147675710
submission
RockDoctor writes:
While today's annular eclipse has just finished proceeding across the Arctic, some news has come out from the 2020-12-14 total eclipse across Patagonia.
Probably few Slashdot readers saw last December's eclipse — between pandemic travel restrictions and the Patagonian land path of the eclipse — but one group of researchers who did get into the path used a modest motorised camera to take a lot of photographs. These revealed unusual kinks and "teardrop" shaped disruptions in the normally simple form of the solar corona — where streamers of plasma trace the path of magnetic field lines.
In a paper released a few days ago on Arxiv, a team report "Serendipitous observation of a coronal mass ejection during the total solar eclipse of 14 December 2020".
Literature search revealed a couple of other possible similar observations, but they're not expected to be common — solar eclipses don't happen that often, and only the corona close to the Sun's limb (perpendicular to our line of sight) is easily visible. But equally, we don't have many ways of actually seeing how the Sun's magnetic field is "wired up", so these sparse data points make a useful contribution to our understanding of the Sun — and therefore to "space weather" which can damage satellites and electrical power systems on the ground.
Although the observations used high-density filters and a motorised mounting to track the Sun (and Moon) through the eclipse, which are not exactly off-the-shelf equipment, the actual camera was a fairly regular Canon T3i camera with a Tamron (third party, but good) lens.
Possibly of wider interest to the Slashdot hacking community is that the camera had been modified by installing the Magic Lantern operating system onto the camera and a Lua script to sequence the 155 images obtained during the 2 minutes of totality and the several minutes before and after. The script is included in the paper (nearly half of the page-count) and includes provision for re-starting the script and re-synchronising to the camera's clock in the event of a halt (one batch of the photos was interrupted — justifying the error logic). This, and the wide range of brightness covered, may make the script useful for others.
Personally, if I'd been looking to do a task like this, I would probably have started with tethered shooting from a Raspberry Pi, but now I know that there exist scriptable control systems for Canon cameras, that's a line definitely worth looking at.
This CME (Coronal Mass Ejection) was pointed almost perpendicular to the Earth-Sun line, so had no real chance of impacting terrestrial systems. (Spacecraft like the STEREO 'B' mission, if it were still operating, are another question.)
146393080
submission
RockDoctor writes:
For a number of years the administrative process for giving asteroids names has had a worsening logjam. Important or "interesting" bodies (such as I1/`Oumuamua, the first definitely interstellar object identified) would still get names rapidly assigned, but in the background myriads of unspectacular objects would persist with "names" based on their discovery date like "1981 GD1". Which is adequate for managing databases, but less than satisfactory for most humans.
A new publication from the "Working Group for Small Body Nomenclature", combines what used to be several steps into one stage. So now one can easily find that "1981 GD1" has the name "Rutherford", to commemorate one of the major scientists of the 20th century.
No doubt there will be complaints of an over-concentration on figures from Classical legend (22 of 179 names assigned), but eventually that mine will play out. Professional and amateur astronomers (34 and 30 names) are, unsurprisingly, the largest groups commemorated. Other scientists get a good showing (16, Rutherford included), along with memorials to teachers, observatories and universities. One architect and one astronaut (there isn't a bar on memorialising living persons) also get mentions, and modest numbers of sports stars, musicians and other cultural figures pad out the list. Chinese, Japanese and Taiwanese contributors have a significant input to this batch, along with a number of South American contributions and a fair number from smaller countries (Pál Erds, for example, in the {dead+ white+ mathematical eccentrics} category). And one entry which I can only class as a joke — 1990 QX19 gets a name which should have been used years ago. Obviously you'll need to RTFA to see the joke, but RTFA-ing is an un-Slashdot activity.
Future numbers of the Bulletin will publish new batches of assigned names, and work away on the backlog. You still need to be the discoverer of a "small body" to submit a name proposal, but that step of the process is also under review. With about 22,000 of the currently-recognised million-plus objects with well-characterised orbits, there is no realistic prospect of running out any time soon — they are being found faster than they get named. But eventually you too could name a pathetic little mudball for someone you despise. Won't that be fun?
144686202
submission
RockDoctor writes:
I am building myself a NAS, unsurprising on this site.
My hardware pool is very shallow.
I eBay'd a desktop chassis, whose mobo claims (I discovered, on arrival) RAID capabilities. There, I have a significant choice — to use the on-board RAID, or do it entirely in software (e.g. OMV)?
I'm domestic — a handful of TB — but I expect the answer to change as one goes through the PB into the EB.
What do the dotters of the slash think?
