Was Jesus Original?

For a long time the idea of a “Suffering Messiah” as a specific individual was assumed to be a purely Christian invention and totally unprecedented in Judaism. However, ever since the Dead Sea Scrolls were brought into the light in the late 1940s the religious opinions of Jesus’ near contemporaries have proven to be contrary to scholarly opinion. Very recent work on a 1st Century BC text written on a stone slab, Hazon Gabriel, has brought an even stronger link with Jesus to light – the expectation that a Righteous One, perhaps a Messiah, would be raised to life after 3 days!

Israel Knohl on the Messiah Before Jesus

…Knohl discusses the Hazon Gabriel as evidence for his own view that a Messiah preceded Jesus.

A PDF of a scholarly article by Knohl on the Hazon Gabriel

…Knohl discusses the dating and reconstruction of the text, in scholarly detail (i.e. with real Hebrew Words! 😉 )

New York Times article on the work… but hurry it might get ‘archived’ and cost money

…so what does it all mean?

For me, as a Christian, it explains the prophetic expectations – as so interpreted in Jesus’ time – that drew the crowds to him and shaped the faith of the first Jews who believed.

Does it damage Christ? Not in the least – how can people hope for a Risen Messiah is there is no expectation that he will do so?

So why do the Gospels claim the disciples didn’t understand what Jesus said about his dying and rising again? Good question, that has two angles – first, what did the disciples really expect of Jesus? That he would be the Triumphant Messiah who would cast out the Romans from Judea? If your long hoped for Messiah says “I’m going to be killed” then it’s only human that you won’t listen, even if you have heard prophecies like that before. Knohl claims there was a previous Messianic figure, Simon, who died c. 4 BC – and there were prophecies about him, and no apparent Rising, so perhaps that’s what the disciples are trying not to see when Jesus starts echoing his (apparently) failed precursor.

Second, how did the editors of the traditions that became the Gospels handle the original material? What really went on between Jesus and his first talmidim? Did it embarass the later Orthodoxy that has, apparently, “ret-conned” much of the Gospel account itself? Actually I have no good reason for thinking that was re-written, but it’s always a possibility.

Breaking Strain Analysed

Arthur C. Clarke wrote some absolutely classic space-travel stories in the late 1940s and early 1950s, which were amongst the first to give a “real life” account of space-travel and its challenges. Some were novels – “Prelude to Space“, “Islands in the Sky” and “The Sands of Mars“ – while others were short stories, like “The Sentinel”, “Earthlight” and “Breaking Strain”. The last story I mentioned was collected in “The Sentinel” – a gorgeously illustrated collection of shorts from 1981 spanning across his career, from “Rescue Party” (Arthur’s first serious sale) to “Songs of Distant Earth” (the movie outline version.)

“Breaking Strain” seems like an odd pick in the selection because it doesn’t involve alien contact, just two spacemen condemned to a slow death by an emptied oxygen tank on their way to Venus. Their vessel, “Star Queen“, is a nuclear powered cargo ship – two spheres separated by a 100 metre boom, a prototype of the “Discovery” from “2001: A Space Odyssey“. Their orbit is a low energy Hohmann transfer orbit which, to Venus, is only 145 days long – much less than the equivalent 258 day trip to Mars. With just 30 days to go the oxygen liquefaction system, which keeps their stored air liquid by cooling it in the ship’s shadow, is punctured by a meteoroid. Their air purifier system is imperfectly able to scrub the ship’s air, but with 10% losses on each cycle through. Thus they have air for 20 days, for the two of them. Thus the conflict that makes a story.

