Photographing a Supernova

Ctein, Apollo 17 Liftoff, Cape Canaveral, 1972

Ctein, Total Eclipse Coronal Streamers, Cabo Pulmo Mexico, 1991

By Ctein

Part of photography is in the hypothetical. Some of it's intellectual exercise; some of it is "luck favoring the prepared." I wouldn't have been able to make either of these photographs if I hadn't spent a lot of time in advance figuring out just what was going to be required to make them.

Recently, a friend asked me about the prospects for photographing Betelgeuse when it goes supernova. Not as far-fetched as it might seem. Betelgeuse is a very late stage red giant (it's the brightest star in Orion, the left shoulder), with large-scale instabilities. It's in the last moments of life.

A red giant lives a million times longer than a human being, so the fact that Betelgeuse has anywhere from "seconds" to "days" to live doesn't have quite the immediacy it does when we're talking about a human being. Still, there's a finite chance the wavefront is already on its way and will arrive in our lifetimes.

I started thinking. How long would it be extremely bright and visible? Answer is, for months, although the peak brightness should only last for a day or so. Still, even days are enough time, unless you're unlucky enough to be clouded out. Or Betelgeuse is lost in the sun's glare. Not much we can do about that.

So, how bright? Here's where it gets interesting. Predictions for this kind of supernova are uncertain. A somewhat arbitrary number thrown around is peak luminance equal to 100 billion suns. There can be variations by an order of magnitude. Supernova 1987a is another reference point, although it was on the dim side.

Betelgeuse is far away, so it wouldn't look very bright to us, would it? Well, it's not all that far away. Merely 600 light years. Our sun is 500 light seconds. So, dividing 500 seconds into 600 years and squaring, it's just about a factor of one quadrillion. Which would make supernova Betelgeuse only 1/10,000th as bright as the sun. Whew, no chance of excessive sunburn! (You'll get zapped by possibly 1000 neutrinos, no big deal. Happily, the main radiation jets will be pointed away from the earth. But no predictions on what happens when the charged particles arrive; I'd have to do more research.)

But, that's bright! The full moon is 1/300,000th as bright as the sun. So this arbitrary calculation says supernova Betelgeuse would be 30 times as bright as the full moon. Huge uncertainties in that number, but it seems safe to say it's somewhere between one and several hundred times as bright as a full moon.

What makes this a photographic challenge is all that light is concentrated into a very small point. For the human eye, it's an area about 1000th that of the moon. So the "surface luminance" of supernova Betelgeuse could be anywhere from a few percent to as bright as the sun. Shining on the landscape that is 10–15 stops darker than a normal sunlit one.

Photographing scenes under a full moon isn't much different than photographing them under the full sun, not counting a 16 or 17 stop difference. Similar size source, similar color characteristics, etc. Here the light source is much more concentrated and bluer, shadows will be sharper and harder, there will be much, much more bright light scattering near to the source, relative to the scene. It will be a real challenge for HDR.

Honestly, I'm not sure HDR could tackle it. A point source that bright in a scene produces a substantial amount of scattered light in any optical system. When you're dealing with luminous ranges that push 20+ stops, it becomes very problematical what any range of exposures captures in the shadows. More food for thought. I hope this doesn't happen tomorrow; I need to work on the problem.

Of course, if it happens in the daytime, it's much easier to photograph. It'll just be a brilliantly bright spark of light in the sky. Boring.

Things might start to get interesting 5–10 years after the explosion. There might be some photographable light echoes and maybe a nice dense nebula, both getting into the size range of the full moon. But I'm not sure about that; need to do more detailed luminosity calculations. Might just be of astronomical interest.

Or maybe not!

Ctein

Comments

[Stephen]

Bravo! Excellent essay.

I'll be keeping an eye to the night sky.

[john robison]

"...zapped by possibly 1000 neutrinos,.."

Don't we have just millions of neutrinos pass through us all day and night from our sun? Whatever, I've always thought Betelgeuse is uncomfortably close if it pops off.

[Bron Janulis]

Ctein,

So, the "wave front" appears soon, when was the occurance? 600 years ago?

Hmphh, scientists.

Ah well, Le Tour is on, the Cubs are losing; the universe is right.

[Ed Buziak]

You lost me somewhere between here and the closest thing up there (the moon)... but I sure enjoyed every moment of it!

