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EricD Solidarity: The weapon of the Roman Legions
Post 1

What motivates a person on the battlefield?

This is a question which disturbs and fascinates me.

Battle, in any period of history, has always been dangerous, loud, painful, and terrifying. It is unpleasant on every level. It leaves thousands of people wounded or dead. There's a very good chance you lose life or limb in a battle. Why do people do it? In the heat of life or death combat with thousands of people struggling against one another, what motivates a person in that moment?

The question becomes more pressing when one looks at the context of a military campaign, outside of just one pitched battle. Men are obliged to march for miles and miles away from home, to endure hunger and fatigue and cold and rain and mud, and countless uncertainties and terrors and discomforts, and then at the end of that they are confronted with the sheer horror of battle. What can motivate anyone to endure such?

Ardant du Picq wrote upon this theme in his Battle Studies: " When, in complete security, after dinner, in full physical and moral contentment, men consider war and battle they are animated by a noble ardor that has nothing in common with reality. How many of them, however, even at that moment, would be ready to risk their lives? But oblige them to march for days and weeks to arrive at the battle ground, and on the day of battle oblige them to wait minutes, hours, to deliver it. If they were honest they would testify how much the physical fatigue and the mental anguish that precede action have lowered their morale, how much less eager to fight they are than a month before, when they arose from the table in a generous mood. " (Battle Studies, Part II, Chapter I)

So what is this elusive factor that gives humans the motivation and mental fortitude to endure all these awful things? One of the most critical factors, military history has found again and again, is group cohesion and social solidarity. Humans fight to assist and protect their comrades and friends in the ranks to either side. As Ardant du Picq also wrote:

"Unity, that first and supreme force of armies, is sought by enacting severe laws of discipline supported by powerful passions. But to order discipline is not enough. A vigilance from which no one may escape in combat should assure the maintenance of discipline. Discipline itself depends on moral pressure which actuates men to advance from sentiments of fear or pride. But it depends also on surveillance, the mutual supervision of groups of men who know each other well.

A wise organization insures that the personnel of combat groups changes as little as possible, so that comrades in peace time maneuvers shall be comrades in war. From living together, and obeying the same chiefs, from commanding the same men, from sharing fatigue and rest, from cooperation among men who quickly understand each other in the execution of warlike movements, may be bred brotherhood, professional knowledge, sentiment, above all unity. The duty of obedience, the right of imposing discipline and the impossibility of escaping from it, would naturally follow.

And now confidence appears." (Battle Studies, Part I, Chapter VI)

Many years later, Dave Grossman found similar results in his seminal work On Killing: "A tremendous volume of research has found that the primary factor that motivates a soldier to do the things that no sane man wants to do in combat (That is, killing and dying) is not the force of self-preservation but a powerful sense of accountability to his comrades on the battlefield" (On Killing, pg 149)

Now the title of this thread speaks about the Roman legions. I am getting to that.

I have before presented on this forum presented views on the nature of Roman armies and their tactics in battle drawn from contemporary scholarship which are rather contrary to the popular understanding advanced by books, movies, games, et cetera. I have argued extensively that they were more javelineers than swordsmen, that they were more interested in aggression than obedience, that their formations were somewhat loose to facilitate movement rather than tight for formation drill, and that the Roman legionary saw his comrades to either side as his competitors for glory. I have pointed out that Roman military discipline, to the extent that it existed, was more a matter of their campaigning discipline rather than battlefield tactics. I also argued that the Marian legions of the Late Republic, after Marius's reforms, were militarily speaking very similar to their predecessors in the Punic Wars and that I didn't see much indication in the sources that Marius really improved the training or behaviours of the Legions in a substantive sense.

