I don’t mind being misunderstood. It give me the opportunity to explain it again more clearly!

Nuclear winter of course!

Although I sure don’t want to actually see that happen.

Er .. Return to Snowball Earth conditions anyone?

If you don’t want to be misunderstood, don’t bring up hot-button issues :/

“An asteroid could give the earth an abortion and everybody would get gay married!!!1″ woulda been just as tactful as what you did up there.

http://business.fortunecity.com/soros/98/zukunft.html

There’s a small astronomical error in the 7 billion year panel – our Sun lacks enough mass to ever be a supergiant star but will be a “mere” red giant at that stage instead.

A supergiant is considerably bigger and more massive and *may* end up going supernovae – which our Sun won’t do. (NB. Not all supergiants and no giants *ever* explode as supernovae.) A supergiant also burns elements beyond just Helium and Carbon at its core while our Sun’s core is only massive enough to burn He & C before shutting down.

There’s also more here via space.com :

http://www.space.com/scienceastronomy/solarsystem/death_of_earth_000224.html
&

http://www.space.com/scienceastronomy/planetearth/earth_move_010207.html

Incl. a timeline down the page on that second one as well as a suggested course of action for really “saving the planet” – literally!

Hope that’s helpful & interesting for y’all.

Hears how and when the world ends: 100000000 AD(or CE if you prefer) sun burns all its hydrogen that it has been burning for billons of years and starts burning helium, cools down turning red, expands engulfs Mercury, Venus, Earths surface heats up forests burn, all water boils humans (if there are any) know there is only one thing that will save humanity : get off the planet find a new one, the sun expands and engulfs the Earth and moon humanitys home and place of orgin is gone forever. the suns expansion stops after engulfing Mars, the sun has gone to the next phase in its life : red giant millons of years after it will become a white dwarf and then burn itself out.

Very close but not quite.

I think the prevailing thinking now is that the Sun will render Earth uninhabitable as it warms towards red gianthood and becomes a yellow sub-dwarf star in about a billion years time. Eventually, over thenext few bilion years our Sun evolves further into first an Orange Giant like Arcturus then a Red giant like Mira before its outer layers stream away into space leaving its core as a newly minted white dwarf “stellar corpse” at the heart of a beautiful but evanascent planetary nebula.

As our Sun balloons outwards it will consume Mercury and Venus for sure. However, our Earth is a boarderline case and may or may not survive depending on exactly how the Sun loses mass as it expands and whether or not tidal braking drags Earth into the red hot vacuum that Sun’s outer layers will become. Mars will almost certainly escape destruction but be left along with other surviving worlds a frozen very dimly lit, sterile globe orbiting the white dwarf cinder that used to be our Sun.

The BA goes into detail about this in his Death from the Skies book too – it gets a full chapter (7) from pages 195 to 224.

Assuming we don’t die off first, I’m pretty sure we’ll develop the required technology long before the sun-red-giant scenario becomes a concern.

I wasn’t the one who initiated the comparison (that was a quote at the top of my #27) – and I wasn’t comparing phenomena, but the way people have reacted to them.

The story of AL00667 is instructive in this regard. The asteroid was observed by a professional astronomer who put the data up on the web without realising that it passed through the Earth. An amateur saw the data, realised its significance, and notified various people. The professionals took note, and gathered more data as required to refine the prediction.

The professionals respect the amateurs. They share data with them. They use them as a valuable additional resource – extra eyes on the sky, extra brains looking out for things of interest or significance. It’s quite certain that if the astronomers spotted an asteroid headed for Earth in 100 years that they wanted us to do something about, all the data and calculations would be on the internet, and they’d make every practical effort to make sure that anyone who wanted to see for themselves, could.

And scientists living in such an ethos naturally assume that other scientists work the same way, and that if the professionals in another area express confidence in a particular conclusion, that they’ll have checked it out properly and we can take it on trust – as much as you ever can in science. And so if you ask them, they’ll say they support the consensus in that field, and not worry that they haven’t looked closely at the evidence or details themselves. (I certainly did, for quite a while.)

Astrophysicists may like to compare it to the situation when the scientific consensus was that black holes were impossible, and some young upstart called Chandrasekhar was going round trying to sell the idea that they had to exist. A physicist working in another area, on hearing that Einstein himself had written a paper proving that they were impossible, would not have even bothered to examine the young Indian’s equations. And the fact that the general public were quite keen on the idea explained neatly why people kept bringing it up – mere populism to garner more attention and funding.