Now, how does one Slashdot a poll — HW-RAID or SW-RAID?
144415526
submission
RockDoctor writes:
A project to create a working example of Babbage's original "steampunk computer", the Analytical Engine is continuing, as this Spring's report to the Computer Conservation Society informs us.
The main news is that a new series of plans, dating from about 1857 have been found and are being examined for incorporation into the final design. These include one "remarkable feature"...
the extension of the Store to 1000 registers
which would compare well with electronic processor design. Not that anyone is expecting this machine, when built, to be blisteringly fast.
Could a steam-powered Analytical Engine support backup DNS services in a post-apocalyptic world? Is this Cloudflare's ultimate plan?
143484832
submission
RockDoctor writes:
For the last few days there has been an intense swarm of earthquakes accompanied by seismic tremor (an acoustic signal associated with the near-surface movement of fluids, perhaps including magma — lava when it comes to the surface).
At 19:00 the Icelandic seismic monitoring service issued a new statement that "it is possible that an effusive (lava-producing) eruption could occur close to Keilir" (a region between Reykjavik and it's airport). The ground is also swelling (as seen by both high-tech satellite measurements (LIDAR and InSAR) and low tech ground measurements (the roads are cracking), in a pattern consistent with material moving in the near subsurface.
While the Icelanders are not getting too excited about it, the possibility of a volcanic eruption occurring on the outskirts of your capital city does tend to focus the mind slightly. Outside Mexico, I can't think of anyone else with a realistic chance of celebrating the impending end of COVID with such ... capital pyrotechnics.
"Interesting times" loom.Link to Original Source
142774234
submission
RockDoctor writes:
Everyone loves a warp drive. The problem is that typically, they require "unphysical" (i.e. very large) amounts of energy, and "exotic" materials (materials with a negative energy density). There has been progress since Albucierre formalised the idea in 1994 ; energy requirements have reduced to using the mass of the Sun to create a "warp bubble" of a whole 10^-15m external diameter (we don't have microscopes that can see that small), which is an improvement. And the progress continues : a recent paper on Arxiv (submitted to Classical and Quantum Gravity ) asserts that a warp drive "can be constructed based on the physical principles known to humanity today." That's a generic warp drive — not an Albucierre warp drive — but that's probably close enough for non-specialists for the moment.
Some of the constraints of the Albucierre drive "may seem artificial" (their words), compared to the more general types of drive which these authors consider, and by relaxing those constraints they say they can construct (mathematically) warp drives without the "exotic" requirements. Unfortunately one of the requirements they relax is (if I understand the maths adequately) that time inside the warp drive travels in the same direction as time outside it. So ... a warp drive may be possible, if you're willing to accept that you travel back in time while doing it.
fun? violation causality Isn't
Of course, that exposes us to the large Fermi Paradox, in addition to the regular Fermi Paradox. ("Where are the aliens from the next trillion years?", instead of "Where are the aliens from the last few billion years?")
141197392
submission
RockDoctor writes:
While the majority of things posted on Arxiv are tedious progress reports and new observational science, occasionally you get some slightly more off-the-wall stuff. In this latter category I include a paper on potentially modifying gravity fields by tweaking superconductors.
No, it's not Star Trek. Someone is trying to find a loophole in modern physics that would (potentially) allow some degree of "artificial gravity" control. An Italian physicist has been working with Maxwell's equations of electromagnetics (in quantum mechanical expressions) to try to identify conditions under which gravitational fields can be manipulated by changing a magnetic field (see the paper's section 4, "Experimental predictions"). If I understand the paper correctly (a big "if"), they describe conditions under which they think a gravitational filed might be increased, if only for a few nanoseconds.
Which would be very interesting, if it could be demonstrated (a big "if"). It is hardly "novel physics" — it is a development of physics some approaching it's second centennial and other parts around it's first centennial. Thus far it seems to suggest a mechanism for increasing gravity (which we can already imitate cheaply using spin) not decreasing gravity. But it's a very interesting wild card to try to understand gravity better. Any fule kno that there is a problem at the heart of modern physics about why gravity isn't quantised (or alternatively why everything but gravity is quantised). So poking around where gravity meets quantisation is a potentially fruitful area of inquiry.Link to Original Source
138939734
submission
RockDoctor writes:
Did anyone feel a sudden wind through their hair at about 17:19+00:00, particularly in the mid Pacific? No?
Good. Nobody else did. Nobody noticed the asteroid whizzing past just above the Earth's atmosphere (for certain values of "above" including "not very far" and "373km above ground"). That's the closest natural body (i.e., not a spacecraft) documented in near-Earth space which hasn't actually hit the thick-enough parts of the atmosphere to glow, fragment, make sonic booms and dent automobiles.