[ctein]

Dear Bron,

Depends upon your frame of reference (relativistic grin).

Yeah, we get a 'delayed broadcast' from old Bee. So our hot news that it's a late stage red giant really has a cover date circa 1400 AD.

---------------

Dear John,

I thought that'd catch someone [g].

Well, it's more like a thousand trillion or so solar neutrinos pass through your body each second. The interaction cross-section is so small that we hardly ever get zapped by one. Once a month? A year? Not often.

But... the sun only converts around a trillionth of its mass into neutrinos in a century. A supernova converts around a solar mass into neutrinos in a few seconds!

The scientific prefix for that number of neutrinos is 1 FLneutrino -- short for one effenlotta neutrinos.

That flux is so high that you'll possibly experience more neutrino hits in a few seconds from Supernova Bee than you'll get from all other sources over your entire life.

pax / Ctein

[Mike Johnston]

"The interaction cross-section is so small that we hardly ever get zapped by one."

And what happens when we get zapped by a neutrino?

Mike

[ctein]

Dear Mike,

Nothing you'd notice. Just one more bit of background radiation.

Ever play with a Geiger counter in science class? It'll go click-click every second or so just from background radiation. You're about a thousand time bigger than that Geiger tube, so you're getting zapped a thousand times a second by background radiation. Doesn't have a noticeable effect on your well-being.

This might double the background dose for a few seconds.

pax / Ctein

[Irv Williams]

Funny coincidence; I just finished reading a science fiction novel, "Calculating God", by Nebula Award winning author Robert J. Sawyer, in which the central disaster of the story is that Betelgeuse goes supernova. In his story, Sawyer has this event as going to cause the end of all life on Earth due to extremely high gamma ray output followed by a torrent of charged particles.

Not being an astronomer or physicist, I can't judge the magnitude of the hazard, but the difference between your estimate and that in Sawyer's novel was surprising.
I definitely hope that you're right!

Irv

[erlik]

"And what happens when we get zapped by a neutrino?"

You turn into Spiderman.

Er, no, it's a radioactive spider bite. Maybe you turn into a Hulk. Or nothing happens, which is the most likely result.

[ctein]

Dear Irv,

Heh. I'll be seeing him next month in Montreal, and if I remember I'll ask him about this. But my guess would be that for the sake of fiction, he's chosen to write about a very unlikely worst-case scenario. IOW, strictly speaking, not impossible, but much more fictionally convenient than at all likely.

Regarding the gamma jet, that normally gets emitted along the axis of rotation of the star, and we know that's not pointed towards us, because we can observe sunspots moving across the face of Betelgeuse.

(Yeah, we call them sunspots, the same way we talk about the "geology" of the moon and Mars. That whole 'selenology' etc. thing was getting way out of hand.)

I suppose one could hypothesize a highly asymmetric explosion that drove the jet way off-axis, although it's not particularly likely. Also, the jet is highly collimated; even if it did occur, there'd be less than a 1% chance it would be pointed towards us. So you're compounding unlikelihood on top of unlikelihood.

As for the charged particle flux, he could be right about that, because I haven't done any calculations on that. But I'm going to guess he's not, because there have been many large stars within 1000 ly of Earth over Earth's history, and quite a few of them would have gone supernova. Yet, major extinction events aren't terribly common and can usually be more readily explained by more conventional events.

My instincts are that if a supernova within the 500-1000 ly range were a biosystem-destroying event, there'd have been a lot, lot more mass extinctions in Earth's history.

Of course there are large stars a lot closer than that. In fact, there's good reason evidence that a supernova went off close to the solar system only a few million years after the Earth was formed. It was close enough to change the isotopic composition of the solar system to a degree that we can measure today. Remarkable.

~ pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
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[Grega]

I think I remember reading somewhere (perhaps it was Neil deGrasse Tyson) that as long as it goes supernova roughly 100 light years away or more it wouldn't have any effect on life on earth. (Notice the egoism here?)

IK Pegasi, a binary system of a white dwarf and a main sequence star is around 150 light years away. It has a potential to go bananas in the near future (astronomically speaking). I believe it is our nearest supernova candidate.

But the interesting thing to me is that when you mention supernova most of the people respond to it in a Hollywood-movie-scenario way: "How will we die?"

