Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

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Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Thu Aug 10, 2023 12:18 pm

New paper in Astrophysical Journal, via phys.org

"Smoking-gun evidence for modified gravity at low acceleration from Gaia observations of wide binary stars".
A new study reports conclusive evidence for the breakdown of standard gravity in the low acceleration limit from a verifiable analysis of the orbital motions of long-period, widely separated, binary stars, usually referred to as wide binaries in astronomy and astrophysics.

The study carried out by Kyu-Hyun Chae, professor of physics and astronomy at Sejong University in Seoul, used up to 26,500 wide binaries within 650 light years (LY) observed by European Space Agency's Gaia space telescope. The study was published in the 1 August 2023 issue of the Astrophysical Journal.

For a key improvement over other studies Chae's study focused on calculating gravitational accelerations experienced by binary stars as a function of their separation or, equivalently the orbital period, by a Monte Carlo deprojection of observed sky-projected motions to the three-dimensional space.

Chae explains, "From the start it seemed clear to me that gravity could be most directly and efficiently tested by calculating accelerations because gravitational field itself is an acceleration. My recent research experiences with galactic rotation curves led me to this idea. Galactic disks and wide binaries share some similarity in their orbits, though wide binaries follow highly elongated orbits while hydrogen gas particles in a galactic disk follow nearly circular orbits."

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Ann » Sun Aug 13, 2023 5:10 am

Jim Leff wrote: Thu Aug 10, 2023 12:18 pm New paper in Astrophysical Journal, via phys.org

"Smoking-gun evidence for modified gravity at low acceleration from Gaia observations of wide binary stars".
A new study reports conclusive evidence for the breakdown of standard gravity in the low acceleration limit from a verifiable analysis of the orbital motions of long-period, widely separated, binary stars, usually referred to as wide binaries in astronomy and astrophysics.

The study carried out by Kyu-Hyun Chae, professor of physics and astronomy at Sejong University in Seoul, used up to 26,500 wide binaries within 650 light years (LY) observed by European Space Agency's Gaia space telescope. The study was published in the 1 August 2023 issue of the Astrophysical Journal.

For a key improvement over other studies Chae's study focused on calculating gravitational accelerations experienced by binary stars as a function of their separation or, equivalently the orbital period, by a Monte Carlo deprojection of observed sky-projected motions to the three-dimensional space.

Chae explains, "From the start it seemed clear to me that gravity could be most directly and efficiently tested by calculating accelerations because gravitational field itself is an acceleration. My recent research experiences with galactic rotation curves led me to this idea. Galactic disks and wide binaries share some similarity in their orbits, though wide binaries follow highly elongated orbits while hydrogen gas particles in a galactic disk follow nearly circular orbits."
Oh wow, Jim, this is amazing! :shock:

They report "conclusive evidence" for MOND - not "compelling evidence", but "conclusive"!

phys.org wrote:

Wide binary anomalies are a disaster to the standard gravity and cosmology that rely on dark matter and dark energy concepts. Because gravity follows MOND, a large amount of dark matter in galaxies (and even in the universe) are no longer needed...

A new revolution in physics seems now under way...

"If this anomaly is confirmed as a breakdown of Newtonian dynamics, and especially if it indeed agrees with the most straightforward predictions of MOND, it will have enormous implications for astrophysics, cosmology, and for fundamental physics at large."

Will dark matter disappear from the universe like the aether? What will now happen to the ΛCDM model of the Universe?

How are we going to explain the Bullet Cluster now?


And would the cosmic web look the same without dark matter?


I thought it was dark matter that created the filaments in the cosmic web, where galaxies made of baryonic ("ordinary") matter then formed as foam on cresting waves. Don't we need dark matter to make the cosmic web?

And what about dark energy? Will the new MOND theory of the Universe do away with both dark matter and dark energy in one fell swoop?

Click to play embedded YouTube video.

Demolition of our cosmic model is underway?

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Tue Aug 15, 2023 8:13 pm

Thanks, Ann.