So, we dodged another bullet, and no windows were broken. This one probably wonldn't have done significant damage even if it had touched down in fire and fury — it was about half the size of the 2013 Chelyabinsk meteor, and so around one eighth of the energy (and potential damage). Everyone can go back to bed and sleep easy. Right?
But one tiny thing to disturb your sleep : we didn't see this one coming until after it had gone past us. Nor did we see it in it's close approaches on 2014-10-26.60152 or 2017-11-06.57008. And with another 39 projected Earth approaches before the next turn-of-century, it's pretty obvious that one day this is going to hit us.
For those who know what an MPEC is, Bill Grey has written up one of his "pseudo-MPECs" with links to other work on this object here, while the actual discovery record is here. The object has been given a formal name of 2020 VT4 unless the discoverers at the ATLAS Mauna Loa Observatory choose to give it a name ("COVID", or "hair-parter", or "hats-off", perhaps. Or just "Rupert".)
Wikipedia has caught up too.
There will be another close-pass, and an impact, one day. This doesn't change the odds of that happening (probability 1), but it might make it feel a little more immediate. Single planet species are extinct.
138049490
submission
RockDoctor writes:
Many stories have been written about the unpleasant potential effects of a large solar storm or coronal mass ejection (CME) hitting the Earth (https://science.slashdot.org/story/19/10/01/1750245/new-studies-warn-of-cataclysmic-solar-superstorms , https://science.slashdot.org/s... , https://news.slashdot.org/stor... , https://science.slashdot.org/s... , https://science.slashdot.org/s...). With some justification, these are often dismissed as "the sky is falling!" fear-mongering. But events like the 1989 tripping out of Quebec's power grid and the 1859 "Carrington Event" give even the most sanguine some pause for thought — and disaster-planners some approximate values for induced voltages and event frequencies.
A new study complicates the planning against such events. A previously-recorded geomagnetic event (auroras seen as far south as Sicily ; Canada's short-wave radio communications were interrupted for 12 hours ; transatlantic radio traffic ceased) in 1938 was actually a run of three events over 9 days (17/18 January, 21/22 January and 25/26 January). Which is a really unpleasant timing — you'd just about get the system (whichever one you are maintaining) working again after a couple of days of really hard work ... and you get hit by another storm just while you're preparing the orders to replenish your spare parts stores. Not nice, but definitely something that people need to be considering in their disaster-recovery plans. If it has happened before — in recorded history, it can certainly happen again, and you really need to be looking at the probability of such events.
Food for thought.
In other food for thought — the solar cycle is starting up again. About 5 years to go until we start getting lots of aurorae again — and DC currents in what should be AC-only power systems, radio interference, intermittent heating of the upper atmosphere and changing drag on low Earth orbit satellites.
137840278
submission
RockDoctor writes:
Arxiv is a useful service, but you do need to use "user discretion" at times. Most articles haven't completed peer review (some won't ever start it!), and are subject to revision. With those caveats, I read this article and thought "That's odd."
Annual variations of the 214-Po, 213-Po and 212-Po half-life values.
Variations in the rate of a nuclear process ... correlated with tiny changes in the gravitational/ electrostatic potentials. WTF! — and by "F" I mean the Flux in nuclei numbers!
Now, the origin is an under-construction neutrino observatory. So they have good reason to be looking at background radiation levels in considerable detail. Painstaking detail, even. The technical details are beyond me (but I bet the answer is there — an unexpected interplay between their clocks and their rate devices), but it is similar to the "neutrinos travel faster than light" false alarm of a few years ago (that was a loose cable, corrupting timing signals) : if the observation is valid, it's caviar (red, not the black caviar that gets exported), Crimean bubbly and Nobel prizes all round. And if it is an instrumentation fault ... well, who hasn't spent months trying to figure out an odd effect, needing external eyes to spot the beam in one's eye. Kudos to the authors (Alexeev and eight others) for recognising that they need external eyes.
A common criticism of "conventional science" is that you have to "follow the consensus" in order to get funding, and that "you can't get funding for potentially ground-breaking discoveries". Well, this sort of report bluntly refutes such claims of community blindness. I'm not a particle physicist, not a physicist even, but I do have a good grounding in the physical sciences — and I can't immediately see an error in this work, nor can I see how it ties into (say) BCD drives at Area 51.5 ; but it is a challenge.
Go, instrumentation nerds! Your worldview needs you!
