Oxford scientists say: Looks like no other intelligent life in whole universe (but keep looking)

[Vertigo]

A couple of comments:

This was not described as a one in a billion (or billion to one) chance but a once in a million years event. Two totally different things. We have so far discovered two previous examples and now this is a third example. There maybe be more but it's unlikely there are many if that is all we have found so far. This isn't some kind of probability thing; it is simply that the Earth is around 4.5 billion years old, the first life appeared around 4 billions years ago and we've now discovered that 3 of these endosymbiosis events have occurred. So it has happened around once every billion years. This is not an observation on the chance of something happening but on the frequency of it happening.

However, the fact that, though rare, it has happened more than once is extremely significant as it indicates that once you have life there is a reasonable chance that you will eventually get complex life. But not very often; 3 or four times in 4 billion years is not a very frequent! Of course there may have been many more but they were not successful ie. they didn't produce anything particularly useful in evolutionary terms, so being unsuccessful they were eventually weeded out by evolution and we see no trace of them now. So maybe the original statement should be that a successful/useful endosymbiosis has only happened once every billion years.

I frequently see the universe being described as almost infinite or as good as infinite. The universe is nothing like infinite. It is finite. We know it is only about 13.7 billion years old and we know it does not have an infinite supply of energy or matter and will eventually suffer some sort of heat death. And to say something is almost infinite is not just a meaningless statement but really an oxymoron.

 

[Ursa major]

we've now discovered that 3 of these endosymbiosis events have occurred

How many organelles does a cell contain... and if they are not there as the result of endosymbiosis, how did they come into existence (i.e. how would a cell have created them)?

Perhaps, it would be better to think of organelles as possible results of endosymbiosis as well as possibly being created by a cell.

 

[Vertigo]

How many organelles does a cell contain... and if they are not there as the result of endosymbiosis, how did they come into existence (i.e. how would a cell have created them)?

Perhaps, it would be better to think of organelles as possible results of endosymbiosis as well as possibly being created by a cell.

That would be beyond my knowledge of biochemistry. However the article does not claim that organelles can only be created by endosymbiosis, just that in these three case that is what happened. It makes no suggestion that that is the only way in which organelles can evolve. Mitochondria and cytoplasms have, I believe, their own independent DNA whereas other organelles do not. Indicating, again I believe, the different origins ie. those two being from endosymbiosis. I would imagine the organelles to have evolved over the millions of years just like any other aspect of life.

 

[Brian G Turner]

Just a heads up that the piece I read on the discovery of a nitrogen fixing organelle says this is at least the 4th time primary symbiosis has happened:

Scientists discover first nitrogen-fixing organelle

Modern biology textbooks assert that only bacteria can take nitrogen from the atmosphere and convert it into a form that is usable for life. Plants that fix nitrogen, such as legumes, do so by harboring symbiotic bacteria in root nodules. But a recent discovery upends that rule.

phys.org

The organelle is the fourth example in history of primary endosymbiosis—the process by which a prokaryotic cell is engulfed by a eukaryotic cell and evolves beyond symbiosis into an organelle.

It's also worth noting that biologists generally aren't looking for new examples, so this was something of a lucky find - suggesting that there may be more examples out there:

The discovery of the organelle involved a bit of luck and decades of work. In 1998, Jonathan Zehr, a UC Santa Cruz distinguished professor of marine sciences, found a short DNA sequence of what appeared to be from an unknown nitrogen-fixing cyanobacterium in Pacific Ocean seawater. Zehr and colleagues spent years studying the mystery organism, which they called UCYN-A.

In other words, they weren't hunting a new example of primary symbiosis, but a specific bacterium they thought they'd found a DNA strand from. It's worth underlining that we have an extremely fractional knowledge of the range of single-celled organisms out there, let alone their functions, so there may be other examples. This is especially as symbiosis is a very common function of biology.

 

[RJM Corbet]

This is especially as symbiosis is a very common function of biology.

I'm not sure that primary endosymbiosis is the same thing?

A symbiotic relationship where one organism lives inside the other is known as endosymbiosis. Primary endosymbiosis refers to the original internalization of prokaryotes by an ancestral eukaryotic cell, resulting in the formation of the mitochondria and chloroplasts.

Primary and Secondary Endosymbiosis (7.2)

 

[Brian G Turner]

I'm not sure that primary endosymbiosis is the same thing?

Indeed, primary endosymbiosis and general symbiosis are different things.

 

[Harpo]

Assuming that any alien species would first notice us by encountering our early radio broadcasts, and further assuming those broadcasts travel at light speed (they don’t, but hey) and will never deteriorate (they will, but hey) here’s a rough indication of how far away we have reached by that method in a hundred years.

Feel free to imagine the blue dot ten times bigger a thousand years from now, of course.

 

[Astro Pen]

Which leads me to the slightly philosophical question:
Does the physical limitation of light speed serve a similar role to the Tower of Babel?
ie Preventing intelligent life from conquering the universe by stymying universal communication.

 

[paranoid marvin]

It's the Universe's world; we just live in it.

 

[BAYLOR]

We can't travel between stars and until we can, we may never have answers to the question of whether other intelligent life in the universe exists.

 

[THX1138]

And if a galaxy 3 million LY away formed at the same time as ours, with intelligent in only one star system in it... 3 million LY's is 3 million LY's.
So, you can't definitively say we are alone.

 

[Extollager]

What do you think will be the effects on people's emotions and imaginations if, say, 50 years from now, people pretty much like ourselves (e.g. not living in radioactive ruins) are round and there is no more evidence for intelligent life on other planets than we have (i.e. none)? I wonder because I think a great many people assume it's just a matter of time before we make contact.

 

[paranoid marvin]

Eric Idle came out of a fridge and told us this 50 years ago.

 

[Vertigo]

Assuming that any alien species would first notice us by encountering our early radio broadcasts, and further assuming those broadcasts travel at light speed (they don’t, but hey) and will never deteriorate (they will, but hey) here’s a rough indication of how far away we have reached by that method in a hundred years.

Feel free to imagine the blue dot ten times bigger a thousand years from now, of course.

View attachment 125774

and will never deteriorate (they will, but hey)

I always come back to this as the fundamental problem for us (and anyone else out there). Our signals are for the most part not directed so the inverse square law applies. My understanding is that this means by around 1 light DAY out the signals will be almost indistinguishable from the background radiation. By a light month they would have to be looking in exactly the right direction with incredibly sensitive equipment. By a light year there's really no chance! The nearest star is over 4 times that distance.

We do have some directed signals, radar, lidar etc. that would reach further but only if they happened to be directed at exactly the right place where someone else is looking in exactly the right place at exactly the right time.

Sadly the chance simply become miniscule. I'm not saying we are alone (how could I possibly know?) but i am saying that the chance of detecting another signal or ours being detected make the lottery look like a dead cert!

I truly wish it were not so. Physics can be a bitch sometimes!

 

[Vertigo]

An interesting extension to that is that, of course, in science something must be repeatable to be provable (that could probably be worded better!). Now remember the "wow" signal from 1977. Well maybe, just maybe, it was something. Maybe it was some sort of alien version of a lidar that just happened to sweep by us and we just happened to be looking in the right place at the right time. But what are the chances of catching a repeat and getting that observation at least reinforced?