I hope it’s not just hype!

Looks like I posted this in the wrong section. Maybe if it’d been posted in “news” it’d have drawn more comments..

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Chris Peterson » Tue Aug 15, 2023 8:44 pm

Jim Leff wrote: Tue Aug 15, 2023 8:13 pm Thanks, Ann.

I hope it’s not just hype!

Looks like I posted this in the wrong section. Maybe if it’d been posted in “news” it’d have drawn more comments..
Even if it holds up, it probably doesn't mean that we don't still need dark matter to explain our observations.
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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Tue Aug 15, 2023 8:57 pm

I don’t see even a hint of any such claim.

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Chris Peterson » Tue Aug 15, 2023 9:00 pm

Jim Leff wrote: Tue Aug 15, 2023 8:57 pm I don’t see even a hint of any such claim.
No, it was more a response to Ann's question about what happens to dark matter. Just continuing that below your comment.
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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Tue Aug 15, 2023 9:33 pm

Ah, ok, gotcha.

Is it odd not to hear more chatter about this, or is it just the slow wheels of science, everyone aware but awaiting replication, etc?

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Ann » Wed Aug 16, 2023 7:21 pm

Jim Leff wrote: Tue Aug 15, 2023 9:33 pm Ah, ok, gotcha.

Is it odd not to hear more chatter about this, or is it just the slow wheels of science, everyone aware but awaiting replication, etc?
I would guess that everybody is waiting for other experiments to confirm the results.

But I, too, find the silence strange.

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by bystander » Wed Aug 16, 2023 7:25 pm

Jim Leff wrote: Tue Aug 15, 2023 8:13 pm ...
Looks like I posted this in the wrong section. Maybe if it’d been posted in “news” it’d have drawn more comments..
I'm moving it to Communications
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Thu Aug 17, 2023 10:34 am

Chris Peterson wrote: Tue Aug 15, 2023 8:44 pm
Even if it holds up, it probably doesn't mean that we don't still need dark matter to explain our observations.
But let me interject some deep scientific knowledge I’ve acquired (by looking up MOND on Wikipedia):

The fact that some form of unseen mass must exist in these systems detracts from the adequacy of MOND as a solution to the missing mass problem, although the amount of extra mass required is a fifth that of a Newtonian analysis, and there is no requirement that the missing mass be non-baryonic

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Ann » Fri Aug 18, 2023 8:45 am

Science communicator and Youtuber Anton Petrov explains why the astronomical community is not abuzz with the announcement that MOND is right and Newton and even Einstein are wrong about the nature of gravity:

Click to play embedded YouTube video.

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Fri Aug 18, 2023 3:42 pm

I have a friend who is into all sorts of pseudo science stuff who keeps pushing me to watch Anton Petrov videos. Is he actually legit?

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Ann » Fri Aug 18, 2023 4:29 pm

Jim Leff wrote: Fri Aug 18, 2023 3:42 pm I have a friend who is into all sorts of pseudo science stuff who keeps pushing me to watch Anton Petrov videos. Is he actually legit?
I think he is reasonably legit. He is sometimes wrong about things that are my expertise (that is, details about hot and massive blue stars and nearby well-known galaxies), but he never makes any crazy claims.

I think he is worth watching. He was probably right about what he said in the video I linked to in my post above, because that would really explain why there has been absolutely no buzz at all in the astronomical community about the amazing MOND claims.

That's not to say that we should conclude that everything about MOND is wrong, or that general relativity can explain absolutely everything about wide double stars. But if other experiments have yielded results that fly in the face of the study that claimed that Newtonian gravity and even general relativity is wrong, then that would at least explain why the astronomical community is keeping silent on the matter.

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Sat Aug 19, 2023 11:56 pm

Yes, as I suggested above, it’s “just the slow wheels of science, everyone aware but awaiting replication, etc?”

