Althouse: Actual sunrise was 7:20, and the temperature was 10°.

December 11, 2019

Actual sunrise was 7:20, and the temperature was 10°.

7:22:

A25EB2D0-6B0A-4E1F-AAF9-2706A38E66F6_1_201_a

7:29:

1C2745CA-DC80-443F-8F32-72BE63544105_1_201_a

7:36:

58 comments:

tcrosse said...: There are strange things done in the morning sun by the folks who brave the cold....; 12/11/19, 1:43 PM
JohnAnnArbor said...: Pretty, watching the earth rotate like that.; 12/11/19, 1:44 PM
J. Farmer said...: “Do you realize the sun don’t go down; it’s just an illusion caused by the world spinning round.”; 12/11/19, 2:29 PM
AllenS said...: If the earth was ever to quit rotating, I hope it quits rotating an hour or 2 after daybreak where I live.; 12/11/19, 2:41 PM
AllenS said...: If the earth quits rotating, we will not have to worry about daylight savings time.; 12/11/19, 2:42 PM
rcocean said...: So lovely. Too bad its so damn cold. I'm not sure what I dislike more "Very cold and Sunny", or Cloudy/Wet and 50 degrees.; 12/11/19, 2:57 PM
Unknown said...: "It's hard to take a person seriously wearing shorts."

Season 10 trailer for Curb Your Enthusiasm

And I'm pretty sure Larry meant, "It's hard to take a person wearing shorts seriously." And I agree.; 12/11/19, 3:03 PM
Tyrone Slothrop said...: When I was at school in Fairbanks, I would jog outside as long as it was above 15°. Below that, it was doing circuits in the gym.; 12/11/19, 3:08 PM
Tommy Duncan said...: Thankfully, most gun manufacturers pack their products in recyclable cardboard. The same is true for ammunition.; 12/11/19, 3:12 PM
Lucid-Ideas said...: Complete tranquility. When I'm reincarnated as a hawk I expect to hang out on a branch of a tree overlooking that lake. Sadly - as a hawk - I'm not skilled at fishing. My eagle-friends are, but they won't share their fish with me. Fine, I won't share my rabbit with them either.

Sunrise

My visions of Aten
Created psychosis
On the slab
Eyelids flutter
And the poppy drip
Isn't nearly enough
To keep me from feeling
Every
Single
Slice
Of my flesh
Aten rises
Again and again and again
Hovering over
This most terrible of days
And shall rise again
To greet me tomorrow
My bloodiest
Of blood-red
Dawns; 12/11/19, 3:52 PM
As my whimsy leads me.. said...: Those are the best of your lake series. So beautiful!

Toy; 12/11/19, 3:53 PM
Lucid-Ideas said...: @JohnAnnArbor

As the world turns. The reality show...not the TV show.

GankTirl

Junk in the trunk
Seventy tons of badunk
You have massive guns
And I want to have fun
You needn't call higher
Or a helicopter flyer
We have all that we need
My platoon
And this creed

They want to bring shells
Like heavy steel rain
This kind of shit sells
Only we bring the pain

If you were only a chick
And your guns weren't
A pic
I'd fondle your muzzle
After foreplay
A Nuzzle
No one would see
And I'd lay it on thick
For my mom and sister
Saying high and goodbye
On late-night TV; 12/11/19, 4:19 PM
readering said...: L. Lin Wood, the plaintiff's lawyer portrayed in the new film Richard Jewel, was the lawyer for "pedo guy" in the recent libel trial against Elon Musk. He is also the lawyer for the Covington Catholic High School kid libel case against the Washington Post. However he just disclosed in a letter to a legal publication that on Thanksgiving he promised his family that Musk will be his last jury trial.; 12/11/19, 4:25 PM
Ann Althouse said...: Running makes the cold a nonissue. You dress for a temperature 15 to 20 degrees warmer, so think of 10 as like 25 or 30. No problem. Dress right and run a little faster. No reason to switch to indoor stuff!; 12/11/19, 5:27 PM
stevew said...: 10 is a good number. If it gets much colder or windier you should consider covering any exposed skin (face, neck, hands).

