Recent comments in /f/explainlikeimfive
Lirdon t1_jabfli7 wrote
The edge of the universe is not necessarily observable for us. But the edge of the universe that is observable to us is not only far away, it is far away in time, more primordial than anything.
According to our current observation and understanding, the universe is expanding and accelerating. That is to say that is expanding ever faster, to the point that at the edge of our observable universe it expands faster than the speed of light. That creates a kind of spacial horizon we cannot observe beyond, because light coming from the other side will never reach us. And this horizon is drawing ever nearer to us. Eventually, many of billions of years in the future an observer from our galaxy, may not be able to see past our galaxy.
FriendlyCraig t1_jabfj6y wrote
Reply to ELI5: If the tongue can only taste five basic flavors (sweet, sour, bitter, salty, umami), why isn't it possible to create any flavor by mixing those five together in precise combinations? by bokbokboi
We can taste a greater variety of flavors than you listed. It is merely a limitation of language that there are limited words to describe different flavors. For instance English also uses the words creamy, rich, tangy, hot, spicy, and herbaceous to describe flavors. These just aren't the "basic" flavors you listed above, but totally distinct flavors.
breckenridgeback t1_jabfez1 wrote
The expansion is not the kind of expansion you're thinking of. It isn't like a sphere getting bigger. It's more like every ruler in the Universe is getting smaller, so all measurements of distance stretch to be longer even though nothing "really" moved.
There is, as far as we are aware, no edge to the Universe even if it turns out not to be infinite (which current evidence suggests that it probably is). If the Universe were finite, it would be more like the surface of the Earth where you could get back to where you started after going "all the way around".
Schmooze58 t1_jabfbj1 wrote
Reply to ELI5: What is a "naturally aspirated" engine? Is it always desirable? Are there "artificially aspirated" engines ? by Gaboik
They can run hotter. Oil viscosity and an oil cooler are considerations. In a turbo aircraft engine the cylinder heads are prone to cracking if the throttles are jacked around roughly.
BurnOutBrighter6 t1_jaber0p wrote
It's the apparent size something appears to be based on how much radar signal it bounces back.
So a stealth bomber with a radar cross section of 10 square feet bounces back as much radar signal as a non-stealth blunt object with a surface size of 10 square feet facing the radar station. So it appears as a tiny object on the radar, if it appears at all, despite actually being big.
BurnOutBrighter6 t1_jabeprl wrote
Reply to comment by its-a-throw-away_ in ELI5: What is Radar Cross Section in stealth fighters? by ChaosRider37
You haven't answered what radar cross section is though. It's the apparent size something appears to be based on how much radar signal it does bounce back.
So a stealth bomber with a radar cross section of 10 square feet bounces back as much radar signal as a non-stealth blunt object with a surface size of 10 square feet facing the radar station. So it appears as a tiny object on the radar, if it appears at all, despite actually being big.
[deleted] t1_jabdvvh wrote
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[deleted] t1_jabdq82 wrote
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SirCarboy t1_jabdgwx wrote
Reply to comment by Gaboik in ELI5: What is a "naturally aspirated" engine? Is it always desirable? Are there "artificially aspirated" engines ? by Gaboik
Yes. With the turbo it's commonly called "Spooling up".
Also, the turbo benefits from air temperature differential (hot exhaust vs. cold intake air).
On really hot days you may get reduced performance impact. (It still works)
Erablian t1_jabcrc5 wrote
Reply to comment by annomandaris in Eli5: How did people know how long a year was in olden times? by Slokkkk
The synodic month averages 29.53 days, quite a bit different from your 28-day month. After 13 of those, your calendar would be 9.6 days out of sync with the actual phase of the moon.
13 synodic months is about 384 days, not 364.
YouthfulCurmudgeon t1_jabcor9 wrote
Reply to comment by beaucoup_dinky_dau in ELI5: Why is it that when fertilizers make their way into waterways, all the oxygen disappears, killing the fish? by Psychological-Dog994
The ones from the Michael Chrichton novel? Cuz that's a turn I did not expect.
zeratul98 t1_jabck7x wrote
Reply to comment by Caucasiafro in ELI5: If the tongue can only taste five basic flavors (sweet, sour, bitter, salty, umami), why isn't it possible to create any flavor by mixing those five together in precise combinations? by bokbokboi
A really weird and interesting thing I learned recently is that even though your nose is doing the smelling when you eat, it's different from smelling when you inhale. People feel a different response to the same compounds when they enter the olfactory center from the back of the throat than through their nostrils
syds t1_jabcfub wrote
Reply to comment by TucsonTacos in Eli5: How did people know how long a year was in olden times? by Slokkkk
and my axe!
