Slashdot submission : An alternative, but common, astronomical habitable zone

Another interesting paper caught my attention.

Yet another provocative paper emerges onto Arxiv from Harvard's Lingam and Loeb.

Today they estimate the volume of space occupied by habitable zones (regions where liquid water is stable) in brown dwarf not-quite stars. They find that it could be orders of magnitude greater than the volume in the atmospheres of Earth-size planets.

Brown dwarfs are masses of gas which are too small to sustain nuclear fusion (so, they're not stars), but can have a brief period of fusion of deuterium or lithium shortly after formation (so they're not planets ; the boundary size is under debate). After this burst of energy, they slowly cool, for billions of years. This leads to a large volume of the star's outer body — or atmosphere — with potentially attractive temperature and pressure. If the brown dwarf is orbiting with a larger star, there may be enough light to allow photosynthesis. Supply of chemicals is uncertain, but not impossible.

While this paper is speculative, the prospects for detecting such life by spectroscopy are plausible with observational instruments being designed at the moment.

Previous work on abiogenesis and the origin(s) of life has speculated that life could persist in the atmospheres of Venus and Jupiter, using comparable pressure-temperature arguments. In this respect, the proposal is more conventional.

I don't know what they're putting in the water at Harvard, but Abraham Loeb is producing a lot of interesting stuff over the last year or so. 

If Slashdot take up the submission, I'm expecting the nerd-claimants there to raise questions about the availability of chemical elements. I don't see that much of a problem, since the relatively gentle convection on Jupiter (driven by the heat release of helium settling down though the hydrogen) is enough to put interesting amounts of hydrocarbons, ammonia, sulphur compounds up to almost the tops of the clouds, producing the visible colour bands and belts of the planet. If anything, the convection on a brown dwarf would be stronger, bringing heavier elements to higher in the body's structure. (Like Jupiter, unlike Venus, it probably doesn't have a fluid-to solid "surface".)

There remains a "dilution problem", but life managed to get around that on Earth, so I don't see that as a killer argument. 

Quite similar arguments about internal temperatures were being knocked around when Brown and Batygin produced their "planet nine" proposal in early 2016, and people were trying to work out if it would be detectable in infra-red detectors. That Brown is now (2019) getting surveying time on the Subaru telescope says what the rest of the astronomical community thought about that. 

Planet Nine (BB2016 ; there are others in the literature) is estimated to be around 10 Earth-masses (about 1/32 Jupiter-masses) so will have cooled a lot faster than a Jupiter-mass planet, let alone a 30 Jupiter-mass (mid--range) brown dwarf. So that proposed planet isn't a credible life habitat. Well, it's less credible than Europa.

Slashdot Submission, A second Interstellar object?

In the aftermath of the recognition of 1I/`Oumuamua as an object originating from outside the Solar system, people have been trawling through the archives for other possible similar events. One such archive is CNEOS, which incororates a list of fireballs - objects that have hit the Earth's atmosphere such as the 2013 Chelyabinsk meteor, or the powerful event over Russian Kamchatka in December of last year.
Searching this database a small event (about 100tons TNT equivalent) of 2014 stood out - the orientation of it's path, time and date allowed it's trajectory to be worked out and back-tracked, showing that it probably came to Earth from outside the Solar system. Before entering the Solar system, the object had a velocity of some 43.8km/s with respect to the Sun and was slightly accelerated by the Earth's gravity before impact. When compared to the "Local Standard of Rest" (LSR, the vector of objects orbiting the galactic centre with the Sun), the object's computed speed was some 60km/s, and at This implies that it was never bound to the Sun. Unlike 1I/`Oumuamua, the bolide was also at a considerable angle to the LSR. If accepted as an interstellar object, this second such body starts to flesh out the size and frequency distribution of such events. The possible power-law distributions within these limits are compatible with the distribution of small Kuiper Belt Objects, which includes objects liable to be scattered from the Solar system in future stellar encounters.
The location of the fireball - above the Pacific Ocean NE of Papua New Guinea does not make finding remains very likely. However, the last word of the paper's Discussion is "panspermia" so "Aliens" graphics can be used.