In other news, the MOND theory (which would throw a large spanner in all of "conventional" physics) is still attracting about 1 paper per month. It is not "mainstream", it is not exactly popular, it is potentially groundbreaking, and it is not (completely) ignored.
133198740
submission
RockDoctor writes:
A recent submission to the journal Astrobiology, from a group of NASA and other researchers, discusses the prospects of finding life on Venus.
Taking an approach "in a similar manner as [the] Drake Equation" they approach the question of extant life on Venus by breaking the question into three factors — of origination, robustness and continuity — which would be necessary for life to exist on Venus :
- Whether life could originate on Venus (or be imported from elsewhere in the Solar system — panspermia is explicitly considered as a possible factor) is obviously a big question, but many models of planetary evolution have Venus possessing an Earth-like environment for billions of years before the brightening Sun triggered the runaway greenhouse effect which will happen on Earth. Similar arguments are made concerning life originating on Mars, and apply to Venus equally well. Arguments are presented why the "origination" factor can't be arbitrarily set to zero; a range of probabilities from 0.1 to 0.4 is proposed. (Life originated on Earth, including the wild card of panspermia : probability 1.)
- The conditions on the surface of Venus are outside those which any (known) life (on Earth, unavoidably) can survive, in terms of pressure, temperature and pH (acidity). But through the atmosphere of Venus, each of those parameters drops to zero (not applicable, for pH) at the top of the atmosphere, leaving a region between about 50 and 70km altitude where conditions are within the ranges which terrestrial life can survive. That life can survive free-floating in an atmosphere is suggested by the presence of microbes high in the Earth's stratosphere (see references ; RTFP!), though whether these require to return to the surface or can subsist on volcanic detritus is a research question to be examined. Arguments are presented why the "robustness" factor can't be arbitrarily set to zero; a range from 0.1 to 0.5 is suggested.
- Whether life on Venus could be continuous from an origin to today is probably the least-constrained question. External factors haven't extinguished life on Earth during it's 3.5+ billion year history (we're here!) so are unlikely to have sterilised Venus either. Some biologically essential elements (C,H,O,N,S and P) are clearly present in the atmosphere ; whether a dozen other "essential" elements are present (from volcanic dust, for example) is a question for future atmosphere-exploring missions with modern high-sensitivity instrumentation (specifying such instruments is part of the purpose of these researches). Whether particular elements are truly "essential" is a question hampered by only having Earth's example of life. The "continuity" factor is poorly constrained, but no good reasons are known for setting it to zero; a range from 0.1 to 0.5 is proposed.
Using logic comparable to the Drake equation they argue that the probability of existing life on Venus is between 0.001 and 0.1. Whether that is sufficient justification for designing new probes for Venus, and how to design them, is a question which this paper stimulates discussion of.
Examining the question of life in cloud decks contributes to understanding the f_l factor of the Drake equation. Since arguments have been made that cloud decks may be volumetrically the most common "habitable" environment in the universe, this is an important factor.
The paper is a submission. Astrobiology and their reviewers may require substantial revision before publication, or reject it outright.
129235198
submission
RockDoctor writes:
Decrepit crones and crumbly greybeards amongst Slashdot's readership may remember the appearance in 1987 of the first naked-eye supernova since Kepler. The development of the debris from that explosion is being observed to this day. Normal astrophysical models (such as predicted the neutrino spike observed in the hours before the visible supernova explosion) predict the production of a neutron star (or possibly a black hole) within the supernova explosion. For thirty years, astronomers have looked for that neutron star — and had not found it.
This was getting a bit worrying. Theorists licked their pencils, compiled computer code and predicted alternatives like quark stars and electroweak stars . All great fun, little hindered by those boring observational astronomers and their dull attachment to "evidence".
It is unlikely to dampen the enthusiasm of the theoretical community, but over the last several months evidence has been mounting for the existence of that dull, boring and predicted neutron star, buried in the debris of the explosion. In October 2019 a team led from Cardiff University reported radio observations suggesting the presence of relatively warm dust near the middle of the debris (well within the region already swept and heated by the supernova's shock wave) — which is compatible with there being a neutron star in the middle of this debris. And on April 14th 2020 another team report calculation that this hot spot totals a luminosity of 40-90 times that of the Sun, (compatible with the expected neutron star) and the position being within reasonable limits on the amount of "kick" the neutron star received from the explosion.
