"Scientists headed by David McKay of the JohnsonSpaceCenter in Houston found that the rock, called ALH84001, had a peculiar chemical makeup. It contained a combination of minerals and carbon compounds that on Earth are created by microbes. It also had crystals of magnetic iron oxide, called magnetite, which some bacteria produce. Moreover, McKay presented to the crowd an electron microscope view of the rock showing chains of globules that bore a striking resemblance to chains that some bacteria form on Earth. “We believe that these are indeed microfossils from Mars”"[1]
I was disappointed that the story fizzled out. One microbiologist concluded that bacteria from Earth had "contaminated the Mars meteorite. Other scientists pointed out that nonliving processes on Mars also could have created the globules and magnetite clumps." But I don't think life is ruled out. This meteorite is hanging in as a "just maybe" like the Viking mission discovery.
[1] https://www.smithsonianmag.com/science-nature/life-on-mars-7...
If genetic material did travel in either direction, it would be easily verified.
The best broad test to look for life would be to look for an entropy source.
```
On August 2008, the Phoenix lander detected perchlorate, a strong oxidizer when heated above 200 °C. This was initially thought to be the cause of a false positive LR result. However, results of experiments published in December 2010 propose that organic compounds "could have been present" in the soil analyzed by both Viking 1 and 2, since NASA's Phoenix lander in 2008 detected perchlorate, which can break down organic compounds. The study's authors found that perchlorate can destroy organics when heated and produce chloromethane and dichloromethane as byproduct, the identical chlorine compounds discovered by both Viking landers when they performed the same tests on Mars. Because perchlorate would have broken down any Martian organics, the question of whether or not Viking found organic compounds is still wide open, as alternative chemical and biological interpretations are possible.
...
In a paper published in December 2010, the scientists suggest that if organics were present, they would not have been detected because when the soil is heated to check for organics, perchlorate destroys them rapidly producing chloromethane and dichloromethane, which is what the Viking landers found. This team also notes that this is not a proof of life but it could make a difference in how scientists look for organic biosignatures in the future.
```[0]
It's funny that perchlorate is likely what confounded the LR experiment, as the discovery of perchlorate in the soil made a lot of folks less optimistic about life being able to survive on the Martian surface.[1]
[0] https://en.wikipedia.org/wiki/Viking_lander_biological_exper...
You’ve been a great audience, I’ll be here for the next 7 sols!
I'm very surprised by that.
Especially since, as the article says, "NASA maintains the search for alien life among its highest priorities".
I thought that would obviously translate to sending life-detection instruments to B̶a̶r̶s̶o̶o̶m̶ Mars.
A big discovery has a high burden of proof and that’s basically where we’re at. There’s definitely reason not to rule it out but I can’t believe conclusive evidence is being sat on by all of NASA for funding reasons.
Let’s speculate for a sec. Tardigrades can survive space. Things have been hitting us knocking earth stuff into space for billions of years. Some of that stuff probably made it to Mars and back in the day it was pretty liveable. It’s not far fetched. None of that negates the above.
https://mars.nasa.gov/mars2020/mission/instruments/sherloc/
There is a standard and open pipeline to getting an instrument on these missions. Scientific American is not part of it. It’s more like AGU, LPSC, Icarus, and the National Academies decadal survey — writing actual instrument proposals with hypotheses and trace back to hardware that can make the measurements needed to test the hypothesis.
If humans go to mars we will be proceeded by the robots.
Popular sentiment would quickly swing (or be swung) towards leaving Mars alone. "We've f*d up one planet, let's not destroy two!", "leave Mars to the Martians", etc.
Vested interests opposed to the space program would get legislation passed that declared Mars indigenous life to be a protected species, and interference with a planetary ecosystem a criminal act.
That would be the end of any exploration or settlement.
But if they don't include life detectors, and declare that "no life has been detected there", then discovering that they were wrong will happen once the colony is already in place. Too late, the ecosystem is already altered, might as well keep going and study it.
Better to ask forgiveness than permission.