I need to do a bathymetry for this one too.

Put onto Slashdot as a submission.

I've done the bathymetry. The red star shows the location of the fireball ; the white line is the line of the profile.

Data is from GMRT and CNEOS, plotted using www.GeoMapApp.org.

Pleistocene Indonesian bathymetry

With the recent announcement of another quite old, non-human hominoid in SE Asia, once again people are asking questions about how such humanoids got there, as if these non-human animals were stupid, or incompetent, or ... whatever reason.
So, I did a bit of bathymetry work, since I've got tools to hand. I'm sure I'll use these again.
The common estimate for the decrease in sea level (compared to today) at the height of the last ice age, is 100m, so I've adjusted the rainbow colour scale to cover the 90-110m range ; anything deeper than that is marked in blue ; anything shallower is white ; present day exposed land is given an altitude palette.

Is Luzon isolated from the mainland by deep water? 

On this first plot, there is an obvious wide gap to the north. It actually goes down to several km depth, but since you normally drown in the top few metres of water, that doesn't really matter. The minimum sea passage is several hundred kilometres. That's quite a challenge.

 Moving to the southern approach, the question is more complex. At a 100m lower sea level, there is no "dry" route to Luzon, but several of the channels are down in the few-tens of km width. These would certainly be easier for people to have crossed, regardless of their species. Whether that is how the Luzon hominids got in ... is at the moment a judgement call. But if I were looking for places to search for bone-bearing deposits, that's where I'd start. 

This next picture I just anticipate I'll need at some point. Constructed from the same data (GMRT) and with the same shading to differentiate 100m+ versus 100m- water depths, it shows the context of the Homo Floresiensis discovery site (Liang bua cave, my typo). You will note that at least one water crossing of about 30km or larger is needed to get from mainland Asia to Liang bua.
The sea to the north of the two Nusa islands is known as the Flores Sea, for which the species was named.

Plots done using GeoMapApp, www.geomapapp.org and the GMRT dataset they pick up.

Fake dinosaur footprint.

Very quick post.

Geology class
A faked dinosaur footprint. A4 clipboard for scale.
On a field trip to Arran.
In 1985
We don't know who carved this fake dinosaur footprint, but the carver didn't notice that he (she?) cut across several sediment beds (NNE to SSW lineation in this view), marking it as an evident fake.

Photo has suffered from fungus and bad storage for years before being scanned. The carving is pretty unrealistic too.
Prompted by the footprints recently reported from Skye.

"BrexitExit" and the costs of Hubris

In the aftermath of the disastrous (for the Tory Government) 2017 general election (for clarity - the one in June ; I remember 1974 and the two general elections that year, and I'm not going to rule out a second one this year), the question of how badly the UK Government's team at the upcoming "Brexit" negotiation will be weakened is obviously of importance. On one side will be a team from the UK's DUP-CUP Coalition of Chaos, constantly looking over their shoulders to see if they're getting the sack this afternoon, and on the other side a team of professional negotiators with homes to go to and careers that won't be badly affected one way or the other by the result. It's not going to go the way that the Government  or their Brexit supporters want. And the deal that will be aimed at by the professional EU negotiators will be one that is so bad for Britain that it becomes an unavoidable question whether or not it is worth carrying on.
 The UK Government is going to have to try to exit from Brexit. Hence the tag "#BrexitExit".

At that point, one would expect - "require", even, since part of the charge of the EU government is to extend and enhance the EU - the EU negotiators to extract some political payment. If membership of a club is considered an attractive thing, then defectors must be punished, and punished publicly. 

I think one of the high probabilities of a demand for suspending Article 50 and ceasing Britain's efforts to leave the EU will be Britain signing up for the Euro.

The fact that this would be utterly repugnant to many of the political engineers of the whole Brexit debacle would, of course, be one of the motives for making this demand. There are swords which have not been fallen upon, and that is not an acceptable end point of the process. 

