Are we alone in the Universe?

[Nitpicker]

I am sure Clark felt it was better to be civilised than to be barbarous. He was clearly a big fan of civilisation(s). But I am not sure the term "barbarian" was always used in a pejorative sense through history. My understanding is that the term was used to classify "foreign" people, or people "not like us". Of course, it could always be used in a pejorative sense, too.

Personally, I feel that Clark's personal opinions, choice of terminology and his propensity for sweeping generalisations, made his TV series a lot more interesting and thought provoking, than a dry, factual report on the history of western European art. He was certainly old fashioned, even in his day. But he also knew his topic very well. I think it is a great series, most especially when viewed as a product of its time. And of course, the BBC have recently produced a more modern and inclusive series: Civilisations (plural).

[geckzilla]

ok.

[orin stepanek]

We simply don't know if we are alone or not, says David Kipping, but we might be,
in which case the Earth and everyone living on it would be incredibly special.

Well...I know for a fact that I'm incredibly special.

+1 +++

[orin stepanek]

that video is incredibly problematic

+++++

[orin stepanek]

In my Opinion! When life exist's on a planet; it spreads its life giving material into the void every time a volcano blows its top! Every viable planet that strays into this region gets this material! Think of it; just like every year when Earth goes through a comet's path we get particles left over from it's path around the sun! The problem with contact is that the life span of life life is short compared to a planets overall life and intelligent life is even shorter! So: contact would have to be made in this short period of time! JMHO! Orin

[neufer]

The problem with contact is that the life span of life life is short compared to a planets overall life and intelligent life is even shorter! So: contact would have to be made in this short period of time! JMHO! Orin

I'm betting on eventual contact between our robot overlords & their robot overlords.

[orin stepanek]

The problem with contact is that the life span of life life is short compared to a planets overall life and intelligent life is even shorter! So: contact would have to be made in this short period of time! JMHO! Orin

I'm betting on eventual contact between our robot overlords & their robot overlords.

OK; sounds good to me!

[neufer]

Future robot overlord

---

The problem with contact is that the life span of life life is short compared to a planets overall life and intelligent life is even shorter! So: contact would have to be made in this short period of time! JMHO! Orin

I'm betting on eventual contact between our robot overlords & their robot overlords.

OK; sounds good to me!

[orin stepanek]

I really don't see any contact soon! !st we would have to find habitable planets; Then/ maybe decide weather to explore or colonize! Then figure on how to get there! Probably it would take several generations of travel time! I just don't see it happening! Not soon anyway!!!!!!! We may as well be alone!

[Chris Peterson]

I really don't see any contact soon! !st we would have to find habitable planets; Then/ maybe decide weather to explore or colonize! Then figure on how to get there! Probably it would take several generations of travel time! I just don't see it happening! Not soon anyway!!!!!!! :rocketship: :b: :bang: We may as well be alone!

The contact would most likely be in the other direction. An AI (or possibly a biological lifeform with an extremely long lifetime) that spent a few thousand years heading this way.

[Ann]

I really don't see any contact soon! !st we would have to find habitable planets; Then/ maybe decide weather to explore or colonize! Then figure on how to get there! Probably it would take several generations of travel time! I just don't see it happening! Not soon anyway!!!!!!! We may as well be alone!

The contact would most likely be in the other direction. An AI (or possibly a biological lifeform with an extremely long lifetime) that spent a few thousand years heading this way.

How do you expect the AI:s to find us, if they have been on their way for several thousand years? How did they know to aim their ship to exactly our itty-bitty unbelievable tiny little target in the unimaginable vastness of the cosmos, if they embarked on their journey a few thousand years ago? Humans didn't exactly yell their presence to the cosmos at the time when the pyramids were built. You mean that the AI:s would have noticed our promising non-equilibrium atmosphere, and therefore they would have decided to check our planet out? But if such atmospheres are common, would they have had the time and the energy to pay a visit to them - us - all?

Ann

[Chris Peterson]

I really don't see any contact soon! !st we would have to find habitable planets; Then/ maybe decide weather to explore or colonize! Then figure on how to get there! Probably it would take several generations of travel time! I just don't see it happening! Not soon anyway!!!!!!! :rocketship: :b: :bang: We may as well be alone!

The contact would most likely be in the other direction. An AI (or possibly a biological lifeform with an extremely long lifetime) that spent a few thousand years heading this way.

