ELI5: If black holes don't let light escape, how do we know they exist?



https://redd.it/1uzubps
@r_explainmelikeimfive

ELI5: Why don't fish get crushed by the enormous pressure at the bottom of the ocean?



https://redd.it/1uzwvpg
@r_explainmelikeimfive

ELI5 How does period underwear work?

I’ve had a period for 16 years. I’ve used basically every kind of period solution. But I don’t understand period underwear! It tends to say it holds 5-7 regular tampons’ worth of blood. Is it meant as a backup to a tampon? Obviously you can’t wear a pad with it. Is it meant to be a substitute? That capacity wouldn’t last me through the day. I could understand it helping with leaks, but does it feel wet since you don’t change as often as a pad? I just have not understood how to use them, but people swear by them.

https://redd.it/1uzyy5h
@r_explainmelikeimfive

ELI5: Why is mercury the only metal that exists as a liquid at room temperature and pressure?

This question has probably been asked a thousand times before, but I haven’t been able to get a proper answer without diving into relativistic effects and electronic configurations.

What are these effects caused by? What exactly is the process that leads to this? I know some other elements like Gallium can exist as a liquid at \~30 degrees, but that has a different reasoning to Mercury’s case.

https://redd.it/1v01aot
@r_explainmelikeimfive

ELI5: Why is everything taking so much longer to make?

Basically the title. Why is everything taking so much longer to make, despite all the technological advances?

Shows used to put out a new 20 episode season every year, now it’s 8 episodes every other year.

The Empire State Building took 16 months to build, Salesforce Tower took 6 years.

AAA studios could put out a flagship game every 3 years or so, now decade+ goes between releases.

The Transcontinental Railroad was built by hand in 5 years during the 1860s, California’s high speed rail has been under construction for 14 years and has 0 miles of working track.

Despite having more manpower, more equipment, more technology, etc,. why has the time to completion for pretty much everything in the modern day and age ground to a halt?

https://redd.it/1v0471b
@r_explainmelikeimfive

ELI5: Why do pads and tampons need to be changed every 4–6 hours, but menstrual cups can be worn for 8–12 hours?

Growing up, I was taught that pads and tampons should generally be changed every 4–6 hours, even if they aren't completely full. But menstrual cups are often advertised as being safe to wear for 8–12 hours.

If they're all collecting menstrual blood in one way or another, why is there such a big difference in the recommended wear time?

https://redd.it/1v03h6c
@r_explainmelikeimfive

Eli5 why did gane development start taking 3x as long after the early to mid 2010s?

It seems like so many games have been "in development" for 10 or 15 years now when the previous games in the series took 3-5, most notably gta 6 and elder scrolls 6 but several others as well.

Why has game development slowed down so much from big studios?

https://redd.it/1v0434g
@r_explainmelikeimfive

ELI5 the difference between SMS and RCS messaging vs iMessage.

As the title says. What is the difference between SMS and RCS messaging, and how does it compare to iMessage between 2 Apple devices?

TIA

https://redd.it/1v07nhe
@r_explainmelikeimfive

ELI5: what lead to some mammals being able to sweat/perspire while a large number (including dogs and cats) today can’t?

Edit for clarity: for thermal regulation.

And what animals besides apes CAN perspire? For thermal regulation?

https://redd.it/1v0a4gd
@r_explainmelikeimfive

ELI5: Glass window on door violently exploded into my hand. How?

I don’t have a picture of the door itself, but I have a picture of how my hand looked after the explosion. I was trying to hold a door shut that was being slammed open by wind, than a microburst happened and the glass spontaneously shattered into my hand. I’m just confused on how this even happened. The glass was not tempered, but it wasn’t particularly weak either. No one else was injured, but glass flew everywhere and severed one of my tendons…

https://redd.it/1v0emzt
@r_explainmelikeimfive

ELI5: How does some small Somali boats take over a huge oil tanker?

Like I understand some of the tactics but can't this huge oil tanker just steer into them or just keep moving while they just run out of gas in their small boats?

https://redd.it/1v0hyzt
@r_explainmelikeimfive

ELI5: What is ACTUALLY in black holes?

I'm almost 30 and still don't grasp the concept of a black hole. Like where does all of matter go? I know it disappears but where do the partials end up? Are they just obliterated so fast that they're just nothing or is there like a portal of junk somewhere

https://redd.it/1v0k6xp
@r_explainmelikeimfive

ELI5: What was the difference between an Earl, Viscount, and a Baron in the Middle Ages concerning land ownership? (History)

I know they all owned land in different ways, but how did they differ in land ownership and duties? Could a Baron have owned land within an Earl's land, for instance?

https://redd.it/1v0jmam
@r_explainmelikeimfive

ELI5 Why does it lower your credit score when you pay off a loan early?

I recently paid off a loan three years early and had a HELOC that I haven’t used in five years expire after ten years which it was contracted to do. My credit score just dropped 30 points from this. How does doing seemingly positive things have such a negative affect on my credit score?

https://redd.it/1v0phjx
@r_explainmelikeimfive

ELI5: If muscles grow from mechanical tension and repair, why can't we artificially create that?

Why can't doctors put someone under anesthesia, use controlled electrical stimulation or other methods to make the muscles experience the same tension as a workout, let the body recover, and repeat the process until the person sleeps with an average body and wakes up looking like Arnold Schwarzenegger? What biological process makes real exercise impossible to fully replace?

https://redd.it/1v0rb6s
@r_explainmelikeimfive

ELI5: Why does waking up from anesthesia feel like no time has passed, compared to waking up from sleep?

I've heard people describe general anesthesia as feeling like they closed their eyes and immediately opened them again, even if several hours passed. But when we sleep at least have some sense that time has passed.

What is happening differently in the brain during general anesthesia compared to normal sleep that makes anesthesia feel like an instant with no awareness of time?

https://redd.it/1v0w2ol
@r_explainmelikeimfive

ELI5 how did medieval people burn their lamps or torches before the invention of matchsticks?

The matchsticks got discovered in 19th century, but how did people light their day to day necessities like lamps, torches and cooking places? Every continent must have different methods for it, no? Was it a tiring process or did they have some quick tools for that as well? I wanna know about medieval India too. What were the tools they used?

https://redd.it/1v0pmm7
@r_explainmelikeimfive

ELI5: Why are seas and oceans so salty?



https://redd.it/1v0zwx6
@r_explainmelikeimfive

ELI5: Why do actors (especially Broadway ones) run their lines with a pencil in their mouth?

I know it's to improve diction but I don't get how that works.

Also as a bonus: is this the only method to do this or are there other alternatives?

https://redd.it/1v0x7g1
@r_explainmelikeimfive

Eli5: Sports betting odds

Today's World Cup final has Argentina as a 5 to 2 underdog. If I understand correctly, that means a payout of $5 for every $2 bet. But why don't they just list the odds as 2.5 to 1? I Googled it and it said they only use whole numbers on each side of the "to", but they didn't say why. Is there some specific reason for this? Or is it just to make it easier by using only whole numbers?

https://redd.it/1v0xszl
@r_explainmelikeimfive