In the course of the telling Arthur mentions that passenger ships make the same crossing to Venus in a third the time for 10 times the propellant expenditure. So what does that involve? To work it out I assumed the passenger ships were on an orbit with the same semi-major axis, a, which simplified the search for an orbital solution. What changed with each new orbit tried was the perihelion (closest point to the Sun) and the aphelion (furthermost point from the Sun.) The assumed starting orbit was Low Earth Orbit at 1,000 km and the destination was a 1,000 km orbit around Venus – and Earth was assumed to be at 1 AU and Venus at 0.7233311 AU. The results don’t vary much with slight variations to these figures. A perihelion of 0.5833311 AU and an aphelion of 1.14 AU gives an angle of 36.25 degrees to the (assumed circular) orbits of the Earth and Venus, and a total velocity change of 46.13 km/s. The Hohmann orbit, for comparison, has an angle of zero at both by definition, and a total delta vee of 13.59 km/s. To get a ten-fold propellant increase between the two means the exhaust velocity is 22.5 km/s – a figure only extractable via iteration.

I’ve no idea if Arthur ever computed the orbits in as much detail. As president of the British Interplanetary Society he would have discussed these sorts of issues over and over again. Probably over beer at the “White Hart”. Whether he remembered the exact figures – if such ever existed – is unknowable now he has left us, but the challenge of describing realistic space-travel will remain with us. Until we actually do it, of course. But no one will seriously contemplate Hohmann transfers, except for robotic vessels. The time penalty is hefty and leaving any crew in space to soak in cosmic rays is detrimental to all. Oxygen recyclers are also somewhat more efficient now, so we may never have a “Breaking Strain” scenario…

300+ Exoplanets…

A milestone was crossed, with relatively little fan-fare, just today… there’s now, officially, over 300 exoplanets

Extra-Solar Planets Catalog… 303 Known Exoplanets

…and there’s five new Super-Earths – exoplanets over Earth’s mass. None have known radii so we’ve no idea if they’re rocky or icy or gas, but they’re not as big as the Gas Giants that have dominated discoveries thus far. A hopeful trend towards Earth-like planets, we can hope.

At this point in time it’s just not worth speculating what they’re like. At most we can tell how much sunlight they receive from their primaries, but not much else can be said. Will they be greenhouse wastelands? Planetary steam-baths? Hyperactively volcanic, or tectonically locked in place? Coated in thousands of kilometres of hot ice? Or something utterly unexpected?

All I can say… Watch the Skies!

Thank God for Evolution?

Christianity is many things to many people – something I learnt the hard way after becoming a Christian, then a fundamentalist, a liberal, an agnostic/atheist and finally a believer in something a bit broader than the easy categories I used to see the world in. So what happens when a Pentecostal preacher falls in love with an atheist biologist? You get evolutionary evangelism…

Thank God for Evolution

…the Reverend Michael Dowd and his wife travel the USA preaching the Gospel, as updated by evolutionary biology. I’m no expert but personally I think it’s about time too, that someone embraced the commonalities between the Christian myth and the tale of creation told by evolution. While that might sound odd to you, consider the idea of “original sin” or “the flesh”, then consider the concept of “selfish genes” – either conceptual group implies some innate selfishness/imperfection within human beings, all creatures in fact, which works against the higher ethics we’re called to by ideals or God or group demands.

I’m yet to read the good Reverend’s book, but the few bits available online seem less theistic than most Christians would be comfortable with. Most aren’t easy with the idea of an impersonal cosmic process as “God” – and cosmic creativity, what Dowd wants badged as “God”, is usually seen as impersonal. Does it have to be? Well read Michael’s book and find out.

The New Milky Way

The latest view of our Galaxy, the Milky Way, can be found at the Spitzer Infra-Red Space Telescope’s newspages here…

The New Galaxy

…seems we’re now officially a few galactic arms short – two arms based on old hydrogen-based maps aren’t evidenced by actual star-counts and thus were an artefact of the limitations of hydrogen-based radio astronomy. The Galaxy is still a BIG place, but it looks more like a pretty barred spiral galaxy than a relatively dull “grand-design” flocculent spiral like it did in the old maps.

But why are spiral arms the way they are? It’s a puzzle, but one astrophysicists have no end of good ideas about – and then along come some new surprises, like this one…

Black Hole Mass determines tightness of the Spiral

…seems the heftier the central Black Hole, the tighter the spiral arms. In our Local Group there are three big Spirals – ours, M31 (in Andromeda) and M33 (in Triangulum) – and the central Black Hole masses 4 million Solar masses (for the Milky Way), 180 million for M31, and just 1,500 for M33. M33 is a pretty loose spiral, though pretty. Andromeda’s M31 is tightly wound, from what we can see as M31 is tilted away from us. SO the Milky Way is somewhere between the two.

