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Hubble sees possible runaway black hole creating a trail of stars

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Re: Hubble sees possible runaway black hole creating a trail of stars

#171

Post by Maursault »

chasil wrote: post #41
Maursault wrote: post #39

Earlier quoted context omitted.

> but the mitochondria and plastids of eukaryotes took a very long time to emerge. Not an expert, but mitochondria didn't " e merge." Mitochondria co-evolved as bacteria, merged and became organelles through complex protein-import machinery and insertion into inner membranes of protein carriers for extracting energy for the host cell.

There were no eukaryotes... and then there were. This was the ignition of complex, multicellular biology. What else could explain it? I will admit that I thought they were closer to the Cambrian Explosion. This is much farther away than I thought. "Eukaryotes emerged approximately 2.2 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs." https://en.m.wikipedia.org/wiki/Eukaryote

What about mitochondria? I did not address your mention of eukaryotes, only mitochondria, which existed as bacteria long before eukaryotes. You're intentionally ignoring the error in your OP and my pun: mitochondria did not emerge with eukaryotes, they "merged." Your lack of addressing mitochondria in your response makes it a straw man.

Re: Hubble sees possible runaway black hole creating a trail of stars

#172

Post by kulahan »

causi wrote: post #150
joshuahedlund wrote: post #138

Earlier quoted context omitted.

> Near the center of a galaxy, where stars are so closely packed together that the night sky is filled with bright lights, perhaps illuminating their world to what we experience around twilight, or even brighter. My understanding is this is unfavorable for life due to any planets being constantly sanitized by too many nearby stars going supernova > Far removed from the center of a galaxy, or even on a rogue star that…

According to a 2022 study, there are up to ten rogue planets for every one orbiting a star.

A rogue planet has pretty much zero chance of harboring life. It needs a sun.

Re: Hubble sees possible runaway black hole creating a trail of stars

#173

Post by Maursault »

s1artibartfast wrote: post #45
Maursault wrote: post #39

Earlier quoted context omitted.

> but the mitochondria and plastids of eukaryotes took a very long time to emerge. Not an expert, but mitochondria didn't " e merge." Mitochondria co-evolved as bacteria, merged and became organelles through complex protein-import machinery and insertion into inner membranes of protein carriers for extracting energy for the host cell.

You are talking about different semantics. You're talking about a merge in the context of a mechanical process, and they are talking about emergence in the context of speciation. There's no reason to expect the verb to be the same if the subject is different.

There are not "different semantics." There is semantics. It's a mass noun and singular. If you're attempting to hand wave by calling my comment a semantic argument, and therefore insignificant, then you are simply incorrect. Semantics are of vital importance to language and communication. Without semantics, no one would have any idea what anyone else was saying. And my use of "merge" was a pun. Woosh!

Re: Hubble sees possible runaway black hole creating a trail of stars

#174

Post by Maursault »

vl wrote: post #62
Maursault wrote: post #34

> Gas in front of it gets shocked because of this supersonic, very high-velocity impact of the black hole moving through the gas. What's the speed of sound in intergalactic space, anyway?

It’s interesting that they used “supersonic” since phenomenon of sound emerges when there is enough molecules to collide with each other to transmit sound waves, which is not the case in the outer space. But most probable speed of hydrogen molecules at 2.7K is surprisingly low - 150m/s. This speed can be used as “sound” speed approximation in the intergalactic space.

The use of "supersonic" was likely metaphor, but I thought it was funny coming from a scientist, as we expect them to usually speak literally with precise accuracy.

Re: Hubble sees possible runaway black hole creating a trail of stars

#175

Post by s1artibartfast »

Maursault wrote: post #173
s1artibartfast wrote: post #45

Earlier quoted context omitted.

You are talking about different semantics. You're talking about a merge in the context of a mechanical process, and they are talking about emergence in the context of speciation. There's no reason to expect the verb to be the same if the subject is different.

