If you're saying to yourself hey, that's where the supermassive black hole Sgr A* is, you're absolutely right! And if you're saying to yourself say, didn't the Fermi 'scope already recently discover some huge lobes of gamma radiation above and below the galactic core, then you're doubly right! Those were the so-called "Fermi bubbles" that I discussed back in September--big radioactive balls 25,000 light years across, just above and below A*.
This new discovery is very likely related to the process that created the Fermi bubbles, because it's just about the same size! Here's a conceptual illustration of the "Gamma-ray beams" (or what they may once have been--see below) superimposed on the bubbles:
Now, it's important to note that sharp-looking jets like those in that illustration are *not* what they actually found; if you look at the diagrams in the afore-linked research paper, you'll see that what they detected are very faint, vaguely cylindrical "cocoons" of gamma-ray-scattering space dust radiating outward about 27,000 light years from Sgr A*, tilted at about a 15 degree angle to the galactic pole. They *think* that these are most likely reflections--light echos, I suppose you could say--of relativistic jets of highly energetic plasma shot out of the poles of our galaxy's central supermassive black hole at some time in the past (at least 55,000 years ago, I guess, since at least some of the plasma would have had to travel 27,000 light years out, maybe at just under the speed of light, then its transmitted energy would have had to bounce back about another 27,000 light years to reach us), as we can see shooting out of distant galaxies whose supermassive black holes are actively sucking in (and jetting out) large amounts of material. Astronomers and astrophysicists have for some time now, based on other evidence of past star births and other things we can see around the core, supposed that A* goes "active" like that maybe every 100,000 years, but this is the first time that traces of the tell-tale jets have actually been spotted.
This may also indicate that A* is or was spinning at a different angle than the rest of the galaxy! It isn't clear yet whether the bubbles and the jets were formed in the same event; they could just as well be remnants from separate active periods. From the press release:
Quote:
The two structures also formed differently. The jets were produced when plasma squirted out from the galactic center, following a corkscrew-like magnetic field that kept it tightly focused. The gamma-ray bubbles likely were created by a "wind" of hot matter blowing outward from the black hole's accretion disk. As a result, they are much broader than the narrow jets.
Both the jets and bubbles are powered by inverse Compton scattering. In that process, electrons moving near the speed of light collide with low-energy light, such as radio or infrared photons. The collision increases the energy of the photons into the gamma-ray part of the electromagnetic spectrum.
and
Quote:
It would take a tremendous influx of matter for the galactic core to fire up again. Finkbeiner estimates that a molecular cloud weighing about 10,000 times as much as the Sun would be required.
"Shoving 10,000 suns into the black hole at once would do the trick. Black holes are messy eaters, so some of that material would spew out and power the jets," he said.
Go A*!
~~~~~
I have the author of the webcomic Variables to thank for pointing out that he and some other webcomic authors have started up a Longform Webcomics subreddit on the popular link-sharing social networking site, reddit. I tossed an A* link in there to see if I could help this new subreddit get going. There are the popular "comics" and less-used "webcomics" subreddits on reddit already, but they tend to favor gag-a-day type comics, which I suppose are better suited to quick bursts of non-committal satisfaction. :) So it would be nice for "long form" webcomic authors such as myself ("long form" just meaning they tell a continuing story from strip to strip) if a thriving subreddit for sharing story comic links should flourish, but I guess we'll see!
^ That's Walter Frederick "Fred" Morrison demonstrating his "Pluto Platter" flying disc in the mid-50's. Morrison had first had the idea for a flying disc toy in '37, at the age of 17, while throwing a popcorn can lid with his girlfriend, Lu, at a Thanksgiving Day picnic (source). Those lids dented easily, but they found that cake pans flew better, and were more durable; the two soon had a small business going selling "Flyin' Cake Pans" for 25 cents a pop.
Back from flying fighter planes in WWII, Morrison came up with the first dedicated flying disc design in '46 ("Whirlo-Way"), and by the early '50's, had his first disc, the "Flyin' Saucer," which he sold at fairs. In '55, he and Lu, now his wife, created another disc, the "Pluto Platter," which Morrison can be seen demonstrating in the photo above; the name was intended to cash in on the UFO craze.