I was surprised by this statement. I thought atmosphere on Mars is too thin to support any kind of combustion.
After some searching the closest thing I found was a bunch of popular science articles seeing aliens in white pixels on images from Curiosity [1]. It seems all very much like people trying to make a thing out of image artifacts. NASA's much more reasonable explanation is stray reflections in the optics or cosmic particles striking the detector.
[1] https://www.cnet.com/news/nasa-mars-curiosity-rover-saw-a-we...
If perclorates were the cause of the Viking positive as many suggest, why not send a new experiment designed to rule that in or out? Why not send a whole lot more chemical tests for biology, or a microscope for that matter?
I suspect there is strong concern about the social effects of the revelation of any extraterrestrial life, even microbes. From what I see of the mass psychosis that is most of current political discourse this concern might not be unfounded.
Who categorizes science as an intrinsically atheistic endeavor other than religious apologists?
The nature of general religious beliefs is that they're essentially non-falsifiable.
And particularly in this case, life on mars wouldn't be shocking due to the fact that there is life on earth and there is a small amount of mass transfer. If there isn't some amount of microbial life on mars it would only because of the dumb luck that there hasn't happened to be anything on earth that could get transferred, survive the transfer, and survive on mars.
If the planet is dead, we as a civilization get the privilege to do whatever we want with it. Also a dead planet means the idea of the Monotheistic God kind of remains.
Ignorance is bliss.
I don't follow why life on another planet would have any bearing on the idea of a Monotheistic God.
But I think the reason it’s not talked about more is that our knowledge is essentially non existent and hasn’t really changed in, say, the last fifty years?
I think that would be a different answer if we found inorganic life, as that would blow up the concept of organic life as singular in "life" bearing capability. I doubt we would recognize inorganic life as "life" in that case however, as humanity has a poor working definition of "life."
Absent a recognizably intelligent form of life found off planet, I doubt much would change (practically or existentially) for us here on earth.
If you don't consider "does life exist on other planets?" to be a fundamental, existential question, can you share an example of what you do think is such a fundamental question?
Finding life on Mars wouldn't necessarily resolve any fundamental questions, but it would open up a whole new realm of questions. Is it similar to life on Earth? How similar? Is there evidence for or against some form of panspermia? (at its most extreme, life arriving on Earth from outside the solar system, but this could also be life arising on Earth and being transported to Mars via impact ejecta, or vice versa)
Also, lots of worthwhile science is done even though it doesn't have an immediate and obvious impact on everyday life. I can't think of any particular way in which the discovery of gravitational waves has changed my life, for example - but I recognize that the work that's gone into it has advanced human knowledge, and probably will indirectly benefit my life (or my descendants' lives) in ways I can't predict.
Edit for a TL;DR - The basic idea is that, if we don't see evidence of intelligent life in the universe, it must be because star traveling species must be rare. If we find life evolving twice in one solar system, then the early parts of life evolving must be relatively easy - which suggests the later parts of life becoming technologically advanced are the hard parts. In other words, life on Mars may mean that there may be more problems ahead of us than behind us.
It depends on how different it is chemically form earth life. If it is similar enough that it shares a common origin, it's no big deal. If it isn't, then that's a massive deal because it means life originated twice in one solar system, therefore is probably widespread.
Or we might get a repeat of when the Spanish brought disease to the Inca and Maya.
The mere knowledge of life is viable off-Earth is huge. If we find it on our nearest neighbour, the chances of encountering it elsewhere rise markedly. Hopefully it would trigger a search elsewhere in the solar system, like Europa.
The anthropic principal becomes less compelling; to say nothing of the religious implications.
For plenty of us, AndrewKemendo is right... learning that there is life on Mars would not answer any particularly fundamental questions. Maybe because a lot of people simply take it as a given that life exists on other planets (whether or not Mars is one of them isn't really a big issue) because they don't have the hubris to believe that there's anything so special about Earth as to believe that life could only emerge here.
Frankly, you can count me in that crowd. I'd be more surprised if it was somehow proven that there isn't life anywhere else.
To me, "fundamental questions" would be more like:
1. Is free will possible? If so, how?
2. How did the universe begin? If there was a "Big Bang" as popularly described, where did all the matter come from that expanded out of the initial singularity? If time did not exist before the universe began, how did the transition from state "no universe" to state "universe" happen, since - presumably - nothing can "happen" without time.
3. What is time?
4. Is space discrete or continuous?
5. Is time discrete or continuous?
6. Are there multiple dimensions of time, analogous to the multiple dimensions of space we know about?
7. Is our "4-D" world actually embedded in a higher-dimensional reality of some sort that we can't access/understand/see/etc.?
8. Is our world a simulation (ala The Matrix)?
9. How, exactly, do fields (electromagnetic field / higgs field / etc) permeate all of space and permit the existence of particles like photons or the higgs boson?
10. Is there actually a way to unify gravity and quantum mechanics?
11. What is dark matter? Where did it come from?
12. How will the universe end? Big crunch? Big freeze? Big bounce? The simulation ends and we all just disappear? Other?
13. Why is there any matter at all in the universe? The fact that there is implies a certain fundamental asymmetry to the universe, since if matter and anti-matter were created in equal amounts at the beginning, they should have annihilated each other leaving no matter behind.
14. Why are right-handed people more common than left-handed people?
15. Why does the universe itself appear to have a "handedness" property[1]?
You would know there's tech out there, the first able to reach to it will have the edge over the rest for centuries ahead.
The effects will be massive, no one dolar, yuan, yen, gold bar would be left unspent in the quest to get there and learn before the others.
Then there's the realities of being an american adult where even science is politicized. Think of all the boomers that grew up watching the space race with baited breath. I bet some of these same people today would support a politician who would defund NASA if it meant saving $30 a year on their taxes.
Bated, as in abated.
Fun fact: bated breath was coined by Shakespeare.
Thus many scientists try hard to dismiss evidence of alien life, because that is fashionable. Or at least, the alternative is very kitschy.
The reason people try to discount aliens is because you can attribute literally anything to aliens. And so you reach another equally simplistic binary. You discover some unknown phenomena. It is aliens, or not? Well we've discovered a whole lot of unknown phenomena throughout the years (and centuries and millennia depending on how you want to play this game) and often times it really did look a whole lot like aliens, but to date it's never yet turned out to be them.
And since the determination of an unknown phenomena often comes down to probabilities, aliens get weighted down a good deal. But nonetheless, I have no doubt that at least lurking in the back of every physicist's mind is that something now as regular as a fast radio burst could indeed finally be those LGM - the kind of joking nickname given to the first radio pulsar discovery. Standing, of course, for little green men. Is it? Well probably not, but it'll always be probably not - including when it finally is.
It is "inconclusive" at best.
http://hopefullyintersting.blogspot.com/2019/04/how-likely-i...
Ultraviolet (UV) activation of the Martian surface material did not, as initially proposed, cause the LR reaction: a sample taken from under a UV-shielding rock was as LR-active as surface samples;
Complex organics, have been reported on Mars by Curiosity’s scientists, possibly including kerogen, which could be of biological origin;
Phoenix and Curiosity found evidence that the ancient Martian environment may have been habitable. The excess of carbon-13 over carbon-12 in the Martian atmosphere is indicative of biological activity, which prefers ingesting the latter;
The Martian atmosphere is in disequilibrium: its CO2 should long ago have been converted to CO by the sun’s UV light; thus the CO2 is being regenerated, possibly by microorganisms as on Earth;
Terrestrial microorganisms have survived in outer space outside the ISS;
Ejecta containing viable microbes have likely been arriving on Mars from Earth;
Methane has been measured in the Martian atmosphere;
microbial methanogens could be the source;
The rapid disappearance of methane from the Martian atmosphere requires a sink, possibly supplied by methanotrophs that could co-exist with methanogens on the Martian surface;
Ghost-like moving lights, resembling will-O’-the-wisps on Earth that are formed by spontaneous ignition of methane, have been video-recorded on the Martian surface;
Formaldehyde and ammonia, each possibly indicative of biology, are claimed to be in the Martian atmosphere;
An independent complexity analysis of the positive LR signal identified it as biological;
Six-channel spectral analyses by Viking’s imaging system found terrestrial lichen and green patches on Mars rocks to have the identical color, saturation, hue and intensity;
A wormlike feature was in an image taken by Curiosity;
Large structures resembling terrestrial stromatolites (formed by microorganisms) were found by Curiosity;
a statistical analysis of their complex features showed less than a 0.04 percent probability that the similarity was caused by chance alone;
No factor inimical to life has been found on Mars.
[1] http://www.leonarddavid.com/curiosity-mars-rover-investigate...
It's his life's crowning achievement as the project leader, and seeing indicators that turned out to be nothing must be a tough thing to come to terms with.
If we make an AI whose thoughts and communication are practically indistinguishable from humans, and it controls a bunch of things that affect the physical world, is it alive?
If there's a disembodied mind somewhere that can think and imagine but never communicate or interact with anything, is it dead?
What about a human in a coma or permanent dreaming state? What about when they later wake up?
Okay nevermind thoughts and communication; What if there's an armada of "dumb" robots, spawned from a single factory, that can't think, only acts according to preset instructions, but still goes on to affect many things for hundreds of years, what should they be classified as? Would they be considered "artificial" life or automatons even if they existed for thousands of years and their creators were no longer around?
I don't think there is any single absolute criteria to classify all possible entities that must be out there or could theoretically exist, but the answer to "What is life?" is probably this:
Whatever other life thinks is life.
That definition catches every single thing you'd call life, excludes all the things that clearly aren't, disambiguates some grey cases, and illuminates one or two new phenomena to be life which you might not have realized.
To be clear, Darwinian evolution means:
- It makes copies of itself (reproduction)
- The copies take traits from the original (inheritance)
- The traits can vary among the copies and between generations (mutation)
- The copies' ability to make more copies depends on the traits they inherit (selection)
Again, what about species that don't reproduce themselves, but spawn from a single "factory"?
That factory may be nothing like them. It could be a mechanical factory producing automatons (with human-level thought if you need that criteria), or a universally-unique "mother" creature, or even a non-sentient spawning pool where they spontaneously form every now and then.
If there are entire planets populated by such entities, and they have governed over many things for as much time as we have occupied our Earth, would you still classify them as not-life in your dealings with them?
That would be like not considering Taiwan a country. (Sorry, couldn't resist injecting contemporary political commentary.)
Could software be alive?
If we make an HN account whose thoughts and communication are practically indistinguishable from Razengan's, and it makes similar comments in all the same threads, is this account actually Razengan's?
The answer to "Who is Razengan?" is probably this: Whoever other HN users think Razengan is.
It's more useful to situate concepts such as 'life' at the center of constellations of other concepts such as 'self-determination', 'will', 'evolution', and so on.
"A distinctive characteristic of a living organism from dead organism or non-living thing, as specifically distinguished by the capacity to grow, metabolize, respond (to stimuli), adapt, and reproduce"
This article does a poor job of explaining the experiment in question: "Labeled Release" (LR).
According to Wikipedia:
> ... In the LR experiment, a sample of Martian soil was inoculated with a drop of very dilute aqueous nutrient solution. The nutrients (7 molecules that were Miller-Urey products) were tagged with radioactive 14C. The air above the soil was monitored for the evolution of radioactive 14CO2 gas as evidence that microorganisms in the soil had metabolized one or more of the nutrients. Such a result was to be followed with the control part of the experiment as described for the PR below. The result was quite a surprise, considering the negative results of the first two tests, with a steady stream of radioactive gases being given off by the soil immediately following the first injection. The experiment was done by both Viking probes, the first using a sample from the surface exposed to sunlight and the second probe taking the sample from underneath a rock; both initial injections came back positive.[1] Subsequent injections a week later did not, however, elicit the same reaction, and according to a 1976 paper by Levin [author of the linked article] and Patricia Ann Straat the results were inconclusive.[12][13] In 1997, Levin, Straat and Barry DiGregorio co-authored a book on the issue, titled Mars: The Living Planet.
https://en.wikipedia.org/wiki/Viking_lander_biological_exper...
