New work suggests that life could have arisen and survived a mere 15 million years after the Big Bang, when the microwave background radiation levels would have provided sufficient energy to keep almost all planets warm. Summary here, and actual article here. This is still very preliminary, but the possibility at some level is extremely frightening. It adds billions of years of time for intelligent life to have arisen that we don’t see, and if anything suggests that the Great Filter is even more extreme than we thought.
Now that is scary, although there are a few complications. Rocky bodies were probably extremely rare during that time since the metal enrichment of the Universe was extremely low. You can’t build life out of just hydrogen and helium.
Doesn’t the relevant number of opportunities for life to appear have units of mass-time?
Isn’t the question not how early was some Goldilocks zone, but how much mass was in a Goldilocks zone for how long? This says that the whole universe was a Goldilocks zone for just a few million years. The whole universe is big, but a few million years is small. And how much of the universe was metallic? The paper emphasizes that some of it was, but isn’t this a quantitative question?
I agree that a few million years is small, and that the low metal content would be a serious issue (which in addition to being a problem for life forming would also make planets rare as pointed out by bramflakes in their reply). However, the real concern as I see it is that if everything was like this for a few million years, then if life did arise (and you have a whole universe for it to arise), as the cooldown occurred, it seems highly plausible that some forms of life would have then adopted to the cooler environment. This makes panspermia more plausible and thus makes life in general more likely. Additionally, it makes more of a chance for life to get lucky if it managed to get into one of the surviving safe zones (e.g. something like the Mars-Earth biotransfer hypothesis).
I think you may be correct that this isn’t a complete run around and panic level update, but it is still disturbing. My initial estimate for how bad this could be is likely overblown.
I’m nervous about the idea that life might adapt to conditions in which it cannot originate. Unless you mean spores, but they have to wait for the world to warm up.
As for panspermia, we have a few billion years of modern conditions before the Earth, which is itself already a problem. I think the natural comparison is the size of that Goldilocks zone to the very early one. But I don’t know which is bigger.
Here are three environments. Which is better for radiation of spores? (1) a few million years where every planet is wet (2) many billion years, all planets cold (3) a few billion years, a few good planets.
The first sounds just too short for anything to get anywhere, but the universe is smaller. If one source of life produces enough spores to hit everything, then greater time depth is better, but if they need to reproduce along the way, the modern era seems best.
I’m nervous about the idea that life might adapt to conditions in which it cannot originate.
Why this happened on Earth? It is pretty likely for example that life couldn’t originate in an environment like the Sahara desert, but life can adapt and survive there.
I do agree that spores are one of the more plausible scenarios. I don’t know enough to really answer the question, and I’m not sure that anyone does, but your intuition sounds plausible.
There’s barely any life in the Sahara. It looks a lot like spores to me. I want a measure of life that includes speed. Some kind of energy use or maybe cell divisions. I expect the probability of life developing in a place to be proportional to amount of life there after it arrives. Maybe that’s silly; there certainly are exponential effects of molecules arriving the same place at the same time that aren’t relevant to the continuation of life. But if you can rule out this claim, I think your model of the origin of life is too detailed.
There’s barely any life in the Sahara. It looks a lot like spores to me.
I’m not sure what you mean by this.
I want a measure of life that includes speed.
Do you mean something like the idea that if an environment is too harsh even if life can survive the chance that it will evolve into anything beyond a simple organism is low?
We should have the data now to take a whack at the metallicity side of that question, if only by figuring out how many Population 2 stars show up in the various extrasolar planet surveys in proportion with Pop 1. Don’t think I’ve ever seen a rigorous approach to this, but I’d be surprised if someone hasn’t done it.
One sticking point is that the metallicity data would be skewed in various ways (small stars live longer and therefore are more likely to be Pop 2), but that shouldn’t be a showstopper—the issues are fairly well understood.
The paper mentions a model. Maybe the calculation is even done in one of the references. The model does not sound related to the observations you mention.
I don’t think this is frightening. If you thought life couldn’t have arisen more than 3.6 billion years ago but then discover that it could have arisen 13.8 billion years ago, you should be at most 4 times as scared.
