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improbably_me t1_jadcrzd wrote

Kinda counterintuitive... Black holes are getting bigger by consuming more matter and packing it more densely and yet are expanding the universe.

Or could this be some sort of invariance or conservation link between spacetime and matter/energy?

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A40 t1_jaddpto wrote

In only a million million million years, too. Time to stock up on our line of tactical survival socks!

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Tjam3s t1_jadfq42 wrote

I was just learning of a theory yesterday that suggests gravitational waves leave an imprint permanently on the fabric of space, forever stretching it where the waves have passed. It's untested because engineering isn't there, but from what I read, it is a phenomenon that comes straight out of relativistic equations. I believe it was called gravitational memory.

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Tjam3s t1_jadhnq3 wrote

The hypothesis, if I read right, is suggesting that there is a correlation between the expansion of the universe and the unexplained growth rate of supermassive black holes.

We don't know why they are as big as they are. We don't know why the universes expansion is what it is, but the 2 appear to be correlated.

Fascinating findings for sure, but what i don't understand is why they are so quick to publish findings that correlation might equal causation when anyone in science knows it does not

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RoDeltaR t1_jadmdzy wrote

Both Sabine Hossenfelder and Dr. Becky (if anyone cares) are not buying into this.

Please remember that this is only a proposal with a lot of assumptions, and it hasn't been proven.

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LivInTheLookingGlass t1_jadofrw wrote

Dr Becky is pretty skeptical of this paper, and its her area of focus. Among other things, she says it doesn't properly account for the historical growth or spiral galaxies

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MayThe4thCakeDay t1_jadpaqy wrote

Replying to Tjam3s (#2,113,817)

This is kinda where "common knowledge" leads you astray. For scientific research even when correlation is not causation, it's usually jumping up and down and pointing to where you should be looking. It's fun to to point out piracy and global warming to be cute, but when you find close correlation you should be digging into it until you find a way to dismiss it.

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ValuableNorth4 t1_jadra27 wrote

What about the whole hologram thing? Black holes are actually 2D and everything goes in and gets projected back out.

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macbowes t1_jadrzqy wrote

Replying to RoDeltaR (#2,115,353)

Yes! Thank you for sharing this information. The authors of the two papers that have led to this recent news story do not address the question of how black holes, which are made of matter that constitutes a small fraction of 4.6% of all the energy in the universe, are responsible for dark energy, when dark energy comprises 70%~ of all the energy in the universe.

[Dr. Sabine Hossenfelder on this issue.] (https://youtu.be/ENGJA1cUe3M)

Dr. Becky Smethurst on this issue.

An interview with one of the lead authors is available here.

They claim that the reason we see a smooth distribution of dark energy throughout spacetime, despite the supposed source (black holes) obviously not being smoothly distributed throughout spacetime, is because of relativistic effects. Intuitively, one would expect the areas near black holes to be expanding faster than areas far away from black holes, if the cause of expansion was the black holes themselves.

Seems unlikely to me. I am hoping that Dr. Matt O'Dowd of PBS SpaceTime also addresses the topic.

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Tjam3s t1_jae5lh6 wrote

Replying to Monday_here (#2,115,306)

It was actually a very recent episode of "Daniel and Jorge explain the universe" podcast, dropped last Thursday. I'm sure they have show notes for papers referenced if your note of a reader

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Tjam3s t1_jae6gkd wrote

Replying to MayThe4thCakeDay (#2,116,234)

I suppose the part they seem to assume is that the black hole is the cause for dark energy, but without actual study into the real cause for the correlation.

It might be the other way around with the expansion of the universe causing the growth, or it may be an indirect mechanism being the cause for both of them.

The assumption that the black hole is helping cause the expansion is what I was digging at.

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Tairaa90 t1_jaeccwc wrote

Replying to Tjam3s (#2,121,871)

I just listened to a Lex Fridman podcast with one of the authors and it didn't seem to me to be as much of an assumption as proposing a possible mechanism that needs to be figured out and then tested.

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KeaboUltra t1_jaeqfiu wrote

I mean, they break physics and make the universe act weird and warp reality as we know it. So i wouldn't be surprised if these things were pretty detrimental to existence itself.

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dont_you_love_me t1_jaeyewe wrote

Replying to Tjam3s (#2,121,871)

Cause in and of itself is a human concoction. You cannot actually prove that anything is caused within the universe. It could very well just be that the information we observe simply presents itself in a specific mandatory pattern and order and our brains totally fabricate the concept of causality.

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BenZed t1_jaf0g0u wrote

So:

  • Gravity slows down time.
  • The higher the gravity a reference frame is subjected to, the slower time passes.
  • Black holes decrease the degree by which matter is evenly distributed throughout the galaxy universe by creating singularities from which matter can't escape

Maybe the expansion of the universe only appears to be accelerating because black holes are increasing the gradient by which time passes?

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Professor226 t1_jaf0twm wrote

Replying to Tjam3s (#2,113,817)

As I understand it increasing the of mass of a blackhole REQUIRES the creation of negative energy for conservation. Like when I figure skater pulls their arms in the have to spin faster.

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Shoddy_Lifeguard_852 t1_jaf3c6r wrote

Sounds the same as politicians. Behind the scenes, they quietly generate enough force and then tear us apart...only they use taxes.

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EricPostpischil t1_jaf3wnb wrote

Replying to thetomahawk42 (#2,134,122)

I think the quotes were to point out the previous commenter’s use of Dr. Smethurst’s first name in that way could be considered diminutive. Unless Dr. Smethurst prefers to be known as Dr. Becky or the commenter has a personal relationship justifying the familiarity, it may be impolite to use “Dr. Becky.” If she does use that form, antiquemule may have been unaware of it or may consider it impolite nonetheless.

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