, steam for example. Others use google authenticator that also has 6 digits.

My question is since these codes need to be input manually, are they more human-friendly or indeed, completely random?

I have noticed on the security token I use for work, since I use it way more often than any other 2FA, that often the code is somewhat easy to remember. Often you get codes like "556 789" or "222 001". Digits repeat, follow one another (478), are close on the keyboard (369) or "skip" (727 545).

Is it normal practice to incorporate some kind of algorithm into these code generators to make it easier for humans to copy them or are they completely random and my confirmation bias is only remembering the "good" combinations?

Thanks.

submitted by /u/Johnny_the_Goat
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Why can we determine the lifetime of short-living particles up to femtoseconds and less, but for the neutron we are unsure on the order of seconds?

Posted: 16 Apr 2019 05:27 AM PDT

I just read this article, and in the last paragraph it says

And the team is already designing its next-generation experiment, which aims to nail the neutron lifetime within 0.3 seconds.

Compared to the lifetime of the Higgs, which is on the order of 10e-22s, this is a pretty large error. How come there is such a huge difference? Do our measurements scale like that? Or is it something like when measuring something like the length of a car we make a bigger error than when doing scattering experiments with nuclear particles?

submitted by /u/Ernst37
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Have there been any recorded instances of stars that have disappeared suddenly (stopped emmiting light)?

Posted: 16 Apr 2019 07:44 AM PDT

I know that GPS systems have a resolution of a few meters. Is there any way to bring this resolution down to the cm? Any available commercial solution?

Posted: 16 Apr 2019 03:42 AM PDT

Maybe an algorithm that takes different measurements and makes another estimation can improve the system.

submitted by /u/ricarvid1
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How and why do bruises form?

Posted: 16 Apr 2019 03:32 AM PDT

How do you predict electronic configurations and bond orders given a molecular orbital (MO) energy diagram (for diatomic molecules only)?

Posted: 16 Apr 2019 01:24 AM PDT

What conditions determine whether a dying star collapses into a neutron star or a black hole?

Posted: 16 Apr 2019 06:45 AM PDT

How do some fish survive so deep underwater? Wouldn’t they get crushed by the pressure?

Posted: 15 Apr 2019 04:39 PM PDT

What is at the center of the Milky Way galaxy?

Posted: 15 Apr 2019 06:13 PM PDT

Whay can't electric vehicles just swap batteries instead of charging?

Posted: 15 Apr 2019 03:58 PM PDT

Are there any limitations to using a battery swapping machine instead of charging station?

submitted by /u/LEOH4Y
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Are tropical storms more frequent and powerful now then they were 50 or 100 years ago?

Posted: 15 Apr 2019 03:08 PM PDT

How have the predictions of climate scientists done so far? What were the predictions? What is the most reliable data?

submitted by /u/ltdata
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Have we lost the ability to see any constellations due to light pollution?

Posted: 15 Apr 2019 04:44 PM PDT

How do you calculate the radius of an atom that isn’t in a bond?

Posted: 15 Apr 2019 03:21 PM PDT

How did the glaciers from the last ice age push sediment south?

Posted: 15 Apr 2019 04:08 PM PDT

If we can use fusion inhibitors to treat HIV, why can we not design other antiviral drugs to target virus-cell fusion?

Posted: 15 Apr 2019 07:11 PM PDT

When antivirals block cell receptors does this cause problems for the cell?

submitted by /u/Pretty_Scientist
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Does putting an aperture in a laser beam make the smallest point it can be focused to larger or smaller?

Posted: 15 Apr 2019 04:40 PM PDT

If you put an aperture in a laser beam to block some of it, I would imagine that the spot it can be focused to becomes larger due to diffraction. The numerical aperture of the system is limited by that truncation of the beam. For a regular laser focusing without an aperture, the beam diameter determines the numerical aperture, not the lens diameter.

But if the spot becomes an infinitesimal pinhole, then it's the same as a point source emitting light. And the equation for how well resolved that point can be is defined by the airy disk using the aperture size of the lens diameter.

So as the aperture is shrunk down, do the two relationships describe different things? For example, does the NA associated with the aperture of the laser beam describe how small of a Gaussian spot can be formed, and the NA associated with the lens itself describe the size of the airy disk that all the light coming through the aperture can be condensed into?

I guess fundamentally it's just confusing because a coherent beam is usually implied to only have a NA related to the beam diameter, but after passing through an aperture it diffracts so the whole diameter of the lens is relevant in picking up and focusing the higher diffraction orders.

Or perhaps my understanding is totally messed up?

submitted by /u/sikyon
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How does the Unix time counter in computers know when a second has passed?

Posted: 15 Apr 2019 12:37 PM PDT

If computers use the unix counter to keep track of time, what does IT use to know when to tick up?

submitted by /u/ZoofusCos
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