It might be boring, but in a reasonable universe it is likely that the closest or first example of any phenomenon which you see is very likely to be boringly average. And sadly (if you're a Star Trek scriptwriter), this supernova is increasingly looking to be averagely normally boring. To quote someone on the Internet, 'when I hear hooves, I think "horses meh", not "zebras WTF!?" The likelihood is strongly that improving observational techniques and the literal dust literally clearing mean the neutron star will become increasingly visible in years to come.
122600266
submission
RockDoctor writes:
The Beeb report (from CES) that a start-up is showing a "beer cooler" that, they argue, could be less inefficient than a hotel room mini bar.
Link "BBC News — CES 2020: Juno 'reverse microwave oven' cools drinks in seconds
https://www.bbc.co.uk/news/tec..."
The piece does not describe the tech (I guess, lots of PeltiÃr heat pumps, but why all the spinning?), but it does raise questions about the efficiency (power use) of keeping a mini-bar full of overpriced drinks cold for months before someone uses it (they are ridiculously expensive!) compared to "chill on demand". There is a genuine question to address there.
The demo uses a tin of beer. The low conductivity of glass raises obvious questions about chilling wine.
And ice-on-demand ... is something I've never seen in a hotel mini-bar.
Other uses are possible.
Their prototype is big and clunky. That is what prototypes are for. BFD.
121594476
submission
RockDoctor writes:
For over a century, the "solar sail" has been a concept in theoretical spaceflight, in science fiction, and in the last few years, actual spaceflight. Recently, the Breakthrough Starshot project has been prompting and funding a lot of work to optimise and explore the operational possibilities of flying spacecraft to nearby stars, and this has produced another (relatively) novel idea for efficient spacecraft propulsion — an electric sail.
It is well known that stars produce both radiation (light) and material outflows ("solar wind"). It is less well known that the momentum transferred by the solar wind can be considerably higher that that transferred by light. Recent calculations by the paper's authors, Loeb and Lingam, with not-unreasonable premises, show that for many classes of star (including the most common star types) the solar wind is considerably stronger than the radiation pressure. They propose that a mesh of wires, positively charged, can drive a spacecraft more efficiently than reflecting radiation. Moreover, by using the radiation to generate electrical power, the wire grid can be kept charged and incident electrons discharged in a beam to keep the spacecraft electrically neutral. Thirdly, maintaining a charge on the grid in interstellar space can act to brake the spacecraft, or even steer it, depending on the "space weather" it encounters.
Clearly, applying these mechanisms to optimising "Breakthrough" spacecraft could considerably widen the range of trajectories and mission profiles possible. That is "work in progress".
"Electric sails" have been examined since the 1990s (the references list in the paper deserves attention), but their profile is considerably raised now.
The thoughtful reader will have noticed the possible magnetic equivalent. The reference list is worth reading for this too. For shielding against low-energy radiation, this also has potential.
116878468
submission
RockDoctor writes:
A paper just published on Arxiv and submitted for formal publication, reports the discovery by spectroscopy, that the interstellar comet 2I/Borisov is emitting about 100kg/s of cyanogen (CN)2 molecules — the significant component of deadly cyanide compounds . Any self-respecting panic-monger can get their teeth into the story so far, and run with it.
Those with a slightly more reasoned point of view may wish to remember that this comet is currently coming into the inner Solar system, but it's minimum distance from the Earth is going to be somewhat more than the Earth-Sun distance. Since the comet is coming from far out of the plane of the planets, the Earth won't pass through it's tail, which the Sun will blow well away into the outer Solar system. Not that a hundred kilos of cyanide is a threat on a global basis — if you dropped that hundred kilos into a large sports stadium, you could evacuate most of the audience alive. It wasn't considered a very good poison gas in World War One, despite it's popularity with detective novelists.
Cyanide (cyanogen) is one of the easier molecules to detect in space — in the 1910 apparition (ohhh, a spooky word as Halloween is approaching!) of Halley's Comet (P1/Halley), cyanogen was also detected in it's tail, through which the Earth actually passed. More people probably died because of press hysteria than died of cyanide poisoning. Detecting cyanogen in a comet's tail is an expected event these decades. So this discovery simply adds to the evidence that this comet is pretty similar to our locally-generated ones. It's a non-story. Don't expect to hear that from the mainstream press though.
When 1I/`Oumuamua was discovered there was a speedy flurry of papers about it. In large part that was because it was discovered while leaving the Solar system and dimming rapidly. 2I/Borisov, in contrast, is still approaching, still brightening, and promises to remain observable until well into next spring or summer. So observing plans can be — and are being — laid in relative calm. Expect more discoveries through the coming year. Even if this turns out to be a really boring comet, that in itself is a useful datum.
