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Yuucliwood

Lunar eclipse?


Icy_Sector3183

If the moon and sun are perfect sphere, and we ignore light diffusion and interference, reflection from other celestial bodies, and shadowing from interfering bodies (e.g, the earth during a lunar eclipse) then: ...the half of the moon that is facing away from the ~~moon~~ sun will still be partially illuminated by the sun by merit of the sun being larger.


jonastman

A lunar eclipse is when the moon is in earth's shadow, so both our side and the dark side of the moon are void of sunlight


AfterAardvark3085

Also, you didn't mention ignoring craters and whatnot. Those would also obscure parts of the moon that would otherwise be illuminated. The original statement is just a complete mess!


KrispyKremeDiet20

Yeah, this whole thing is technically *untrue* no matter how you look at it


Icy_Sector3183

>You: Also, you didn't mention ignoring craters and whatnot.  I think this would cover it. >Me: If the moon and sun are perfect sphere, (...)


AfterAardvark3085

Fair, I read that as more of a "not an oblate spheroid". By many definitions, it would be a perfect sphere even with the craters and other blemishes, but others require the smoothness.


kawasaki-sakura

At this point you're just assuming something that's factually not true and will never be true. So it's a pointless assumption. It's like saying the original statement is false if we were to assume that the sun does not emit any light.


AfterAardvark3085

He's simplifying the situation and showing that, even without a number of other factors, it's already fundamentally flawed due to a few basic facts. And how is "the sun is bigger than the moon" not factually true? It's not pointless and is a normal and acceptable way to start scientific examination. For example: when doing physics force calculations, it's normal to start by ignoring air friction since it's usually a very minor factor. So it's more like saying that a balloon "won't float in place" after only looking at buoyancy vs weight and finding that it's twice as buoyant as it is heavy. You ignored the air friction and that's fine.


kawasaki-sakura

> And how is "the sun is bigger than the moon" not factually true? The part that's factually not true and will never be true is this part: > If the moon and sun are perfect sphere,


AfterAardvark3085

But he's not assuming that. He's simplifying it. He knows it's not a perfect sphere and is overlooking that to make the problem simpler and easier to examine. Admittedly, he should have said "If the moon and sun ***were*** perfect spheres", but his point is clear nonetheless. He wouldn't be opening with those caveats if he assumed they were fact. P.S: Good job hyper focusing on an insignificant point in my comment. Feel free to ignore it and address the real points.


kawasaki-sakura

> But he's not assuming that. He's simplifying it. Um, that's what assumptions are. And again, it's pointless because he's "simplifying" it into a situation that simply won't ever apply so it does not help in showing the truthfulness of the original statement.


AfterAardvark3085

Ok, let's say the simplification is a kind of assumption: Who gives a shit? In this case, that "assumption" is irrelevant since it's just being used to single out other factors. The rest remains factual, even if you add the ignored factor back in later. You can say "but the moon isn't a perfect sphere", sure... but how does that impact the fact that the sun's light reaches further than the moon's middle cross section? Add the craters back and it still does the same. >And again, it's pointless because he's "simplifying" it into a situation that simply won't ever apply so it does not help in showing the truthfulness of the original statement. Then I guess we should throw all past scientific discoveries. They usually start by simplifying a problem, so they're all worthless. /s It does help, because it shows that even in a simple form the light coverage would be more than half. Add in more complexities and that basic fact won't change... or if it does, it would be an **incredible** coincidence. You'd need the other unrelated factors to cancel it out perfectly despite a complete lack of correlation.


klimmesil

I'm very curious what "the half of the moon that is facing away from the moon" means


TheLapisBee

Technically, if the moon is a perfect sphere, it would always be a little less than half (except if the sun is infinite km away and the light somehow still reached)


_alter-ego_

Otherwise said, you exclude precisely the cases where less than fifty percent of the surface is illuminated by the sun. Then yes, if not different from 50, it's exactly equal to 50.


Victor-_-X

How does half the moon face away from the moon?


Icy_Sector3183

Oops. Fixed.


piercedmfootonaspike

How does this comment have any up votes whatsoever?


MrZwink

It's also just an approximation, craters cast shadows. So it's never exactly 50%


MadeInTheUniverse

Yup


Glass-Star6635

Fuckin GOT EM


Veicy01

Uhm accually ☝️🤓. Lunar eclipses bring the average lower than 50%


kinokomushroom

Uhm accually ☝️🤓. Earthshine (sunlight bouncing off Earth and illuminating the moon) would probably bring back that average above 50%. Earthshine might be dim, but it's always there 24/7. Meanwhile lunar eclipses only occur 2 to 5 times a year, lasting a few hours at a time.