its-a-throw-away_ t1_jabccwg wrote
Radio waves bounce off stuff. Radars send out radio waves, then measure how much bounces back, and from where. Stealth lets an airplane redirect or absorb most of these radio waves so what bounces back resembles something more like a goose than a fighter jet.
beaucoup_dinky_dau t1_jabc757 wrote
Reply to comment by YouthfulCurmudgeon in ELI5: Why is it that when fertilizers make their way into waterways, all the oxygen disappears, killing the fish? by Psychological-Dog994
you know the park motherfuckers
Gaboik OP t1_jabc710 wrote
Reply to comment by MakesMyHeadHurt in ELI5: What is a "naturally aspirated" engine? Is it always desirable? Are there "artificially aspirated" engines ? by Gaboik
Is it because they run hotter or what ?
Gaboik OP t1_jabc3fi wrote
Reply to comment by Middcore in ELI5: What is a "naturally aspirated" engine? Is it always desirable? Are there "artificially aspirated" engines ? by Gaboik
Woah awesome! Thanks for pointing it out !
I had heard about pilots needing to adjust the mixture and all but it hasn't occured to me the less oxygen = less combustion hence less energy !
AliMcGraw t1_jabc0b8 wrote
Reply to comment by annomandaris in Eli5: How did people know how long a year was in olden times? by Slokkkk
Lunar months are actually about 29 1/2 days; most ancient lunar calendars that don't correct for the sun use 12 months and come out with 354 days ... which is why Ramadan moves back 11 days every year (purely lunar calendar).
Most ancient calendars do correct for the sun. :) They stick in bonus days in various ways -- whole bonus month every couple years, bonus week somewhere, etc.
dbx999 t1_jabbqj1 wrote
Reply to comment by VRFireRetardant in ELI5: Why is it that when fertilizers make their way into waterways, all the oxygen disappears, killing the fish? by Psychological-Dog994
You would think that fertilizer is expensive and you wouldn’t want to let it go to waste by running off places that won’t help you grow your cash crops.
Hanzo_The_Ninja t1_jabbjuq wrote
There are two types of radar: Primary and secondary. Secondary radar works by detecting an aircraft's transmitter and doesn't apply here, but primary works by sending radio waves from a ground station and then monitoring for signals that are returned to the ground station -- reflections -- to make a determination about an aircraft's speed and bearing. The radar cross-section of an aircraft is a measure of how susceptible it is to detection by primary radar from different angles.
AliMcGraw t1_jabbit3 wrote
Reply to comment by annomandaris in Eli5: How did people know how long a year was in olden times? by Slokkkk
Also deadass giveaway that someone is a man who doesn't know much about women and generally lacks curiosity about the world when it doesn't occur to them that a lunar cycle would be of INTENSE INTEREST and OBVIOUS USE to the 50% of humans who menstruate on roughly a lunar cycle.
"Well, I don't need to know the lunar cycle, so I don't see why ANYONE would," u/icelandichorsey harrumpfs to himself, before explaining to the woman unfortunate enough to sit next to him on public transit how science works, actually.
Gaboik OP t1_jabbh79 wrote
Reply to comment by SirCarboy in ELI5: What is a "naturally aspirated" engine? Is it always desirable? Are there "artificially aspirated" engines ? by Gaboik
So you'll get the benefit of a supercharger continuously whereas you have to rev up the engine to get the benefit of the turbocharger before it kicks in ?
urzu_seven t1_jabb5qy wrote
Reply to Eli5: Saving difference problem by theBloodsoaked
The difference is you made a false assumption that 1 month = 4 weeks. This is only true for ONE month (most of the time, hi leap years!) February. Every single other month has 2-3 more days which makes up the difference.
- Jan: 4 w + 3 d
- Feb: 4 w + 0 d (1 d in leap years)
- Mar: 4 w + 3 d
- Apr: 4 w + 2 d
- May: 4 w + 3 d
- Jun: 4 w + 2 d
- Jul: 4 w + 3 d
- Aug: 4 w + 3 d
- Sep: 4 w + 2 d
- Oct: 4 w + 3 d
- Nov: 4 w + 2 d
- Dec: 4 w + 3 d
Totals: 48 w + 29 or 30 d = 52 w + 1 or 2 d
bella_68 t1_jabft8p wrote
Reply to ELI5: How and why did North Americans decide that certain foods are “breakfast foods”? by curlycattails
I watched an episode of The Food that Built America and learned that cereal was marketed as a breakfast food because it is quick to make and very effort. This meant no one had to wake up early enough to cook a meal as long as they had some milk and a box of cereal.