The number of habitable planets in the galaxy over the number of habituated planets is a scary number.
The time span of earth civilization over the time span of earth life is a scary number.
If it were just a date, then, yes, a factor of 4 is lost in the noise. But switching to panspermia changes the calculation. Try Overcoming Bias [Added: maybe this is only a change under Robin Hanson’s hard steps model.]
It changes my epistemic position by a helluva lot more than a factor of 4. If an interstellar civilization arose somewhere in the universe that is now visible, somewhere in a uniform distribution over the last 3.6 billion years, there’s much smaller chance we’d currently (or ever) be within their light cone than if they’d developed 13.8 billion years ago.
It’s potentially scary not because of the time difference, but because of the quantity of habitable planets. It’s understood that current conditions in the Universe make it so that only relatively few planets are in the habitable zone. But if the Universe was warm, then almost all planets would be in the habitable zone, making the likelihood of life that much higher.
As I said in my reply to JoshuaZ though, the complication is that rocky planets were probably much rarer than they are now.
There weren’t any planets 15 million years after the Big Bang. The first stars formed 100 million years after the Big Bang, and you need another few million on top of that for the planets to form and cool down.
It seems to take a lot more than 15 million years to get from “life” to “intelligent life”. According to the article this period would only have lasted for a million years, so at most we would probably get a lot of monocellular life arising and then dying during the cooloff.
1 - why should no intelligent life arising from a set of places that were likely habitable for only 5 million years (if they existed at all, which is doubtful) be surprising?
2 - I raise the possibility of outcomes for intelligent life that are not destruction or expansion through the universe.
Edit: Gah, that’s what I get for leaving this window open while about 8 other people commented
The paper implies that it only adds millions of years, not billions.
a new regime of habitability made possible
for a few Myr by the uniform CMB radiation
Once the CMB cools down enough with the expansion of the Universe, the Goldilock conditions disappear. The CMB temperature is roughly inversely proportional to the age of the Universe, so 300K at 15 million years becomes just 150K 15 million years later.
New work suggests that life could have arisen and survived a mere 15 million years after the Big Bang, when the microwave background radiation levels would have provided sufficient energy to keep almost all planets warm. Summary here, and actual article here. This is still very preliminary, but the possibility at some level is extremely frightening. It adds billions of years of time for intelligent life to have arisen that we don’t see, and if anything suggests that the Great Filter is even more extreme than we thought.
Now that is scary, although there are a few complications. Rocky bodies were probably extremely rare during that time since the metal enrichment of the Universe was extremely low. You can’t build life out of just hydrogen and helium.
Is that a relevant number?
Doesn’t the relevant number of opportunities for life to appear have units of mass-time?
Isn’t the question not how early was some Goldilocks zone, but how much mass was in a Goldilocks zone for how long? This says that the whole universe was a Goldilocks zone for just a few million years. The whole universe is big, but a few million years is small. And how much of the universe was metallic? The paper emphasizes that some of it was, but isn’t this a quantitative question?
I agree that a few million years is small, and that the low metal content would be a serious issue (which in addition to being a problem for life forming would also make planets rare as pointed out by bramflakes in their reply). However, the real concern as I see it is that if everything was like this for a few million years, then if life did arise (and you have a whole universe for it to arise), as the cooldown occurred, it seems highly plausible that some forms of life would have then adopted to the cooler environment. This makes panspermia more plausible and thus makes life in general more likely. Additionally, it makes more of a chance for life to get lucky if it managed to get into one of the surviving safe zones (e.g. something like the Mars-Earth biotransfer hypothesis).
I think you may be correct that this isn’t a complete run around and panic level update, but it is still disturbing. My initial estimate for how bad this could be is likely overblown.
I’m nervous about the idea that life might adapt to conditions in which it cannot originate. Unless you mean spores, but they have to wait for the world to warm up.
As for panspermia, we have a few billion years of modern conditions before the Earth, which is itself already a problem. I think the natural comparison is the size of that Goldilocks zone to the very early one. But I don’t know which is bigger.