How do you expect the AI:s to find us, if they have been on their way for several thousand years? How did they know to aim their ship to exactly our itty-bitty unbelievable tiny little target in the unimaginable vastness of the cosmos, if they embarked on their journey a few thousand years ago? Humans didn't exactly yell their presence to the cosmos at the time when the pyramids were built. You mean that the AI:s would have noticed our promising non-equilibrium atmosphere, and therefore they would have decided to check our planet out? But if such atmospheres are common, would they have had the time and the energy to pay a visit to them - us - all?

Our atmosphere has certainly been indicating that some sort of complex biology has been going on here for a long time. That may well be enough to attract interest. And humans have been modifying our atmosphere for several thousand years... and the pattern of that modification might suggest a technological species.

(And I wasn't suggesting the contact was likely, only that if it occurred it was more likely to be them contacting us, not us contacting them.)

[neufer]

humans have been modifying our atmosphere for several thousand years...

Several thousand years

[Chris Peterson]

humans have been modifying our atmosphere for several thousand years...

Several thousand years :?:

Yes. Ice cores show changes in CO2 that appear to correlate with human caused deforestation going back at least 2000 years, maybe more. I don't know how someone with an advanced understanding of geological and climatological processes would view that, but I certainly don't exclude the possibility that they would interpret it as an indicator of technological life.

[neufer]

humans have been modifying our atmosphere for several thousand years...

Several thousand years

Yes. Ice cores show changes in CO2 that appear to correlate with human caused deforestation going back at least 2000 years, maybe more. I don't know how someone with an advanced understanding of geological and climatological processes would view that, but I certainly don't exclude the possibility that they would interpret it as an indicator of technological life.

Ice ages, sea level changes, super volcanoes have made a noticeable impacts on CO₂ amounts ...but pre-industrial revolution man?

Concentration of atmospheric CO2 over the last 40,000 years

---

<<The Last Glacial Maximum (LGM) was the most recent time during the Last Glacial Period when ice sheets were at their greatest extent. Vast ice sheets covered much of North America, northern Europe, and Asia. The ice sheets profoundly affected Earth's climate by causing drought, desertification, and a large drop in sea levels.] The ice sheets reached their maximum coverage about 26,500 years ago (26.5 ka BP).

Deglaciation commenced in the Northern Hemisphere at approximately 20 ka and in Antarctica approximately at 14.5 ka, consistent with evidence for an abrupt rise in the sea level at about 14.5 ka.>>

[orin stepanek]

Oh; My!

[Chris Peterson]

Ice ages, sea level changes, super volcanoes have made a noticeable impacts on CO₂ amounts ...but pre-industrial revolution man?

Absolutely, pre-industrial revolution and pre-technological man.

[orin stepanek]

I really don't see any contact soon! !st we would have to find habitable planets; Then/ maybe decide weather to explore or colonize! Then figure on how to get there! Probably it would take several generations of travel time! I just don't see it happening! Not soon anyway!!!!!!! We may as well be alone!

The contact would most likely be in the other direction. An AI (or possibly a biological lifeform with an extremely long lifetime) that spent a few thousand years heading this way.

Who would want to make such a long boring trip! You probably need a self sustaining ship with a dedicated crew where a life style could exist with families! where as families and or generation of such could finish the journey! What a disappointment if the planet turned out to be a dud! Just musing; but what if?

[Chris Peterson]

I really don't see any contact soon! !st we would have to find habitable planets; Then/ maybe decide weather to explore or colonize! Then figure on how to get there! Probably it would take several generations of travel time! I just don't see it happening! Not soon anyway!!!!!!! :rocketship: :b: :bang: We may as well be alone!

The contact would most likely be in the other direction. An AI (or possibly a biological lifeform with an extremely long lifetime) that spent a few thousand years heading this way.

Who would want to make such a long boring trip! You probably need a self sustaining ship with a dedicated crew where a life style could exist with families! where as families and or generation of such could finish the journey! What a disappointment if the planet turned out to be a dud! Just musing; but what if?

This assumes that some other lifeform sees 1000 years as long. Or that it's even capable of boredom. Or that they have families. And if it's an AI (as seems more likely), none of these things are a factor.

[neufer]

Who would want to make such a long boring trip! You probably need a self sustaining ship with a dedicated crew where a life style could exist with families! where as families and or generation of such could finish the journey!