I would like to today engage further with some of the often repeated axioms about the Marian Legion that emerged in the Late Republic. It is said, often, that Marius made the Legions professional, better disciplined, better trained. I don't think these things are necessarily true, or at least not in the usually assumed way. Nothing in the primary texts that I can identify points towards substantively different training, tactics, or campaigning behaviours. Marian legions fought with the same weapons as pre-Marian legions did, they still flung their pila prior to gladius charges, still fought in relatively loose groups clustered around their centurions and standards, they were still aggressive to the point of disobedience at times, they still sought to prove their prowess by glorious individual actions and were praised and rewarded for doing so. In most objective respects, the Marian legion was more similar than different from its predecessors.

But I think the Marian legions were more militarily formidable armies even so, for a different but still very significant reason.

The traditional recruitment method for the Roman legion in the Republic as described by Polybius would divide up each of the tribes of Rome among the four legions recruited for each campaigning year. This had the effect of ensuring that any peacetime pre-existing social cohesion among the recruits was broken up, which was very, very weird for cultures of the Mediterranean at this time. Essentially every army leveraged peacetime social organization and social bonds to create unit cohesion at war. The armies of Antiquity had the kind of social cohesion which du Picq and Grossman speak about because they were drawn from social groups to which the man had been a member his entire life. Gallic armies marched to war in their tribes, Germanic lords had a warband of warriors which lived and slept and ate alongside their lord at all times, the battalions of the Macedonian army were drawn from the regions and villages of the Kingdom, this was the normal state of affairs in premodern war. This was necessary. The social trust necessary to hold men together as a military unit were ensured by the maintenance of a man's peacetime social units during wartime. So for the Romans it was very odd that they did otherwise, and I believe part of the reason for that was to foster a spirit of competition for glory among the men of the army, to make them braver and more aggressive in order to prove themselves better than their comrades.

Now it is inevitable that over the course of a long campaign, a legion in that pre-Marian period would develop its own internal social bonds. Men of the same tent group, century, and maniple would inevitably build friendships and trust, would help each other in their daily tasks, and despite the fierce competition for glory would also rely on each other in battle. Roman soldiers were rewarded for aggressive individual actions, but they were rewarded for saving the lives of fellow citizens with great honour also. At the end of a given campaign however, the legion would be stood down and men would be sent back to their peacetime social groups (Families, clans, et cetera). The legion pre-Marius was a temporary social unit. There are many cultural and economic reasons for why that might be, but it is sufficient for purposes of this thread to state that pre-Marius, the Legions were temporary social units. The long campaigns of the Punic and Macedonian Wars would have led to these temporary social units becoming firmly bonded to each other, but even so with the end of war came the end of the Legion and a return to civilian life. This divide between military and civilian social lives was more stark in Rome than in many other contemporary cultures, as far as I can tell by my current research anyways.

Among Marius's many military reforms, one of the most underestimated but most significant was that his Legions were permanent social units, or at least long term ones. Where pre-Marius, a legion only existed for the duration of a given conflict (Which could be long, but even so the legion would be stood down at the end of said conflict). The sheer time spent under the colours after the Marian reforms was very long indeed, service lengths of sixteen years were expected and later increased to twenty under Augustus.

Now, consider this from the socialization perspective. You're a Roman lad of 17 or 18 (Maybe younger even), you join the Legions to serve with Marius (or Pompey, or Caesar). You spend 16 years under the colours. Your entire adult life is spent with the Legions. Your friends are in the Legions, the closest social relationships you have are to your tentmates, your century, your cohort. You're not legally allowed to have a wife or a family (Though of course those rules must have been bent often). Your whole social existence, your whole way of life, is within the Legion. You don't have a trade, you don't have a farm, you left your village or your neighbourhood behind, your family is the Legion. With such long periods of service, often far afield in remote provinces for years far from your homelands, the Legion is your primary social unit. With the experience of long continuous campaigns and many battles large and small, these post-Marian legions would not only gain longer military experience than their pre-Marian counterparts, but would become more and more solid, cohesive, tightly bonded social units held together by countless horizontal links of comradeship between soldiers and by vertical links of trust between leaders and led.

