This Universe Today article on panspermia, published last week, adds nothing new to the debate, (other than perhaps tacitly acknowledging its likelihood?) and I wonder what the thinking might be behind decisions for whatever media to publish such articles.

Is it because panspermia continues to gain momentum as a credible theory for the origin of life on earth, or is it simply an attractive idea that might gain reader/listener/viewership?

Others' thoughts?

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

Panspermia means that the question "How did life start on Earth?" can be answered simply "it didn't." It does not answer the real question, which is "How did life start?"

I'm not entirely convinced living (or viable) organisms can survive the likely trip times that natural objects require (on a probabilistic basis) to travel between planets, let alone between stellar systems. I do know that there have been reports of bacteria frozen in ice for several tens of thousands of years being revived, but being frozen in ice is a much more benign environment than being blasted into space, being exposed to ionizing radiation, a high likelihood of significant heat spikes, and, if the organism is lucky, a definite heat spike upon atmospheric entry.

Of course, if they find DNA-based life with the first probe to ε Eridani or τ Ceti, I will cheerfully eat my words. Without salt.

The latter I think. Along with things like UFO's or Pyramids on Mars, or Nemesis 2012, but not so obvious to the non-specialist reader.

The article does make the effort to scotch interstellar panspermia, but it is also possible panspermia remains a convenient idea to planetary exploration advocates.

"For a start, there's pretty good evidence that at least some kinds of bacteria and archaea – and perhaps simple eukaryotes too, a protist for example – could survive a journey between Mars and Earth, inside a rock blasted off by a meteorite impact."

So where is this 'pretty good' evidence? Actually there is no positive evidence for this. There may be better evidence that prolonged exposure to a space environment is a good way to sterilise stuff.

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plenty of woo, at the hotel hoagaland...

Well then, shame on science writers for pandering ...

Ever heard of "Conan the Bacterium?"
Deinococcus Radiodurans is quite the resilient extremophile, and a good candidate for space travel.
Tardigrades, or "water bears," too, appear to be capable of surviving space travel.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

Well, lets put them in space for a few years and collect some survivorship data, instead of endless speculations, so we have some evidence to talk about.

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plenty of woo, at the hotel hoagaland...

The latter. I'm not interested in moving the goalposts. The crux of it is, as swampyankee says:

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Conscious reasoning is an attempt to justify the choice after it has been made.

"After all, there are a number of meteorites, found here on Earth, which came from Mars (and some from the Moon too), and their interplanetary journeys could have been as brief as a century (or less)..."

This is a another very dodgy claim. The youngest recovered mars meteorite has a transit time of three quarters of a million years. The modelling of impacts seems to give theoretical transit times as low as 0.115 million years for one particle in many many thousands (and smaller particles go faster up until the point at which they vapourise), so the possibility of any significant size object travelling between mars and earth in a century is so infinitesimally small as to be effectively impossible.

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plenty of woo, at the hotel hoagaland...

According to this Survival in Space article, bacillus subtilis survived at least six.

For more evidence, you can get the full paper here.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

I think I've even read conjecture on transit times being as low as one year.
Transit times are determined by cosmic ray exposure, I think, and an important variable is whether the meteorite was the size it is all along, or was it part of a larger body for some time before being deposited on Earth.

However, I'm not so sure microbes and their spores are necessarily constrained by transit times less than a million years.

From Hitchhiking on a Meteorite: Is there Mars Life on Earth?:


Some bacteria have been revived from permafrost that is several millions of years old. Other research, most notably on bacteria recovered from the gut of bees fossilized in amber 25-40 million years ago suggest that revival can occur after many millions of years. Bacteria recently sent into space inside of salt crystals survive the trip rather nicely. Remaining essentially inert while dormant solves a host problems about the trip itself. But others remain.
...
The microorganism Deinococcus radiodurans has developed the ability to not only withstand tremendous desiccation (drying) but is also capable of surviving radiation exposures that would easily kill virtually any organism known on Earth many times over (3,000 times the lethal dose for humans for example). Such organisms are dubbed "polyextremophiles" since they are able to withstand multiple extreme conditions - conditions most other forms of life would not be able to survive.

D. radiodurans can survive massive radiation exposures that literally blow the organism's genome into pieces. Once allowed to repair the damage, everything returns to normal within a matter of hours. Placed inside a rock blown from Mars to Earth, D. radiodurans (or an organism much like it) has an excellent chance of making the trip intact.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

Oh yeah, I meant to include this little bit as well:

Microbial survival in space shuttle crash.

Abstract:

A slow growing, heat resistant bacterium, identified by 16S rRNA gene sequencing as Microbispora sp., was recovered from the wreckage of the ill-fated space shuttle Columbia (STS-107). As this organism survived disintegration of the space craft, heat of reentry, and impact, it supports the possibility of a natural mechanism for the interplanetary spread of life by meteorites.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

I'd add: it came from elsewhere... so, where?
It at least answers one facet of the question.

Good science, I think, in providing answers, also begets more questions.

I don't find this to be such a damning question for panspermia.
It's important, yes, but I also recognize we may never figure out how life came from nonlife.
"Moving the goalposts" is rather what science does, actually.
It falsifies an idea which begets a new idea to be questioned.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

If panspermia is not already prevalent, we will make sure it becomes so. Watchout universe, humans are on the prowl.

