Scientists Debate Signatures of Alien Life | Hacker News Reader

Scientists Debate Signatures of Alien Life

quantamagazine.org

70 pointselorant31 comments

For those who are wondering before reading - article looks at the issue of what is considered a "highly likely" indication in an alien planet's atmosphere that would indicate life. Oxygen used to be considered that, but other processes have been found that can lead to significant O2 without life.

Thanks for the TL;DR. I find these magazine-style articles that start with waffle instead of the conclusion very frustrating!

> I find these magazine-style articles that start with waffle instead of the conclusion very frustrating!

Imagine there was a rule that popular-press science articles were required to have an abstract that candidly summarized the article:

Title: "Is there life elsewhere in the universe?"

Abstract: "We have no idea, and this article doesn't change the status quo."

How about life without oxygen? I always wonder why alien life or any other life cannot happen without it.

I think this is finally being considered. Just because we're carbon based doesn't mean all life must be.

There a good reasons for organic chemistry being the main one. Carbon is abundant and can be combined in numerous ways to make complex molecules and stable ones at that. There are very few other elements in the periodic table that can hope to offer similar properties. So carbon based life is not just a guess, its a high probability.

I don't know where this myth comes from that scientists have some sort of strong belief that no other form of life is possible, but it's not true. What we have is a lot of ignorance, so many scientists will often concentrate only on those forms of life (plural) we know exist because we share a planet with them, because those are the forms of life we can actually discuss with confidence, but I doubt you can find a serious scientist who will confidently proclaim no alternatives are possible.

There are good reasons to believe that ours is quite likely and good reason to be skeptical of alternatives, in the proper scientific sense, but certainly not disproved or something.

> I doubt you can find a serious scientist who will confidently proclaim no alternatives are possible.

Undoubtedly. The problem is that very few people, even among the well-educated and technically proficient, actually form their views about the state of science by talking to scientists.

Well eventually, oxygen et al will just be catalysts to silicon based life :)

There is already life on earth without oxygen. Deep sea bacteria lives on sulphur and carbon dioxide.

> How about life without oxygen?

It's thought that life began here in the absence of oxygen, and only over time did oxygen begin to play a part in cellular life. As another poster points out, there are still some cellular organisms here that do without oxygen, indeed they would find it toxic.

> I always wonder why alien life or any other life cannot happen without it.

But that's not true, not even here. Oxygen is regarded as a sign of life, but its absence doesn't suggest the absence of life, only the kind of life that requires it.

> How about life without oxygen? I always wonder why alien life or any other life cannot happen without it.

If by oxygen you mean molecular oxygen, O2 -- rather than atomic oxygen as part of some other compound -- we know life can happen without it, since there is life on earth that lives without it. And, IIRC, we have strong reason to believe that life that could live without O2 predates life that needs O2, and, in fact, it is life that made free O2 available, not free O2 that made life possible.

> And, IIRC, we have strong reason to believe that life that could live without O2 predates life that needs O2, and, in fact, it is life that made free O2 available, not free O2 that made life possible.

Yes, early life on Earth was all anaerobic. That started around 4.1 Gya (billion years ago)[1]. The Great Oxygenation Event[2] happened around 2.3 Gya - that wasn't the first appearance of photosynthesis, but it was the point at which it changed the atmosphere enough to wipe out most of the other life on Earth at the time. Obligate aerobes - organisms that need oxygen to survive - were later still.

[1] https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h...

[2] https://en.wikipedia.org/wiki/Great_Oxygenation_Event

A lot of people seem to be so ready to read a different article that they aren't noticing what this one is about. This is not an article about "If a given planet holds life, how could we detect it?" This article is about "If a given signal is detected from a planet, what characteristics of the signal would allow us to conclude it could only be from life?" It's a completely different question. It's not about avoiding false negatives, it's about avoiding false positives. It is obvious that a planet could hold life, and we could fail to detect it; we're still arguing about whether Mars has or had life, after all! And we've actually landed probes on it.

Any time I see this discussed, I feel compelled to post the transcension hypothesis: http://accelerating.org/articles/Smart-2011-TranscensionHypo...

