Don't forget technical debt. Those excel spreadsheets and what not work fine for a while. When a version of excel makes some change, or deprecates part of the code used, or someone wants to put it in a proper system where the data isn't siloed, all hell breaks loose. And seeing as there are lots of these things around in an average enterprise, it can get to be a real headache.
You've pretty much just described a light form of RAD tools, giving that level of detail. And they've been translating logic to code since the '90s.
Oh, and the third prospect for evolution of a recurrent nova system : the donor star gets a sudden dose of stellar hiccoughs - say, it swallows a gas giant, and does a sudden big release of gas, which piles up fast enough on the recipient to make it go Boom. Essentially, at random.
But it's unlikely that a donor star would be precisely stable in it's mass loss rate - it is drinking at the Last Hydrogen Saloon, has already left the Main Sequence, and is evolving rapidly (in stellar terms) ; so what it throws off onto the recipient is likely to be changing, even if (by human terms) slowly changing.
When the recipient star (the originally more massive of the pair, now the smaller in mass, and a white dwarf) goes through it's red giant phase, that is likely to shed some mass onto the star which would become the donor, changing it's evolutionary path. How long would it take for the donor star to settle down after that episode of late middle-age spread?
A 4th option - which I don't recall having seen discussed because it violates Occam's razor : if you have your recurrent nova pair orbiting away, occasionally having a little-bang, but they are actually in a wide triple - that's not an inherently implausible stellar system. Hell, our neighbours (Alpha Centaurus A and B, plus Proxima Centaurus) are just such a triple. And if A and B were merrily cycling away, doing their recurrent nova thing with no obvious trend towards SN-Ia fireworks. Until star C (Proxima - alike) comes barrelling back in for it's quarter-million year fly by. Now, that could certainly stir things up - particularly if it were a close pass.
And a wide triple like that wouldn't leave that much of a mark in the subsequent supernova remnant, would it? Not like the multiple star shenanigans going on in Eta Carinae/ the Homunculus nebula.
Never heard of "SCTV", and from that description, I wouldn't bother to watch it. Who cares what celebrities do to each other/ have done unto them?
There is a lot of research into recurrent novae, of which T CrB is the closest (known) and therefore the brightest (known). Fortunately there are some with considerably shorter cycles than T CrB, allowing a better view into their behaviour. Whether they blow off 99% of their accumulation each cycle, or 99.9%, or if the amount blown off is significantly variable, I think are all still on the table. (If you follow the subject more closely than I do - is this right? How tight are the bounds on between-cycle variability?) Is it possible that the trigger is sufficiently variable that each cycle is, effectively, a random variable which might result in a Type Ia SN, or just a recurrence? That would make life "interesting" for astrophysically-aware near-neighbours, say a Sirius-distance away. Hell, if they survive the first Boom, they'll be "astrophysically-aware" for the rest of their lives! With a major aversion to sudden bright lights.
The idea that recurrent novae keep recurring, with a trend of increasing mass accumulation (because of a brightening/ expanding trend in the secondary star) is a hypothesis for how SN-Ia happen, but it's a hypothesis that needs testing. Hence, the queue of observatories with DDT programmes lined up to wring every last meaningful photon they can get out of T CrB. By the time the news gets there (5028 or thereabouts), the poor bloody star will have grounds to become camera shy. Talk about paparazzi and their intrusive big-lens cameras.
At first, we have to master artificial planetary size gravitation.
Spin it. Live on the inside.
Even Newton understood inertia and it's pseudo-force consequence "centrifugal force" well enough to have worked that out, if he'd been posed with the question.
Dunno. I haven't used Google for
Do they still do search?
Barring unforeseen events (e.g. close-encounter with a 2 Solar-mass star), no.
The Solar system will still exist. The Sun will be a cooling white dwarf ; the planets from Mars out will be in approximately the same orbits (slightly out - the Sun will have lost some mass by stellar wind while a red giant) ; Earth is a 50:50 for existing or not ; Mercury and Venus will be dirt in the Sun.
It could even contain humans - but they'd be living in artificial habitats, not natural ones.
Dark matter is believed to somehow cause friction based on some things I've read (don't have link yet), and it hangs out at the outskirts of galaxies,
Errr, no.
DM is distributed, probably spherically, around galaxies, with the highest concentration in the middle of the galaxy. It's not as closely concentrated as baryonic matter (because it's got fewer interactions, that's what the "dark" means), but when people model the mass distribution of a gravitational lens, for example, the put the centre-of-mass of the baryonic matter (visible matter) and the dark matter at the same point, and the spread function for the distribution of dark matter around that point a factor of (several ; it varies ; often it's explicitly a variable they try to optimise for) times that of the baryonic (visible) matter. It seems to be an accepted procedure.
The alternative take : what force is it, which DM responds to but BM (baryonic matter, visible matter) doesn't, that constrains the DM to the outskirts of the galaxy?
The reason that the outer parts of Joe Random Galaxy rotates faster in a DM model than in a BM-only model is that the DM+BM model has more matter at a large radius from the (mutual, DM & BM) centre-of-mass model would have. Both are similarly distributed around the c-o-m, but the BM is more concentrated to the core than the DM. So, unlike a Newtonian model of orbits in the galaxy, with essentially all the mass near the centre (e.g. the Sun (98.5%) in the central million km of the Solar system ; Jupiter (1% of the Sun) at 750 million km, and the remaining 0.5% smeared between 1 million km and about 1000 million km) there appears to be mass out at (say) 2000 million km. But really, you need to integrate the mass distributions against radius in the two distributions.
Yeah, I had to read various papers about 5 times to work that out. It's not DM in an annular structure around the BM part of the galaxy, it's two overlapping distributions with a different central concentration.
where early passes typically occur. Thus, I'm referring to what might be called "non-baryonic friction".