There are not "different semantics." There is semantics. It's a mass noun and singular. If you're attempting to hand wave by calling my comment a semantic argument, and therefore insignificant, then you are simply incorrect. Semantics are of vital importance to language and communication. Without semantics, no one would have any idea what anyone else was saying. And my use of "merge" was a pun. Woosh!

I'll try to be helpful and not combative.

I think it is a matter of semantics because it seemed like you have a different understanding of the meaning of the word emerge then the person you are responding to. Within the context of the original post, the word emerge has nothing to do with the physical location of mitochondria and the eukaryotic cell. Instead, the meaning of emergence was to come into existence from non-existence. That is to say, your objection relies on a different semantic understanding of the word used. It is unclear to me if you don't understand this meaning or if you understand it but disagree with others using it.

Similarly, I would argue that a "mitochondria" not living in a parent so is not a mitochondria at all. Again, this is a matter of semantics. It relies on the meaning of the word mitochondria and how it is defined.

Bay way of comparison, is a person who buys a house homeless or a homeowner? Are humans prototocells because our evolutionary history can be traced back to them?

Re: Hubble sees possible runaway black hole creating a trail of stars

#176

Post by gattr »

empyrrhicist wrote: post #122
gattr wrote: post #105

Earlier quoted context omitted.

> Inside a 'thick' nebula, obscuring all other entities in the sky except for their own star and planets. Similarly to the alien planet in Eric Flint's "Mother of Demons"; there was a permanent thick cloud cover, and the the slowly moving sky illumination due to the unseen sun was called "the mother of pearl" by the locals. I also like the idea of living in a dense globular cluster. Interstellar probes and, later, ma…

I thought the consensus was that stars in globular clusters are exceedingly unlikely to host planets, since they'd be ejected by the frequent interactions with other stars.

Quite unlikely, but see e.g. [1]:

> Therefore, it is still possible that planets exist around main sequence stars in globular clusters, although at small numbers because of the low metallicity, and at orbital periods of >~10 days.

[1] Expected Planets in Globular Clusters (https://arxiv.org/abs/0704.1067)

Re: Hubble sees possible runaway black hole creating a trail of stars

#178

Post by vikramkr »

kulahan wrote: post #172
causi wrote: post #150

Earlier quoted context omitted.

According to a 2022 study, there are up to ten rogue planets for every one orbiting a star.

A rogue planet has pretty much zero chance of harboring life. It needs a sun.

There's plenty of chemosynthetic life on earth that doesn't need a sun - even if earth style life needed the sun to evolve, if the earth became a rogue planet those organisms might be fine. And life might not have needed the sun to evolve.

Re: Hubble sees possible runaway black hole creating a trail of stars

#179

Post by scdlbx »

JackFr wrote: post #159
denton-scratch wrote: post #129

Earlier quoted context omitted.

I believe anywhere near a neutron star is going to be extremely inhospitable. A very compact massive object, spinning really fast, and with a strong magnetic field, will produce intense synchrotron radiation, right? Wikipedia says the magnetic field of a neutron star is between 10^8 and 10^15 times the Earth's. The amount of energy in a magnetic field that strong is mind-boggling. Anything anywhere near a neutron sta…

How about the surface? https://en.wikipedia.org/wiki/Dragon%27s_Egg

The starquakes can make life difficult. https://en.wikipedia.org/wiki/Starquake_(novel)

Re: Hubble sees possible runaway black hole creating a trail of stars

#180

Post by lmm »

skripp wrote: post #132
lmm wrote: post #72

Earlier quoted context omitted.

No. It's a tedious slog, devoid of interest on any axis: characters, plot, worldbuilding and science are all paper-thin. Its popularity baffles me.

Did you read all three? The first one isn't great but as a trilogy I found it quite good. There are several places where the story building contradicts itself but if you are willing to look past those then it's solid science fiction. It's not on the level of Arthur C. Clarke or Asimov but they were obviosly big influences.

No. I was ready to give up on the first one about a third of the way through but people told me "it gets good later"; it didn't. So when I hear people saying that about the trilogy it's a bit of a "fool me once, shame on you" situation.
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