The real question is really "How would we live without supernovae?". They are the supply of heavier chemical elements. In fact, you, me and the computer I'm typing on are made of the stardust of the past supernovae explosions.

But don't worry, we still die. The Hollywood industry still gets an ending. If not sooner, in about 5 billion years our sun will swallow us. Gulp.

[Mike Johnston]

"The Hollywood industry still gets an ending. If not sooner, in about 5 billion years our sun will swallow us. Gulp."

Grega,
This is getting pretty far afield, but...seriously? Let's see...we're smack in the middle of a major extinction event, population is increasing exponentially, average global temperature is rising a significant fraction of a degree per *year*, and we're creating pollution at a *frantic* rate, as if it was what we were put on Earth to do. And there's utterly no way to stop *any* of those things from continuing...you really think we get the luxury of calculating our survival on an *astronomical* timescale? I don't think we get even a geological one...our little species is going to be outta here on a mere historical timetable. Homo Sapiens will be very, very lucky not to be extinct within 300 years, and it could be half that. I can't see how it would be double. We're an evolutionary dead end if there ever was one, a little blip between the giant lizards and whatever manages to thrive after the earth recovers from us.

Not meaning to bum anybody out. Just my opinion.

Mike

[Grega]

"This is getting pretty far afield, but...seriously? Let's see...we're smack in the middle of a major extinction event, population is increasing exponentially, average global temperature is rising a significant fraction of a degree per *year*, and we're creating pollution at a *frantic* rate, as if it was what we were put on Earth to do. And there's utterly no way to stop *any* of those things from continuing...you really think we get the luxury of calculating our survival on an *astronomical* timescale? I don't think we get even a geological one...our little species is going to be outta here on a mere historical timetable. Homo Sapiens will be very, very lucky not to be extinct within 300 years, and it could be half that. I can't see how it would be double. We're an evolutionary dead end if there ever was one, a little blip between the giant lizards and whatever manages to thrive after the earth recovers from us."

I agree with you perfectly (I did mention a potential HOLLYWOOD movie, right?). I teach physics in high school (ages 15-19) and when we come to the end of astronomy period, I always ask pupils how long do they think we will survive. In an average class of 30, there is usually 1 or 2 who believe we will be still here by 2500.

I like George Carlin's view of human race. "Maybe the planet wanted plastic."

[Robert P]

@ Mike -

Right on. We all seem to agree on that, but nothing is changing.

http://www.youtube.com/homeproject

RDP

[Jim Richardson]

Seems to me something fundamentally important is being lost in all this scientific chit-chat. Are you telling us there is a limit to the utility of the photographic advice "F8 and be there" when faced with a supernova only 600 light years away?

Can I at least assume that synchro-sunlight will fix the problem? If so (and since you seem to have such a secure grasp on the math) which bulb (or bulbs) would do the trick? How about a G.E Focal Plane No. 6 delivering 15,500 lumen seconds?

As for Mike's apocalyptic consequences of this event, it is my own opinion that even after humans are gone from the face of the earth there will still be photographers (slimy lizards or cockroaches that they may be) and so my question stands: what about synchro-sunlight for supernovas?

[Colin Work]

Homo Sapiens will be very, very lucky not to be extinct within 300 years, and it could be half that.

Well that will be a relief to those who worry about long term permanence of their prints :)

Seriously, ever since I can remember there has always been a threat (real or perceived) In the 70's we were about to enter a new ice age. In the 80's we were told the ozone layer would be pretty much gone by today.

Now I don't know how much we are to blame for global warming, and how much is natural, but things are always changing. Mankind survived the last ice age. We survived the Black Death (arguably benefited from it).

As a species we have, perhaps above all others, the ability to adapt - and very rapidly (compared to evolution!). Hence we may have a better change than most species of survival.

True, at an individual and community level, we have left ourselves very vulnerable. But although I might starve once the lights go out, that's due to my personal inadequacies, not my genes.

History I think shows us that, when pushed to the wall, we have an astonishing ability to face hardship, adapt and rebuild. Perhaps our biggest strength is we sometimes don't have the sense to know when to give up.

I have no doubts at all that during the next century there will be some profound impacts on the human population (but is this anything new?) But I suspect the biggest risk is to our lifestyle rather than the species.