I'm also trying to remember an aphorism to the effect that "Those who the Gods wish to destroy [for their sin of hubris], they will first drive insane." [See footnote-2]

Boy, was PM Theresa May suffering a severe attack of hubris when she called the election, and now it's either Furies or Harpies that are keeping her awake at night.

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Links : (submitted as comment/ idea to a journalist on NZZ, Neue Zürich Zeitung) Back-link?

Footnote 1 : "DUP-CUP" Democratic Unionist Party is well known ; the official name of the Tories has always (well my political lifetime, at least) been the "Conservative and Unionist Party" ; normally Tories refer to themelves as "Conservatives", but when first toadying to the DUP, May started using the full name, and telegraphing what was coming by that wording.

Footnote 2 :  That phrasing actually seems to be from the 1870s by Longfellow, but the concept has been traced back via multiple re-uses to Sophocles' Antigone lines 622-624

that a man can reason the bad
into good, when a god
seduces his wit.

 That's the common (in 5th century BCE Athens) condemnation of Sophists.

Musings on Climate Change and it's Mitigation.

What to do about global climate change?

Lots of BLAH but several things are clear :
- Climates are complex. Certainly more complex than we DO understand;  possibly more complex than we CAN understand (without using machines) ;
- People are in deep - ostrich mode (obvious from coverage) ;
- by combination, the two above mean that nothing will be done, until too late. (It may already be too late.)
Hence, the increasing interest in "geoengineering". But which of the many possible schemes to follow? Surely a more difficult, and important, question.

The first point is important. Many proposed schemes interfere with complex systems in complex ways. It is perfectly hard to predict the consequences. Another concern is the time LAG between action and effect and (not unreasonable ) concerns of overshooting the desired end point. Another reasonable concern is the plausible disproportionate effect of controls on people less responsible for the problem.
SO . . .  I see the simplest solution as
(1) change insolation, not the atmosphere. The atmosphere is just too complex.
(2) change the insolation in space
(3) add components  (and so effect) in small but simply additive increments.

My proposition: combine magnetic force propulsion with solar sail technology and the properties of the L1 Lagrange point.
- Orbital objects near L1 stay there with little station-keeping effort.
- This is an area around 1Gm (a million km) from Earth, on the Sun-Earth line.
- The Sun (and Earth) has a non-trivial magnetic field in the region of L1
- At L1 the area covered by the Sun is AROUND 10000 km across. Area ~750000 sq.km.
- We have TRIED  (failed, not for relevant reasons) to launch a solar sail of around 100m diameter. 0.03sq.km
- To reduce insolation by 1%, 7500sq.km of blocking solar sail would be needed. That is a lot of launches, but not immense. Incremental improvements will increase effectiveness of each vessel and launch.

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Update : Does the Earth's magnetic field extend out to a million km (L1)?

Eta Carinae - (yet) Another Hypothesis

Was the nineteenth century giant eruption of Eta Carinae a merger event in a triple system?

2015 paper referring to the 1838 to 1860-ish Eta Carinae outburst
S.F. Portegies Zwart and E.P.J. van den Heuvel

They propose that before 1838 (in Earth's reference frame) Eta Carinae was a triple massive star system. The 1843 outburst was the result of a merger in 1838 (which formed the ~90 MSol main star of the present system), followed by the 1843 impact of the third (non-merging) body of the initial trio with the expanded envelope of the merged star.

Interesting idea. Stimulates the obvious question of what is the prognosis?

Ohhh, I hope they passed it through a native-English speaker (or translator) before publishing things like "Also if our model would finally not be the one that explains all the characteristics of Eta Car, still and evolution as discribed and modelled here is expected to happen not rarely in nature."

So, what is the lookout for the future of Eta Car? Apart from "uncertain"?

Issues with Oolite

Contradictory messages in Stellar Serpents.OXP(z)

Someone got to it first.