What a disappointment if the planet turned out to be a dud! Just musing; but what if?

Click to play embedded YouTube video.

duds (n.) c. 1300, dudde "cloak, mantle," later, in plural, "clothes," especially "ragged clothing" (1560s), of uncertain origin but probably from an unrecorded Old English word. Compare Old Norse duði, Low German dudel. Related: Duddery "place where rags are kept for sale" (1550s); dudman "scarecrow, man made of rags" (1670s); duddy "ragged, tattered" (1725).

dud (n.) 1825, "person in ragged clothing," from duds (q.v.). Sense extended by 1897 to "counterfeit thing," and 1908 to "useless, inefficient person or thing." This led naturally in World War I to "shell which fails to explode," and thence to "expensive failure."

Well...I know for a fact that I'm a useless, inefficient person.

[orin stepanek]

AI: Artificial Intelligence = scares me; either good or evil! Whatever man can invent; he will! If it's an AI; send it somewhere else! I can see how that would be useful in exploring the unknown! But other types of computers could do the same! What happens when AI needs maintenance?

[Chris Peterson]

AI: Artificial Intelligence = scares me; either good or evil! Whatever man can invent; he will! If it's an AI; send it somewhere else! I can see how that would be useful in exploring the unknown! But other types of computers could do the same! What happens when AI needs maintenance?

I imagine in the end AI will be the creation of AI. And why can't it maintain itself? Why won't it be subject to evolutionary pressures? Really, there's no fundamental difference between natural and artificial intelligence.

[orin stepanek]

AI: Artificial Intelligence = scares me; either good or evil! Whatever man can invent; he will! If it's an AI; send it somewhere else! I can see how that would be useful in exploring the unknown! But other types of computers could do the same! What happens when AI needs maintenance?

I imagine in the end AI will be the creation of AI. And why can't it maintain itself? Why won't it be subject to evolutionary pressures? Really, there's no fundamental difference between natural and artificial intelligence.

Maybe we are AI; But I hope not!

[Doum]

Hello all,
I read an article a long time ago that was saying that the supernova rate start diminish enough for life to appear around 5 billions years ago. And before that life was probably destroy as it was create because of that rate of supernova that was high. Just saying that if it's true then life could start and evolve only 5 billions years ago in the entire univers not before that.The earth being 4,8 billions years old, we might be among the first intelligent life form to exist. And the closest intelligent life form might be very far from us. What i say is just a possibility. But it's possible. And as for what reason an alien might come to our solar system, well if we start exploring the univers someday we might arrive at a planet that have an intelligent lifeform and they will ask themself, why are they coming to us? How did they know we exist? And the answer will be: We come to your planet because it is were we are at in our exploration. We didnt choose you in particular, we discover you. Now we are pushing further. And if there are alien on our next exploration, they will ask the same question. Why come to us?

That's my grain of salt.

[neufer]

I read an article a long time ago that was saying that the supernova rate start diminish enough for life to appear around 5 billions years ago. And before that life was probably destroy as it was create because of that rate of supernova that was high. Just saying that if it's true then life could start and evolve only 5 billions years ago in the entire univers not before that.The earth being 4,8 billions years old, we might be among the first intelligent life form to exist. And the closest intelligent life form might be very far from us. What i say is just a possibility. But it's possible.

The greatest threat from a near-Earth supernova is the destruction of the ozone layer.

However, we didn't have an ozone layer before the Great Oxidation Event 2.45 billion years ago:

<<A near-Earth supernova is a supernova close enough to the Earth to have noticeable effects on its biosphere. Depending upon the type and energy of the supernova, it could be as far as 3000 light-years away. Gamma rays from a supernova would induce a chemical reaction in the upper atmosphere converting molecular nitrogen into nitrogen oxides, depleting the ozone layer enough to expose the surface to harmful ultraviolet solar radiation. This has been proposed as the cause of the Ordovician–Silurian extinction 444 million years ago, which resulted in the death of nearly 60% of the oceanic life on Earth.>>

<<The Great Oxygenation Event, the beginning of which is commonly known in scientific media as the Great Oxidation Event, was the biologically induced appearance of molecular oxygen in Earth's atmosphere. Geological, isotopic, and chemical evidence suggests a start of around 2.45 billion years ago (2.45 Ga), during the Siderian period, at the beginning of the Proterozoic eon.>>