Even worse, a few physicists had examined his equations and agreed privately that Chandrasekhar was right, but would not give any public support because they did not wish to antagonise Eddington.

Scientists are human.

So in some alternative history, the idea that astronomers might have declared cometary doom in error, such as I suggest, is not really ridiculous. “100%”? We get hit by big comets every hundred million years or so, but scientists make mistakes every day – which of these, a priori, is the more likely hypothesis?

Anyway, I thought it an interestingly alternative way of looking at it, and the Climategate stuff just an entertaining setting for it. Pete Jackson got there first, though.

http://www.b612foundation.org

One of those involved in B612 is Rusty Schweickart, of Apollo 9 fame. Hopefully, they, and other groups, can get the funding they need before it’s too late to develop proper technologies and strategies.

What? Oh.

After that I’d expect trillions to be spent ensuring it never happens again.

The chances of this is much higher than the next big impact being extinction level.

Or at least the script for another Bruce Willis movie.

But there have been asteroid-to-collide-with-Earth scares before. XF11 in 1997, for example. Plus a few where we have had a few days warning of a possible collision (AL00667). And there have been significant collisions far more recently than the Triassic (Mahuika in 1443). It’s not that unlikely a scenario, and we sort of know from past experiences roughly what the reaction would be. It would be unlikely that we’d have enough data to be sure, and unless there was specific action we could take, like issuing tsunami warnings, most of us would shrug and carry on. In public, I’m sure there would be arguments about whether the data was right, but astronomers share their data with amateurs, so the scenario wouldn’t happen as I suggested.

If we were told about it 100 years in advance, as proposed, I think we could do something relatively easily. Probably, we’d do nothing at all for 80 years while we developed the technology, and then we’d go and move it.

Thanks, David, for that very intelligent contribution. I am pleased to see that the standard of debate here is as high as ever.

Incidentally, to get back to the original topic of the discussion, I thought that the best sort of planetary doom would be a small planetoid captured in Earth orbit below the Roche limit. The sight of tidal stresses destroying it, creating a vast ring system, and then falling to Earth in a continuous rain of fireballs would be spectacular.

A: “The world is going to end! A mighty comet will strike the Earth in 2100! The oceans will rise and turn to wormwood!”
B: “Gosh! That sounds serious! Show me your calculations, please, I gotta see this!”
A: “Why should I make the data available to you, when your aim is to try and find something wrong with it?”
B: “Huh? What? Give me the data!”
A: “It’s proprietary!” (aside to colleague, in stage whisper: “Just sent loads of telescope data to S. Make sure he documents everything better this time! And don’t leave stuff lying around on ftp sites – you never know who is trawling them. The evil doubters have been after the raw telescope data for years. If they ever hear there is a Freedom of Information Act now in the UK, I think I’ll delete the file rather than send to anyone!”)
B: “Hey! What’s this here on your ftp site? There’s a directory called “CENSORED” with a load of different results in it. It says the comet is going to miss! What is this?!”
A: “Nothing! Nothing! Wrong data! It’s all your fault, you downloaded the wrong data.”
B: “And here. There’s something screwy with this principal components calculation here… PCA doesn’t work with missing data, but you got good results, even with data full of gaps. What did you do?”
A: “You’re doing it wrong! Ha! It’s laughable how you doubters can’t even do a simple calculation.”
B: “Hang on, this is new. What’s in this HARRY_READ_ME.txt file? The one somebody leaked? Oh… My… God!!!”
A: “Religious!! He’s religious! Don’t listen to him!”
B: “This is written by one of your own programmers! It says your code and data is a mess. It says you have no configuration control. It says you can’t replicate your own results. It says some of the data files have been lost. It says you fiddled with the processing until you got the results you expected, that when anomalous values in the data caused the processing to fall over, you just edited the raw data to remove them and moved on. The programmer is “seriously worried” that “our flagship gridded data product” is calculated wrong, rendering parts of the results “totally meaningless”.
A: “We’ll have an enquiry. Yes… Yes… A totally independent enquiry. One headed by the world’s biggest “comet umbrella” manufacturer, by a mate who used to work here for several years, but doesn’t any more, by my University, all completely independent… Exonerated! Totally exonerated! The science has been verified!”
B: “But according to the enquiry reports themselves, and this email, none of the enquiries looked at the science.”
A: “None of the enquiries found any factual errors in the science. There might have been a few tweaks needed, but the main results still stand.”
B: “But none of them looked! Oh, for heavens sake…”
A: “Doom! Dooooom!! The end is nigh!”
B: “We want our money back!”
A: “Doom! …”

And so it goes, for the next 90 years.