Cheers,

Colin

[Erik Petersson]

Hi Mike, I would like to continue the off-topic thread that you created. It is perfectly viable to see a major catastrophy for human civilization in a close historical timescale - say 100 or 150 years or maybe shorter. Extinction would lie further ahead, though. I am sure that there will be bands of humans hanging around for at least a few tens of thousands of years after the catastrophy as well. Or are you implying significant change of the atmosphere or similar?

[Mike Plews]

Last year my wife graciously took me to the Badlands of South Dakota for a couple days of R&R shooting landscapes.
The park has a evening star party during the summer. Lots of binoculars and an 11" Celestron to look at the night sky with, very nice. It also doesn't hurt that the Badlands at night are darker than the inside of a cow.
The ranger running the show talked at length about Betelgeuse being on it's last legs. He said it was predicted to go super nova perhaps within the next two years.
My day job is in the news business and this seemed like a terrific feature story. If Rigel was going to blow it would have a bit more of an edge to it but that's another matter.
Anyway I could not find much out there on the impending demise of Betelgeuse so I sent an inquiry to NASA. They have a thing called "ask an astrophysist". I didn't expect an answer but about a month later one did come.
According to the scientist who responded this Betelgeuse business is the astronomical equivalent of an urban myth.
I do not have an opinion one way or another on this matter. I'm just passing on what they sent me. Heck I slept through high school physics.
On the other hand if you find yourself in western South Dakota and do not stop for a day or two in the Badlands you are missing out of one of the best places to take pictures in the National Park system.
Also when you show your fiends your prints you won't get that "nice but I've seen Arches" eye roll.

[JonA]

"We're an evolutionary dead end if there ever was one, a little blip between the giant lizards and whatever manages to thrive after the earth recovers from us."

Paging Dr. Zaius...

[David Long]

300 years, huh? So if I shoot a roll of Kodachrome now and store the slides in the dark, it should last just about until the end of humanity. Not bad!

[Adam Richardson]

On a related note, I happened to come across this pretty interesting interview with David Malin, who creates photographs off of large (ie not back yard) telescopes. http://seedmagazine.com/content/article/photographer_to_the_stars/

[Player]

Beam me up, Scottie.

[Andrew Kirk]

Mike, you forgot to mention deforestation, draining of marshes, and over-harvesting of fisheries.

[Dan Dill]

"Happily, the main radiation jets will be pointed away from the earth."

How do we know this? Just statistically, since the chance of the axis aligning with Earth are negligible?

[Pedro Estarque]

A great article indeed, but maybe a brilliantly bright spark of light in the sky would not be so boring.

Who knows, it could coincide with the sunset or rise somewhere on earth, in an interesting landscape, with nice weather and some lucky well prepared fellow could have his day.

Mike, I have an unshakeable faith in humankind and I think there are ways of stopping the ongoing assault on the biosphere. What we currently lack is coordination and will, but I think we respond faster under extreme pressure. So, unfortunately, the uglier it gets, the faster we'll move, I guess.

But I agree, we are a much more imminent and serious threat to ourselves than whatever catastrophe the outer space may hold.

[Mike Johnston]

"I am sure that there will be bands of humans hanging around for at least a few tens of thousands of years after the catastrophy as well. Or are you implying significant change of the atmosphere or similar?"

Erik,
It's a very interesting question, and one that is of course impossible to answer. Many scenarios simply call for a subsidence of population, not a species-ending catastrophe. That could well be the case. It's certainly true that small, self-sufficient bands of humans lived successfully on earth for many thousands of years; a few more or less still survive that way, here and there. It's quite plausible.