The coloring of the photos these last few days have been remarkably similar. Doesn't make me like them any less.; 12/11/19, 5:42 PM
Michael McNeil said...: “Do you realize the sun don’t go down; it’s just an illusion caused by the world spinning round.”

True, but only from a specific, parochial point of view. As Einstein calculated — and a hundred years of experiments and observations have verified — from another point of view it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours.; 12/11/19, 5:49 PM
Fernandinande said...: We were watching some show about Henry Lee Lucas and his cutting off heads and having sex with the bodies, and I said, "If they're still warm, what difference does it make, it's not like Ted Bundy digging them up a week later" and she said "I'm not talking to you any more."; 12/11/19, 5:59 PM
gilbar said...: i take it ALL BACK! these democrats are Fucking Rocket Scientist level SUPER GENIUSES !

They've Dedicated themselves to DESTROYING TRUMP!!!! and because of those efforts...
NOW!
Polls say:
The MAJORITY of people oppose Impeachment
President Trump's Approval ratings are climbing (on Rasmussen to OVER 51 percent!)
That President Trump now beats ALL comers... In EVERY battleground state
ALSO:
The Senate has just confirmed the President’s 50th addition to the federal appellate courts
{50 is “a record for a president this early in a term}
Meanwhile:
Nancy Polosi is BRAGGING about how she was able to get President Trump's USMCA bill passed

What can i say? I doubted the wisdom of the democrat's strategy; but: you can't argue with results; 12/11/19, 6:24 PM
gilbar said...: No reason to switch to indoor stuff!
except ICE! i hope you're careful (or wear cleats); 12/11/19, 6:26 PM
effinayright said...: Lucid-Ideas said...
Complete tranquility. When I'm reincarnated as a hawk I expect to hang out on a branch of a tree overlooking that lake. Sadly - as a hawk - I'm not skilled at fishing. My eagle-friends are, but they won't share their fish with me. Fine, I won't share my rabbit with them either.
**************

What makes you think you call the shots on this?

How many billions have died thinking they would be reincarnated as...something?

Where is the evidence to back up their claims?

It always seems to be a case in that in a past life people were kings, princesses (esp. princesses) or the like, but have come back as ordinary people, with memories of their royal past.

George S. Patton is the only counter I can think of, who thought himself a reincarnation of warrior ancestors. But...HE was a warrior.

So...where's the beef?; 12/11/19, 6:47 PM
effinayright said...: Michael McNeil said...
“Do you realize the sun don’t go down; it’s just an illusion caused by the world spinning round.”

True, but only from a specific, parochial point of view. As Einstein calculated — and a hundred years of experiments and observations have verified — from another point of view it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours.
*********************

What *other*, privileged point of view is that?

Where is that view taken? Why is it LESS specific, less parochial ?

How do you explain the evidence that the Earth,lying in an outer arm of the Galaxy, is rotating around its center every 200 million years or so.

How do you explain that the Milky Way Galaxy seems to be hurtling at enormous speeds toward
the Andromeda galaxy?

STAND AND DELIVER!; 12/11/19, 6:56 PM
Pilo said...: Please, Ann. No more sunrise photos. We get it. You go out for morning runs. The sun rises. Constant reminder of this aren't the reason we go to your blog. Enough already.; 12/11/19, 6:56 PM
etbass said...: "...it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours."