Here are three environments. Which is better for radiation of spores?
(1) a few million years where every planet is wet
(2) many billion years, all planets cold
(3) a few billion years, a few good planets.
The first sounds just too short for anything to get anywhere, but the universe is smaller. If one source of life produces enough spores to hit everything, then greater time depth is better, but if they need to reproduce along the way, the modern era seems best.
Why this happened on Earth? It is pretty likely for example that life couldn’t originate in an environment like the Sahara desert, but life can adapt and survive there.
I do agree that spores are one of the more plausible scenarios. I don’t know enough to really answer the question, and I’m not sure that anyone does, but your intuition sounds plausible.
There’s barely any life in the Sahara. It looks a lot like spores to me. I want a measure of life that includes speed. Some kind of energy use or maybe cell divisions. I expect the probability of life developing in a place to be proportional to amount of life there after it arrives. Maybe that’s silly; there certainly are exponential effects of molecules arriving the same place at the same time that aren’t relevant to the continuation of life. But if you can rule out this claim, I think your model of the origin of life is too detailed.
I’m not sure what you mean by this.
Do you mean something like the idea that if an environment is too harsh even if life can survive the chance that it will evolve into anything beyond a simple organism is low?
We should have the data now to take a whack at the metallicity side of that question, if only by figuring out how many Population 2 stars show up in the various extrasolar planet surveys in proportion with Pop 1. Don’t think I’ve ever seen a rigorous approach to this, but I’d be surprised if someone hasn’t done it.
One sticking point is that the metallicity data would be skewed in various ways (small stars live longer and therefore are more likely to be Pop 2), but that shouldn’t be a showstopper—the issues are fairly well understood.
The paper mentions a model. Maybe the calculation is even done in one of the references. The model does not sound related to the observations you mention.
I don’t think this is frightening. If you thought life couldn’t have arisen more than 3.6 billion years ago but then discover that it could have arisen 13.8 billion years ago, you should be at most 4 times as scared.
The number of habitable planets in the galaxy over the number of habituated planets is a scary number.
The time span of earth civilization over the time span of earth life is a scary number.
4 is not a scary number.
If it were just a date, then, yes, a factor of 4 is lost in the noise. But switching to panspermia changes the calculation. Try Overcoming Bias [Added: maybe this is only a change under Robin Hanson’s hard steps model.]
It changes my epistemic position by a helluva lot more than a factor of 4. If an interstellar civilization arose somewhere in the universe that is now visible, somewhere in a uniform distribution over the last 3.6 billion years, there’s much smaller chance we’d currently (or ever) be within their light cone than if they’d developed 13.8 billion years ago.
It’s potentially scary not because of the time difference, but because of the quantity of habitable planets. It’s understood that current conditions in the Universe make it so that only relatively few planets are in the habitable zone. But if the Universe was warm, then almost all planets would be in the habitable zone, making the likelihood of life that much higher.
As I said in my reply to JoshuaZ though, the complication is that rocky planets were probably much rarer than they are now.
It’s the scariest number.
There weren’t any planets 15 million years after the Big Bang. The first stars formed 100 million years after the Big Bang, and you need another few million on top of that for the planets to form and cool down.
It seems to take a lot more than 15 million years to get from “life” to “intelligent life”. According to the article this period would only have lasted for a million years, so at most we would probably get a lot of monocellular life arising and then dying during the cooloff.
1 - why should no intelligent life arising from a set of places that were likely habitable for only 5 million years (if they existed at all, which is doubtful) be surprising?
2 - I raise the possibility of outcomes for intelligent life that are not destruction or expansion through the universe.
Edit: Gah, that’s what I get for leaving this window open while about 8 other people commented
See the conversation with Doug up subthread.
Does it add billions of years? That’s not saying that life could have arisen and survived since 15 million years after the Big Bang.
The paper implies that it only adds millions of years, not billions.
Once the CMB cools down enough with the expansion of the Universe, the Goldilock conditions disappear. The CMB temperature is roughly inversely proportional to the age of the Universe, so 300K at 15 million years becomes just 150K 15 million years later.