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Ann » Sun Aug 20, 2023 5:19 am

I found another video that discussed (or dissed) the claim that MOND can explain the motion of wide binaries in a way that Newtonian gravity or general relativity can not. The person behind the video calls himself ParallaxNick, and I have never heard of him before or seen any of his videos. By contrast, I watch many (though very far from all) videos by Anton Petrov.

Anyway, ParallaxNick claimed that another study of wide binaries had come to the conclusion that Newtonian gravity can explain the orbital motion of these stars extremely well. You may want to watch the video, or not.

https://www.youtube.com/watch?v=k8jOQPU4t5U

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Sun Aug 20, 2023 7:53 pm

Ann wrote: Sun Aug 20, 2023 5:19 am ParallaxNick claimed that another study of wide binaries had come to the conclusion that Newtonian gravity can explain the orbital motion of these stars extremely well.
Wasn’t that precisely the contrast Petrov offered in his video?

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Chris Peterson » Mon Aug 21, 2023 2:47 am

Jim Leff wrote: Sat Aug 19, 2023 11:56 pm Yes, as I suggested above, it’s “just the slow wheels of science, everyone aware but awaiting replication, etc?”
It's not really all that much about replication. It's about MOND's reputation as science crackpottery. About year after year of failed ideas and bad observations. About an utter lack of underlying theoretical basis. About its inability to explain a great deal that dark matter does explain. All this against abundant evidence for dark matter and no serious theoretical impediments to its existence.

So what it's really about is a pretty high hurdle that MOND proponents are going to have to pass before many people take them seriously.

Extraordinary claims require extraordinary evidence.
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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Ann » Mon Aug 21, 2023 3:35 am

Jim Leff wrote: Sun Aug 20, 2023 7:53 pm
Ann wrote: Sun Aug 20, 2023 5:19 am ParallaxNick claimed that another study of wide binaries had come to the conclusion that Newtonian gravity can explain the orbital motion of these stars extremely well.
Wasn’t that precisely the contrast Petrov offered in his video?
Indeed. Petrov and ParallaxNick said the same thing in their videos.

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Mon Aug 21, 2023 4:59 pm

Chris Peterson wrote: Mon Aug 21, 2023 2:47 am So what it's really about is a pretty high hurdle that MOND proponents are going to have to pass before many people take them seriously.
OTOH, I don't see anyone impugning Kyu-Hyun Chae or his university. No one crying bullshit. So while I in no way would have imagined open-armed acceptance of this one report (especially as it's contradicted by similar reports), I guess it is, as I say, entirely a matter of awaiting replication and consensus. You've noted that acceptance is unlikely, for reasons both somewhat pertinent (much theory would need to be discarded) and less so (cranks make similar claims). But I never imagined it to be likely! :ssmile:

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Chris Peterson » Mon Aug 21, 2023 7:31 pm

Jim Leff wrote: Mon Aug 21, 2023 4:59 pm
Chris Peterson wrote: Mon Aug 21, 2023 2:47 am So what it's really about is a pretty high hurdle that MOND proponents are going to have to pass before many people take them seriously.
OTOH, I don't see anyone impugning Kyu-Hyun Chae or his university. No one crying bullshit. So while I in no way would have imagined open-armed acceptance of this one report (especially as it's contradicted by similar reports), I guess it is, as I say, entirely a matter of awaiting replication and consensus. You've noted that acceptance is unlikely, for reasons both somewhat pertinent (much theory would need to be discarded) and less so (cranks make similar claims). But I never imagined it to be likely! :ssmile:
Again, I don't think replication is necessary. I think using MOND to explain the observation is what's going to be a really big challenge.
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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Ann » Thu Aug 31, 2023 8:23 pm

Jim, you may want to watch Dr Becky's take on this:

Click to play embedded YouTube video.

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Re: Astrophysical Journal: Evidence for modified gravity at low acceleration in wide binary stars

Post by Jim Leff » Tue Sep 12, 2023 12:05 pm

Thanks, Ann. Not that different from Anton Petrov‘s central point, but a lot more meaty. And I’m looking forward to that Bayesian analysis (though I don’t expect a gangbuster for MOND therein).