This would mean the cosmos outside our solar system is travelling well in excess of the speed of light? Not too swift on relativity but I thought that was impossible.; 12/11/19, 7:01 PM
etbass said...: "Enough already"

Back to rats?; 12/11/19, 7:09 PM
narciso said...: That seems improbable:

https://thefederalist.com/2019/12/11/hillary-clinton-chris-steele-allege-boris-johnson-is-a-russian-stooge/; 12/11/19, 7:11 PM
Ann Althouse said...: “ except ICE! i hope you're careful (or wear cleats)”

When there is ice, sure.; 12/11/19, 7:26 PM
Original Mike said...: "it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours."

Blogger etbass replied..."This would mean the cosmos outside our solar system is travelling well in excess of the speed of light? Not too swift on relativity but I thought that was impossible."

I don't know what "perfectly correct" means, but I think etbass has hit upon a problem with this "relativistic view."; 12/11/19, 8:03 PM
Michael McNeil said...: I'll reply on the foregoing “relativity” topic later. I have a choir Xmas program dress rehearsal in a few minutes.; 12/11/19, 8:15 PM
Titus said...: Don’t your feet get cold. My mom said it was 6 last night.; 12/11/19, 8:21 PM
J. Farmer said...: @Michael McNeil:

True, but only from a specific, parochial point of view. As Einstein calculated — and a hundred years of experiments and observations have verified — from another point of view it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours.

It's a song.; 12/11/19, 8:30 PM
J. Farmer said...: @Fernandistein:

We were watching some show about Henry Lee Lucas and his cutting off heads and having sex with the bodies, and I said, "If they're still warm, what difference does it make, it's not like Ted Bundy digging them up a week later" and she said "I'm not talking to you any more."

Ever hear of a “dead fish lay?”; 12/11/19, 8:50 PM
rhhardin said...: Running makes the cold a nonissue.

It depends on how near your aerobic capacity you go. Cold weather will slow you down if you run near it (on the point of getting out of breath but not getting out of breath), because a lot of blood oxygen goes into heating all the air you breathe into body temperature air. That takes out of your aerobic capacity for running and you run slower. Or bike riding, for that matter.; 12/11/19, 9:05 PM
chuck said...: >> from another point of view it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest <<

There is evidence that the earth is rotating: the Foucault pendulum, the coriolis force, etc. See Newton's Bucket, Artificial Gravity, Absolute Rotation, and Mach's Principle . For a current take on the question of whether the universe is rotating, see Is the universe rotating? for an analysis of current data.; 12/11/19, 9:20 PM
Seeing Red said...: Via Rantburg:

Virginia Democratic leaders abandoned their gun confiscation proposal Monday following a grassroots outpouring of opposition to gun control across the state.

Governor Ralph Northam (D.) and incoming Senate majority leader Dick Saslaw (D.) said they will no longer pursue their marquee plan to ban the possession of "assault weapons." Instead, they will include a provision to allow Virginians to keep the firearms they already own. The reversal comes before the newly elected Democratic majority has even been sworn in, after a majority of the state's counties declared themselves "Second Amendment sanctuaries."...

They’re still going to register guns. Good luck with that.; 12/11/19, 9:29 PM
narciso said...: Thats why time travel theories fail to consider not only the point in time, but the point in space and what plane they are on, only timecop factored in those variables to my recollection.; 12/11/19, 9:48 PM
David Begley said...: Someone here went to Cloisters on the Platte. What did you think of it?; 12/11/19, 9:54 PM
Seeing Red said...: Via Rantburg:

Career Officials Thwart Aid to Christian, Yazidi Genocide Victims

Real Clear Politics

Of course it’s the State Dept. Pence had to get involved and they didn’t like the VP of the US interfering.

https://www.realclearpolitics.com/articles/2019/12/11/career_officials_thwart_aid_to_christian_yazidi_genocide_victims__141929.html; 12/11/19, 9:57 PM
Seeing Red said...: State needs to be flushed.; 12/11/19, 9:57 PM
stephen cooper said...: time travel is easy.
creating new universes is easy.

You know what is hard?

Going back to yesterday and being a better person than you were, because you were just too fucking lazy to be nice to the Hispanic ladies who took out the trash and cleaned the bathroom, when they wanted to have a two minute conversation with you in order to practice their English you were all like (I AM SO BUSY I HAVE MORE IMPORTANT THINGS TO DO);

because you thought you were funny when you sneered at your dog for wanting to take a twenty minute walk when you were thinking fuck this dog, he ought to be happy with a ten minute walk, and you had that disgusting sneer on your face that so many people have who were gifted with dogs but who don't appreciate them enough .....

you know what is hard?

realizing you are not nice, you are not kind, that you are just scheming to make life comfortable for yourself.

time travel is easy.
creating new universes is easy.

not being the loser you want to be, that is hard.

Good luck my friend I am praying for you.; 12/11/19, 10:05 PM
stephen cooper said...: did I mention that time travel is easy that creating new universes is easy?

what is hard is being a decent human being.

Good luck my friend I am praying for you.; 12/11/19, 10:07 PM
stephen cooper said...: feel free to have the last word I don't do back and forth any more but remember this

tonight if you are reading this tonight you probably live in America

in a town where many of the good people have put up Christmas lights

likely you live in one of the most beautiful places that ever have existed in the entire history of the universe

you are one of God's chosen, to live in such a place at such a time

trust me

I mean the Christmas lights at my house are humble and not all that spectacular

but they shine with the light of someone who prays for others under the beautiful December night that God created a long time ago with GREAT LOVE in a DIVINE HEART

I would not trade that for a warehouse full of billion dollar paintings; 12/11/19, 10:10 PM
Original Mike said...: I've never been comfortable with the subtleties of "the bucket" experiment. But in my defense, apparently neither was Einstein.; 12/11/19, 10:18 PM
FullMoon said...: Science:
Tidalgate: Climate Alarmists Caught Faking Sea Level Rise.

Man whose farts kill mosquitoes hired to make repellent...; 12/11/19, 10:24 PM
Josephbleau said...: Foucault’s pendulum proves nothing, the earth may be fixed and it may be the nature of pendulums to precess on their strings along with other discordant complex motions of heavenly bodies. How has Foucault falsified this fixed earth theory? Occam’s razor is a dodge to select the most rational among theories but there is no proof of anything beyond abstract postulate systems. Ho ho, I am such a pedant. (In grade school we called them piss ants.); 12/11/19, 10:29 PM
stephen cooper said...: Julian Barbour on Mach is where you want to start.

Mach much more intuitive than poor Einstein ever was about the bucket experiment, trust me

that being said Barbour is totally wrong about Time

not just totally wrong but spectacularly wrong

a bright little fellow though, but still WRONG WRONG WRONG

God created Time

Time and God are friends,

Julian went to a posh English school and never learned how to have the humility to

UNDERSTAND THAT TIME AND GOD ARE FRIENDS

and that TIME is humble, and GOD IS FULL OF LOVE FOR ALL OF US, EVEN EINSTEIN

and Epstein did not kill himself; 12/11/19, 10:31 PM
Churchy LaFemme: said...: So, this time tomorrow we should know if Britain is still a real country.; 12/11/19, 10:36 PM
Titus said...: I walk to and from work, 5 miles, and I wearing llbean boots, and my feet get cold. Boston is never as cold as Wisconsin. How do you do it Mary?

I am going to Wisconsin for Christmas. I am my moms fave and my sisters know it. She calls me her little angel. My partner always says if she only knew. Because I am a whore.

