APOD: Kepler 78b: Earth Sized Planet... (2013 Nov 05)

[BDanielMayfield]

Because of what I do I have one foot in the astronomical sciences and one in the biological sciences. Its very curious that the only scientists who are enthusiastic and optimistic about extraterrestrial life are physical scientists (astronomers, physicists, mathematicians, statisticians). Almost without exception because of their backgrounds they view all science in a deterministic manner...believing everything can be predicted with the right equation. Unfortunately biological systems defy deterministic approaches. Evolution proceeds in a manner which is not in any way deterministic....the evolutionary process is an opportunistic one, shaped in a large part by chance and opportunism. The expectation that life is ubiquitous in the universe is a very naive one IMO. Perhaps simple life (prokaryotes) may be somewhat common...but complex multicellular life....and civilizations ....I'm not at all optimistic about that, Evolutionary biologists have a very deep respect for the improbability of complex life to form even here on earth. If one studies the history of life on earth it is impressive that after the first simple lifeforms...bacteria...nothing much happened for another 2.5 billion years...more than half the age of the earth. Complex life only occurred in the last 10% of earth's history. In fact in the course of 4.5 billion years over a trillion species have come and gone and only one species has evolved which eventually produced technology....and not until the last 1% of its existence as a species. This does not bode well for the expectation of extraterrestrial civilizations. The other interesting observation is that there exists two earth like planets (mars and venus) in our own solar system and each is totally devoid of life.

I find Rob Gendler’s comments in this thread to be refreshingly candid. Spontaneous generation of life from non-living matter is an extraordinarily difficult thing. Many who doubt this must be unaware of the vast complexity of even the simplest single celled organisms. The evolutionary biologists Rob mentioned know this, which explains their reluctance to jump on the exobiology band wagon.

It’s easy to think that since life exists here on Earth it must have self generated here, and if it did so here it must easily arise elseware too. It amounts to a great deal of wishful thinking, IMO.

[Nitpicker]

We already have a good understanding of how dark matter fits into cosmology, and some very plausible ideas of where it is in the Standard Model. We also have a nice model of dark energy as a component of our best cosmological model, even in the absence of any real understanding of its fundamental nature. Indeed, we can understand many things quite well while knowing nothing about their true natures (if that's even a meaningful question). Our understanding is largely satisfied if we have a predictive theory that is consistent with observation. Right now, the evidence supports the supposition that as we learn more about both dark matter and dark energy, our basic cosmological model isn't going to change radically.

Sure, but we cannot detect dark matter directly yet (although check the date when reading this). If we can figure out a way to detect dark matter, and then perhaps even interact with it, it could conceivably open doors to new scientific phenomena previously unobserved. It is not just about understanding how galaxies form. It is about "stuff" that might yet prove to be extremely useful in our day to day lives. If there is so much dark matter, I like to imagine it has a greater potential than simply "weighing us down". I don't know this of course, but I want to find out.

Edit reason: an "It" that was meant to be an "If". (I even nitpick myself.)

[geckzilla]

I find Rob Gendler’s comments in this thread to be refreshingly candid. Spontaneous generation of life from non-living matter is an extraordinarily difficult thing. Many who doubt this must be unaware of the vast complexity of even the simplest single celled organisms. The evolutionary biologists Rob mentioned know this, which explains their reluctance to jump on the exobiology band wagon.

It’s easy to think that since life exists here on Earth it must have self generated here, and if it did so here it must easily arise elseware too. It amounts to a great deal of wishful thinking, IMO.

It should be noted that there is evidence that single celled life did evolve rather quickly as soon as conditions were right. It's possible that part is not so difficult. The few billion years between those first organisms and the formation of complex life is something else to ponder, though.

[Chris Peterson]

I find Rob Gendler’s comments in this thread to be refreshingly candid. Spontaneous generation of life from non-living matter is an extraordinarily difficult thing. Many who doubt this must be unaware of the vast complexity of even the simplest single celled organisms. The evolutionary biologists Rob mentioned know this, which explains their reluctance to jump on the exobiology band wagon.