But why the correlation? Dark Matter? Weird gravity lanes? Something in hyperspace? Who knows? And that’s why astronomy is both fun and worth doing…

Where we’ve been III

In science there’s always a second opinion – some better informed than others. I can’t fault anything that John Hawks, anthropologist, has to say on his speciality, so check out his corrective to the claim humans went through a bottleneck some 70,000 years ago…

Sub-Saharan Population Size

…basically some questionable assumptions have to be made to produce the proposed bottleneck at 70,000 bp. As John explains somebody hasn’t done their maths or the science media has jumped on ambiguous statements without checking a bit harder. The bottleneck can be produced by a higher mutation rate, but it would have to turn-off before the move Out-of-Africa, some 60,000 years ago, else some weird results would arise (like American Indians originating 7,000 years ago, not 14,000, or modern Asian/Australasian groups appearing 30,000 years ago, some 20,000 years too late for the Australian Aborigines.)

Assumptions about populations and isolation between them might change the picture, so only better data can bring that time period into more definite focus.

Where we’ve been II

Human beings are a lucky species and just how lucky is coming clear through population genetic analyses. One scary finding is the confirmation of a population “bottleneck” – we were reduced in numbers to a mere 2,000 people some 70,000 years ago (70 kya.) Our species had a common female ancestor ~200 kya (traced by mitochondrial DNA) and a common male ancestor ~100 kya (traced by Y-chromosomal genes), and in the time since “Eve” we broke apart into small groups and remerged just prior to the bottleneck according to this recent news report.

Consider the fate of our near kin:

  • Asian Homo erectus extinct at 40 kya
  • Homo neanderthalensis extinct at 30 kya
  • Homo floresiensis extinct at 12 kya

    • and ponder just how lucky we were.

    POST SCRIPTUM the original research the news bite was based on is available online at the American Journal of Human Genetics here: The Dawn of Human Matrilineal Diversity

Where we’ve been and where we’re going…

Humans are bipedal apes. Yet we find that rather odd because our ape kin aren’t usually bipedal on the ground. Did we get bipedal on the ground too, or did some other environment suit that peculiar locomotive style better? A sextet of pictures from a Public Library of Science article….

Gorilla female plucks a stick from a swamp floor

…which evokes so many resonances for me. Look at how she walks clutching that stick.

At the other end of our journey, as a species, is the prospect of Interstellar Migration. The Ultimate Project is a plausible plan for an Interstellar colonization mission, but of World-Ship proportions. The basic plan is for a vast million-person “Star City” to traverse 20 light years at 0.002c (600 km/s) on a ten millennial journey to a new star system for humanity. For propulsion the Star City will use immense D-He3 fusion rockets, taking a century or so to build up speed.

Such fusion drives have exhaust velocities of ~ 15,000 km/s, so I wonder why the Star City isn’t going faster? To avoid interstellar debris, which is pretty lethal at speeds over ~ 0.01c, and to spend as much time between the stars as seems reasonable, I suspect. Such a Star City would allow for incredible astronomical collaborations between it and our Solar System, for example measuring the nearby Galaxies with stunning precision – imagine parallaxes out to the Virgo Super-Cluster. Thus why I call it “Star City” as it seems more like a mobile Observatory than a colonizing mission.

Read more, check it out, and best of all any contribution you make now will, possibly, shape events 500 years from now when the Project launches.

Pluto’s mysterious atmosphere…

With the New Horizons probe rushing to Pluto, this is a good time to ponder just what we might find. Spectroscopes have told us that Pluto has a wispy methane atmosphere, probably with a dash of nitrogen thrown in – but just how much? Pluto has undergone quite a few occultations – passages in front of distant stars, which causes Pluto’s shadow to pass our way every few years. This technique has told us how big Pluto’s largest moon, Charon, is i.e. about 606 km in radius. But Pluto’s atmosphere refracts the starlight and so we can’t directly measure Pluto’s shadow, merely the shadow of his atmosphere and surface combined.