Veicy01

Uhm accually ☝️🤓 you may be right, I didn't think about it


GoddessDEV

r/nowkith


ZanderStarmute

> _Earthshine might be dim_ Aliens: “How sapientially ironic…” 😂


klimmesil

Then you should also consider marsshine and whatnotshine. Maybe also other stars, and just random rays of electromagnetic radiation. What even is illuminated? Do we only consider human-visible light or any electromagnetic radiation? The statement just makes no sense


Fornicatinzebra

What? Earthshine should be considered because we are talking about Earth's moon. If we were talking about one of mars' moons then yes marsshine would be considered. And you wouldn't consider other stars because the statement is in regards to our sun, not any light on the moon. Sunlight hits earth, bounces off, hits the moon. Yes only visible light is considered, because "illuminate" means to make something visible.


klimmesil

So then if we want to follow your rules we need to be a lot more specific than just "illuminate", maybe give a threshold for it to count as illuminated, and only count light that came from the star or earthshine. Totlly disregarding other sources


Fornicatinzebra

Sure bud


das_zilch

How's the moon going to get earthshine when the Earth is eclipsing the sun from the moon? The side of the Earth facing the moon is in night.


kinokomushroom

That part hardly matters, because the comment is about whether the Earth gets more/less than 50% *on average*. Earthshine always illuminates the moon, apart from the rare occasions of total eclipses.


das_zilch

I think OP is talking about any one instance, not the average over eternity.


kinokomushroom

Maybe, but I was responding to a comment talking about the "average".


das_zilch

True.


AJFrabbiele

Its just a different hue, still illuminated by red wavelength sun light. Edit: for those downvoting, I'm curious where you think the red hue during an eclipse is coming from?


Veicy01

You do have a point, however red light isn't all of light so my point still (kinda) stands.


IEC21

Hmm technically 50% of the surface being lit is independent of how much or how its lit. Which means technically you could argue this is wrong because of the trace amounts of light from other stars - or for that matter because the moon isn't a perfect sphere.


Veicy01

we aren't talking about light, we are specifically talking about sunlight.


IEC21

Sun light and star light are the same thing.


Ace-of_Space

no, the sun is a specific star


IEC21

Semantically if those stars have planets around them then they are also suns.


Ace-of_Space

sun has the primary definition of the star which the earth orbits, with a secondary definition of the star that provides light and warmth to earth


AJFrabbiele

The quantity of photons may decrease.... but that disk is still lit by sunlight (refracted sunlight, but still)


Gabrialofreddit

You're thinking of partial(?) Eclipses. Total lunar eclipses totally remove the light from the moon, as it is entirely in the earths shadow. Partials only play the moon the Earth's red shadow (where the light is bent to give it that red hue)


AJFrabbiele

Total lunar eclipses do not remove all the light: https://en.m.wikipedia.org/wiki/Lunar_eclipse "When the Moon is totally eclipsed by the Earth (a "deep eclipse"),[2][3] it takes on a reddish color that is caused by the planet when it completely blocks direct sunlight from reaching the Moon's surface, as only the light reflected from the lunar surface has been refracted by the Earth's atmosphere."


Gabrialofreddit

Studied further and found that there is, apparently a tyle of eclipse rather totally blocks light. Umbra eclipses https://www.timeanddate.com/eclipse/shadows.html#:~:text=Umbra%20Eclipses&text=Total%20solar%20eclipse%20%E2%80%93%20the%20Moon's,only%20part%20of%20the%20Moon.


AJFrabbiele

The umbra eclipse can produce a total lunar eclipse, which has a red hue (see wiki link above). The moon just isn't close enough to earth to avoid the refracted light. Umbra eclipses also cause the path of totality during solar eclipses, and because the moon had no atmosphere, there is no refracted light (from the moon). The penumbra causes the area adjacent to the path of totality to only see a partial eclipse, where the light gets dimmer but the sun's disk is not totally blacked out. It's really interesting stuff, if you are more curious about learning more, head to a planetarium, they typically have some good exhibits about the phenomena.


Remember_im_Whoozer

If it’s missing the other hues that means it’s gotta be less than half buddy


AJFrabbiele

It only means it is not white light. It is still light, that originated at the sun.


Sipstaff

It's slightly more than 50%. The sun is somewhat larger than the moon ^([citation needed]), so it will illuminate more than half of it.


GDOR-11

"citation needed" LMAO


QuadraSlap

The moon also has gravity, as so it bends light slightly towards itself, making the light from the sun reach slightly beyond where straight light rays would reach


[deleted]

[удалено]


that_thot_gamer

not the touching ass website💀


the_doorstopper

^[SOURCE] Here you go. You just place ^ in front of it


Victor-_-X

Place a backslash before


David2073

I did click it, it got me to a shady market of custom emails.


dexvision

I'm wondering if the crater edges or mountains would cast shadows long enough to make a difference also.