I believe Rob is incorrect in his assessment. There are a number of biologists working in the area of exobiology. More than there are physicists, I think. Of course, modern biology really took off when physicists started becoming biologists. Biology is one of the last scientific disciplines to become rigorous, rather than just observation and classification, which is what it mainly was until about 50 years ago, or even less.

We have no grounds to make the claim that the initial creation of life is a difficult process. There is very good work being done in this area, and no reason to even think there is a well defined distinction between living and non-living. It is as likely that life is nearly inevitable under the right conditions as that it is rare. But given how quickly life formed on Earth, and how unremarkable our planet appears to be, I think the most reasonable view is that life is probably quite common in the Universe. Simple life. The history of life on Earth suggests that the step up to complex multicellular life may be more difficult than the initial development of life, and the evolution of technological intelligence even rarer yet.

[Nitpicker]

It should be noted that there is evidence that single celled life did evolve rather quickly as soon as conditions were right. It's possible that part is not so difficult. The few billion years between those first organisms and the formation of complex life is something else to ponder, though.

I know very little about biology, but I estimate that the evolution from zero-celled life to single-celled life was rather swift indeed.

[geckzilla]

Of course, modern biology really took off when physicists started becoming biologists.

[Chris Peterson]

Sure, but we cannot detect dark matter directly yet (although check the date when reading this). If we can figure out a way to detect dark matter, and then perhaps even interact with it, it could conceivably open doors to new scientific phenomena previously unobserved. It is not just about understanding how galaxies form. It is about "stuff" that might yet prove to be extremely useful in our day to day lives. It there is so much dark matter, I like to imagine it has a greater potential than simply "weighing us down". I don't know this of course, but I want to find out.

We can't detect electrons directly. That doesn't seem to bother most people. I would argue that we are detecting dark matter just fine, and are simply in the process of developing other types of detectors- rather like we can detect photons with both electrical and magnetic detectors (but again, no "direct" detection, whatever that might even mean).

[Nitpicker]

Of course, modern biology really took off when physicists started becoming biologists.

Very good geckzilla. My father once told me about his old physics professor, who was fond of saying "it us up to the mathematics department to prove that my theories are correct" in the middle of his derivations.

[Chris Peterson]

Of course, modern biology really took off when physicists started becoming biologists.

Quite accurate, except mathematics doesn't belong in the list at all, since it isn't a science. It is a completely different discipline, useful for creating tools that science can use. Unfortunately, it can also lead scientists down strange and wrong paths, since there is no connection between mathematics and reality.

[geckzilla]

Quite accurate, except mathematics doesn't belong in the list at all, since it isn't a science. It is a completely different discipline, useful for creating tools that science can use. Unfortunately, it can also lead scientists down strange and wrong paths, since there is no connection between mathematics and reality.

Go to the site and hover the comic. (Assuming you are using a mouse, another thought will appear.)

[Nitpicker]

Sure, but we cannot detect dark matter directly yet (although check the date when reading this). If we can figure out a way to detect dark matter, and then perhaps even interact with it, it could conceivably open doors to new scientific phenomena previously unobserved. It is not just about understanding how galaxies form. It is about "stuff" that might yet prove to be extremely useful in our day to day lives. It there is so much dark matter, I like to imagine it has a greater potential than simply "weighing us down". I don't know this of course, but I want to find out.

We can't detect electrons directly. That doesn't seem to bother most people. I would argue that we are detecting dark matter just fine, and are simply in the process of developing other types of detectors- rather like we can detect photons with both electrical and magnetic detectors (but again, no "direct" detection, whatever that might even mean).

We can interact with electrons, photons, etc ... useful little things. But can we interact with dark matter in non-gravitational ways? Does it have any other uses? I don't know. So, I would argue that there are still a few more question marks surrounding dark matter than "traditional" matter.

[Ann]

Neufer wrote:

The square root of Sagan's number is geometrically half way between:

1) The maximum number of star systems that might generate intelligent life (i.e., Sagan's number) &
2) The minimum number of star systems that have generated intelligent life (i.e., one: us).