What might be possible within the bounds of current data? Here’s a study from MIT’s Planetary Astronomy Laboratory…

Changes in Pluto’s Atmosphere: 1988-2006

…a couple of possibilities might be encountered by New Horizons in 2015. Firstly a cold surface at ~35 K with 3.3 microbar of 99% N2 atmosphere – this means a solid radius for Pluto at about ~ 1168 km. Or a hazy troposphere and a surface at 1120 km radius, 43 K and 310 microbar of 99% N2. Both are cold, but the last means more gas, warmer surface and less crustal ices. If the crust is frozen N2/CH4 coated water-ice (density ~ 0.94 at those temperatures), then it might be about 114 km thick over a core of muddy silicates (density ~ 2.7.) Assuming the radioactive isotope levels seen in chondritic rock (i.e. stony meteorites) the global heat flow is ~100 GW. This is not quite enough to produce liquid water beneath the icy crust unless the frozen surface gases slow down conduction, or the liquid isn’t water. A eutectic mix of ammonia/water freezes at 176 K, while a eutectic mix of sulfuric acid/water melts at 211 K. Both sound nasty, but they’re conceivable media for some kind of biochemistry.

But a pure ice Ih crust is unlikely on Pluto – it’s more likely to be, at least partly, methane clathrate, with a much lower conductivity (0.4 W/mK vs 7 W/mK for H2O at 95 K) and thus an ocean might be feasible if there’s enough heat from Pluto’s core. Will it be water? Cloudy ammonia? Dilute acid? Or ammonium sulfate in solution? According to a study by Dominic Fortes and colleagues ( Ammonium sulfate on Titan: Possible origin and role in cryovolcanism, Icarus 188 (2007) 139–153 ) the ammonium sulfate should allow rapid transport of clathrate towards the surface and quite explosive volcanism should result as the clathrate decomposes with a large release of pressurised gas.

So will we see splashes of ammonium sulfate across the surface of Pluto? And will New Horizons detect it? Perhaps… and in doing so we might get a glimpse of Titan’s own cryovolcanic processes too.

It’s the Whole, not the Part…

Uber science-writer Carl Zimmer muses on some utterly fascinating research on rewiring E.coli’s gene networks…

The More We Know About Genes, the Less We Understand

In the latest issue of Nature, scientists reported an experiment in which they wreaked havoc with E. coli’s network. They randomly added new links between the transcription factors at the top of the microbe’s hierarchy. Now a transcription factor could turn on another one that it never had before. The scientists randomly rewired the network in 598 different ways and then stepped back to see what happened to the bacteria.

You might expect that they all died. After all, if you were to pop open the back of an iPod and start linking its components together in random ways, you’d expect it to crash. But that’s not what happened.

About 95 percent of the rewired bacteria did just fine with their new networks. They went on with their lives, feeding, growing and dividing. Some even performed better than microbes with the original wiring, under some conditions.

…which is an incredible result. Carl muses there’s “something about gene networks” – gene networks being the program that controls an organism’s DNA activities – which lets them handle massive perturbations like a total rewiring. The puzzle is profound, but it indicates a great truth in biology – the whole, the organism, is greater than the sum of its parts, the genes, proteins and so forth that make it. They work together in a harmony that may have a higher-level abstract structure that allows great stability.

Here’s the Nature paper in abstract… Evolvability and hierarchy in rewired bacterial gene networks Ref: Nature 452, 840-845 (17 April 2008) | doi:10.1038/nature06847

…and it’s truly an amazing result. But just what does it mean? I think it means that genetic mutation – via gene changes or changes to regulator sequences – is just one step in the process leading from genome to living thing. The whole of an organism acts as an “editor” that decides if a DNA change makes sense – that’s the first level of “natural selection” and it seems a lot more able than the old “random mechanism” view that treated cells as intricate clockwork. Instead the cellular system is much more responsive and dynamic in a way we have trouble grasping because so much collective molecular behaviour is involved.