StuffYouFear ,

Is the common ground the fact both rotate around the super massive blackhole at the center of our galaxy?

Eufalconimorph ,

No, they orbit around a common barycenter. Even if there were no other bodies in the solar system, that wouldn't be exactly at the center of mass of the sun.

hperrin ,

I mean, no, not really. The gravitational center of the sun-earth system is within the sun itself, so the earth definitely orbits the sun and the sun definitely does not orbit the earth. Let alone the fact that the sun’s movement is predominantly driven by Jupiter. (The gravitational center of the sun-Jupiter system is just above the sun’s surface.)

gapbetweenus ,

Pretty sure you can chose earth as fix point and have everything rotate around it on really strange orbits. Everything is kind of relative.

Ashelyn ,

Wouldn't that break relativity tho if you treat the earth as a fixed point? Stuff really far out would have to be going absurdly faster than light to orbit the earth once every 24h. I feel like that's one of the ways to tell whether or not you're rotating, or stuff is orbiting you.

gapbetweenus ,

Why would objects far out need to orbit earth every 24h?

Wouldn’t that break relativity tho if you treat the earth as a fixed point?

To be honest, physics was never my strong point. If I remember correctly you could chose any point as your observational (?) point but maybe someone with some real physics cred can chime in.

paholg ,

If the earth is fixed (not just in position, but in rotation), you're using a non-inertial reference frame, and things get wonky. But you can make the math work.

Natanael ,

Relativity works when earth is the center because it's relative, we just calculate everything with earth as the frame of reference. It does make a lot of math harder, but that's what we already are doing when using earth based telescopes (although we try to shift the math to a more reasonable frame of reference for most stuff, but earth is always the starting point because we're making all the measurements from here)

douglasg14b ,
@douglasg14b@lemmy.world avatar

Except that any two gravitational bodies orbit a common center...

The Earth orbiting the Sun causes the sun to wobble slightly, moving its orbital center away from its center of mass, which means the sun and earth actually orbit a common center point no?

Even if that center point is within the other body it still isn't the center of that body, therefore they both orbit a shared gravitational center that is not the center of either body.

hperrin ,

I would not call it orbiting if the center is within the body. So, since the center of the sun-Jupiter system is just outside the surface of the sun, I would say the sun and Jupiter orbit the center of their system, but since the center of the sun-earth system is within the body of the sun, I would not say the sun orbits the center of this system. The path the sun takes in this system is entirely contained within its body.

Now, since the sun, Jupiter, and earth are all in the same system, there’s even less reason to say the sun orbits the earth, since the earth has a negligible effect on the sun’s motion.

douglasg14b ,
@douglasg14b@lemmy.world avatar

Just because you believe that a negligible effect means that it shouldn't be called orbiting doesn't change the fact of the matter that there is still a shared gravitational center that both bodies orbit around...

It doesn't matter if it's negligible or not, the fact of the matter is that such a point exists and both bodies orbit around that point.

hperrin , (edited )

Then literally everything is orbiting literally everything else, and the word orbit is completely useless.

I have a gravitational effect on the earth. The earth-hperrin system has a gravitational center that both bodies revolve around. Does that mean the earth and I orbit that center? No, because my effect on the earth is negligible. The absolutely immeasurably small wobble my mass gives the earth is not an orbit. There are bodies much more massive than me that the earth orbits (despite how many Doritos I eat).

To put in less hyperbolic terms, Mars’ moon Phobos and Mars have a gravitational center, deep deep deep within the Martian core that both bodies revolve around. Does that mean Mars orbits this point? I don’t think a reasonable person would say so. A massive body wobbling because of a small body orbiting it is not orbiting. Only one thing in such a system is orbiting.

simin ,

the three body problem being one of my favorite scifi until it was kinda solved a couple years ago

kajdav ,

What are you referring to? I haven't heard anything about the three body problem being "solved" - there's still no general solution afaik

TheFonz ,

Oh shit I'm like four chapters in. Now I'm really scared.

gandalf_der_12te ,

Is this... an introductory course in relativity, disguised as a joke?

Am I accidentally learning something here?

Guys?

moosetwin ,

xkcd

yes it is

jungle ,

Not really, relativity plays no role here. It's classical Newtonian physics.

moosetwin ,

I was more referring to the fact that xkcd's comics have a lot of science in them, rather than the specific type of science

netvor ,
@netvor@lemmy.world avatar

relativity plays no role here

I still count that as learning.

JasonDJ ,

Relatively speaking, though…

kurosawaa ,

XKCD is basically all math jokes.

niktemadur ,

It's called a barycenter, kids, a common center that both objects circle around. That common center happens to be inside the sun, but that's a topic for next week's class in this semester's AP Astrophysics program.

WhiskyTangoFoxtrot ,

Goddammit, Barry.

Everythingispenguins ,

Always trying to compromise

Johanno ,

Same for earth and moon. The center is inside earth. But not that close to the center of the earth itself

niktemadur ,

Meanwhile, Pluto and Charon noticeably orbit each other, the barycenter being fully outside of Pluto's surface.

Klear ,

And Jupiter is so massive that its barycentre is (barely!) outside of the sun!

ByteJunk ,
@ByteJunk@lemmy.world avatar

I don't think the barycentre is inside the sun? Wikipedia says on the barycentre article:

When the less massive object is far away, the barycenter can be located outside the more massive object. This is the case for Jupiter and the Sun; despite the Sun being a thousandfold more massive than Jupiter, their barycenter is slightly outside the Sun due to the relatively large distance between them.[2]

hypertext5689 ,

I don't think the barycentre is inside the sun?

The Jupiter-Sun barycentre in outside the sun.

The Earth-Sun barycentre is inside the sun.

CosmicCleric ,
@CosmicCleric@lemmy.world avatar

If this topic proves anything, it's that we should make sure everyone is assuming the same thing before discussing, or clarify before discussing.

You can literally come up with different answers without further clarification.

MNByChoice ,

Remember when we had to list all of our assumptions before making an argument?

Those were good times. (I don't remember when, maybe in Linear Algebra or an engineer or philosophy course.)

Hamartiogonic , (edited )
@Hamartiogonic@sopuli.xyz avatar

Apply that to the flat earth debate and you get an oblate spheroid.

Telodzrum ,

…fuck

Thcdenton ,

You're an oblate spheroid

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

As a middle ground kind of guy, I would like to pre-emptively state that a lot of us don't actually think the answer is always the middle ground between two stances. It's just that we're more likely to propose a middle ground solution because we evaluate the plausibility of both stances in a more balanced way (as opposed to existing-stance-holders who are prone to bias towards their own stance.) When the two seem roughly equal in plausibility (which happens fairly often, otherwise the argument would be more one-sided,) that's an indication to evaluate the middle ground as well.

Middle ground folks are often caricaturized as wanting to find the middle ground between an objectively sensible point A and a radically wrong point B, when the spectrum of opinions is sort of like [ - - - - - A - | - - - - - - B ]. In that caricature, we're looking for a middle ground at point C [ - - - - - A - | - - C - - - B ], when in actuality we're evaluating (and not automatically accepting) something two or three steps closer to A. In some such cases, A might already be the most sensible middle ground.

ForgotAboutDre ,

Middle of the ground people are mostly cowards too scared of conflict, or devoid of insight.

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

Maybe there's a middle ground between our two views.

riskable ,
@riskable@programming.dev avatar

Why are you so scared of conflict?

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

I'm not scared of conflict, I'm averse to needless conflict. I may get involved in a conflict for the purpose of breaking it up, or I may initiate a conflict for a good cause such as combating hatred and averting future conflicts - if I feel it'd be productive.

riskable ,
@riskable@programming.dev avatar

Great reply but... I was being facetious; making fun of the guy you were replying to 😁

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

I figured.

WhiteHawk ,

Why waste your time fighting when there's a solution everyone is happy with?

thecrotch ,

More likely a solution nobody is happy with but everyone can live with. Your point stands though.

gandalf_der_12te ,

"compromise is when all sides are unhappy"

CazzoBuco ,

Middle implies middle. If you are leaning towards a side, then you're side-leaning. You can't have your cake and eat it too, centrist, that's what everyone makes fun of ya'll for.

AeonFelis ,

It's "somewhere in the middle". You are putting to much emphasis on "middle" and not enough of "somewhere".

CazzoBuco ,

Somewhere in the middle means there's a middle and side-leaning, yes.

AeonFelis ,

Somewhere in the middle means it doesn't have to be dead center - it just has be between the two extremes and not exactly one of the extremes. To put it in numbers, somewhere in the middle between 0 and 1 is not just 0.5. It can also be 0.4. Or 0.7. Or 0.00000000001.

Ookami38 ,

This is why people hate pedants. You're technically correct, it's just a useless distinction that only exists to make you feel better.

CazzoBuco ,

That's exactly how I feel about centrists. Curious.

ZDL ,
@ZDL@ttrpg.network avatar

You seem nice.

RedditWanderer , (edited )

It's hilarious he had to make us a little drawing making up his own scale that fits this narrative.

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

It's an abstraction of a caricature I've seen. Point A was civil rights, point B was the KKK, and the middle ground guy was like "what if we only kill half of Black people?"

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

a lot of us don’t actually think the answer is always the middle ground between two stances.

Jarix ,

If i have a very plain boring hamburger. Bun cheese patty bun, are the cheese and patty in the middle? Middle doesnt always mean center, center doesnt always mean exactly in the center between 2 points either because thats why the term dead center exists

kbal ,
@kbal@fedia.io avatar

In an n-dimensional problem space, the probability of the truth lying anywhere on a line between point A and point B is infinitessimally small.

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

This is also true. I like to evaluate solutions outside the presented dichotomy in general, and that often means outside the line between them, but I didn't want to complicate my initial explanation that much.

kbal ,
@kbal@fedia.io avatar

It's just the same point xkcd made.

BeMoreCareful ,

https://lemmy.world/pictrs/image/37d6f078-a1ad-467f-9d3f-2f0630465d3e.png

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

I'm actually not as neutral as I may seem. There are quite a few cases where I hold more extreme opinions, but as a general trend, I average somewhere around the middle.

NewAgeOldPerson ,

I don't know. But if I die, tell me wife I said hello.

Ookami38 ,

Wow. You just succinctly explained the position I've held most of my life. Very well done!

CosmicCleric ,
@CosmicCleric@lemmy.world avatar

You're my hero. Thank you.

ilinamorato ,

Ok, but let's realize that you're not necessarily the one who's defining the spectrum of options; or put another way, there's not an objective spectrum of options.

For instance, in the case of Israel and Gaza, you could define the leftmost bracket as "give Israel to the Palestinians" or "the second-state solution" or just "a cease-fire," and likewise the rightmost bracket could be "let Israel keep the war going but let civilians out through Egypt" through "Israeli settlement of Gaza" all the way up to "glass Gaza." Depending on who's talking, and how extreme each person is in the discussion, the most humane solution might not be in the middle at all.

Sotuanduso ,
@Sotuanduso@lemm.ee avatar

I'm not seeing a conflict here. The point I'm making is that the middle ground is not necessarily in the middle of any two given opinions, because the spectrum is wider than that. And also that the middle is not necessarily the best, just worth evaluating.

ilinamorato ,

It's not a conflict. What I'm trying to say is that what people hear when you say you want to "evaluate the middle option" is entirely dependent upon the options presented in the argument, which is why the caricature is so common.

prex ,

https://aussie.zone/pictrs/image/5bc9991f-b757-47f5-ba67-863d4934bac2.jpeg

TimewornTraveler ,

I appreciate the origin story being included in this cliché, cuz it got repeated so often on Reddit that people seemed to forget it was said by a parody of an obnoxious heartless bureaucrat and repeat the phrase without irony.

Huschke ,

You know, you are technically correct.

SatansMaggotyCumFart ,

Which is a kind of correct.

What kind we’ll never know.

muntedcrocodile ,
@muntedcrocodile@lemmy.world avatar

Surly the sun is big wnough that the point actually being orbited is still within the sun?

JimVanDeventer ,

For our solar system: mostly. But if we lived in a binary star system, the distinction would be much more obvious.

muntedcrocodile ,
@muntedcrocodile@lemmy.world avatar

Well we aint in a binary star system are we.

JimVanDeventer ,

How would physics know that? We orbit the same point, regardless of the number of stars. (It’s called the barycentre).

WhiskyTangoFoxtrot ,

I haven't asked the solar system for their pronouns.

spujb ,

yes, the earth-sun barycenter is still well within the sun.

not sure why other commenters felt the need to give snark lol

billwashere ,

And that point is inside the sun.

dirtbiker509 , (edited )

No the comic is pointing out that the sun and the earth are both orbiting the milky way galactic center.

Edit: While also true, I was wrong, they orbit the center of mass of the two body problem (earth and sun). I still think that's too simple of a way to look at it. It's not a two body problem and the other planets and the whole galaxy are also in play.

nonfuinoncuro ,

I mean technically every body in the entire universe exerts gravity on everything else as long as it's in your light cone

hypertext5689 ,

What's a light cone?

TheGreenGolem ,
@TheGreenGolem@lemmy.dbzer0.com avatar

A not too heavy cone.

nonfuinoncuro ,

https://en.wikipedia.org/wiki/Light_cone

this doesn't give a very good explanation but I'm sure there's some good YouTube video that breaks it down. essentially maps out everywhere in space and time that could possibly interact with you in any way. this maximum is represented by how fast light can move away from you.

for example if you stole my car and ran away from me, I can draw a circle on the map every hour for how far you could have gone (assuming I knew my car's maximum speed). if I put those circles on top of each other it'll make a cone.

blanketswithsmallpox ,

True in reality it's just the sun and Jupiter orbiting each other in a common point...

Inside the sun lol.

