It's completely possible that abiogenesis (or Panspermia) did occur many times, but whatever organisms emerged as a result became extinct early on or are not preserved in the fossil record.

The places on earth right now (that we know about) where sterile but minimal materials for self replication machinery are available are very rare, and only on very specific parts of the Earth. Given that, whatever primordial soup pocket that does pop up now has to compete with any loose complex organic matter around it, so good luck to my little progenitors....

Hard to imagine how that might work in the overall landscape of evolution. Let's assume there were two successful evolutionary lineages that began from two separate abiogenesis events. Do you expect both lines to produce their own, say, bacteria? Plants? Animals? I think what you would expect, hypothetically, is that one line produced its own kingdoms of life, and the other produced its own kingdoms of life, and they'd be unrelated.

So, like, you'd have fungus over here and plants over there, but they'd be entirely unrelated. And that's not what we see. They are related.

The other alternative is that these simple forms of life can intermix. In which case, it makes less sense to think of it as happening multiple times, and more sense to say they were so undifferentiated as to be the same thing. This is sort of a chicken and egg problem. If the conditions necessary to spawn life essentially produced a population, rather than an individual, then I don't know that we'd be able to tell the difference without seeing it in action. And the result would be that we're descendents of all of that life, rather than a single moment of abiogenesis.

Intuitively, it would be surprising for two separate abiogenesis events to produce two forms of life that are that compatible, but perhaps such life is so simple that there's not enough complexity to actually differentiate them.

[removed]

Think of the ripples on a lake made by throwing a stone. The water is only going up and down, but the waves move forward. Is that the same wave, or is it a new one?

How would you label a wave to distinguish it from a different wave?

I think I'd take your statement on the fungibility of photons further to say that the "particle" is more illusory than the "wave".

I tend to think of seeing a particle as somewhat analogous to seeing an eddy in a flow of water*. The water (/electromagnetic field) is the "thing" and the eddy (/photon) is just an observable behaviour of that ground truth.

The wave behaviour of particles can matter for electrons, and atoms, and even surprisingly large molecules! As you look at larger and larger things, though, the downsides of treating them as particles become more and more irrelevant. One major reason for this is that the "wavelength" of a wavicle gets shorter in proportion to its momentum going up.

While a photon of visible light has a momentum in the region of 10^-27 Kg.m.s^-1 and a wavelength in the region of 10^-7 metres, Schrödinger's cat moseying along at walking pace has a momentum in the region of 1 Kg.m.s^-1 and a "wavelength" in the region of 10^-34 metres. That's about 1/1,000,000,000,000,000,000,000,000 the size of an atom - a little smaller than the size of the cat, and squirting a stream of cats through a 10^-34 metre slit would probably give you a somewhat messy version of the classic diffraction pattern (sorry, Tiddles!)

(Note, the numbers in that last paragraph are all essentially to zero significant figures and within the limits of my patience of counting zeros, but with those kinds of numbers, even a couple of orders of magnitude really doesn't make any difference :-P)

* A closer analogy would be waves in water, but eddies are easier to visualise as being distinct entities. To be fair, eddies can exhibit some properties (destroying / combining with each other / splitting) that can be entertainingly analogous to colliding subatomic particles, but probably not in ways that help my use of the analogy :-P

[removed]

Incredible video, but I still don't understand how does a wave not loses energy as it passes through mediums, or the energy it loses is negligible since it has so little? What happens? I've understood something and now I understand even less.

[removed]

[removed]

It’s possible in some extreme environment that could have been the norm billions of years ago here on Earth—but a life form from scratch would have to compete with evolved organisms soon enough and would likely end up as food for some other organisms.

look up the single electron theory where the universe consists of only one electron bouncing back and forth in time.

Honestly it's pretty abstract even if you know what's going on. Just think of it like light causing other waves that look mixed with light making it all muddled up and looking slower.

Seismic tomography, which exploits changes in seismic wave speed as a function of temperature and other properties to "image" the interior structure of the lithosphere and mantle, can help fill in some details of the geometry of plate boundaries with depth, but I'm not aware of an application where it's been used to reveal the location of a plate boundary we didn't already know about through other means.