On the other hand there will be some very different conditions faced by survivor bands after the inevitable population crash. For one thing, it's quite possible that most large fauna will be gone by then--and domestic fauna of the type used for food have been genetically engineered to the point that they won't be able to survive in the wild. Or the "wild," whatever that will be. Pollution and pollution-related disease could have significant impact on small bands (pollution has already significantly impacted human breast milk and is beginning to impact male sex characteristics, and we're at the very beginning of a rapidly accelerating cycle). Third, climate instability, weed species, and invasive species will have significantly disrupted the stability of natural environments and the range of native plant life; most plants have considerable range, but they don't move quickly. The larger they are, the less quickly they move. Consider, for example, what happens if the temperate band moves a few thousand miles. The equator is desert and the comfortable temperatures center on 40 degrees of latitude. But what crops will grow on barren land that's been mostly covered with ice for thirty thousand years? Then there's the issue of how well we can cope with new problems and diseases if we lack technology and centralized medical care--even the folk medicine knowledge common on American farms in the early 1900s has all but died out. Finally, there's the social problem. A catastrophic result from the increase of population will be accompanied by a breakdown of social order. It's the matter of degree that's key. Just like large plants move their ranges slowly, so does human social organizing evolve and adapt slowly. Morals are a luxury; people fall back on savage behavior if they have to. Lack of resources could occasion savage competition for survival. And one last point about that: the survivor bands will likely be armed. Banditry might well be an easier way to "make a living" than organized attempts to reform in small, stable societal groups. That's one of the bases for my pessimism--I think it's more likely that people will wipe each other out competing for the scarce remaining resources, rather than pull together and regroup. Or rather, some groups will pull together, and other groups will come raid them for whatever they're able to produce.

It all sort of depends on how big we get, how much damage we do before we're unable to do more, how quickly or slowly the negative changes occur, and how many resources are left (good and bad) when we're done.

Any of it is virtually impossible to predict with accuracy, surely. Futurism is a most disreputable science. But perhaps my own biggest worry is that human minds have evolved to be very good at coping with immediate problems and impacts, and very bad at planning for long-term consequences. We love our children and grandchildren, but we tend to die in threescore-and-ten and the range of our concern doesn't go much past the threescore-and-ten of our grandchildren. But we're in an era where our actions are creating problems with a much longer "tail" of consequences than our minds are comfortable conceiving of. Just the fact that we thought it was a good idea fifty years ago to take radioactive waste in 55-gallon drums, encase the drums in concrete, and ***dump them in the sea*** illustrates the problem. We have a dangerous toxin with a half-life of 10k years, and we put it in a container that won't survive a fraction of that time and deposit it where people in the future won't be able to get at it. We just don't think well in the timeframes we're now required to consider. We haven't evolved for it. Nature will take care of that, but it's probably not gonna be pretty. Or easy on our kind.

Mike

[Mike Johnston]

And here I've hijacked a thread, one of the very things a moderator is tasked to prevent. Tsk, tsk!

Mike (slapping self on wrist)

[Lubo]

I've been worried about the coming decades for a long time now.

Therefore, I say, give in to your LBA a bit more ... she will treat you nice in the meantime.

[robert e]

You guys haven't mentioned potential biological effects of a supernova other than "extinction" or "none". Is that because in-between effects (perhaps a significant change in mutation rates or fertility, or disruption of circadian or migratory mechanisms) are less likely, or because they are just too complex to speculate about?

OK, headsplitting to contemplate, for sure, but I would think at least as likely, and also a little more interesting than "nothingness" vs "nothing happens". For example, wouldn't even a slight change in the nature of, say, algae, or e. coli, or earthworms profoundly effect most life on earth?

[Erik Petersson]

Mike,

Thank you for your long and elaborate answer. My thought on this is that the world is large enough to at least allow some groups to survive in the least populated areas. Siberia, Amazonas, Central Asia, etc, if the earth is at all inhabitable.

And North America? I read an entertaining article recently that stated that christians from the midwest would take over and create theocracies after the catastrophy. They have great internal solidarity and faith in a higher cause, the writer thinks, and they have the guns. What about that as a future for the USA?

[Charlie H]

Mike, you have to stop reading "The Road" before bed. ch

[MJFerron]

Mike says "Homo Sapiens will be very, very lucky not to be extinct within 300 years, and it could be half that. I can't see how it would be double. We're an evolutionary dead end if there ever was one, a little blip between the giant lizards and whatever manages to thrive after the earth recovers from us.

Not meaning to bum anybody out. Just my opinion."

Hey Mike remember that hit song from the 60's 2525? (think that's the name of it.) Goes something like" In the year 2525 I wonder if man will be alive? We've taken all this world had to give and we ain't put back nothing" Kinda prophetic is it not? Anyway I think we humans, destructive little termites that we are have the ability to keep climbing higher and have an incredible ability to survive. At what level of comfort might be the big question. Even bigger question is how many megapixels will the top cameras have by then?

[ctein]

Dear Grega,

In looking up the information on IK Pegasi, I realized that I had mentally swapped the relative luminosities of Type I and Type II supernovae. My bad. Sorry about that!