Morrison was quite the inventive and enthusiastic marketer of the Platters. But just a few years later, in '57, he sold the marketing rights to the Wham-O toy company. Morrison would produce several others inventions for the company, but he didn't approve of the new name they came up with for the Pluto Platter later in '57: they'd seen college students in Connecticut (Yale appears to take the credit) playing catch with pie tins from the Frisbie Pie Company
--the name "Frisbie" was popular among the students. Apparently wishing to cash in on that youthful vibe, Wham-O decided to rename the Pluto Platter to the copyright-avoiding respelling, "Frisbee"--and the rest, as they say, is history.
Morrison won the patent for the disc's design in '58, and continued to be an enthusiast for another fifty-some years, if this Wham-O publicity photo of him tossing a Frisbee in 2006 is a fair representative of his activities. He passed away in 2010, at the age of 90.
Maybe it's a truly ominous sign of global warming, as some would have it, but...a huge iceberg rolling over off the Upsala Glacier in Argentina makes for (WARNING: auto-playing video with sound) a pretty cool tourist video.
~~~~~~
Listening to Tall Tale Radio episode 146 this evening while drawing today's page, I heard Kenosha Festival of Cartooning founder Ann Hambrock mention growing up on the cartoons of Charles Addams (1912-1988), whose most famous creation took his name: The Addams Family. They began as recurring characters in his often macabre cartoons, many of which were done for The New Yorker. Perhaps his first gig, touching up photos of corpses (removing the nasty-wasty blood) for True Detective magazine was quite instructive!
Anyway I mention him because his cartoons were done--somewhat unusually--in ink wash, which is what I use, much more crudely, for A*. If you check out some of his cartoons, such as this one and this one and this one and maybe even this one, you'll see just how neatly he managed both sharp shadows and smooth gradients. Man! Well, practice, practice, practice I guess. :o
A few days ago I posted about the new finding of what appears to be fairly solid evidence that our galaxy's central supermassive black hole, Sgr A*, shot out a galaxy-spanning beam of plasma some tens or thousands of years ago, the result of swallowing something like the equivalent of 10,000 Suns. Well that reminded me that I wasn't too sure what exactly is covered by the term "plasma," so I went and looked it up!
According to Wikipedia, plasma "is a state of matter similar to gas in which a certain portion of the particles are ionized." Oh! Well, that's pretty easy. Like a gas, it doesn't have a definite shape, BUT--unlike a gas--plasma, being ionized (positive or negative ions, or electrons), can be shaped or guided by magnetic fields.
You've probably manipulated plasma with the magnetic field of your body, in fact, by touching the outside of one of these babies:
But you can get plasma all over the place! For instance, the Space Shuttle Atlantis left a trail of plasma as it plunged through the atmosphere to come in for its last-ever landing last July:
And in fact, plasma is the most common state of matter (as opposed to solids, liquids, or gasses) in the visible universe! It's plasma that makes for much of the cool glowy stuff I do so love to post in space photos. Let's review some of A*'s greatest plasma hits!
You see a big ball of plasma in the sky probably nearly every day. That's right, we call that plasma the Sun! Stars are fusion-powered plasma:
Of course we already know that plasma can be shaped into huge jets by the incredibly powerful magnetic fields generated by supermassive black holes, like this 5000 light-year-long (!!), near-light speed jet coming out of the center of galaxy M87, one of the most massive galaxies in our little corner of the universe (~53 million light years away, and maybe 200 times as massive as the Milky Way):
And on a more local scale, you're seeing plasma when you see lightning. And it can be generated for space travel purposes, as with the slow-but-efficient Hall Effect ion thruster ("Over 240 thrusters have flown in space since that time [of the Soviet "Meteor" satellite in 1971] with a 100% success rate")
(Mind you, not even the ambitious Nikola Tesla liked the idea of sitting that close to such a powerful electrical field, so he had his photographer use a double-exposure to *appear* to capture him alongside that raging plasma in his Colorado lab in 1899.)
