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Possible exposure of Earth to dense interstellar medium 2-3M years ago

nature.com

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Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#41

Post by westurner »

gliptic wrote: post #33
westurner wrote: post #5

Are there fossil records that correspond to higher levels of dense interstellar medium radiation 2-3M years ago? Punctuated equilibrium: https://en.wikipedia.org/wiki/Punctuated_equilibrium

Punctuated equilibrium is not about higher mutation rates or even faster evolution, but about long periods of _stasis_ interrupted by "normal rate" evolution due to an upset in the equilibrium such as a sudden geographic isolation of two populations.

Was there a higher rate of cladogenesis 2-3M years ago?

Higher levels of radiation do correlate to higher rates of genetic mutation; presumably because radiation so affects transcription.

Does the punctuated equilibrium theory model radiation level in estimating rate of evolution?

Rate of evolution: https://en.wikipedia.org/wiki/Rate_of_evolution

Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#42

Post by noobermin »

Just a comment, I sent this to my advisor who was an astrophysicist a few years back (he and I are in plasma physics today) and here's something he pointed out,

"[...]Abraham Loeb is about as controversial of a figure in astronomy as you can find. He is also the head of a UFO monitoring project and he still insists that the rod like object that telescopes saw pass through the solar system about a decade ago had an extraterrestrial origin."

Googled his name (he's one of the co-authors of this article) and found this on his wiki page:

"In 2018, he suggested that alien space craft may be in the Solar System, using ʻOumuamua as an example.[7] In 2023, he claimed to have recovered material from an interstellar meteor that could be evidence of an alien starship,[8] which some experts criticized as hasty and sensational,[9][10] and for which other experts found more Earth-related explanations instead, demonstrating that the seismic signal attributed by Loeb to the alleged interstellar space craft was actually caused by ordinary truck traffic.[11]"

Take from this what you will. The section on the Galileo project talks more about the controversy surrounding him.

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

Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#43

Post by snowwrestler »

noobermin wrote: post #42

Just a comment, I sent this to my advisor who was an astrophysicist a few years back (he and I are in plasma physics today) and here's something he pointed out, "[...]Abraham Loeb is about as controversial of a figure in astronomy as you can find. He is also the head of a UFO monitoring project and he still insists that the rod like object that telescopes saw pass through the solar system about a decade ago had an ex…

Keep reading down that Wikipedia page and you’ll see that he is also a serious and well-respected scientist.

Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#45

Post by itishappy »

s1artibartfast wrote: post #28
NooneAtAll3 wrote: post #11

are there no tree fossils from that era that can show one part of the year being different from the rest? I remember reading that dinosaur meteorite was discovered to have fallen in spring by those marks surely regular pattern of getting in-out of heliosphere be noticeable?

>surely regular pattern of getting in-out of heliosphere be noticeable? Why do you say that? What would you look for?

Interstellar isotopes!

> By studying geological radioisotopes on Earth, we can learn about the past of the heliosphere. Fe60 is predominantly produced in supernova explosions and becomes trapped in interstellar dust grains. Fe60 has a half-life of 2.6 Myr, and Pu244 has a half-life of 80.7 Myr. Fe60 is not naturally produced on Earth, and so its presence is an indicator of supernova explosions within the last few (~10) million years.

Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#46

Post by itishappy »

mlhpdx wrote: post #22

I wonder what effect this would have had on the sun itself — not like blowing in a fire, apparently.

None! The Sun has a forcefield called the heliosphere to protect it, and this protects the planets as well. This paper is arguing that the interstellar medium may have been dense enough to shrink the heliosphere to within the orbit of some planets, but it'd take a helluva lot more to shrink it down to the Sun's surface.

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

Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#47

Post by DiggyJohnson »

noobermin wrote: post #42

Just a comment, I sent this to my advisor who was an astrophysicist a few years back (he and I are in plasma physics today) and here's something he pointed out, "[...]Abraham Loeb is about as controversial of a figure in astronomy as you can find. He is also the head of a UFO monitoring project and he still insists that the rod like object that telescopes saw pass through the solar system about a decade ago had an ex…

He's controversial but not crazy. Lots of interesting people are controversial. I think you understand that, but I'm sharing this comment so that others aren't immediately turned off at the notion.

Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#48

Post by SJC_Hacker »

EnigmaFlare wrote: post #19
jcims wrote: post #6

Every square meter of a space ship passing through this at the speed of light would interact with ~3e13 hydrogen atoms per second. I don't know if I did this correctly but that's only ~27kJ per second of mass energy. I thought it would be a lot more.

In the space-ship's frame, it would be a lot more.

If it was the speed of light, it would be infinite mass-energy.

Which is why you normally talk of "x% of the speed of light", e.g. 99% of the speed of light.

Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#49

Post by barfbagginus »

pvaldes wrote: post #40
barfbagginus wrote: post #10

Why does this make me feel a little dirty and exposed ? Like, who knows what kinda alien DNA strands or spores are carried by the ISM?! I wonder if it would be possible to track biodiversity increases caused by the transit? Assuming there is biological material in the ISM, perhaps some of it made it into our biosphere! Very fun!

> what kinda alien DNA strands or spores are carried by the ISM? None that we are aware (and would be fried by the earth atmosphere probably). > Would be possible to track biodiversity increases caused by the transit An entirely new set of new forms of life appearing from nowhere and without any known ancestor in a small line of the "evolutive script" would not be missed. This is the opposite that we observe in that…

I'm not saying this to be non-scientific or conspiratorial or anything. This is actually very cool!

And respectfully, I think a real xenobiologist can come up with more creative ways to get spores from the ISM into the atmosphere.

For instance maybe they come in on small meteorites, right?

Maybe they come in around the modified heliosphere termination shock, as the earth swings through it. The turbulence in the boundary layer manages to decelerate the ICM so that components of it can drift into the atmosphere on low energy trajectories. Fun right?

So to be clear if you were trying to reduce my anxiety here, that's not really what I'm feeling. I'm feeling wonder and creativity. I would prefer for you to brainstorm cute scientific mechanisms that might allow it to happen!

Re: Possible exposure of Earth to dense interstellar medium 2-3M years ago

#50

Post by thegrim33 »

noobermin wrote: post #42

Just a comment, I sent this to my advisor who was an astrophysicist a few years back (he and I are in plasma physics today) and here's something he pointed out, "[...]Abraham Loeb is about as controversial of a figure in astronomy as you can find. He is also the head of a UFO monitoring project and he still insists that the rod like object that telescopes saw pass through the solar system about a decade ago had an ex…

Can you believe that Galileo guy? What a crank. What a controversial figure. He actually insists that the Earth goes around the Sun. That's not science, that's just a madman, all our scientists know that the truth is the other way around. Don't read this new paper he wrote guys, look at the controversy surrounding him. Take from this what you will.
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