Cuts my estimate of the brightness for Supernova Bee by anywhere from 10-100. Given the huge uncertainties already stated, probably not of great import in terms of photography.

I could plausibly believe something in the range of 50 ly might be a real problem. That would drop the incidence rate down into the range of one every billion years or so. That's no longer inconsistent with Earth's history.

What you said: as a certain songwriter wrote:

"We are stardust, we are golden, we are billion-year-old carbon."

--------------------------------

Dear Jim,

Be there? Be there?! After you, Alphonse!

To misquote Butch Cassidy and the Sundance Kid, "Hell, the neutrino flux alone'll kill ya!"

--------------------------------

Dear Colin,

"In the 70's we were about to enter a new ice age."

No, that's a myth. The vast majority of researchers even back then disagreed with that claim by a very few. For the most reliable science, you look to the consensus, not the extremes.

If you still don't know if we are much to blame for global warming, then I suggest you start reading primary sources like Science and Nature, instead of wherever you get stories like the "Ice Age" from. As someone very smart once said to me, "So who are you going to learn your science from, the editor of the Wall Street Journal or the editor of Science?"

--------------------------------

Dear Mike P.,

Yes, a myth. All we can say about old Bee is it's a late stage, unstable red giant, "soon" to die. For some very uncertain value of "soon."

Simple explanation for this: we have never got to see a supernova precursor close-up. So we don't actually know what a star looks like shortly before it's going to go BOOM. Maybe when it's about to go it will be utterly obvious. Or, maybe, it will only be an after-the-event look back that tells us what symptoms to look for.

A red giant like Bee only hangs around for a few million years, so if this one is really "late stage" then its date of death is considerably less than 1 million years. Even plausibly within our lifetimes. But right now we have no ability to pin that down.

I have been to the Badlands a couple of times and there are wonderful, but I've never visited them at night. I should.

--------------------------------

Dear Dan,

I think I answered that in my message to Irv, but if you've got any further questions feel free to ask.

--------------------------------

Dear Mike,

Bad hijacker. Bad BAD hijacker!!!

No dessert for you. Now go to your room!

~ pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
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-- Digital Restorations http://photo-repair.com 
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[Robert Noble]

The biggest cosmological question actually is which will happen first, the destruction of the earth or the completion of Ctein's MacSpeech training process, which has been apologizing for "word-salad" for several years now IIRC.

Just kidding; great article. Much food for thought.

[john robison]

"And here I've hijacked a thread,..."
Yes you have Mike. But, you still haven't answered the question burning in all our hearts. Will people still be predicting the death of the Leica M rangefinder in the year 2309? Answer that and you won't have to slap your wrist very hard.

[Mike Johnston]

"But, you still haven't answered the question burning in all our hearts. Will people still be predicting the death of the Leica M rangefinder in the year 2309? Answer that and you won't have to slap your wrist very hard."

I predict that all other makers of 35mm film cameras will cease production, but that the Leica M will hang on by a thread thanks to the spectacular success of the S2 system among professionals and rich enthusiasts, a market Leica will own due to Universal acclaim despite catch-up efforts by Canon, Nikon, and Sony, as Apple now owns the iPod despite other brands of MP3 players. And then, just as M production is rationalized to make it even better made and not so prohibitively expensive, a "film revival" will hit in the Summer of 2018 thanks to a mysterious confluence of seemingly random cultural events and the inscrutable movement of global fashion; Leica will be perfectly situated to take advantage of the new trend, and production will ramp up to the point that Leica becomes once again ensconced as an iconic brand. The entire trajectory will resemble that of Harley-Davidson.

Mike

[_#_]

WTF? My latest P&S cam has a Supernova mode. Yup, right next to the Smile Priority button.

[ctein]

Dear Robert e,

Fair question. The neutrino dosage has no measurable effect. The effect of having another full-Moon-like light source in the nighttime sky for several months might or might not present a problem for some nocturnal species. I think the effects would be subtle, and since the changes aren't permanent, my intuition is that there would be no lasting harm.

The charged particles are another matter entirely. Since I haven't calculated what kind of dosages are involved there, I don't even want to speculate.