Veterans of modern wars like Vietnam and Afghanistan have at times reported closer emotional bonds and relationships to their military comrades than to their wives or children. If that was the case after a year in country in Vietnam, how much more would it be the case for a Legion after 10 years or more in the provinces?

What Marius did was, in effect, create a military caste in Roman society. Where previously war was an activity which the whole of male Roman society participated in, after Marius it was increasingly the province of the Legions, and the Legions were organized such that they became their own social units independent from the Roman state or society.

These effects have been discussed in the scholarly literature before, but usually from the perspective that the legionaries were more loyal to their generals than to Rome. There is truth to this analsysi. But the other side of that is that the legionaries were more loyal to the Legions than to Rome as a society.

And on the battlefield, solidarity is a powerful weapon. Solidarity, the desire to help one's comrades and do one's duty so to avoid the shame of one's comrades, motivates men to do things in battle or on campaign they might not otherwise be willing to do. They will stand and fight when a rationally self-interested person might instead run away.

The blogger T. Greer has a good short article on this subject: Solidarity, Weapon of Modernity.

I would disagree with him on some of his statements about the Romans however. I think that the social nature of the post-Marian legions indicates that, perhaps by accident or perhaps by design, Marius had created a long term social solidarity within the Roman legions that gave them a critical morale advantage on the battlefield.

As du Picq writes, and many modern military members will tell you, true unit discipline is not entirely about the obedience to orders from above. It is often just as much or more about each individual's accountability to the group, and the group's willingness and ability to police its individuals in service of the interests or needs of the group. People who know each other, who trust each other, who care about each other and care about what the group thinks of them, will work harder to maintain the group's respect and will be more responsive to the group's demands. A strongly bonded social group will hold together under the pressures and terrors of campaigns and battle. Individuals will do more than just seek to preserve their own lives when the needs and interests of their primary social group, and more importantly that group's respect for the individual, are on the line. Individuals will work harder and fight harder when they fight protect their comrades or to avoid losing the respect of their comrades. Multiplied across the 5,000 men of a Legion, this social solidarity becomes a force multiplier.

By creating these long term social units, Marius created much stronger social bonds for his soldiers within the Legion. Group membership in the Legion was very likely more important for these men than any other social relationship they might have possessed. That, I think, was one of the critical military advantages of the Roman legions on the battlefield and was key to their legendary tenacity in battle and on campaign.

To provide a primary source illustration of this tenacity, I ask you to consider Caesar's account of the Ninth Legion at the Battle of Ilerda:

"Finding nearly the whole of his line panic-stricken — an event as unusual as it was unexpected — Caesar exhorts his men and leads the Ninth Legion to their support. He checks the foe who are pursuing our men with insolent daring, and compels them again to turn and retreat to the town of Ilerda and halt beneath the walls. But the men of the Ninth Legion, carried away by zeal in their desire to repair the loss received, rashly pursuing the flying foe too far, get into unfavourable ground and approach close under the hill on which the town of Ilerda was situated. When our men wished to retreat from this position, the enemy in turn kept pressing them hard from the higher ground. The place was precipitous with a steep descent on either side, and extended only so far in width as just to give room for three cohorts drawn up in battle array, so that supports could not be sent up on the flanks nor could cavalry be of any use if the men were in difficulties. But on the side of the town sloping ground with a slight descent stretched to the length of about four hundred paces. In this direction our men stood at bay, since, carried forward by their zeal, they had recklessly advanced thus far. The fighting took place in this spot, which was unfavourable both from its confined limits and because they had halted just under the very spurs of the mountain, so that no missile failed to reach them. Nevertheless they strove with valour and endurance and sustained every description of wound. The forces of the foe were increasing and cohorts were continually being sent up to them from the camp through the town so that the unexhausted were always taking the place of the exhausted. Caesar was obliged to adopt the same course of withdrawing the exhausted and sending up supporting cohorts to the same place.