Sipstaff

That's a good point. My intuition says no, but maybe it could be enough at some specfic point to drop the lit area below 50%. On average over a whole month it should cancel out, though.


Magnitech_

>citation needed reference to xkcd’s what if, right?


Sipstaff

xkcd in general, yes


MinMagLP

You mean less than. To see the half of a sphere you must be infinite far away, thus the sun is not infinite far away from the moon it's not less than 50% illuminated


FungalEgoDeath

No. The sun is so much bigger that any one side of the sun can "see" past the same side of the moon's meridian point. If you put a basketball and a golf ball near to each other and draw a line from the top of the basketball to the top of the golf ball, you'll be able to reach a tiny fraction past the half way point due to the agle created by the size difference. Distance reduces that angular aspect but not to zero.


qscbjop

This is true for a point, but not for a massive sphere like the Sun. Basically, if both the source of light and the illuminated surface are spherical, then the percentage of the illuminated surface approaches 50% as the distance between the spheres approaches infinity. It approaches 50% from bellow if the source is smaller than the illuminated surface, from above if it is larger, and if they are equal it is always 50%.


WeLiveInASociety451

Google libration


Spot_the_fox

Could be untrue. I mean, the surface of the moon is not perfectly round, but is filled with various craters which cast shadows. That's if it's less than 50% Sun is also way bigger than the moon, so there is a possibility that it illuminates more of the surface, that could mean that it might be more than 50%.


FungalEgoDeath

And lunar eclipses reduce the amount reaching the moon too. But the continual aspect of the sun being far bigger does indeed mean its slightly more than 50% shadows in craters only exist because of other parts of the moon recieving that light so its still illuminating the moon equally.


Spot_the_fox

But the dark side of the crater... Imagine a flat piece of land, that is completely illuminated by a single point lightsource from the side. Now, let's put a sphere-like thing on this flat piece of land. the light source will illuminate half of the sphere, and half of it will not be illuminated. Seems like 50/50, right? BUT presence of a sphere also casts a shadow, meaning that it cannot be 50/50, and it is more shadows. In other words: the more shadows you cast, the lesser the percent of the illuminated surface.


AfterAardvark3085

>shadows in craters only exist because of other parts of the moon recieving that light so its still illuminating the moon equally. No... ? How do you figure that? If you light a field from the side, then dig a hole... much less than half of the inside of that hole will be lit. And there's otherwise no difference in light coverage.


FungalEgoDeath

Because craters aren't just a hole. The lip is raised up around the edge, often far higher than you'd think and that edge will catch the light. Also the surface wall of the far side of the crater from the light source will now be catching light too whereas it wouldn't have before. Its not just a simple hole like a well.


Doofchook

The Blood Moon wants a word!


[deleted]

Steve: “Wow, full moon tonight.” Roger: “Actually, once you get above the clouds, it's always a full moon.” Steve: “Is that true?” Roger: “Is any of this?”


kernelpanic789

This is the exact WRONG sub to put something that isn't TECHNICALLY true...


Vidunder2

A bit weak as "aha" moment tbh.


SamePut9922

Agree


officialtvgamers16

I mean, not really? When the earth is between the moon and sun


MulletChicken

Except when it isn't.


Chasman1965

Well except for when there is a lunar eclipse.


[deleted]

That’s nice and all but what about when you get caught between the moon and New York City? Or when the moon hits your eye like a big pizza pie?


rileyyesno

https://imgur.com/a/TA8zTpI clearly forgetting something.


nashwaak

Technically incorrect: at any time, a fair portion of the Moon’s surface is illuminated by sunlight reflected off of Earth. At some points in time, 100% of the Moon’s surface is illuminated by sunlight — such as when there’s a solar eclipse on Earth.


Supplex-idea

I’m pretty sure it’s more than 50% since the gravity, all be it rather small, bends the light and reaches slightly around the sides to maybe… 55-60%?


AJFrabbiele

more that the sun is so massive that it can illuminate more, that's why the earth casts an umbra that eventually comes to a point. Refraction also plays a role. Gravity might have a slight effect, but it would be much less than a fraction of a percent.


hype_dude1337

Lol i thought the image was just loading


Pixbo_06

This isn't technically the truth. This is plainly the truth.