The term is "dynamical friction", and it's a property of granular distributions of non-light particles under gravity. It's nothing unique to DM, or BM. Again, it was a several-paper comprehension dawning - can I recommend again Mike "PlutoKiller" Brown's Caltech course on the structure of the Solar system, which is available every few months on Coursera. The course is around 20 hours of lectures, and you'll need another 100 or so hours of reading course material to do the homework. But it is well worth the investment.
PlutoKiller's use of the concept is in analysing the motion of "planetesimals" (say, 1km blobs of dust and ices not zero-mass points) accreting onto larger planetesimals, which become planets. Or, as the surface density decreases, stay as independent planetesimals et voilá - Kuiper-Edgeworth Belt. Dynamical friction keeps the orbit of the planetesimals circular while they're still accreting, but once the distributed mass has accreted into a few (dozen~hundred) point masses, they can start evolving in both eccentricity and inclination, which leads to a period of hierarchical growth, and Bang! - Moon-forming (Venus-reversing ; Mercury de-mantling ; Mars-Polar basin, Uranus side-flipping) impact as a general outcome.
Really, that course is worth the effort. It will make a lot of things clearer.
Oh, this paper defines "merger" as galaxy positions within 20kpc of each other, then goes on to say the results are not particularly sensitive to them varying this parameter. 20 kpc ~=70 kly, which is not that much further out than the Solar System's position in the MW. It's a pretty central hit. Body-shot, not limb-shot.
Poor fools are more common than poor bookies.
Thanks for the reminder to check last week's lottery "lucky dip" tickets.
Yeah, you're not the only person here to have read university-level astrophysics textbooks. Even more think that reading a single article on IFuckingLoveScience is equivalent to actually getting a degree in astrophysics.
reaching hundreds of times the rate it fuses in the Jupiter-sized largely hydrogen core powering the Sun over the 10 billion years of its Main Sequence lifetime
For clarification, that's Jupiter-diameter "size", and tens to hundreds of Jupiter-mass "size" (the density varies significantly through the radius). With significant error bars for stars in general, depending on the percent or so of dirt in the mix (a.k.a. "metallicity").
The level of mixing between the interesting stuff happening in the core, and the boring radiation happening in the envelope (from which we can detect light, and therefore composition) is an open question. If only stars were transparent to something other than neutrinos! We geologists have the same impossible dream - and uncertainty over Earth's core composition and processes. If only 3000-odd km of mantle (the average of "Earth") were transparent to something more tractable than neutrinos.
There is current scientific uncertainty as to whether the Type Ia supernova can be triggered by infall of fresh hydrogen or if this fizzles into an "ordinary nova", or whether a Type 1a is the result of the merger of a pair of white dwarf stars spiralling in to each other.
Which is part of the reason for a lot of telescopes having DDT (Directors Discretionary Time) allocated for the Real Soon Now outburst of T CrB. As my email signature has said for over a year,
Quoth Clavdivs, "Let All the poisons that lurk in the mud, hatch out."
But NOW is the time to check TCrB.
https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fwellsite-geologist.blogspot.com%2F2024%2F04%2F2024-04-27-1-t-corb-recurrent-nova.html
I just checked with AAVSO - it hasn't 'gone'. Yet.
a common discussion by families around the breakfast table
When I still lived with my parents, yes, astrophysics and the fate of the universe was a breakfast topic.
We'll have to learn how to turn space rocks of average composition (CHONSPFeNi) into a habitat. Not a natural habitat (feel free to propose your proposals ; but I bet it won't get through the Assembly of the People), but a high-redundancy collection of artificial habitats.
We might even find a naturally habitable planet - which could produce a schism between
Since no human alive then (certainly none in communication with the travellers) will have ever lived on a planet, nostalgia will be an intellectual exercise, not an emotion.
Hang on - have you got "inhabitable" and "uninhabitable" crossed over? Doesn't really affect my point, but
It's about 50:50 whether the Sun's red-giant expansion will reach to Earth's current orbit, I agree.
I also agree that the Earth will be uninhabitable (no oceans ; possibly a Venusian climate) long before then. It might be as much as 2 billion years in the future, not 1 billion, but it's unlikely to be as long as 3 billion.
We may already have the technical capabilities for interstellar travel. Not the necessary experience, but we can envision how to do it. Just not as living individuals, as a living society. And a lot of frozen gametes.
How can you plan our advanced human-minds downloaded into computing machinery civilization without reliable galaxy merger predictions?
Ignore them.
In the event of a merger, the likelihood of two stars somewhere in the merged galaxies actually colliding is about 50%. 4 stars having two mergers, in the combined galaxies - about 25%. 8 stars in 4 merger events, about 12.5%.
Likelihood of a triple merger -close to zero.
Disruption of molecular clouds and new star formation - substantial, but given a billion or so years time lag between building a star/ planet system within a molecular cloud, and possibly having an origin of life, the consequences of that (whether it will increase, or decrease, however briefly, star formation rates) are not likely to be major.
It's very unlikely to be a major event. We (Milky Way denizens) have gone through dozens if not hundreds of such mergers in the past, and are probably going through 2 or 3 at the moment. Nobody will notice or care.
"Wild-Animal Markets Pose Rising Pandemic Threat"
My bet would be that the last is the most likely to be changing, by the largest amount.
Is preparedness for another pandemic rising or falling globally? I'm not sure - probably it is rising in some nations, and falling in others. Ones where they put science-deniers in charge of what passes for their health services are likely to suffer most in the next pandemic.
... humans are disgusting animals which do unhealthy things to themselves and every -thing/ -one around them.
Next question?
C++ is the best example of second-system effect since OS/360.