When they had fought in this way continuously for five hours, and our men were being grievously harassed by superior numbers, having spent all their missiles, they draw their swords and, breasting the hill, charge the cohorts, and after laying a few low, they force the rest to retreat. When the cohorts were thus pushed close up to the wall, and to some extent driven by terror to enter the town, an easy withdrawal was allowed our men" (Caesar, De Bello Civili, Book 1, Chapter 45-46)

The Ninth Legion faced five hours of combat on unfavourable ground against an enemy that was steadily increasing its pressure, outnumbering them and striking them with missiles from higher ground. In such a disadvantageous position, many forces would have broken and ran rather than endure. From the rational perspective of self-preservation alone, any individual within the Ninth might have preferred to run from that fight. But the Ninth had been with Caesar's armies since Gaul, they had served together for many years, they had the benefit of long experience and many battles but they also would have been a tightly cohesive social group after such long experience. That cohesion, that desire to aid one's comrades as well as advance the glory and prestige of the Legion's name, maintained combat morale even in a decidedly unequal struggle and in the end it was the enemy's will that broke and not the Ninth's. That, I think, gives some indication of the power of solidarity on the battlefield.

A key question that Ilerda also raises though is why the Pompeian legions, similarly organized and with a similar length of time together as a unit, had their own morale break at Ilerda when they were fighting in the advantageous position. The question gets into how the pressures of war can break down social bonds and trust over time as much as build them up. That's a discussion for another time however.

I think the takeaway here is that understanding military discipline does not mean some system of instant obedience to commands. I think more accurately it means understanding the nature of the social groups which soldiers of all time periods form during their time at war, understanding how those groups are created, function, and how the pressures of war either strengthen them or break them down. The Roman legions, even after Marius, were often prone to aggressive disobedience as Caesar often recounts. Their battlefield maneuvers were in essence the same as anything done pre-Marius. But I theorize that they were still a more militarily formidable body of troops than their predecessors, as their nature as permanent standing forces created both greater accumulation of military experience and a more tightly bonded, cohesive social unit which would hold together against the rigours of war with greater resilience.


Septentrionalis - The Stoic philosophy thread
Post 2

Flinn is right on the money here. Stoicism is very much an everyday practice, and there is no component in it that would require you to either personally believe or, when being among other Stoics, pretend to believe something that is against your scientific knowledge of the world. Some concepts and practices may have the resemblance of religion to someone who is unfamiliar with Stoicism, though. However, the philosophy is based on reason and anything that does not work in practice can and must be replaced with something that does work. I will try to illustrate a bit.

We come across situations in our everyday lives in which we have previously let ourselves think worse thoughts or managed to think fewer good thoughts. Or in fact have let irrational negative emotions regularly get the better of us. Now we study the many principles honed over 2,400 years by a number of insightful people, many of whom have seen some really tough situations. We try to remember their teachings (which we view as educated opinions, not some prophetical, divine truths) and consciously alter our thoughts and actions to a better outcome.

Above, I mentioned the example of getting angry at inanimate objects, which may sound like a theoretical thing or an insignificant curiosity, but it is not. To give you an example, some of us allow ourselves behavior such as getting angry and hitting a tennis racket against something because we fail consecutive shots or are losing a game. While the racket cannot suffer injustice as such, Stoics are likely to think that we are doing injustice to ourselves by letting us incorrectly assume that we are being wronged by circumstances in what is really our own failure. The better way is to humbly accept the fact that we occasionally fail and need more practice. And that getting angry will only make our game worse. Also, we are ruining the joy of our friends that we have the privilege of being on the court with by such displays of bad sportsmanship.

Stoics also believe that not manning up to our shortcomings and accepting responsibility builds our character the wrong way and, as it is often put in this religious-sounding way, "hurts our soul". What next if we let ourselves get away with things? Because the world doesn't cater to us the way our unchecked ego would want, can we cheat in a game? Or steal because we did not have the same advantages as someone else? In another example, if it is raining, the Stoic way would be not to frown and curse at the bad luck or be angry at the rain that we cannot control no matter how intensely we decide to ruin our mood. One Stoic way would be to smile at the rain and remember how great it is that we do not have draught, crop failure, and starvation. Praise the rain! Or at least tolerate it with good composure.