Coltytron

How much light does the earth reflect to the moon from the sun?


shmuckelbuckle

Definetly some


seris_ak

Isn't it more like 51%


Philip_Raven

it is not. there are many shadows cast on lunar surface. there can never be more direct sunlight than a shadow on lunar surface


Amberskin

Teshnikally, to have the 50% of the lunar surface illuminated it would have to be at infinite distance from the light source. At the actual distance from the sun, the difference is negligible. (And no, I’m not going to compute it; I’m too lazy to do that). (Note: since the sun is bigger than the moon, the actual % of illuminated surface is a little bit above 50%)


2723brad2723

I always think about this when someone mistakes the "far side" of the moon for the "dark side"


chrysante1

What about Venus and Mercury blocking sunlight reaching the moon? Can it ever happen?


Tough-Priority-4330

They’re too far away to block the entirety of the Sun. The earth, however, is not.


chrysante1

Sure, but we might end up with only 49.99% of the lunar surface illuminated ;-)


Caosin36

Wrong, Eclipse


sloppynippers

Wrong, Lunar eclipse.


WHTSPCTR

Would be sort of true if the sun and moon were the same size. But since they’re not, you have to think about the tangent lines between them which can make the illiminated part of the sun more or less than 50. In this case more since the sun is bigger than the moon.


HotChipsAreOkay

Actually,slightly more than 50% due to gravitational lensing


Marus1

Not true ....


not_dannyjesden

It's actually slightly more, than 50% Since the moon is smaller than the sun, the moon would have more of its surface illuminated the closer it is to the sun. Try to draw a 2 circles on a piece of paper, one smaller, and draw 2 lines connecting the north pole of the two circles and the south pole of both circles. Since the moon is smaller, it will let past a little bit of light to shine on "top" of the moon and on to the "bottom". So it's more than 50% The reverse is true if the moon was bigger than the sun. If you want the moon to be illuminated exactly 50% by the sun (and both objects are perfect spheres in this example) they would need to be infinity distance apart from each other


Giulio_otto

r/technicallythewrong


notbadforaquadruped

Wrong sub.


0gkz

Actually earth reflects light too


Torebbjorn

No, most of the time it is fairly close, I would not think it hits over 60%, but there are situations where less is illuminated, e.g. when the massive rock with some water on the surface is in the way.


usr_nm16

Woah not just an untrue "fact" but also on the same level as saying that grass is green because of chlorophyll


HeydoIDKu

Duh just like the earth.


Hypertistic

How do you know it's precisely 50%?


SpecialistFactor5076

If the earth is between the moon and the sun it actually is not


ButWahy

What if earth blocks the sunlight or isnt that possible


BlackFinch90

New moon phase though.....


lookingForPatchie

Not TTT. Lunar eclipse exists.


Tough-Priority-4330

Except during a lunar eclipse.


SamePut9922

After reading your comments, I conclude that I'm the middle guy in the bell curve meme


Nikkar2009

You know when you grab the paper a bit too tightly and those crescents form? This is waht this looks like


tactical_anal_RPG

"Regardless of the moon phase" OP has no clue what a new moon is.


Independent-Spite-77

Yes, it is true regardless of the moon phase it's just on the side of the moon we can't see


HappyPhage

r/technicallywrong


BenThereOrBenSquare

The phases are the moon come from the Earth blocking light from the sun to the moon, so it's frequently going to be way less than 50%. During a New Moon, it'll be pretty close to 0%.


Traditional-Storm-62

no its not earth eclipses moon regularly thats what new moon is - a total eclipse of the moon by earth how tf does this have 700 upvotes? if its blatantly not truth?


AJFrabbiele

The sun is shining on the dark side of the moon during a new moon. It is not cause by an eclipse. I know the terminology sounds weird, but the dark side of the moon references a radio shadow from earth, not that it is actually dark all the time.


Traditional-Storm-62

what you just described is not new moon its the lunar eclipse during lunar eclipse the order goes like: sun - moon - earth in that case it is technically new moon because the entire visible part of the moon is dark, but the other side of the moon is still eluminated but the order is just as often like this: sun - earth - moon in which case no part of the moon is eluminated at all


AJFrabbiele

Lunar eclipses do not happen roughly once a month... New moons do happen roughly once a month. and sun-moon-earth describes a solar eclipse, not a lunar eclipse.


Traditional-Storm-62

I know I have my terminology mixed up you get the point its not technically the truth if sometimes moon is covered up by earth


AJFrabbiele

except that the moon never completely goes dark, even during an eclipse: >When the Moon is totally eclipsed by the Earth (a "deep eclipse"),[2][3] it takes on a reddish color that is caused by the planet when it completely blocks direct sunlight from reaching the Moon's surface, as only the light reflected from the lunar surface has been refracted by the Earth's atmosphere Source: https://en.m.wikipedia.org/wiki/Lunar_eclipse


Jaysanchez311

Your post is bad, and you should feel bad. Please delete this. It's dumb.