And eventually, the world ran out of exclamation marks, and silence fell.

Just like the last time.

Fritz – That’s a rocket launch at high altitude. Since the video is from China I presume it’s either a Chinese or Russian military test or satellite launch. It’s heading almost due north which is not the way you launch commercial or manned flights.

The launch is right after sunset, so what you’re seeing is the particulates in the exhaust being lit up by the sun (which is below the horizon for the observer, but sill up at the altitude of the rocket). The altitude is high enough (say, over 50 miles) that the atmospheric pressure is so low that the particles travel in straight lines (well, technically ballistic) rather than “billowing” like they do around the pad at ignition. That exhaust plume is some tens of miles across and incredibly thin. The only reason you can see it at all is due to the sunlight on it, but not on the observer giving a mostly black sky behind.

The coolest part is that you can see staging. The cloud suddenly stops being generated when the lower stage engines cut off, which gives you some idea of the speed of the particles. The cloud picks up again, but smaller, as the upper stage comes up to thrust.

This is the coolest and clearest video of these events I’ve ever seen, and to think it was done by an amateur who just happened to be staring the right direction at the right time!

- Jack

We’d get a cool show with the Aurora Borealis and, if the supernova was not strong enough to kill us all off right away (as opposed to a gradual extinction due to a destroyed environment), then we’d get to see a huge planetary nebula in the sky.

Ya, ya.. no nearby stars will go SN, I know.

Hey Phil.. I saw you at TAM8 as well! You won’t remember me.. I was the long-haired freak who posed for a pic

“Across the Earth’s southern hemisphere, people were having a normal day, shopping, working, playing, walking, hunting. When the beam reached Earth that all changed instantly. The sky looked perfectly normal for one second then literally in the next it suddenly lit up, like a switch had been flipped. An intensely bright spot flashed in the sky, so bright that anyone looking at it instinctively looked away, eyes watering from the onslaught. The new star in the sky was so fantastically bright that it could outshine the full Moon, but didn’t last long. It started to fade after half a minute, and was bearable to the eye after a few minutes. People stood in the streets, in the deserts, on the Antartic plains, on ships at sea in the South Pacific and Indian oceans, and boggled at the incredibly bright but rapidly dimming new star in the sky.”

- Page 104, Chapter 4, ‘Death from the Skies’ Phil Plait, Viking, 2008.

Then the nasty stuff starts happening!

First *hours* later a flood of sub-atomic particles causing deaths by radiation exposure. Then *within weeks* we get the destruction of the ozone layer, then a global layer of smog formed by the reactions with the Gamma ray particles in our atmosphere induces a ice age and acid rain.

The last line of that GRB chapter intro. makes it sound pretty fast :

“The mass extinction the star triggered would be the worst the Earth had ever seen and when it was finally over, there were no humans left to wonder at how a single star trillions of miles away could destroy all of history in less than a minute.” P. 105, ibid.

But it still sounds like a GRB would be pretty speccy after all!

So did you forget what you’d written BA or were you testing to see if we’ve actually read your book?

Plus “a Gamma Ray Burst would be instantaneous” BA? Wouldn’t it only be instant death for those on the side of the planet facing the GRB? For those on the other non-GRB side of the globe wouldn’t the End of the World be a rather slow and drawn out affair as the after-effects of the GRB took their toll? Don’t I recall reading something like this in a certain book about Death from the Skies featuring a GRB caused by Eta Carinae?

Great video, Phil. You should write a book!

I’ll second that – I’d love to see *another* book from the BA! I’ve already suggested he do a “Best ofthe BA blog” one that immortalises in print a number of the best posts from here.

Thinking of spectacular disasters, I think supervolcanoes or a nuclear holocaust have that going for them – as would the LHC turning the Earth into a Black hole!

PS. Yes I *do* know that’s not going to happen. The LHC is perfectly safe. I’m just saying from a hypothetical point of view – maybe with a “flashforward” to the next super-supercollider model?

PPS. Hypothetically and hyper-improbabally, how about a time machine disaster accident where a temporal field envelops the whole Earth and reverses our planet’s course through time – we un-eveolve backwards through time past the ice ages, the dinosaurs and trilobites and the huuge spans of time when Earth had nothing but bacteria all the way to the point where the planet un-forms!

(Of course, then the time machine wouldn’t be build so we’d have a grandfather paradox scenario too but anyhow… It would be spectacular as seen from ground or LEO – if we were aware of it! )