One of the key principles in Stoicism is that our happiness is determined by the quality of our thoughts, and that we can learn to master our thoughts by voluntary appliance of reason and rejection of negative emotions. The more you do it, the easier it gets, and you will notice a clear improvement in your level of courage, personal integrity, compassion, self-control, and mood. And no, I have never heard of anyone who learned to reject negative emotions by reasoning to suffer later on by some kind of "bottled-up" emotions. That is some kind of modern pseudo-psychological gobbledygook of all feelings being "natural". Yes, destructive feelings are natural occurrences like homicide, polio, and pollution, but we are better off with fewer of the kind and we can do things to prevent them.


Kritias - Greece: MPs vote for permanent police presence in Greek universities
Post 3

More controversial news from Greece since earlier this week the government majority MPs voted on a widescale education reform. Potentially writing off around 30% of the student body and placing stricter limits to young students achieving university education, the lawmakers also decided on a permanent police presence inside the campuses. Disguised as ‘campus police’, this security force will answer to the police minister instead of the university faculty, have rights of arrest, calling reinforcements and even the riot police without permission from the university authorities. Misinformation by the Oxford-schooled minister for education regarding police role in the esteemed university forced Oxford to issue a statement voicing their concern over academic liberty in Greece. Indicative offenses the campus police can proceed to an arrest range from the reasonable (ie. Damaging property, graffiti etc) to Orwelliesque like handing out leaflets or “noise disturbance”. More scandalously, the funding for this campus police will come out of ELKE, a joint university fund reserved for university research.

The undeclared war between the government and parties of the opposition over the issue of universities has been waging for over a year now. The co-author of the bill, Police Minister Michalis Chysohoidis has accused the opposing academic authorities to be operating under some sort of Stockholm Syndrome, and the Prime Minister declared that “the police will bring democracy in the universities”. A student uprising during the junta that left at least 26 people dead when tanks busted through campus gates on November 17th, 1973 stood as reason for the restored democracy to issue the so-called “university asylum law”: that no state force could enter campus grounds unless serious crimes were being committed or else invited by the university authorities.

The government narrative paints Greek universities to be completely lawless grounds. The narrative sometimes points to petty crime happening in campuses like selling contraband items, weed etc while others to assaults from unknown individuals on faculty. A significant such attack, the rector of the Economic University of Athens was forced to pose for a photo with a sign across his chest writing “I support squats”. However, professors have spoken out against the bill pointing towards statistics, both from police themselves and independent actors, showing that criminality in Greek universities is as limited as in the rest of the developed world. Opposition MPs have laid blame on the sorry state of the Greek universities primarily to the government funded and backed student union DAP-NDFK: the student union has been regularly accused of hiring thugs to break up student elections, of selling test answers to students, of buying test scores for students from government-inclined professors, of hosting parties with certain ‘benefits’ (and not a few cases of rape) inside campus grounds for recruitment efforts, and of generally being sexist fratboys. The opposition states that the government utilizes the pandemic and strict home orders for health purposes to pass as many unpopular laws as it can. Its indicative that right before this bill reached the parliament there was a lot of talk for issuing a curfew after 6 in the afternoon to combat the pandemic. Similarly, important dates for the student movement in Greece like 17th of November and 6th of December were declared extremely dangerous for public health. In the former case Michalis Chysohoidis, the Police Minister, imposed a ban on public congregations of more than 4 people.