In short: Life is common in the universe, black holes are better than Dyson spheres, and eventually everyone uploads their brains to computers.

Far fetched or not, really interesting reading!

It's sad "scientists" are wasting their time on this close-proximity alien fantasy when they could be working on real problems.

Sad? I don't see anyone crying.

It's not as if the entire scientific community is just dropping whatever they're doing to work on this. The value of an endeavor is its likelihood of success times its potential reward. So while the probability that these people will succeed is very, very low, the potentially incalculable rewards of discovering alien life offset that.

This is no different than my Father coming home every night without food telling us the same thing, that when he wins big we'll have all the bread in the world. He never won, then he died.

People wasting time on things that have an extremely low probability is still a waste of time at the expense of everyone else currently living on the planet.

If anything, discovering alien life will probably end us.

How short-sighted and small minded. In the pursuit of answering these questions the people involved develop new techniques and new knowledge that ultimately aid in our overall scientific progress.

Yes but you haven't said anything tangible. This does nothing for people suffering from lack of fundamental necessities. How much hubris do you need to completely skip our planet and get right to fantasy? I'd get it if we were all so smart we solved everything we needed to but we can't even solve our own planet.

Your casual philandering with space exploration doesn't put anything on anyone's table but your own, much like how lots of minds are wasted crunching pointless numbers for data startups.

Nor have you provided any evidence that it has negatively affected society, your argument is weak. As a matter of fact, NASA has made hundreds of contributions to society, particularly in material sciences. Here is a list I found on a pop-culture site after a few seconds of googling (I am sure there are more detailed lists elsewhere): http://www.independent.co.uk/news/science/50-years-50-giant-...

I believe it is quite common for knowledge to permeate across domains (e.g. math->computer science->internet or astrobiology->biology->medicine). You adopt a naive view where you make the assumption that the works of these scientists are trivial because YOU don't see the benefit to our society. With that sort of reasoning we should never embark on any endeavor where we are unsure the outcome would benefit us.

By virtue of not pursuing something that doesn't efficiently get basic necessities to everyone, I don't need evidence as you're doing the work for me.

Great, but they could have added more if they abandoned space altogether and used all those billions on aid.

There is quite literally no point in wasting money on manned interplanetary missions. It's futile because we can't move at light speed, so even if we did find something it'd prompt an "oh, ok, cool" and everyone would move on. And we'd still have slavery and poverty and starvation.

  casual philandering with space exploration

Pure research is such a critical part of scientific advancement. Where would we be today without all of the work done by military rocketry and civilian space programs? Without various nations' space programs, scientists working on diseases including malaria, HIV/AIDS, and tuberculosis would not have had access over the last twenty years to high-bandwidth communications services via communications satellites at hospitals, clinics, laboratories, and schools scattered across some of the most remote areas of the African continent---to name just one region with which I have direct involvement. I cannot even begin to stress how important that kind of access is even in this modern age of relatively good 2G/3G coverage (there are still plenty of locations in which we work to cure disease where satellite communications are still a necessity). It made it possible for our scientists to not only train their colleagues in country and raise up new generations of skilled doctors, nurses, and scientists, but also to access the sum total of scientific knowledge from places where good people frequently suffer and die from the kinds of endemic disease rarely seen in the West. Maybe searching web sites or holding conference calls seems droll and ordinary to you, but to our scientists and their colleagues, getting Internet access via satellite in the middle of sub-Saharan Africa during the late 90s and early 00s was revolutionary. So much good work---the fruit of which we see bearing now, like not just one but several effective malaria vaccines as well as mosquito population control programs---became possible, all because fifty years ago, people started "philandering" with space exploration.

How much hubris do you need to think that you alone know how best to allocate not only the scarce resources of this planet but also the lives of every single human being on this planet, and to sit in judgment of what work is worthy and what isn't? To transcend the current boundaries of human knowledge and engineering skill has a direct impact on our (collective) lives, and for the better. This world is not zero-sum; it is not in thermodynamic equilibrium. For some people to work in space for the eventual benefit of mankind as a whole does not require other people to suffer and die of want and neglect (quite the opposite, in fact).

