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OK, we have a lot to get through this week. We have a new president coming along, and even though this charlatan may well usher in the end times, he is certainly known for grabbing ratings (among other things). Also, last week, I promised to write about why I am having trouble with ‘Romance of three Kingdoms.” It is a book about deceit, trickery, and cruelty as the tools of leadership. Perhaps now is a good time to talk about its dark lessons. However before we get to any of that, today let’s take a quick trip off-world to our sister planet Venus (a planet which endlessly fascinates me) where some exceedingly strange developments have been in the works.
Venus is currently being monitored and observed by the Japanese Space Agency probe Akatsuki. On December 7th, 2015, the probe spotted a huge crescent wave 6,000 miles long in the atmosphere of Venus. The probe lost sight of the massive bow shaped phenomena as it moved through its orbit, and, when it returned to position a few days later, the wave was gone.
So what produces a 6,000 mile long super cloud on a planet already known for extreme fast moving clouds of sulfuric acid. Scientists theorize that this was a gravity wave. Gravity waves are not too be mistaken for the gravitational waves of deep space (which are caused by distortion of spacetime from supermassive objects). Instead a gravity wave is a wave propagated within a fluid (like air or liquid) through the effects of gravity. When water flows over a sandbar, gravity restores equilibrium on the other side–which causes a wave effect. This is a familiar pattern in all sorts of fluid dynamics–including clouds passing over mountains. It is believed that the giant crescent wave within the atmosphere of Venus originated from the atmosphere flowing over vast mountain ranges on the surface.
Even if this is not as unfamiliar a phenomena as it might deem when first hearing the name and looking at the pictures, it is very beautiful and it is appearing on a scale hitherto unknown in terrestrial parts (although the supermassive planets have their own bizarre cloud structures which put it to shame. for now lets just enjoy looking at the huge bow shaped cloud on the closest planet to Earth. Thanks JAXA for making this discovery! What will the strange hot caustic atmosphere of Venus do next?
Bullockornis (with human-size silhouette for comparison)
My sincere apologies for being such a truant blogger last week! Not only did I fail to post any new articles since Tuesday, I unpardonably left you stuck with nothing but the flimsy Ms. Perry during that time. In order to apologize, allow me to take you on a trip to the island continent of Australia…15 million years ago during the Middle Miocene. During this time one of the largest birds ever lived across Australia: a giant fowl named Bullockornis.
Bullockornis
Bullockornis was a 2.5 meter tall (8 foot 2 inch) gooselike bird. The creature weighed in at approximately 500 kilograms (1100 pounds) and scientists believe it was actually related to the modern geese and ducks. If you have ever met a modern goose, you will realize that a goose the size of a bear would be a formidable creature indeed. Additionally Bullockornis possessed a razor sharp beak with immensely powerful jaw muscles. It is hard not to imagine the giant bird nipping off a he-man’s arms like corn kernels or biting through bridge cables with this monstrous beak, but the truth is scientists don’t know what the bird used it for. The monstrous goose could have been a hunting carnivore (like certain ducks are today) or an herbivore which grazed on heavy dense plants. Perhaps, like contemporary geese, it was an omnivore which hunted, grazed, and opportunistically scavenged whatever it could get.
Bullockornis was discovered in 1979 but it only became well known when some PR savvy writer christened it the “Demon Duck of Doom” (which strike me as a silly 1930s Disney-style name, but I guess whatever gets people involved in paleontology is good). The scientific name “Bullockornis” means “bullock-bird” but, even though the bird was the size of an ox, it is actually named for Bullock Creek (a rich fossil location in the Northern Territory). Bullockornis was not the only giant of the Miocene in Australia. The Bullock Creek fossil beds also contained fossils of Giant horned tortoises, marsupial “lions” (i.e. thylacoleonids) and grazing Diprotodontids—giant wombats (although nothing so large as the mighty Diprotodon which evolved in the Pleistocene).
Fossil Bullockornis Skull
The constellation Sagittarius (from “Urania’s Mirror” a set of constellation cards published in England circa 1825)
My apologies for the blogging break last week. Usually I try to write a new post every weekday, but last week was a blogging holiday. To reinvigorate things after the lost week, let’s turn to a big subject—in fact a super-massive subject! Long ago, Ferrebeekeeper featured a post about Eta Carinae, a blue hypergiant with a hundred times the mass of the sun (which is itself a million times more massive than Earth). Stars like Eta Carinae are rarely formed and short lived—there are probably less than a dozen in our galaxy. However compared to the most massive object in the galaxy, Eta Carinae is puny and common. Twenty six thousand light years away from the solar system there exists a truly monstrous space object!
In 1974, Astronomers discovered an astronomical feature which was emitting exotic radio waves in the Sagittarius constellation. The scientists named the feature “Sagittarius A” and set out to determine what it was. Part of the feature seems to be the remnants of a star which had gone supernova. A second part of the feature is a cloud of ionized gas surrounded by an even larger torus of molecular gas. In the middle of Sagittarius A is something which is emitting most of the high energy electromagnetic radiation visible to radio telescopes. The cloud of ionized gas seems to be emptying into it and nearby stars orbit it with greater velocity than stars move anywhere else in the galaxy (in fact the object affects the proper motion of thousands of nearby stars). And yet the space object at the center of Sagittarius A has a diameter of only 44 million kilometers–a bit less than the distance between the middle of the sun and Mercury at its perihelion (when the rocky planet is closest to the sun). By calculating the proper motion of thousands of nearby stars, scientists determined that the mysterious object at the center of Sagittarius A (which they took to calling Sagitarrius A*) has mass of 4.31 million suns (i.e. solar masses). Whatever lies at the center of Sagittarius A–which I probably should have mentioned, is also the center of the Milky Way Galaxy–is smaller in volume than a large star, but has a mass which exceeds by many orders of magnitude even exotic hypergiants like Eta Carina.
Of course the only kinds of discrete objects which we know (or even hypothesize) to be capable of attaining such mass are black holes. It is believed that most (indeed probably all) galaxies have super-massive black hole at their centers. Smaller galaxies have small super massive black holes (forgive the oxymoron) but large galaxies have immense central black holes which can equal billions of solar masses. Radio astronomers have observed plumes of exotic electromagnetic radiation coming from the center of other galaxies, and they wondered where the Milky Way’s galactic center was located. It seems that a supernova near the galactic center blew away a great deal of the dust and gas on which the black hole would otherwise “feed” thereby making the galactic center of the Milky Way less energetic than the active center of farther (e.g. older) galaxies.
Artist’s Conception of Galactic Center
The super massive black holes which lie at the center of galaxies may be a result of the accretion of matter around stellar-sized black holes (which could grow quickly in matter-rich galactic cores) but most astrophysicists believe they are instead a primordial feature of the Big Bang around which galaxies themselves coalesced. The ultimate nature of super massive black holes remains unknown and seems to be tied to the nature and shape of our universe.
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