At the same time when Greek media over-sensationalize police brutality in neighboring Turkey as a sign of increasing discontent for the Erdogan government, native police brutality seems to go significantly under reported. On the bill’s ramification day, students throughout the country took to the streets and were faced with significant violence from the police. In one instance a policeman allegedly crushed a student’s jaw with a fire extinguisher while 25 detainees were taken to the hospital with fractured skulls before taken to the police station to be processed. Earlier this year MPs of the opposition have repeatedly reported being witnesses to police violence against citizens and journalists, while an MP and Speaker of the House reported being assaulted by the police herself. On November 17th 2020, MPs were also assaulted by police during the march to commemorate the fall of the military junta of 1967-1974. On the same time the special guard’s union speaker tweeted that a “significant part of Greek society is ailing and needs to be cured” eerily rehashing junta rhetoric.

Making the situation more complicated, MPs for the opposition produced documents from Wikileaks where the US Ambassador in Athens in 2008, Daniel Speckhard, outlined US-backed reforms for Greece’s education system and the need to “police the overly politicized Greek students.” The documents produced demonstrate alleged pressures by the US government on the Greek government 13 years before a bill with the entirety of the suggestions made its way to the parliament. The government has declined to comment on the allegations of giving in to foreign pressures on the matter of policing Greek universities.


Vanoi - Wall Street & Social Media
Post 4

Quote Originally Posted by Sir Adrian View Post
Demand went up when word got out about WSB raising the price. It's when you heard about it, it's when I heard about, it's when everyone heard about it. WSB bought stock for over 9 months, the stock was shorted in December 2019, and you only heard about it 2 months ago.
No, one member of WSB bought Gamestop stock years ago. He told everyone the stock had potential for years and people laughed at him. Once stock got massively shorted he convinced people it was the time to buy stock because would go up due to the stock being shorted. That is what caused the demand.

In fact 140% of GameStop's public float was shorted. That's a big reason why the stock even able to ride in price so dramatically.



No, the only difference between Tesla and Gamestop is that there was nothing organized with Tesla, it was just investors trading normally, there was no throng of amateurs lured in by inflated demand, there was no coordinated action, there was no campaigning. Tesla was normal trading.
Again please provide evidence or the relevant US law that makes organizing together to buy stocks illegal. Otherwise it doesn't matter.

If you say so.

Just that the plan was that the shorters bring Gamestop stock to 0 by february.
No it was to lower the price, not make it zero. Its not possible for Gamestop to trade at 0$.
That means bankrupt. WSB got in specifically because it was the perfect bait to harm the hedgies, as GS was sure to go under within the year. So yes, it was a lure and squeeze. In fact the paragraph describes exactly what happened with the shorted stock. You can argue sematics all you want but facts are facts.
You do realize the value of a company is not solely determined by their stock price? Gamestop can't go bankrupt solely because it's stock price crashed. That makes absolutely no sense at all.

https://www.cnet.com/personal-financ...-be-surprised/

. Was GameStop going under before the stock price jump?
Though the retailer struggled in recent years, it wasn't at death's door.

"I actually think they are in a good position to grow revenue and earnings again with the console launches," said Wedbush analyst Michael Pachter. "Earnings power like that supports a price in the high teens or low 20s."
Gamestop isn't doing great but it wasn't bound for bankruptcy as you claim it was.


Jadli - The Astronomy Thread
Post 5

(Yaaay, I originally lost the post, so had to write most of the stuff again)

Nice to see such a thread on TWC, studying astrophysics myself (4th year), so obviously interested in all this stuff (the topics discussed here is kinda why I started studying it)...

I pretty much agree with everything Flinn said...

Anyway, A very good point about space engine/drive and movement in space PoVG. This all comes from "basic" physics and has been kinda known from the beginning of space travel, so its really sad that most of mainstream sci-fi movies/shows have completely neglected it. Its not just about time durations, but simply the movement of the ships... they cant just suddenly "stop" or "change directions and so on, without killing everyone inside (due to the artifical acceleration created).

The efficiency of our (propulsion) drives has been a core issue since day one, because as you all very likely know, the large majority of fuel (which is abot 75% mass of the rockets) is used just to leave Earth, so there is very little left for some actual movement in space, the ships are mostly just slightly "pushed" in the beginning, and then they mostly just continue with no thrust till they reach the destination, hence it takes a long time.