I'm sort of surprised I never posted this NASA picture because it's one of their better known ones of our galactic scenery, I think, but better late than never:
image by NASA/CXC/SAO (X-ray), NASA/JPL-Caltech (Infrared), MPIA, Calar Alto, O.Krause et al. (Optical) (source)
^ That rainbow fuzzball is Tycho's Supernova Remnant, also known as SN 1572--which I suppose stands for "Supernova of 1572," since that was the year in which it appeared in Earthly skies: "the New Star, never before seen in the life or memory of anyone," as Danish astronomer Tycho Brahe put it in the title of a tract he published containing his detailed observations of the startling phenomenon--a newly appeared star so bright that it was visible to the naked eye in broad daylight. Here's one of the diagrams he made showing the star among other stars in the constellation Cassiopeia--it's the one marked "I" in the upper-left: "Noua Stella":
The apparition--one of perhaps eight supernovae visible to the naked eye in recorded history--faded from view within a few years. Thanks to the observations of Tycho and other contemporary astronomers, though, scientists armed with radio telescopes were able to locate a radio signal from its recorded position in the '50s, and achieved an optical observation of the remnant of the explosion in the '60s.
Tycho's observations and deductions of the "new star" revolutionized fundamental astronomical concepts:
Quote:
Because it had been maintained since antiquity that the world beyond the Moon's orbit was eternally unchangeable (celestial immutability was a fundamental axiom of the Aristotelian world-view), other observers held that the phenomenon was something in the terrestrial sphere below the Moon. However, in the first instance Tycho observed that the object showed no daily parallax against the background of the fixed stars. This implied it was at least farther away than the Moon and those planets that do show such parallax. He also found the object did not change its position relative to the fixed stars over several months as all planets did in their periodic orbital motions, even the outer planets for which no daily parallax was detectable. This suggested it was not even a planet, but a fixed star in the stellar sphere beyond all the planets.
Tycho, "the last major astronomer to work without the aid of a telescope," seems to have been a pretty interesting fellow--a nobleman as well as the leading observational astronomer at the time--and the Wikipedia page on him is worth a read. But if you want something a bit more dramatic, I encourage you to check out the bit from Carl Sagan's classic "Cosmos" series dramatizing the meeting, in 1600, between Brahe and Johannes Kepler, who needed Brahe's observations of the movements of the planets--the most accurate ever made up to that time--to help work out his theories of planetary motion--these would eventually help Kepler discover that the planets move in elliptical orbits around the Sun, but not until after Brahe's death from overindulgence. That fun movie-like bit is on YouTube, beginning here. It also explains for instance why Brahe had a gold nose. :o Kepler had previously believed that the planets followed circular orbits; Brahe, for his part, did not follow the "heretical" heliocentric Copernican model of the heavens favored by Kepler, but "proposed a 'geo-heliocentric' system in which the Sun and Moon orbited the Earth, while the other planets orbited the Sun." This gained a following, particularly after 1616, when the Catholic church officially decreed that "the heliocentric model was contrary to both philosophy and Scripture."
The photo above is a false-color composite view; NASA's description runs as follows:
Quote:
The explosion has left a blazing hot cloud of expanding debris (green and yellow) visible in X-rays. The location of ultra-energetic electrons in the blast's outer shock wave can also be seen in X-rays (the circular blue line). Newly synthesized dust in the ejected material and heated pre-existing dust from the area around the supernova radiate at infrared wavelengths of 24 microns (red). Foreground and background stars in the image are white.