Click to view full size image

Still from the movie Flood

This reasoning is equivalent to taking the position that if one person claims that the great City of London is located in Great Britain, and another person insists that London is located on the eastern coast of the United States, then the most probable location of London is half way between these two extremes. Such a conclusion would place London on the mid-Atlantic ridge, almost certainly submerged under water.

Ann

[Nitpicker]

This reasoning is equivalent to taking the position that if one person claims that the great City of London is located in Great Britain, and another person insists that London is located on the eastern coast of the United States, then the most probable location of London is half way between these two extremes. Such a conclusion would place London on the mid-Atlantic ridge, almost certainly submerged under water.

A wise person once said:
"A statistician can stick his head in the oven and his bum in the freezer, and claim to be perfectly fine."

[Chris Peterson]

We can interact with electrons, photons, etc ... useful little things. But can we interact with dark matter in non-gravitational ways? Does it have any other uses? I don't know. So, I would argue that there are still a few more question marks surrounding dark matter than "traditional" matter.

Why is gravitational interaction somehow less important, valuable, interesting than electromagnetic interaction? What is useful? We only make use of a handful of the menagerie of particles that make up the Standard Model. What use is a neutrino, or a quark?

I sense a bias that exists only because our most information rich biological sense happens to be electromagnetic.

[Nitpicker]

Why is gravitational interaction somehow less important, valuable, interesting than electromagnetic interaction? What is useful? We only make use of a handful of the menagerie of particles that make up the Standard Model. What use is a neutrino, or a quark?

I sense a bias that exists only because our most information rich biological sense happens to be electromagnetic.

Gosh, I reckon we'll find a decent use for dark matter before you'll concede a single point, Chris. I'm an engineer, trained and inclined to apply science for the benefit of humanity. Biased? Guilty, as charged, sir!

[Beyond]

We can't detect electrons directly.

I guess you've never walked across a rug on a cold dry day and grabbed a metal door handle. It's a good way to meet many electrons up close and personal and is safer than sticking your finger into an electrical outlet. Electrons can be nasty little buggers, when driven by EMF.

[Ann]

I find Rob Gendler’s comments in this thread to be refreshingly candid. Spontaneous generation of life from non-living matter is an extraordinarily difficult thing. Many who doubt this must be unaware of the vast complexity of even the simplest single celled organisms. The evolutionary biologists Rob mentioned know this, which explains their reluctance to jump on the exobiology band wagon.

I believe Rob is incorrect in his assessment. There are a number of biologists working in the area of exobiology. More than there are physicists, I think. Of course, modern biology really took off when physicists started becoming biologists. Biology is one of the last scientific disciplines to become rigorous, rather than just observation and classification, which is what it mainly was until about 50 years ago, or even less.

We have no grounds to make the claim that the initial creation of life is a difficult process. There is very good work being done in this area, and no reason to even think there is a well defined distinction between living and non-living. It is as likely that life is nearly inevitable under the right conditions as that it is rare. But given how quickly life formed on Earth, and how unremarkable our planet appears to be, I think the most reasonable view is that life is probably quite common in the Universe. Simple life. The history of life on Earth suggests that the step up to complex multicellular life may be more difficult than the initial development of life, and the evolution of technological intelligence even rarer yet.

I can't argue with you, Chris. I note, however, that the kind of magazines that popularize science for the general public have yet to publish articles claiming that we now know how life on Earth got started. At least I haven't seen any such articles. (If I had, I would read them, because I sure need to brush up my understanding of this subject!)

Ann

[rstevenson]

I can't argue with you, Chris. I note, however, that the kind of magazines that popularize science for the general public have yet to publish articles claiming that we now know how life on Earth got started. At least I haven't seen any such articles. (If I had, I would read them, because I sure need to brush up my understanding of this subject!)

Maybe start with the May 14, 2009 and Aug. 19, 2009 issues of Scientific American, and go on from there. There's been a lot of material published in the popular science press about the subject, going back well before 2009 too. And there's been lots of discussion since then as well.

Rob

[Chris Peterson]

We can't detect electrons directly.

I guess you've never walked across a rug on a cold dry day and grabbed a metal door handle. It's a good way to meet many electrons up close and personal and is safer than sticking your finger into an electrical outlet. Electrons can be nasty little buggers, when driven by EMF.