The next step very likely is something based on fusion or fissions (hence a very little fuel and lot of energy), so the ships would be able to accelerate/deccelerate (which means just turning the ships an accelerate in opposite direction of course) during the flight, hence things would get faster. That would definitely allow/speed up our inevitable colonization/exploration of Solar System (at least for mining purposes). It would also solve many other issues, because long term survivability in zero G is an issue ...

Based on the current knowledge physics (which is pretty complete in regards to how space travel works) even this wouldnt be enough to reach other stellar systems, and hence the exoplanets... Because as PoVG pointed out, it would still take a long time, as you cant go as fast as you want with manned missions. Sending an unmanned mission might be possible, as you might be ble to accelerate as much as you want. But of course, even the most efficient fuel is not endlessly efficient, and the faster you go, the more quickly you burn it... so the question is how much fuel would it have to carry to get there in a reasonable time even with the most efficient drives anyway (talking decades minimally, plus dont forget the information delay itself would be years).

So we cant get there "personally" for sure, though we are already able to extract impossible information about exoplanets from observations due to our crazy machines... and we are working on even crazier missions (both earth and space), so we will be able to know much more in the foreseeable future

Though that shouldnt bother us too much right now, as we have more than things to explore in our Solar System, we have barely set foot in it, so our focus should be mainly here I think. There are more than enough interesting objects in it. It seems our Solar System is not somewhat unique, so what we learn here can be easily extrapolated to the exoplanets. We already know many organisms that can live in crazy conditions... I think we will find some "fossils" on Mars perhaps, but much more interesting may turn out to be the moons of gas giants, especially Saturn and Jupiter of course, such as the ones with seas under their ice crusts, or Titan with ith methan cycle (similar to water cycle on Earth). If we find something even in such hardly habitable worlds, that would easily prove that some form of life is very common in space (at least bacteria and so on).

I definitely agree with Flinn's opinion about probability of life.... Even if the probability of life was infinitely small, there are so many stars with (exo)planets in habitable zones out there (billions of billions) that the their number is pretty much infinite, hence, looking at it from the opposite angle, its pretty much impossible that some form of life wouldnt form. Also, there are so many complex molecules flying around in space, they pretty much just need to "fall" to a good planet. Of course, the question is what kind of life would be formed.. in 99,99% it would be just some bacteria and so on, so not someone you could talk to...

Quote Originally Posted by Flinn View Post
So I'm pretty confident basic forms of life could be found almost everywhere there are the basic conditions for it: water in liquid form and basic chemical elements that are used to assemble amino acids.
I honestly have no clue, though, of how rare "intelligent" life could be, for various reasons: first, it is obvious, by looking at our own system, where we have millions of bodies, that a combinations of elements like the ones you have on the Earth are pretty rare (giving for assumed that only rocky planets similar to our can give birth to intelligent life, for obvious reasons); second, it is not clear yet which kind of stars are better suited for hosting Earth-like planets: as of today, it seems that both yellow dwarfs (such as the Sun, approx 1/13 of all the stars) and orange dwarfs (approx 1/8) have the best chances, due to the fact that they seem to be more stable that red dwarfs (red dwarfs show to have frequent powerful solar flares that can possibly destroy any atmosphere and/or form of evolved life in their systems, and they represent approx 3/4 of all the stars!!!) or bigger stars (from white dwarfs up to blue giants, here I'm referring only to main-sequence stars of course), due to the fact that those stars have a shorter life, which might not allow enough time to develop superior forms of life; third, the very definition of "intelligence" is pretty subjective and can make the difference at that regards: for instance, most animals do have a form of intelligence, therefore if we look at this as our starting point, it needed roughly 250 millions year for the life to evolve from bacteria to intelligent life on Earth.. but if we believe that intelligence is the ability to shape the word around you, then we have to wait for hominids, sometimes like another 250 millions years; more points could be listed, but I'm sure you got my point by now.
Yea. Imho, I like Drake's equation a lot, even tho its just a guess, not math. But its a very good guess that includes almost all/most things one needs to think about, when thinking about extrasolar life. One definitely needs to to think about time scales.... near us, there could have been many intelligent civilizations before us, or will have been before us, but its possible we are just not gonna live "in the same time" as them... If you look at Earth history, like 99,9% of its history there was no "intelligent civilization" able to space travel/communicate, and Earth is about 4 billions of years old, so yeah...