> How much hubris do you need to think that you alone know how best to allocate not only the scarce resources of this planet but also the lives of every single human being on this planet, and to sit in judgment of what work is worthy and what isn't?

By looking at their merits? Giving a sandwich to a guy sleeping on the street does infinitely more for them than us reaching Mars.

Are video games worthy? Anything consumer for the sake of consumption is arrogance in its purest most refined form.

You must have grown up with a Mommy and Daddy that got along well and always provided for you, so you think space exploration is something noble, when in reality its a rich elitists nationalistic jerkoff game, where you engineers are the pawns fueled by childish and selfish ideals. Yes, you might discover something that helps elsewhere, but coincidence is hardly synonymous with intention.

Repeat to yourself how silly it is to look for aliens. "I am looking for aliens." Repeat that 1000 times to yourself until you realize how stupid of a goal that actually is.

I think that our fundamental point of disagreement has to do with investment. Given a field full of wheat, you want to eat it all. I think you have to reserve some of it, because even when the winter is bad and some people are starving, come springtime you have to be able to plant _something_ or else everybody will starve. This difference manifests in our approaches to social problems. You want to meet someone's immediate need, like adding oil to a car with leaky seals, while I want to address the underlying problem---fixing the broken engine, or even better, replacing the broken engine with something that works a thousand times better.

That's OK, because in reality, we need both short-term (just feed the guy!) and long-term (fix the engine!) solutions to the problems that beset our world.

> This does nothing for people suffering from lack of fundamental necessities.

This is a basic philosophical question -- shall we give the poor a fish, or shall we teach them how to fish? The answer should seem obvious, and in the modern world, science is the fishing pole.

> I'd get it if we were all so smart we solved everything we needed to but we can't even solve our own planet.

The problem on Planet Earth is very simple -- there are far too many people. The problem is easy to state, but almost impossible to solve. How do you tell people to have fewer children without violating one of the most basic rights we have?

How do we know there are too many people? Science. How do we know that's a nearly impossible problem to solve? Science.

> Your casual philandering with space exploration doesn't put anything on anyone's table but your own ...

Christopher Columbus heard this argument too, as did every pioneer throughout human history. Your analysis overlooks the fact that space exploration is so valuable that it's in the verge of becoming a profitable enterprise and have no more need for public funding. How will you complain about it then?

> ... much like how lots of minds are wasted crunching pointless numbers for data startups.

A "data startup" succeeds or fails based on private funding by people who understand and accept the risks, so it can't be part of your argument about global poverty.

> People wasting time on things that have an extremely low probability is still a waste of time at the expense of everyone else currently living on the planet.

If your views were policy, we would have no modern medicine or agriculture, people would have an average lifetime of 30 years, and ignorance would be the norm In other words, we would live in the world that actually existed when your views were policy.

> ... that when he wins big we'll have all the bread in the world. He never won, then he died.

He didn't win because he didn't understand probability, like most lottery players today. He would have been better off spending his limited resources on feeding and educating his children.

I'm sure he loved his children and was a valuable person, but the story might have had a nicer outcome if he had had an education -- an education with roots in science.

Your analogy assumes that - as a species - we're spending all or most of our resources on this endeavor when we're actually spending next to nothing on it.

And if alien life will end us, perhaps we should discover them before they discover us.

Lovelock's work at NASA philosophizing about the possible chemical processes which might go on on other planets led to his considering life+atmosphere as a combined system, which directly drove a lot of scientific investigation of the effect of human activity on the atmosphere and the atmosphere's effect on life, and therefore to much of our current understanding about global warming. This kind of research is not isolated, it helps us understand planetary dynamics and find other examples of planet-scale atmospheric systems which help us learn more about our own.

By every objective measure, we are living in the greatest time in human history. There are fewer deaths per capita due to war, poverty, disease and famine than at any other time.

... when they could be working on real problems.

What constitutes a real problem is not as absolute and self-evident as you seem to think. There are any number of science stories in which a seemingly impractical pursuit led to something valuable in the long term. That's in the nature of science, which has always cost less than the budget allotments for "real problems" like defense, entitlements and grain subsidies.

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