Indications are that it was a Type Ia supernova, ie a white dwarf star that sucked in enough material--usually from a binary star companion--to reach the Chandrasekhar limit--the maximum mass in which matter's electron degeneracy pressure is able to resist the force of its own gravity--in other words, the point at which gravity, having squeezed the white dwarf down to just barely larger than nothing, overcomes the normal quantum mechanical laws of matter, and matter collapses entirely. Or forget that and see if you can figure out this rather more technical explanation:
Quote:
"...observe that, as we add mass to a white dwarf, its radius will decrease, so, by the uncertainty principle, the momentum, and hence the velocity, of its electrons will increase. As this velocity approaches c, the extreme relativistic analysis becomes more exact, meaning that the mass M of the white dwarf must approach Mlimit. Therefore, no white dwarf can be heavier than the limiting mass Mlimit, or 1.4 Solar masses."
Although actually, in the case of a Ia supernova, the white dwarf doesn't *quite* reach the ~1.4 solar masses of the Chandrasekhar limit; instead, as it approaches the limit, the pressure raises the temperature, which increases the rate of fusion at the core until it reaches such a state that all the remaining carbon in the star detonates at once.
(Interestingly enough, in the past ten years or so, at least four Super-Chandrasekhar mass supernovae have been observed, starting with the Champagne Supernova of 2003; these are believed to be type Ia supernovae in which the white dwarf exceeded the Chandrasekhar limit by as much as 100% before exploding--several theories have been put forth as to how this is possible: a) the dwarf was spinning so quickly that centrifugal force helped hold it up, or b) two white dwarfs merged.)
The more spectacular nebulae tend to come from other types of supernova explosions--one where an incredibly massive star collapses all at once--but as in the case of Tycho's Remnant, Ia supernovae can still leave a pretty cool cloud of debris behind. The superhot cloud is thought to be expanding at maybe around 5,000 km/s; by way of comparison, the speed of light is 300,000 km/s.
The observations forming the above photo were done in 2003, and the photo was published in 2009. Immediately after that, though, succeeding observations would begin picking out details of the Remnant--which is maybe about 9,000 light years away and 20 light years across--that may contain clues not only to the forces driving such debris clouds, but even to how exotic cosmic rays are generated! I will get into these in another post soon. :D
~~~~~~
Here's what's on the back of today's A* page (click it for the "subscription preview" HD version):
I sketched out what would become the final page, but as a light ink sketch it looked way too...normal. So I flipped the page over and tried something a bit more dramatic and gestural, and it had some nice things in it, but the features weren't quite Thierry, you couldn't see him hiding behind the big guy, and I couldn't figure out what to do with the hair. I flipped back to the first sketch and threw some heavier black onto the eyes, the sides of the head, and the shoulder, and then it started to look a little more interesting, so I went forward with that instead.
While looking up the stuff for yesterday's article, about Kepler's Copernican heliocentric model of the solar system, and Brahe's "geo-heliocentrism," I came across this baby:
That's Orlando Ferguson's 1893 diagram demonstrating how the Earth can be both the center of the universe, and square, as certain folks who take every colorful translated turn of phrase in the Christian Bible absolutely literally--and without researching it, generally--seem to want to believe, even in recent times--these are the modern geocentrists, and they have some fascinating ideas of how the universe works. Rather ironically, though, it appears that most of them now take the "out" provided by relativity--the whole thing about everything being a matter of your particular frame of reference, so from our Earthbound frame of reference, you could pseudo-scientifically say that relativity supports your claim that you're at the center of the universe. Clever!
The geocentric view, of course, has been around since at least the Greeks in the 6th century BC. Likewise, the idea that the Earth is flat goes back...well, probably to the first time some human bothered to think about what the thing they were walking on was shaped like in the big picture--but in terms of being written about, back to Homeric times in Greece (8th century BC), and quite far back in a multitude of other cultures as well. The Greeks, though, started figuring out that flat couldn't quite explain everything they were observing, and by the 1st century AD it appears that the spherical Earth was pretty much an accepted thing in Greek society.
This, along with a lot of other science from the ancient world, struggled to get passed along in the tumultuous upheavals of late antiquity, and, again, Christian writings seemed happy with the idea of a flat Earth, which thus began regaining ground in medieval Western culture. The round Earth idea never disappeared, though, and was in fact espoused in some of the most well-known learned tracts of the early Middle Ages--and it only became more widespread when the West was introduced to Islamic astronomy in the 11th century.