Note, though, that there is a considerable amount of background radiation in the environment normally. Lay people tend to overestimate the impact of new natural radiation sources. For instance, some alarmists have made much of the fact that the Earth's magnetic field is about to undergo a collapse and reversal (timescale until collapse: somewhere between a few decades and 1000 years, with several centuries being the common estimate). During the collapse, which lasts for some time, the Earth's magnetic field is no longer there to funnel cosmic radiation towards the poles and it hits the atmosphere unimpeded, where it generates secondary radiation. That is a very substantial increase in the cosmic background dosage we get... but it translates to an increased risk of cancer over the human lifetime of only a couple of percent. That's bad if you're one of the unlucky ones, but it's not a particularly large perturbation of the biosystem.

A "slight change in the nature of" any widespread organism *could* profoundly affect life on Earth, but the vast majority of such changes don't. They just constitute another step in the random walk down genetic Wall Street.

~ pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
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[Chuck Holst]

The first A-bomb was detonated on my first birthday. Apollo 9 blasted off on my 25th birthday. Comet SL-9 began impacting Jupiter on my 50th birthday. Now I know what's going to happen on my 75th birthday.

Colin: The global cooling myth (more of an urban legend) was debunked last fall in the Bulletin of the American Meteorological Society. More info at this link (WARNING: PDF link):

http://ams.allenpress.com/archive/1520-0477/89/9/pdf/i1520-0477-89-9-1325.pdf

[Chuck Holst]

Correction for those trying to figure out my birthdate: It was Apollo 11 that blasted off on my 25th birthday.

Recent news about Betelgeuse is that the star has shrunk over the last few years. No one knows what it means: whether it is temporary or a precursor to a supernova. It'll be interesting to find out.

[Kerry Glasier]

What a super, wide ranging heap of comments. With great effort of will and self discipline I shall respond to just the one. If a dedicated team can build 'new' Messerschmidt 262s from scratch long after they 'ceased' production, I am sure another team can, probably will make/build 'new' Leicas after they cease being produced by their parent company. And Mike, breaking my initial effort here, why cant global warming be stopped? In pessimistic mood today??

[Colin Work]

Ctein - I won't disagree with the 'urban legend' status of the pronounced ice age of the 70's, (I was too young to fully appreciate the science at the time). Nonetheless there was a small amount of media hype at the time, and I wonder how different things are now?

I agree, look to the scientists, but things aren't quite that simple. I would say (in the UK at least) you get the science you pay for. Working in academia, I am very aware of the games people play to get research funding. In very simplistic terms your proposal stands a much greater chance of being funded if it focuses on current 'hot topics' and accepted beliefs.

In other words, it is more likely for a researcher to be funded supporting the assumption that mankind is responsible for global warming than to argue against. There is certainly MORE research in support of man's impact. This does not mean it is better research.

Behind all this we also need to factor in that it is in many people's interest to "promote" global warming - for governments it is a cash cow as it allows the creation of "green taxes". Not that these are necessarily a bad thing, but I do wonder at times if we are doing the right things for the wrong reasons.

Cheers,

Colin

[ctein]

Dear Colin,

1) Lay media are not a good source for judging the merits of scientific disagreement. The instincts of a reporter are to give both sides a hearing, even favor the unusual ("man bites dog" is a better story than "dog bites man"). A handful of holdouts doesn't make good science.

2) Wanna talk money? The world's most powerful corporations worked to prevent acceptance of global warming for decades. That should have been settled 15-20 years ago, because the preponderance of credible science said so (it's been a good 10 years, BTW, since it was clearly established it's primarily anthropogenic).

3) The "I can't get funded" whine is an old one in science. It's trotted out by every crackpot and holdout whose pet theory has been discredited. You hear it from the supporters of Peter Deusberg, of Halton Arp, of cold fusion, even of creation "science," all who claim a conspiracy against them. Now the climate change deniers. Well there's a good reason for that!

In science, when 95% of the relevant researchers have gotten on board and 5% are holdouts who aren't raising any new questions, there's no reason to keep feeding money to the holdouts. Deusberg, Arp, and cold fusion got plenty of research money for years; now they don't. The anti-global-warming researchers got their grants and papers published in the 70s and 80s. They had their chance. By the beginning of the 90s, the broad science was settled; everything since then has been mopping up the details.

Yes, there's a conspiracy: it's called not throwing good money after bad, and it's how good science gets done.

~ pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
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