That's what I meant by a bias driven by our own immediate senses.

In any case, how do you know that what you feel comes from electrons and not tiny invisible unicorns? "Electron" is just the name that we give to a phenomenon that produces several different observed phenomena. What an electron "really" is we can't say.

[Chris Peterson]

I can't argue with you, Chris. I note, however, that the kind of magazines that popularize science for the general public have yet to publish articles claiming that we now know how life on Earth got started. At least I haven't seen any such articles. (If I had, I would read them, because I sure need to brush up my understanding of this subject!)

Of course, we don't know. But people have very interesting ideas- ideas that are consistent with our understanding of the early Earth environment and with our understanding of chemistry and biology. (There is a report out just today about the role of clay in the creation of life.) From a scientific standpoint, we're probably back in the realm of complex systems, meaning that no simple theory may exist to describe how life formed on Earth. Instead, we probably have a complex interaction of chemical and geophysical systems, along with an evolutionary process (evolution even before something reached the stage that we'd unambiguously call "alive"). And this over millions of years, perhaps. So it may not be testable in a lab at all, except in pieces, subsequently modeled by simulations. A complicated bit of science, to be sure.

To be clear, I'm not saying that life is easily created, only that the claim that it is difficult is not based on any solid evidence.

What we do know, with absolute certainty, is that life did form on the Earth, very quickly once conditions here stabilized. We have every reason to believe that the Earth has no unique qualities, that there are many planets like it (even if that's only a fraction of a percent of all planets). This is why my personal weighing of the evidence leads me to the conclusion that life is likely to be pretty common out there.

[FloridaMike]

I certainly do hope that science gains a better insight into dark matter and dark energy in my lifetime. But whenever it happens, I am confident it will bear some similarity to the current understanding.

Your confidence is more a matter of faith than of knowledge. That's fine, you may well be right, but we don't know yet. And faith is a powerful force. It's is helpful, however, to be clear about when we're acting on faith.

No faith is required. We already have a good understanding of how dark matter fits into cosmology, and some very plausible ideas of where it is in the Standard Model. We also have a nice model of dark energy as a component of our best cosmological model, even in the absence of any real understanding of its fundamental nature. Indeed, we can understand many things quite well while knowing nothing about their true natures (if that's even a meaningful question). Our understanding is largely satisfied if we have a predictive theory that is consistent with observation. Right now, the evidence supports the supposition that as we learn more about both dark matter and dark energy, our basic cosmological model isn't going to change radically.

Could it be that the biggest difference in this conversation may be in what constitutes a fundamental change in understanding? If, for example, we were to discover that dark energy and gravity are somehow one and the same, I would consider that a fundamental change. Chris may view it as an evolution of our understanding.

And Chris? Faith is ALWAYS required. If science did not have the faith it can find the answers, no one would be looking.

[geckzilla]

And Chris? Faith is ALWAYS required. If science did not have the faith it can find the answers, no one would be looking.

You are anthropomorphizing science. Science is just a way of thinking. It doesn't have any emotions, let alone faith. But I will now assume you meant to write "scientists" and not science. And for that I would argue that faith is not the driving factor in the search for answers. Curiosity and a drive to simply know is. Science is the tool for that cause.

[Chris Peterson]

Could it be that the biggest difference in this conversation may be in what constitutes a fundamental change in understanding? If, for example, we were to discover that dark energy and gravity are somehow one and the same, I would consider that a fundamental change. Chris may view it as an evolution of our understanding.

I would consider it a fundamental change if it required throwing out a major theory like GR. I would consider it an evolutionary change if it simply required adding one more term somewhere in the equations.

And Chris? Faith is ALWAYS required. If science did not have the faith it can find the answers, no one would be looking.

I disagree. At least, you are defining "faith" very differently than I am. Faith is believing in something without evidence. My belief that science works as a method of finding answers is strongly evidence based. I will change my beliefs freely (and have done so many times) as the evidence changes.

[FloridaMike]

You may study the stars Chris, I study something much, much more complex. Humanity.

[geckzilla]

You may study the stars Chris, I study something much, much more complex. Humanity.

Non sequitur?