I like lots of sex. I blame the steroids which keep my body rock hard. And my dick rock hard.; 12/11/19, 11:00 PM
narciso said...: No god created time as he did things, we think we have been around for a blink of an sye, are masters of things. We can reorder the universe.; 12/11/19, 11:01 PM
Original Mike said...: "it may be the nature of pendulums to precess on their strings"

yeah, right...; 12/11/19, 11:01 PM
narciso said...: Now they say that the progenitors adam and the like couldnt have lived hundreds of years why, because of modern biology.) There are other organism that have long live span; 12/11/19, 11:04 PM
n.n said...: the progenitors adam and the like couldnt have lived hundreds of years why, because of modern biology.) There are other organism that have long live span

Conflation of logical domains. Science is, with cause, a near-domain philosophy and practice. Well, it was. Today, science is the philosophy of the plausible with liberal license (e.g. assertions/assumptions, speculation, pattern matching, brown matter, social inclusion), inferred from physical myths, forward, backward, near and far. People want to... need to believe, in something. For profit, for-profit nonprofit, leverage, exclusion, redistributive change, etc. The "secular" quasi-religion ("ethics"), faith, ideology, and rites.; 12/12/19, 1:40 AM
Michael McNeil said...: J. Farmer said...
It's a song.

I know — but that doesn't mean one can't reply to the philosophical sense of it. And though millions believe in what the lyrics express (believe that it's totally correct modern science), yet according to the modern theory (“law”) of gravity (Einstein's General Theory of Relativity), that's wrong — or at least not exclusive in its rightness — moreover it's an idea that is more than a century obsolete.; 12/12/19, 2:39 AM
Michael McNeil said...: Re: the question of Relativity

Folks are questioning how it could possibly be that Einsteinian (general!) relativity — the modern theory (or “law”) of gravity — could really mean what it says: that all (all) motion is relative.

In the progress of science one aspect or characteristic of that progress is too seldom articulated — and that is the steadily increasing unification of nature which science progressively achieves — whereby physical entities hitherto regarded as being obviously distinct and qualitatively different, are discovered to in a very real sense actually be the same, or at most mere variant aspects of a single unified concept.

We see this kind of continual progress occurring throughout the 19th century, a time when physicists learned, for instance, that the differing kinds of energy (kinetic vs. potential, heat, electrical, chemical, et al.) that they had discovered were really all just energy: ultimately constituting a single type of “thing” in the physical world as physicists understood it.

Then, too, during that same time-frame the diverse kinds of matter (dozens of elements along with myriads of compounds of elements, of greatly varying properties: sometimes solid, liquid, or gas; hard or soft; colored or clear; etc., etc.) were also found to actually be closely akin to each other — all ultimately distinguished by their being made out of differing ratios of protons, neutrons, electrons.

For (pre 20th-century) physicists there were also particles vs. waves (an apparently valid distinction ultimately united by 20th-century quantum physics) — and even different kinds of gravity, which may be expressed in the question, “Do (and if so, why do) objects of widely differing mass and composition always accelerate due to gravity (or resist due to inertia) at the same exact rate?” — questions which go back to Galileo and the very beginnings of modern (post-medieval) science.

In his new General Theory of Relativity (1915) Einstein took that scientific-conceptual unification process thus-far attained several steps further.

First of all, Einstein discovered that the (newly united by physicists) matter was really just yet another aspect of (the newly united by ditto) energy — which fact emerging from relativity theory was expressed in Einstein's famous equation E = Mc^2.

Secondly, Einsteinian general relativity elegantly solved the long scientific mystery of why there's no distinguishing between gravity and inertia, by finding that they're really one and the same thing: that is, gravity is inertia — which is to say, gravity is acceleration — and vice versa.

How is this possible? Basically gravity is simply acceleration as seen from another coordinate system (known as a reference frame to physicists) moving at a different velocity from the first one. Note that such reference frames in general relativity do not have to be inertial — that is, non-accelerated — which they did in Einstein's preceding, more limited Special Theory of Relativity (1905). Inertial frames move at a constant, unchanging velocity, but acceleration — all kinds of acceleration — is allowed in general relativity!

This equating of inertia and gravity is really at the very core of Einstein's general relativity, where this characteristic feature of the theory is termed the equivalence principle.