[removed]

Wdym by „straight line is longer than bent line”?

hey this is a super interesting question! I don't have the answer but in case someone does i'll leave this comment to find it at some point.

Based on my limited understanding I don't see where such an energy contribution would arise. I get it in the case of fermions but boson statistics are unfamiliar. The normalisations are weird.

As other commenters mentioned, the word genetic did already exist

This quote essentially uses "genetic connection" in reference to what we now call "blood related"

But the thing that actually is crazy about Darwin in terms of genes is that he discovered natural selection, a phenomenon about genes, without knowing genes existed.

Evolution had be hypothesized / theorized for a long time before Darwin, it dates back to 495–35 BCE. Much of the terms he used in that book are not terms now, but were terms already developed by other evolutionary scientists prior to him using them. "genetic connection" had been used already to mean descended from the same being. The major evolutionist before Darwin was Lamarck, who coined and described many of the terms like that and described them quite accurately. Lamarck knew about inheritance and acquired traits already and did refer to this using terms like genetics, so Darwin did have that information.

Darwin did notice patterns that he assumed must be due to traits the animals must have in order for the patterns to be happening. He usually used the term "undergoing modification". He said many things that were about genes and inheritance without using modern terms before model, he definitely understood and noticed genetic patterns without figuring out what was causing them.

[removed]

The post below was something I posted on a UK motoring forum 20 years ago, so I've just copied and pasted it.

https://www.honestjohn.co.uk/forum/post/index.htm?t=6781

I also mentioned car/truck windscreen washer bottles as a legionella risk, which was 8 years before the UK's HSE issued a warning about using screen wash to kill the bacteria.

https://www.bbc.co.uk/news/10293519

"The wet cooling towers are the problem, as stated by many others.

The heat removed by the cooling process is rejected at the condenser, where the refrigerant vapour is condensed into a liquid and it's latent heat of condensation is released.

In wet AC systems the condensers are cooled by water. The water is cooled at the cooling tower and recirculated. The cooling tower ponds tend to collect all the particles in the air, limescale, leaves, insects, etc, and are often at lukewarm temperatures, providing ideal conditions for the growth of many organisms. The water is intentionally sprayed into the air to cause some of it to evaporate, creating an aerosol of water droplets containing any organisms that have been cultivated in the water.

The legionella bacteria is present in water everywhere and will multiply if given favourable conditions.

The risk of infection is much greater for the elderly or infirm, so the disease has affected many hospitals, in the past. The risk wasn?t recognized until a group of elderly ex-servicemen, attending an American Legion Convention were felled by a hotel cooling tower in Philadelphia in 1976. The disease had existed prior to that, but had been regarded as yet another strain of pneumonia.

The (UK) HSE's Code of Practice on Legionnaires' disease, L8, states that a foreseeable risk exists in;

a) water systems incorporating a cooling tower;

b) water systems incorporating an evaporative condenser;

c) hot and cold water systems;

d) other systems containing water at which is likely to exceed 20 degC and which may release a spray or aerosol."

Did it happen more than once? Probably, however, it would have been very similar in composition. There would also be practically no evidence of any additional lines as only the dominant line remained.

Is it still going on today? Most likely not. There's too much life around, and to a lot of organisms, the components required for abiogenesis look tasty.

But there's no paradox because there is an objective preferred frame in a universe that loops around, which is imposed by the choice of at what times you "connect the opposite edges" of the universe.

Ok, so, aren't we back in the paradox, where depending on the preferred frame we choose, the shower twin is not the same, then?

[removed]

They probably inhaled contaminated water droplets outside.

There was an outbreak in Cumbria, UK, 15 years or more back and it was random people passing through the vicinity who were infected.

For the same reason you don't see such "trails" of the cars on the road next to you. The light coming from the time when object was in different location already reached you in the past.

The "trails" you refer to are essentially what you perceive as "object moving".