Well, its actually somewhat clear which stars are better suited... exoplanets are a very new field in astrophysics, so most basic principles and so on is being researched or formulated right now (this year, we had an exoplanet class for the first time.... Therefore I also have lot of new interesting info I suppoe )

Stars on main sequence of spectral types F,G (Sun),K are definitely kinda the only ones suitable (see spectral classification). So "slightly" heavier or lighter stars compared to Sun, which is the majority of stars. So you are prety much right with your assumptions (though Im not sure what do you mean by dwarfs). So basically heavier stars have too short lives for proper planets to even form (thats a pretty lengthy process itself indeed), and the lighter ones are too active (and if you realize that their luminosity is much weaker, it means that exoplanets must be much closer to their stars to be in a habitable zone, therefore the flares, eruptions are even more destructive).

Other thing that is essential for stars to have planets in first place is definitely the abundance of heavier elements, as without them you of course wouldnt have any terrestrial planets (and moons similiar to the Jovian Moons), just gas giants. Pretty much all younger stars, such as our Sun, have them, but of course some systems might not (as that again may depend on many things). Plus, the elements are of course also needed for more complex molecules, hence the life.

Based on current (theoretical) statistics, in average most (exo)planets are slightly larger than Earth and have orbital periods between 10-400 day, so thats good. (and pretty much every star that lives long enough is very likely to have planets of course)

About the creation of life/habitability, a liquid water is essential, its basically a catalyst of life creation, because it allows all the various molecules to do a bunch of interesting life, and life may eventually come of it. There are not many other chemical compounds that can do the same, but it seems that methan and ammonia can serve a similar purpose (but less efficiently), so that opens more doors for life... possibly that means life is possible on Titan, despite the crazy low temperatures, we will have to see.

Well, as you say Flinn, there is insane amount of information, topics and angles that we could discuss (after all, I have been studying it for years, so yea). Though I suppose lets throw in an interesting fresh thing or two from my recent exoplanet course to spark up some discussion.

Regarding the question, whether our Solar System is unique or just a regular one(therefore, also asking whether life is a regular thing), I find this graph below extremely interesting...




It shows all known exoplanets (so a few thousands) and our planets together, comparing the planet radius (in earth radius units, so 1 equals the radius of Earth) vs the distance of a planet from its star (in astronomical units, 1 equals a distance of Earth from Sun). So it shows that almost all exoplanets are much closer to their stars (hence mostly not in habitable zones as well of course), apart of other huge implications...

So, curious what you guys think about it? It apparently seems to deny that our Solar System is a regular system (as based on the graph, our Solar System is completely different than the other ones, and parameters of our planets are not very usual as well, compared to the "mainstream")...


BTW, to anyone interested in realistic space exploration/astronomy, I would definitely recommend the tv show The Expanse. Except the story, characters, meaning and all the stuff being extremely well done on its own (after all, its (one of) the best tv show(s), period, you are missing out, if you havent seen it yet), the future in it is portrayed so well, one is willing to accept that this is how thing are probably going to look in 200-300 years. Its science is very correct (compared to other sci-fi), the showrunner has a physics PhD after all, all the things we talked about in regards to moving in space are in it (the accel/decel,its effects on human body,..) and so much more other scientifically accurate stuff in it. Itd hard to watch most other sci-fi afterwards, because you see all the physics nonsense in it