Not only does the equivalence principle lie at the center of general relativity — of modern gravity — but modern physicists actually require that any new theory of gravity — for it to be considered as possible improvement and replacement for Einsteinian relativity — must itself also satisfy the equivalence principle!

The equivalence principle is thus regarded as a ratchet-step in the evolution of modern physics.

{Continued on the next page: page 2}; 12/12/19, 2:53 AM
Michael McNeil said...: {Continued from previous page; page 2}

Here's how Einstein described his principle of “exact physical equivalence”: [quoting…]

We arrive at a very satisfactory interpretation of this law of experience, if we assume that the systems K and K' are physically exactly equivalent, that is, if we assume that we may just as well regard the system K as being in a space free from gravitational fields, if we then regard K as uniformly accelerated. This assumption of exact physical equivalence makes it impossible for us to speak of the absolute acceleration of the system of reference, just as the usual theory of relativity [i.e., Special Relativity] forbids us to talk of the absolute velocity of a system; and it makes the equal falling of all bodies in a gravitational field seem a matter of course.

[/unQuote]
____
(Albert Einstein, “Uber den Einfluss der Schwerkraft auf die Ausbreitung des Lichtes,” Ann. Phys. (Germany) Vol. 35 (1911), pp. 898-908, English translation in Lorentz et al. (1923))

____

Thus the unique status of the equivalence principle as integral to Einsteinian General Relativity, the modern theory of gravity, and how it unites the two disparate phenomena of gravity and inertia.

Getting back to the original question of a rotating and/or moving (vs. not) planet earth, as noted above General Relativity allows accelerated reference frames — while rotation per se is simply another kind of acceleration in physics.

Thus, it's just as possible, under general relativity, to regard (what others would call) a rotating accelerated reference frame as actually being motionless (or vice versa), as one can do by declaring a linearly accelerating reference frame to be motionless (or vice versa).

Here, for instance, Einstein described how a Foucault pendulum (traditionally “proof” of the earth’s rotation) really provides no such evidence at all in the context of general relativity (a letter to physicist Ernst Mach, concerning the latter's famous “Mach’s Principle” in physics): [quoting…]

[To Ernst Mach, regarding confirmation at a forthcoming eclipse]

… If so, then your happy investigations on the foundations of mechanics, Planck's unjustified criticism notwithstanding, will receive brilliant confirmation. For it necessarily turns out that inertia originates in a kind of interaction between bodies, quite in the sense of your considerations on Newton's pail experiment. The first consequence is on p. 6 of my paper.

The following additional points emerge: (1) If one accelerates a heavy shell of matter S, then a mass enclosed by that shell experiences an accelerative force. (2) If one rotates the shell relative to the fixed stars about an axis going through its center, a Coriolis force arises in the interior of the shell; that is, the plane of a Foucault pendulum is dragged around (with a practically unmeasurably small angular velocity).

[/unQuote]
____
(Albert Einstein's appreciation to Ernst Mach, written on June 25, 1913, while working hard at arriving at his November 1915 formulation of standard general relativity — quoted in Misner, Thorne, and Wheeler's Gravitation)

____
{Continued on the next page: page 3}; 12/12/19, 3:01 AM
Michael McNeil said...: {Continued from previous page; page 3}

Now we'll answer some few of the questions which have been sent my way up-thread.

“True, but only from a specific, parochial point of view. As Einstein calculated — and a hundred years of experiments and observations have verified — from another point of view it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours.”

What *other*, privileged point of view is that?

No points of view in the universe are “privileged” or special according to the modern theory (“law”) of gravity, Einstein's General Theory of Relativity.

Where is that view taken? Why is it LESS specific, less parochial ?

It isn't less specific, less parochial. It — a viewpoint where the earth is regarded as standing completely at rest — is exactly as parochial, and exactly as specific, as any other point of view where earth is considered to be moving and/or rotating (with regard to something else).