V0lD ,

No actually. Due to Jupiter, the centre of mass of the solar system is actually very slightly outside of the sun

billwashere ,

Cool. I learned something today

afraid_of_zombies ,

Leave it to Jupiter to mess yet another thing up

frezik ,

Stupid lazy ass diabetus planet doesn't even have enough mass to fuse its hydrogen.

RememberTheApollo_ ,

Wouldn’t the center of mass constantly be shifting by the planets’ varying positions in orbit?

uriel238 ,
@uriel238@lemmy.blahaj.zone avatar

relative to the center of the Milky Way, yes.

Sadly, the quantum foam has no gridlines.

starman2112 , (edited )

Yes, but it's mostly shifting because of Jupiter. It's just so dang heavy. Like, a couple times heavier than every other planet put together. I don't have the brain wattage to do the cool math right now, but a quick google search says that while the barycenter of the solar system does depend on all the planets, more often than not, it is outside the sun

gandalf_der_12te ,

Easy reminder:

sun ~ 10^30 kg
jupiter ~ 10^27 kg
earth ~ 10^24 kg

so the ratio is always 1000:1

niktemadur ,

But I think the math of the argument is only about the common center between Earth and the sun, taking away all other planets out of the equation, especially Jupiter.

Flumpkin ,

So doesn't that mean the earth and sun do not orbit a common center but a varying point based on mostly Jupiter?

Centrists have bamboozled me again!

WoahWoah ,

Wait I'm sorry, are we saying that the earth's orbit isn't almost entirely dictated by the gravitational pull of the massive star at the center of our solar system? I am a simple man, I apologize if that is a stupid question.

ramble81 ,

When dealing with gravitational systems the gravity of each object has to be taken into account. So even though the sun is 99.999% (hyperbole) of the gravity in the equation, the earth’s gravity contributes that small 0.001% and thus the “center” of where they orbit isn’t truly the center of the sun. Tack on Jupiter, which is much more than a fraction of a percent and that “center” moves even farther away from the middle of the sun.

To look at it further, if you had two objects of perfectly equal mass and no other gravitational interference, they would orbit around a point in the middle of each other since their pull is equal. So it’s basically a sliding scale of sorts.

Hope that explains it!

WoahWoah ,

That did help, thanks for taking the time. I think I was thinking about mass and gravity not orbits. Again, I'm an idiot, so that's probably why I missed the central point of the cartoon. 😁

CptEnder ,

Ah yes, Sgr A*

StuffYouFear ,

This was my thought too

CptEnder ,

And then after that I guess the Local Group? Haha

MxM111 ,

All is relative. All are right. Or wrong. We are orbiting galactic center.

Teppic ,
@Teppic@kbin.social avatar

Mobile friendly version: https://m.xkcd.com/2898/

lugal ,

Sometimes, both can be wrong. Both orbit the moon

Teppic ,
@Teppic@kbin.social avatar

...whoosh.
In no logical sense does the sun orbit our moon. The earth does however indeed orbit the moon (or technically they both orbit a common centre between the earth and the moon).

Deceptichum ,
@Deceptichum@kbin.social avatar

Are you saying that in no way shape or form, does the moon and its affect on the earth and earth-moon barycenter not influence the solar barycenter?

Id accept no way worth caring about, but as an absolute?

Teppic ,
@Teppic@kbin.social avatar

You seem to be saying that the earth-moon barycente can be logically referred to as just 'the moon' ?

Deceptichum ,
@Deceptichum@kbin.social avatar

The earth does however indeed orbit the moon (or technically they both orbit a common centre between the earth and the moon).

Heres you referring to the Earth moon barycenter as just ‘the moon’

Teppic ,
@Teppic@kbin.social avatar

You've got me there, but by logical extension you are now saying the celestial body the ISS orbits is ...the moon?

lugal ,

I've talked to the man in the moon and he said the sun rises and sets on the moon like it would if the sun orbits the moon. Same for the earth. Both orbit the moon. Face it.

RobotToaster ,
@RobotToaster@mander.xyz avatar

The Earth–Moon–Sun three body problem is apparently something that has been studied quite a bit in physics.

lugal ,

And of cause there are 3 camps and alot of disagreements but essentially, the majority of scientists argue, like me, that it is the moon which is the center. You can always cite some fringe scientists arguing otherwise, that doesn't change the general consensus.

gandalf_der_12te ,

you are the barycenter of your own opinion

yo opinion so massive she needs a crane to get out of bed.

lugal ,

I'm not sure about that but for sure I am the center of my personal narrow Overton Window

  • All
  • Subscribed
  • Moderated
  • Favorites
  • •
  • random
  • xkcd@lemmy.world
  • test
  • worldmews
  • mews
  • All magazines
    •