Recent comments in /f/explainlikeimfive

virtualchoirboy t1_jee7tps wrote

Short answer: It's a law called the CAN-SPAM Act which requires email list senders to include an unsubscribe method.

As with all laws though, it just gives the scammers a framework that allows them to dodge the law. The most common dodge I've heard is that they use the fact that you clicked on unsubscribe to confirm that you're a real person so that makes your contact information "verified" and they can sell it to another "business" to still make a profit off you. If they're a more reputable company, the link should actually work and help you remove yourself from the list.

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skiveman t1_jee6j89 wrote

At present, that is. If the cost of clean water gets high enough then it becomes economical for both desalination plants to create profit but also so that civil construction projects make financial and resource security sense.

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chimpaflimp t1_jee6fls wrote

The information I supplied came directly from the CDC website.

Viruses infect cells and use the host cell to spread itself to other ones. They're preprogrammed to replicate by the most efficient available means, which in the case of rabies is biting, as it spreads though saliva.

You're not more correct, you're just pedantic.

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zolotuchien t1_jee6372 wrote

The space by itself however definitely has energy. There are two theoretical concepts to talk about. The first one is vacuum energy described by quantum physics. Due to uncertainty principle, vacuum energy simply cannot be zero. Even more interesting, an energy of any finite volume of vacuum has to be infinite. We can think of vacuum being a constant factory of spontaneously created and then annihilated pairs of particles and antiparticles. And that happens by virtue of it being space, not due to anything in said space.

The second concept to talk about is a cosmological constant in general relativity theory. It can be thought of as an energy density of an empty space. It is one of the candidate for the dark matter phenomenon, the fact that the expansion of the universe is accelerating.

Due to both things describing an energy of an empty space, there is an idea that those to concept has to be related.

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savage-dragon t1_jee4n5q wrote

Ah the cursed existence of mankind, born with a brain equipped to understand the "here" and the "there", the "beginning" and the "end" because those are concepts familiar to their frail, mortal lives. The brains are built to comprehend such concepts, for that is all millenia of evolution have given them. Yet their ambitions often far exceed their brain's imagination. They gaze upon the stars and the vastness of the void inbetween and wonder what is the beginning of time and what is the end of the nigh infinite as if the universe itself must be like everything they know: having defined births and defined dimensions.

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SifTheAbyss t1_jee3x3g wrote

Multiplying with negative is just turning around the direction of whatever you're doing.

Using the classic fruit example, adding gives you more apples, adding "negative apples" takes away apples. You can draw a card that says "you need to hand over 1 apple".

Now, adding 1 of these cards really just removes 1 apple. It's like a negative apple.

What happens if we remove 1 of these cards? You have 1 more apple than you had before.

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SYLOH t1_jee3dvy wrote

Let's take a number like 3 divided by 7.
That would be 0.428571428571428571 with 428571 repeating infinitely.
That would be analogous to periodic tiling.
You put shapes in a certain order and you can tile infinity by just repeating those shapes in that order.
It might not be 1 shape, the arrangement might be quite complicated, but it still repeats.

Now think of a number like Pi.
The first few digits of pi are:
3.141592653589793238462643383279502884197... but it continues on forever.
You will never find a series of digits that's finite in length that makes up Pi by just repeating it infinitely.
This is like aperiodic tiling, you will never find a finite group of shapes that makes up the whole thing by repeating it infinitely.
The arrangement of any part is always at least slightly off.

Now math guys have known about aperiodic tiling for a while, but they found it worked with only a few different shapes put together.
They did more math and didn't find anything that said they couldn't do it with just 1 shape.
That's why the hat is exciting to the math people. Knowing something can exist and actually finding the thing are two very different things in math. So they were really excited when they found that it was a relatively simple shape.
It could have been some monstrous shape that takes up 200 GB, or something that would only be found in the year 2723 or something.
They're just glad we have it in the here and now and on a regular screen.

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