~~~~~
News has just broken that a US spy agency, the NRO (National Reconnaissance Office), has given two "spare space telescopes" to NASA; each has an eight-foot-wide primary mirror, plus a secondary mirror, making them potentially more powerful than the optics aboard the Hubble Space Telescope, which has a 7'10" mirror. While NASA thinks the earliest they could get the gift 'scopes refitted and launched would be 2020, a surprisingly long-sounding way off, that could work out quite nicely, as Hubble, already 22 years old, is expected to begin ailing by around that time, both due to equipment failures and to the gradual decay of its orbit--no further repair or boosting missions to extend the life of the telescope further are planned.
So two Hubble+ scopes to swing right in as replacements would be grand, especially since there really isn't a true successor to Hubble in the works; the James Webb Space Telescope is the official successor, but it's an infrared telescope, so even though it is due to have a whopping 21 foot mirror (consisting of carefully fitted smaller mirrors) at its planned launch date in 2018, it won't be able to return the type of spectacular visible light images that Hubble can. It's actually been downright puzzling to me that they *didn't* have an optical replacement in the works...but maybe somebody knew about these gift telescopes years ago? Well, who knows. Anyway, this is an excellent development for people like me who love spectacular visible light space photos!
Don't know about you but I just watched the 1974 (the year I was born!) sci-fi movie Dark Star over on (warning: auto-playing video with sound) AMC's streaming B-Movies site. [As I post this, that whole site appears to have gone blank, but eh I'm sure it'll be back shortly. >_>] It's pretty weird! Written by John Carpenter and Dan O'Bannon--Carpenter of course went on to fame in the horror film genre, and O'Bannon, who passed away in 2009, did computer effects for a little film called Star Wars three years later, and then went on to write some films you may have heard of, including Alien (1979), two segments of Heavy Metal (1981), Blue Thunder (1983), Total Recall (1990), and Alien vs Predator (2004)--back when they were film students, and on a $60,000 budget they were able to squeeze out this bizarre dark comedy tale of a highly dysfunctional crew sort of trying to complete a questionable deep space mission on a damaged ship. Carpenter did the music, O'Bannon did the special effects and starred as one of the main crew members (the incredibly hapless "Pinback," who didn't even qualify for the mission but was selected in a case of mistaken identity), and while the bottom-of-the-barrel production values and highly wacky plot (engaging in existential arguments with their own planet-busting artificially intelligent bombs, for instance) solidly relegate it to B-movie status, it's...well, it's pretty fun if you go for this type of thing.
I tried to take some representative screenshots:
Wikipedia says the student film was 45 minutes long, and a producer wanting to take it commercial paid to have them add 38 minutes to bring it up to feature film length for theatrical release--if that's so, I suspect the added part is the oddly long and otherwise pretty much plot-and-actor-isolated slapstick segment of Pinback (O'Bannon) vs "the alien." While the episode is patently and purposefully absurd, the theme of a bickering crew on an isolated space ship haunted by a rogue alien, not to mention a mission gone horribly awry, and AI that don't necessarily act in the best interests of the crew, would be reworked by O'Bannon into the wildly popular Alien.Dark Star, unsurprisingly, was wildly *un*popular--not being helped by the producer deciding to market it as a horror movie, which it most certainly is not.
The "science" in the movie is absolutely awful, except that some of the outer space landmarks they mention are real; one of their destinations, the Veil Nebula, for instance, is the large but very faint remnant of a supernova that exploded 5 to 8 thousand years ago; at maybe about 1500 light years away and having six times the diameter of the full moon, it is one of the brightest X-ray sources in our sky. Here are some photos of various parts of it:
false color multiwavelength image by NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration (source)
false color image by NASA, ESA, and the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration. Acknowledgment: J. Hester (Arizona State University) (source)
~~~~~~~
Venus just crossed (or "transited") the Sun from our Earthly point of view, which got people excited since it won't happen again until 2117. A glance at the live stream on NASA's site the other day was predictably unexciting (a small dark dot on a big white dot), but their Solar Dynamics Observatory spacecraft in Earth orbit captured some rather stunning high resolution footage of the event at multiple wavelengths, which they've cleverly spliced together as a time-lapse music video sort of thing:
Does that remind you of the Death Star headin' places, or what?