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For those inclined to oppose human meddling with the structure of the universe or the composition and configuration of objects and groups of objects within the universe, consider:
Whether there is a limit to the magnitude of a modulation of chaos below which order remains invariant? Or, is order but a fiction invented by perspectives applied over finite, however large, time intervals?

Here's their tacit acknowledgment: "An interstellar source of seeded life – an older planetary system perhaps – seems quite unlikely, because survival of the seeding life is thought to be zero... and the possibility of a suitable life-bearing vessel (a cm-sized rock, say) arriving intact in as short a time as 500 million years or so also zero..."

You yourself have pointed out the difference between transpermia (which the Universe Today article describes) and panspermia.

Even if Universe Today and many others misuse the terms, I wish you would not. It's confusing to those of us who know you champion some universe-wide panspermia theory when you use the term to describe the simple ride on a rock from Mars to Earth.

If you know I "champion some universe wide panspermia theory" even while I'm discussing litho- or ballistic panspermia, what's there to be confused about necessarily?

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

How am I supposed to know what kind of panspermia you are referring to when you say, "Is it because panspermia continues to gain momentum as a credible theory for the origin of life on earth..." in your opening post?

As I understand it, you do not believe that life could have arisen on Earth, so you must believe it could not have arisen anywhere in this solar system. Do I have that right?

Does it really matter what kind of panspermia, necessarily, when the crux of it all is the origin of life on Earth?
Had I used "litho panspermia" in the OP does it change much?

No.
I believe life could have arisen on Earth; I just don't think it did.
It could've arisen elsewhere in our solar system, too; I just don't think it did.

I think life's origin is far more ancient than even our solar system.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

The difference is, a person can believe life began on Earth or Venus or Mars, or somewhere else in the solar system and was then transferred elsewhere in the solar system. This person can use 'ballistic panspermia' as a rational for their belief.

You believe that life did not originate in the solar system at all. You CAN NOT use 'ballistic panspermia' as a rational for your belief. I'm just trying to make sure that that is not what you are trying to do.

It's just interesting to see someone who believes that life did not originate in the solar system at all arguing the fine points of whether it originated on Earth or on Mars.

I see.
I'm interested in panspermia in whatever form as an origin for life on Earth.
I've laid out the rationale for this many times over.

Well, I'm not really arguing over anything, centsworth II.
It's just interesting to see panspermia in the media.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

Well, it's a nice idea, and it might even turn out to be right.

But it doesn't seem to have much evidence in support of it, and it seems orders of magnitude less likely than life emerging on Earth.

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Nothing beautiful was ever made from gravel.

The Planetary Society is sending a capsule on Phobos-Grunt with a variety of small organisms (even some tardigrades) to see what remains viable after a couple of years in space.

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If they can get you asking the wrong questions, they don't have to worry about the answers.

Panspermia (transpermia) is an interesting idea, and simple enough to be understood by anyone. It's natural that it would show up in mass media.

Yes. For the same reason, "men from Mars" have long been mentioned in the mass media, both before and after it was established that there aren't any.

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Nothing beautiful was ever made from gravel.

Established?

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For those inclined to oppose human meddling with the structure of the universe or the composition and configuration of objects and groups of objects within the universe, consider:
Whether there is a limit to the magnitude of a modulation of chaos below which order remains invariant? Or, is order but a fiction invented by perspectives applied over finite, however large, time intervals?

Well, I thought the current existence of men from Mars was pretty much ruled out.

Is it the use of the particular word that you are questioning?

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Nothing beautiful was ever made from gravel.

I think you're reading too much into it, with respect to intentions. I believe it's just a short bit of text explaining what "panspermia" means, presumably so it can be linked to when the word appears in a "normal" UT story.

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"Ignorance more frequently begets confidence than does knowledge" -- Charles Darwin
"Your right to hold an opinion is not being contested. Your expectation that it be taken seriously is." -- Jason Thompson
Meet the OOONG TOE.

I read an interesting bit the other week stating that the platinum content gradually increases from about 3.5 billion years to 2.9 billion years ago.

“This tells us that the deep source where the komatiite came from, down near the boundary between the Earth’s core and mantle, was gradually gaining platinum over time”.

The paper’s authors now think they know why.

“When the Earth’s core formed, it took all the available platinum with it, leaving the mantle and crust with none,” Dr Barnes said.

“Following that, a steady rain of meteorites created the so-called Late Veneer - a thin surface layer of meteorite debris rich in platinum.”

The same came be said for many elements to include iridium.

Okay, but what's the relevance?

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Nothing beautiful was ever made from gravel.

I disagree, as you know.
Extremophile findings over the last 15yrs or so have changed our thinking significantly with regards to survivability; space, other planets and moons have become considerably less inhospitable to life as we know it. Microbes, bacteria and spores are plausible candidates. The ingredients for life so early in Earth's history, and still today, are more abundant off-planet than on, and are of course thought to have been brought to Earth. Numerous "prebiotic" (I daresay we begin calling them biotic) molecules have been discovered in space.

By contrast abiogenesis on Earth is frought with incomplete competing theories and has yet to experimentally produce anything remotely resembling life as we know it.
But anything's possible ...

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill

Curious, what's abnormal about this UT story?


I'm of the opinion we're reading so much about panspermia because it is not only a "sexy" subject but the evidence seems to be leading us off planet, and Science is recognizing it.

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"Where the telescope ends, the microscope begins. Which of the two has the greater view?" - Hugo

"Men occasionally stumble over the truth, but most pick themselves up and hurry off as if nothing had happened." - Churchill