To recap, martian soil was incubated with small organic molecules bearing a radioactive label. A chemical process that converted them into CO2 would give off some radioactive gas. The gas was detected by both landers the first time the experiment was run, but not the second time.
It should be kept in mind that non-biological processes can also convert small organic molecules into CO2. Simple combustion will do this, for example.
This possibility is discussed later in the Wikipedia article (but not in the linked article):
> Despite the positive result from the Labeled Release experiment, a general assessment is that the results seen in the four experiments are best explained by oxidative chemical reactions with the Martian soil. One of the current conclusions is that the Martian soil, being continuously exposed to UV light from the Sun (Mars has no protective ozone layer), has built up a thin layer of a very strong oxidant. A sufficiently strong oxidizing molecule would react with the added water to produce oxygen and hydrogen, and with the nutrients to produce carbon dioxide (CO2).
However, this does not explain the discrepancy between the first and second test. And it leaves open the question of why both landers' experiments gave the same odd result (first test positive, second test negative).
The small organic molecules used as nutrients were those produced in a famous lab simulation of early earth. Its results showed that many of the basic building blocks of life could be formed by passing an electrical current through gases thought to be present in the early Earth atmosphere.
Think about what you could do with an Apple II (8-bit CPU, 4/8/16k memory), and the Vikings were much more powerful. They were also the size of a Volkswagon, but I'm not sure how much was equipment vs computer.
A software update killed one of the landers by accidentally overwriting the antenna software. (40 years later, not much has changed...)
More info:
I'm pretty sure this is the whole point of the article.
Planetary Protection is already a thing, even though we haven't found anything yet.
I want to believe.
Part of this is that it's expensive to do experiments on Mars, and space is limited. Each experiment you choose to do excludes you from doing others, so NASA has evaluated the evidence and doesn't think its the most efficient thing to pursue right now. Levin is trying to convince folks that the evidence is sufficient to warrant pursuing further experiments that would clarify what is going on here.
Consider for instance how many US citizens are still religious today, and largely govern their lives according to religious beliefs. Consider how the current president has deliberately weakened the separation of church and state by making it legal for churches to be political - pastors of tax-exempt churches can now outright advise congregation on who to vote for.
Discovery of life elsewhere threatens the foundation of a lot of religious dogma.
Maybe it was on earth
Maybe NASA should book space for a biologist on that flight. A botanist would do.
Xkcd reference that got me to read it: https://xkcd.com/1536/
If life is found NASA will not get funding.
Therefore NASA is doing all the science it can before it does a test for life. At least we will be able to say something about what it is and the context that it's in.
Then the plug will get pulled.
There are no aliens. With the money wasted on looking for aliens we could have saved millions of lives with clean water, shelter, food and education.
Scientists need to stop deluding themselves and tricking congress into funding pet projects that are so far fetched they border on fraud.
Military spending is a strawman whataboutism.
It's not about "cuts" it's about sanity. There are no aliens, no proof of aliens, nothing. These programs should not have been started in the first place.
If these peoples lives are so devoid of meaning that they have to spend their lives researching fantasies, they should fund in themselves instead of taking tax payer money for it.
Proving a negative in a virtually infinite universe looks like an uphill struggle, don't you think?
There is not a single shred of evidence _ever_ found to support one iota of research funding. It's science fiction run amok.
Alien research is faith based, not fact based.
The Polynesians sailing into the unknown Pacific is a different case, but that was most likely (based on what I've read) a situation of "the poor" venturing out to find new lands for themselves, not well funded expeditions paid for by existing kings.
Aliens is 100% pure fantasy.