How do you explain the evidence that the Earth, lying in an outer arm of the Galaxy, is rotating around its center every 200 million years or so.

It's all relative. If the sun and earth are collectively revolving (not “rotating”) around the center of mass of a galaxy which is itself regarded as being at rest (in the coordinate system one is using), that's one valid point of view. Another, however — equally valid — is to consider the sun and its planetary system as lying at rest (choosing coordinates which indicate it's not moving), whilst the rest of the galaxy rotates (rotate is correct in this case) around it/us — at exactly the same 200-million-year orbital rate.

Both points of view (and more) are valid.

How do you explain that the Milky Way Galaxy seems to be hurtling at enormous speeds toward
the Andromeda galaxy?

If the “Milky Way Galaxy seems to be hurtling at enormous speeds toward the Andromeda galaxy” then Andromeda is being presently regarded as at rest, while the Milky Way is at motion moving toward it — which is one valid point of view. But, equally, one could consider the Milky Way as lying at rest whilst Andromeda hurtles toward it. Or, some combination of motions can be inferred. All are correct.

STAND AND DELIVER!

Done!; 12/12/19, 3:06 AM
Michael McNeil said...: “…it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours.”

This would mean the cosmos outside our solar system is travelling well in excess of the speed of light? Not too swift on relativity but I thought that was impossible.

I'm not a physicist; though I was trained in physics as an undergraduate, my calculus, differential equations, and the like decades ago collapsed into rust. So, I can't answer your question and complaint mathematically. However, despite that math deficiency I've studied general relativity at a qualitative (if not mathematical) level for many decades — including perusing Misner, Thorne, and Wheeler's great general-relativity tome Gravitation extensively. As a result, I'm confident that (real) physicists have an answer.

(For one thing, the speed of light limitation comes out of relativity theory itself — and [I predict] the theory isn't baffled by scenarios where the universe exceeds the speed of light with regard to… itself.); 12/12/19, 3:21 AM
Fernandinande said...: from another point of view it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours.

Bzzt. Relativity uses "inertial reference frames", which the earth isn't because: There is evidence that the earth is rotating: the Foucault pendulum, the coriolis force, etc = 'fictitious forces' = not an inertial reference frame.; 12/12/19, 8:23 AM
Michael McNeil said...: Fernandistein said...
“… from another point of view it's perfectly correct to regard the Earth as (not flat!) but a spheroid which lies totally at rest, while the rest of the cosmos including the sun rotates around it, once every 24 hours.”

Bzzt. Relativity uses "inertial reference frames", which the earth isn't because: There is evidence that the earth is rotating: the Foucault pendulum, the coriolis force, etc = 'fictitious forces' = not an inertial reference frame.

Bzzt! Wrong in turn! (I knew I'd get this kind of response — despite my explicitly addressing this particular, ignorant “point” up-thread. It's sad, in general — even though I'm laughing in this case.)

The fact is that the requirement that reference frames be inertial (i.e., non-accelerated) in relativity theory is only a limitation found within Einstein's Special Theory of Relativity (1905). Einstein in his succeeding General Theory of Relativity (1915) explicitly removed that limitation. Thus, non-inertial frames are allowed in general relativity — indeed, it is precisely those kind of (accelerated) reference frames which constitute general relativity's solution for how gravity operates!

Indeed, speaking of so-called “fictitious forces,” according to general relativity the “fictitious force” of centrifugal force (the “force” on rotating bodies such as merry-go-rounds that tends to throw you radially off the ride) is actually real, live gravity. (Ditto for being forced back in your seat as your car accelerates.)

It's amusing in these cases watching how folks' recollections of their college physics classes (if any!) decades before progressively get dimmer and dimmer over time — so that the words special (applied to what one knows), and general (applied to what one doesn't know), become harder and harder to recall.

(You might try reading people's postings in the future before deciding your glorious knowledge is so supreme you needn't bother….); 12/12/19, 10:48 AM