NASA's Goddard Space Flight Center recently posted a nifty video showing a simulated view of how the X-ray emission in a nearby galaxy with an active central supermassive black hole doesn't come from the exact position of the hole, but rather from a point above its accretion disc; an *echo* of these X-rays then bounces to us off of the hole's accretion disc:
It sounds like they don't know exactly why the X-rays are being emitted from that other point, but then we still don't really understand how the intense, jet-forming magnetic fields around massive and rapidly spinning objects in space really work anyway--but maybe this will give smart people some clues!
The finding was made from data captured by the ESA ("European Space Agency") X-ray-detecting satellite observatory XMM-Newton, launched in 1999. The galaxy being examined, NGC 4151, at just 43 million light years away, is one of the closest galaxies to us that has an actively feeding supermassive black hole, which makes it a good galaxy to look at if you want to learn about how they work! It's been nicknamed the "Eye of Sauron" for reasons that this composite Chandra image (blue = X-rays, yellow = optical, red = radio) may make clear:
image by X-ray: NASA/CXC/CfA/J.Wang et al.; Optical: Isaac Newton Group of Telescopes, La Palma/Jacobus Kapteyn Telescope, Radio: NSF/NRAO/VLA (source)
~~~~~~
My June art show opens tomorrow (okay, today--Friday!) in Seattle's Phinney neighborhood, 6-9 pm! I got a glimpse in while driving by today and it looked like they had a full wall of my artwork--there are hm something like 17 original A* ink paintings, and another ten or so framed prints of art from A* as well as a few from my other (now discontinued) comics, The Princess and the Giant and Sketchy. They will have refreshments and maybe even a DJ! :o But if you want some free eats you'd better come early, otherwise I'm liable to eat them all. :d
The opening bash for my art show at Chocolat Vitale in Seattle's Phinney neighborhood was this evening, and it was pretty darn successful I think! Loads of people came by and chatted, and some were even artists I got to compare notes with! The live DJ was great AND she had some really cool and unusual records to play, plus there were so many refreshments on hand I couldn't even eat them all myself. Also I think three or four of my pieces even got purchased right off the bat!
The show goes for a month so there's *still* loads of time to check it out if you happen to be in the vicinity. You won't be able to escape the A* art attack there: it's coming at you from all four walls. Here are two of them:
(^ That wide white coffee mug on the stone table there, by the way, contains free samples of black licorice Scottie dogs. Highly recommended! :d Unless you don't like stuff getting stuck between your teeth, because MAN those dogs come home to stay I tell ya.)
Thanks to everyone who came by so far, to my dad who pretty much made it all happen, to my friends and family who have been so supportive, and to the generous and enthusiastic proprietors of Chocolat Vitale. :) It was a swell opening party. :D
Here the doodle I doodled on the back of today's page while waffling over some of its fiddlier bits (click for the smaller version if this one is just too big to take in :D):
Looks like a certain webcomic author might be missing drawing his main character in the actual comic! >_>
I got a bit more of the some-time-upcoming "subscription mode" done over the weekend, in fact it's about the last of the sort of back end / secondary functions that I have to do as far as I know, so next I get to work on actually making the comic appear at the selected size based on your cookie-stored setting, which should be more fun. This last thing I did was the whole surprisingly convoluted process of how to get a new password if you lose yours, which involves emailing a time-limited code that takes you to a special form and so on...which isn't quite working yet exactly as the script is crashing when it should be taking you to that form. So yeah I didn't really get a chance to start debugging that part yet. :P BUT after that I get to do the more fun part involving the actual comic size, so that's nice.
Users browsing this forum: Google [Bot] and 0 guests
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum
