Even a casual reader of this blog will know that I’m one of those people who likes to look up at the night sky. Seriously, given the choice between watching some banal sitcom or gazing at the Moon, the stars and the planets you’ll find me outside every night surveying the heavens. In fact right now Venus, Jupiter and Mars are all easily visible in the early evening.
Better than any TV show. The heavens above are endlessly entertaining. (Credit: Scholastic Watch and Learn Library)
At the same time I also enjoy finding Low Earth Orbiting (LOE) satellites as they pass overhead here in Philadelphia in the early evening or just before dawn. The easiest to spot is the International Space Station (ISS) which I’ve seen now hundreds of times but I’ve also seen China’s Space Station (CSS) a couple of dozen times, the space shuttle back when it was flying, Space X’s Dragon capsule along with the Air Force’s secret shuttle the X37B, some communications satellites and Earth observation satellites. Those last are really cool because unlike the others they are in polar orbits. I even remember one time as a kid when I was on a Boy Scout camping trip and the Echo 2 satellite passed overhead as we were sitting around the campfire.
Just a big balloon coated with aluminum foil to reflect radio waves the Echo 2 satellite was the first attempt at a communications satellite and very easy to spot from Earth’s surface. (Credit: Space.com)
If you’d like to try to observe some of these satellites as they fly overhead here are a couple of web sites that will get you started: https://spotthestation.nasa.gov/
Now for each of those satellites that are big enough and bright enough for me to see with my naked eye, and despite the light pollution of living in a big city, there are probably a hundred smaller satellites that are also orbiting the Earth along with a lot of space junk. In fact NASA keeps track of 8,000 objects that are orbiting the Earth.
75 Years ago the Earth had only one moon but today it has more than any other planet. Most of these objects are junk but there are some 2,000 active satellites and more all the time. (Credit: Smithsonian Magazine)
To me those satellites are just more interesting objects to look at in the sky but to professional astronomers they are a real nuisance, and becoming more and more of a problem with time. Just imagine, you’ve been given a precious few hours of observing time on a big telescope that cost millions of dollars, you go though all the steps of pointing the ‘scope at the object you wish to study, spend hours gathering the light of the object, only to have your observation ruined by a streak of light from some passing satellite.
The observatory atop Mauna Kea in Hawaii. Time at big instruments like these is precious and to have an important observation ruined by the light of a satellite passing in front is becoming a more and more common problem. (Credit: Institute for Astronomy)
And that problem is growing as more and more satellites are being launched. In fact Space X has over the past (two) years has begun placing and entire fleet of its Starlink satellites into orbit to provide Internet service anywhere in the world. Each time a Falcon 9 rocket is launched for Starlink another 50 satellites are placed in orbit, 50 more objects that could impact astronomical observations.
Dozens of starlink satellites being packed into a nose cone ready for launch. As miniaturization has made satellites cheaper and reusable rockets has done the same for putting them into orbit the number of satellites is increasing at an ever growing rate. (Credit: Spaceflight Now)
Meanwhile Blue Origin plans on establishing its own fleet of 3,200 Internet satellites while AST Spacemobile intends to launch 100 or more Bluebird satellites. The first of the Bluebird satellites, a prototype designated as Bluewalker3 already has astronomers worried about what is to come. You see, once in orbit Bluewalker3 unfolded into a 64 meter square communications array that is almost as bright as the ISS. A hundred such satellites could be devastating to science.
When unfolded in orbit the Bluewalker series of Internet satellites will have almost as much reflective surface as the International Space Station. Blue Origin plans on putting hundreds of these satellites into orbit. (Credit: Universe Today)
Worse yet the problem doesn’t only affect visual light telescopes, the radio signals emitted by all of those satellites also interfere with the observations being made by Radio Telescopes. As companies like Space X continue to make putting a satellite into orbit cheaper and engineers find more and more uses for satellites in LOE the problem of interference can only grow worse.
Radio Telescopes are affected as well because of the the signals being put out by satellites in orbit that is just noise to instruments like these. (Credit: SETI Institute)
In the long term the only real solution is the one that Science Fiction writers like Arthur C. Clarke suggested all the way back in the 1950s, astronomical instruments themselves need to go into space. In fact with space telescopes like Hubble, the Chandra X-ray telescope and now James Webb the most important discoveries are already being made by space telescopes. Getting telescopes out of the fog caused by Earth’s atmosphere has been a dream of astronomers for over a hundred years.
Hubble is still the best known space telescope but it has a lot of company. Being well above most other satellites Hubble has an almost unobstructed view of the Universe. (Credit: BBC Sky at Night Magazine)
Starting a few decades from now we will probably see the first actual observatories being constructed on the Moon not far from the first manned bases. Observatories on the Moon, particularity the far side, will not only escape the interference from LOE satellites but also city light pollution and, for radio telescopes electromagnetic interference from TV and radio stations as well. And having telescopes on the Moon, where they can be serviced and repaired from nearby Lunar bases, would be a big advantage over having them orbiting in space, remember the problems Hubble had at first and the dramatic shuttle mission to fix it.
Someday, not too far in the future, astronomy will be conducted from observatories on the Moon or even beyond, to get away from the glare of the Sun. (Credit: Astronomy Magazine)
So observatories on the Moon is almost certainly the long term solution but the transition period will be a long and hard one as numerous important observations are ruined by the streaks of light caused by Earth orbiting satellites, space pollution if you like.
We humans like to flatter ourselves that we rule the Earth. After all there are eight billion of us spread across the globe and our cities, highways and other structures dominate the surface of the planet. Deep down inside however we know that’s not true, we know that scurrying beneath our feet, or hiding just out of sight, or even buzzing in the air around us are untold trillions of little creatures, insects. They were here hundreds of millions of years before us and they’ll be here hundreds of millions of years after we’re gone.
The Number and diversity of the Insects is simply mindboggling. Here is just a small sample of how insects can differ. (Credit: Encyclopedia Britannica)
O’k so insects outnumber us, just take a walk outside and look around and you can see that, insects are pretty much everywhere you look. But just how many insects there are would be enormously difficult thing to calculate. Just think of all of the different kinds of insects there are, all the different environments in which they live, the different ways in which they live.
Our world contains a great many different environments and insects have evolved to fill many ecological niches in all of them. (Credit: Meltano)
That amount of work would take more than the life span of any single naturalist or small group of naturalists. Recently however a team of entomologists, that’s the formal name for scientists who study insects, from the University of Hong Kong did just that for at least one very important family of insects, the ants and the answer is simply mind blowing.
With all of the different kinds of insects in the world, many as beautiful as these moths, the work of entomologists can be endlessly fascinating. (Credit: Bohart Museum of Entomology)
Now to be honest the entomologists did not actually do any field research themselves. Instead what they did was to compile the results of 489 papers written about ants by scientists from all over the world and over the last hundred years dealing with hundreds of different species of ants. The entomologists who carried out those 489 studies may have had to get down on the ground and estimate the number of ants in each square meter of ground from hundreds of locals spread around the world but the researchers in Hong Kong simply used that data to get an estimate for the total number of ants living here on Earth. 20 Quadrillion, that’s 20,000 trillion.
A map showing the distribution of ants around the world. They do concentrate in the tropics, but then so do living things in general. But basically they are everywhere. (Credit: Science)
To put it another way, that’s about 2.5 million ants for every person alive today, and although ants may be small, that means that when put together they would outweigh all of us. So try to remember that the next time you’re walking down the sidewalk and you see an ant’s nest sticking out of a crack in the cement with a lot of ants around the entrance. If you’re tempted to step on the ants just because you’re big and strong and they’re not, don’t forget they have a lot of friends and in the long run they’re going to outlast you and all of us.
In many ways they really do run the world, and they’ll continue to do so long after we’re gone! (Credit: Active Wild)
As we all know ants are social insects, with many thousands living together in a nest that’s ruled by a single queen who produces all of the eggs from which the many worker ants develop. And in some species the nests have been discovered to carry out some rather amazing, and intelligent construction projects.
Like a beehive an ant nest is centered around a queen ant who lays all of the eggs that turn into worker ants. (Credit: Wagner Pest Solutions)
Leaf cutter ants for example are known to grow, tend and harvest a form of fungi in their nest underground that they use for their main source of food. Several species that don’t like the sunshine use leafs and other ground litter to build covered highways to their sources of food. And the fire ants of the American southeast can avoid being killed during heavy, flooding rains by literally building rafts out of their own bodies.
If their nest is flooded Fire Ants will literally use their own bodies to build a raft to survive until they find solid ground. (Credit: Animals – How Stuff Works)
Fire ants may be a considerable pest in the states along the Gulf Coast of the United States but they are also one of the most highly organized of all the social insects. So synchronized are their movements that in large numbers they seem to flow more like a liquid than as a collection of individual creatures. So coordinated are the ants that their behavior has even been given the name ‘active matter’.
There are even considerable signs of intelligence in the building of a Fire Ant raft. Here it can be seen how the nest’s eggs are kept on top to protect them. (Credit:BugGuide.net)
Now in a series of two articles, one in the journal Bioinspiration and Biomimetics while the second has been accepted at the Physical Review – Fluids (There’s a combination for you) Dr. Hungtang Ko, who recently moved to Princeton University after several years as a graduate student at Georgia Tech, has described some of the details of how fire ants not only build their rafts, but actually control them.
Sounds like a fun seminar to sit in on! (Credit: Twitter)
Right from the start the ant’s actions show a considerable degree of intelligence, at the first sign of rising water levels they begin to gather up the nest’s eggs in order to preserve the next generation. Once the nest is flooded the individual ants don’t swim toward each other but rather just allow the ‘cheerios effect’ to bring them together. The cheerios effect is the name given to the way that surface tension causes small objects floating in water to clump together, like the last few cheerios in a bowl of milk. The skin of each individual ant is water repellant to a small degree but this property increases as more ants join the raft, grabbing a hold of each other with their mandibles and claws. Every ant seems to know what it is supposed to do so the raft can be assembled in about 100 seconds, even storing the precious eggs onboard.
We’ve all seen the ‘Cheerios Effect’ where a small number of floating objects will tend to come together and stick together. (Credit: Ars Technica)
If the floodwaters are quiet, with little or no movement or turbulence, the ants maintain their raft in a flat circular shape but if the water is flowing the ants can actually streamline the shape of their raft to make it more stable. The ants can do this because the raft is actually constructed in two layers with the bottom layer providing stability so that the ants in the upper layer can change their positions to alter the raft’s shape.
Because it is literally built of living material a Fire Ant raft can reconfigure itself even while it’s being used. (Credit: Science News)
The brainpower of each individual ant may be tiny, but studies like Dr. Ko’s provide strong evidence that collectively they are one of the most intelligent animals on this planet.
Here in America our founding fathers were both admirers and students of the Iron Age Greek civilization that was considered by some in the 18th century to be the founding fathers of the European civilization of their day. Many of the ideals of classical Greece, like personal liberty, democracy and a liberal as opposed to religious education became part of American culture because our founding fathers respected the ancient Greeks so much.
The western ideal of ancient Greece. A bunch of guys talking to each other. By the way all those arches were actually invented by the Romans, Greek architecture didn’t use arches! (Credit: Khan Academy)
So then who did the Iron Age Greeks regard as their founding fathers? Who did Socrates, Pericles, Herodotus and Euripides admire and look back to for inspiration? Well, that would be the still more ancient Bronze Age cultures that archaeologists have named Mycenaean on the Greek mainland and the earlier Minoan on the Island of Crete. These two peoples built the first civilizations in Europe and therefore are therefore the founding fathers of so much of human history.
The lands of Bronze Age Greece. The Minoans were centered on Crete and the islands of the Aegean while the Mycenaeans lived on the Greek mainland. (Credit: AllatRa Canada)
For thousands of years most of what we knew about these Bronze Age peoples came from the myths and stories told by the Iron Age Greeks like Homer and later authors. Starting from the late 19th century however archaeologists have learned a great deal about the Minoans and Mycenaeans, sometimes confirming, sometimes contradicting the ancient tales.
Theseus slaying the Minotaur as shown on a jar from the classical Greece period. This is the best known story concerning the Minoan civilization. (Credit: Quatr.us)
Let’s get one thing straight from the start. The Mycenaeans and Minoans did not call themselves by those names. Those terms are strictly archaeological labels for a large number of excavated sites that have been dated to the time of Bronze Age in Greece and Crete. Even Homer didn’t call the heroes of his epics Mycenaeans or Minoans, he called them Achaeans to differentiate them from his own people the Dorians. Recent analysis of the diplomatic archives of the Hittites and Egyptians have indicated that the Mycenaean people may have called themselves something like the Ahhiywans, similar to Homer’s Achaeans, but we have no idea what the ancient Minoans may have called themselves.
According to Homer the warriors who attacked Troy called themselves ‘Achaeans’ and Homer did not considered them to be the same race as his people. (Credit: Reddit)
Whatever they called themselves Homer considered the Mycenaeans to be a completely different people and culture from his own Doric people. And judging by the myths the Mycenaeans considered themselves to be different from the Minoans.
The palace of Knossos as it would have been during the height of the Minoan civilization. (Credit: Hercynian Forrest)
The name Mycenaean comes from the ruins of Mycenae, the largest and wealthiest of the Bronze Age palatial centers that have been excavated in mainland Greece. According to myth Mycenae was the palace of Agamemnon, the leader of the Greeks during the Trojan War. The Minoans, on the other hand were named for King Minos the most powerful king of Crete in the ancient myths.
The citadel of Mycenae as seen from the air as it exists today. Obviously the Bronze Age people were very concerned with defense. (Credit: Mycenae Archeology Department)
Both the Minoans and Mycenaeans possessed a form of written language that have been given the names Linear A, for the Minoans, and Linear B for the Mycenaeans. A major advance in understanding these Bronze Age cultures came in the 1950s when Micheal Vintris succeeded in deciphering the Linear B of the Mycenaeans and it was discovered that their language was Greek, not too different from the Greek of Homer. Linear A however has resisted all attempts at translation and we have only guesses as to what kind of language the ancient people of Crete spoke.
Linear B is known to have used symbols to both represent syllables the way our modern letters do……and also ideas the way Egyptian hieroglyphs do. (Credit: Mathweb.ucsd.edu)
Now archaeologists and historians have a new tool with which to try to understand who the Minoans and Mycenaeans were, where they came from and what relations they have to the people of modern Greece, DNA analysis. A study has just been published in the Journal Nature that details the genetic makeup of nineteen individuals whose remains were unearthed from Bronze Age sites across mainland Greece and Crete. The study also compared that ancient DNA to that of 334 living people from around the world including 30 individuals from modern Greece.
As ancient people migrated around the world their DNA went with them. By studying the DNA of people around the world today scientists can learn something about those prehistoric migrations. (Credit: Wikipedia)
What the researchers found was continuity; some 60-80 percent of the Bronze Age DNA was shared with the modern Greeks. What’s more, when the ancient DNA was compared to DNA samples from sites dated to the Neolithic period, some 7000 BCE, they again found a great deal of overlap. So it seems that Homer was incorrect when he asserted that the Achaeans were a completely different people than his own Dorians.
The Spartan King Leonidas, leader of the 300 Spartans and played by Richard Egan in the center, claimed to be descended from Heracles. He may have been right. Modern studies show that a lot of Mycenaean DNA lived on to the Dorian people of classical Greece and still lives on today. (Credit: Obscure Hollywood)
So genetically the people of Greece today pretty much come from people who lived in that part of the world nearly 10,000 years ago! Oh, the study did show some foreign influence; about 10% of the Minoan and Mycenaean DNA appears to have come from the region around modern Iran. Also the Myceaeans, but not the Minoans had genetic similarities to people from the steppes of Eastern Europe and central Asia, the land of the people who the classical Greeks would call the Scythians.
During the Classical Greek period the steppes of southern Russia and Ukraine belonged to the nomadic Scythians who the Greeks considered the prototype of a barbarian. (Credit: Wikipedia)
Still, for the most part, the Greeks have been Greek for longer than recorded history, a testament to the Greek spirit and the impact it has had on the Human spirit around the globe.
Every year representatives from nearly 200 countries come together at a chosen location to discuss efforts toward fighting global warming and the harmful changes in our planet’s climate caused by it. The first such conference was held in 1995 and given the title COP 1.
The slogan for COP27, the international conference on Climate Change was a ‘New Era of Implementation’, but not much got implemented. (Credit: IFLR)
Each succeeding forum has added one to the number with COP 20 back in 2015 generating the famous ‘Paris Accord’ where a target figure of a rise in global temperature of no more than 1.5º C above pre-industrial levels was pledged by every nation in attendance. However no concrete plan to eliminate greenhouse gasses such as CO2 and Methane was agreed upon in Paris and every conference since then has basically failed to stop the ever increasing rise in fossil fuel emissions.
The difference in the damage done to our environment but 1.5 degree and 2 degree rise in temperature. We’re basically already at 1.5 degrees and doing little if anything to stop getting to 2 degrees. (Credit: CBC)
Last year’s COP 26 in Scotland could not even reach an agreement on how or when to eliminate the use of coal, the worst emitter of CO2. Plans to issue a strong final statement on ‘Phasing Out’ coal were scuttled by India, the world’s forth largest emitter of CO2 but a nation still considered to be ‘developing’ and which in fact has plans to greatly increase its fossil fuel emissions. The wording that was finally agreed to was to ‘Phase Down’ coal use instead of ‘Phase Out’.
The use of coal to generate energy is the worst polluter but at COP26 in Scotland the nation of India refused to accept the wording of ‘Phase out’ the use of coal instead forcing the term “Phase Down’ on the conference. (Credit: The Wire Science)
With so much contention making it impossible to develop any realistic plan to fight global warming it not surprising that the negotiators at COP 27, held in the Egyptian resort city of Sharm el-Sheikh on the Red Sea, spent more of their time tackling a different part of the climate problem. The negotiators concentrated their efforts on the question of how to help those of the poorer countries of the world who are already suffering from climate change. Over the last year the flooding in Pakistan and Niger coupled with severe droughts in east and south Africa have brought attention to the fact that many of the countries that produce the smallest amounts of greenhouse gasses are enduring some of the worst consequences of global warming.
It’s estimated that one third of the nation of Pakistan saw flooding this year, millions suffered and the chances of more of this happening just keeps growing. (Credit: The Diplomat)
For the past thirty years these poorer countries have been pushing the richer countries, who just happen to be the biggest polluters, to establish a reparations fund that will help pay the costs of disaster relief. And for the past thirty years the richer countries have resisted signing a blank cheque that could keep them paying into this fund for decades. Another complication was the status of China, which back in 1995 was still a small economy producing only a small amount of greenhouse gasses but which since then has become the world’s second biggest economy and the biggest emitter of both CO2 and methane. So should China contribute to this fund or should it, and this would be a real farce, actually benefit from such a fund?
China has swiftly become the world’s worst polluter (top), but it’s still considered to be a ‘Developing Country’. The harm the Chinese are doing to their own country is easily seen (bottom). (Credit: Financial Times / New York Times)
Right at the start of COP27 the European Union signaled that they were now ready to support the reparations proposal but the United States was still reluctant. When the US’s chief negotiator, former US Senator John Kerry tested positive for Covid-19 it appeared that the entire conference might end without any real progress.
Former Senator John Kerry is America’s special representative for climate change. He’s pushing hard but there’s only so much one man can do. (Credit: The American University in Cairo)
Only a willingness to extend the negotiations through the weekend allowed the conference to come to an agreement. The world now has an established fund, endowed by most of the world’s richer nations, to help poorer countries pay for the damage done to them by climate change. Before you start thinking that a tremendous achievement was made however bear in mind that the richer nations have yet to announce how they will contribute and for how long and the status of China has yet to be decided.
The poorer nations of the world, who have contributed little to the huge amounts of greenhouse gasses in our atmosphere are nevertheless suffering the most. They want those nations that profited from fossil fuels to pay for the damage. (Credit: WNYC)
The worst part however is that by appearing to make progress on who will pay for the damage caused by climate change absolutely nothing was achieved toward reducing, let alone eliminating the use of fossil fuels for energy production. So the release of greenhouse gasses is going to continue, in fact increase, increasing both the severity and length of the whole problem.
They just keep rising. Greenhouse gasses are being released in ever growing quantities and we’re simply not doing enough to stop the trend. (Credit: Institute for European Environmental Policy)
The final report from COP27 did restate the goal of preventing global temperature rise from exceeding 1.5ºC over pre-industrial levels but it also restates that coal use is to be ‘phased down’ not ‘phased out’. The world still has no agreement on or plan for how to stop making the problem of climate change worse.
The whole world is in this position! (Credit: Shutterstock)
And while the politicians dither more greenhouse gasses are being dumped into the atmosphere every day causing the world’s temperature to continue to rise bringing with it ever more severe climate crisis.
Back when I was in college the standard model of Cosmology consisted of a Big Bang that happened between 10-15 billion years ago. That detonation led to an expansion of the matter in the Universe that could be seen in the red shift of light coming from distant galaxies, the rate of that expansion was given the name ‘Hubble’s Constant’.
No, not that ‘Big Bang’. (Credit: Rotten Tomatoes)This ‘Big Bang’. The evidence for this basic model of how our Universe evolved is now overwhelming. However there are still some discrepancies in the details that could be clues to new Physics. (Credit: Wikipedia)
Even as the Universe as a whole expanded locally matter clumped together due to gravity to form the galaxies and stars we see today. The model also predicted that the force of gravity between the galaxies would slow down the rate of expansion so that today Hubble’s ‘Constant’ would be smaller than it was billions of years ago.
Carl Hubble’s graph from his original 1929 paper where he announced the expansion of the Universe. The general trend of greater velocity with greater distance is easy to see but determining the exact slope of the line is very difficult. We still are having problems with that. (Credit: Universe Today)
The big Question, back when I was in college, was whether or not the force of gravity was strong enough, was there enough matter in the universe to eventually bring the expansion of the Universe to a stop billions or even trillions of years from now. If that happened the Universe would begin to contract until there was a ‘Big Crunch’. Or if there wasn’t enough matter in the Universe then it would just expand forever with all of the stars dying out as they ran out of fuel. A cold, empty Universe that was paradoxically called ‘Heat Death’ because the entire Universe would be at thermal equilibrium so that no work could be done.
Will the expansion of the Universe someday come to a stop and reverse itself into a ‘Big Crunch’ or will the expansion go on forever, maybe even accelerate. That’s the big question right now. (Credit: Astronomy Magazine)
Oh, and then there was something wrong with the way the galaxies behaved, their dynamics. They acted as if they contained more matter than we could see, so astronomers called the problem ‘Dark Matter’. The astrophysicists had a few ideas what Dark Matter could be but really had no evidence to back up their hypothesizes.
Using Newton’s law of gravity and what matter we can see in other galaxies we can calculate what their rotation curves should be. Our measurements don’t match the calculations so something is wrong. ‘Dark Matter’ is the leading theory to explain the discrepancy but it also has problems. (Credit: Universe Today)
Things began to change in the late 1990s as two groups of astronomers led by Adam Riess and Saul Perlmutter tried to answer the question of whether the expansion of the Universe was slowing fast enough to come to a stop. What they found was that the expansion wasn’t slowing at all, it was accelerating.
Along with Brian Schmidt, Saul Perlmutter and Adam Riess recieved the 2011 Nobel Prize in Physics for their discovery of the acceleration of the Universe’s expansion. (Credit: Wired)
Riess and Perlmutter used observations of Type 1 supernovas to make their measurements, see my post of 18 January 2020. Type 1 supernova occur when a white dwarf star steals matter from a nearby companion star. Eventually the white dwarf steals too much matter and explodes as a Type 1. Since all Type 1 supernova happen at the same mass our theories predict that the supernova explosions should all have the same total amount of energy and can be used to measure the distances to other galaxies. That is, if all Type 1’s are the same absolute brightness then if one Type 1 supernova looks brighter it must be closer, if another looks dimmer it must be further away. Whatever it was that was that was pushing the galaxies apart was given the name ‘Dark Energy’ in correspondence with Dark Matter although it is really more of a pressure than an energy.
Type 1 and Type 2 Supernova are very different animals. The interesting thing about Type 1’s are that they all release about the same amount of energy so they can be used as ‘Standard Candles’ to measure distance. (Credit: Lifeng.lamost.org)
Another, more technical problem also came out of the work of Riess and Perlmutter, the value for Hubble’s Constant that they measured over the last few billion years differed slightly from the value obtained by the astrophysicists who studied the Cosmic Microwave Background (CMB), the leftover radiation from the era of the Big Bang itself.
The Cosmic Microwave Background as measured by the Planck satellite. This is our Universe’s baby picture and as such it tells us a lot about what our ‘adult’ Universe should look like. (Credit: European Space Agency)
Now a group of astronomers led by two former students of Riess, Dillion Brout of Harvard’s Center for Astrophysics along with Dan Scolnic of the Department of Physics at Duke University have published a greatly expanded data set of over 1500 Type 1 supernova observations, ten times as many as Riess and Perlmutter gathered. This study has been given the name Pantheon+ and has produced a value for Hubble’s constant over the last 10 billion years of 73.4 kilometers per second per megaparsec with an uncertainly of only 1.3%. This value is significantly larger than the value obtained from the CMB for the early Universe 13 billion years ago.
Compare this graph of the Pantheon+ supernovas with Hubble’s graph above. We’ve learned a lot in the last 90 years but there are still details to be worked out. (Credit: ResearchGate)
These measurements give us the most precise account yet of the effect that Dark Energy has had on the evolution of the Universe. It also solidifies the discrepancy between the measurements of Hubble’s constant using Type 1 supernova and those made using the CMB to a better than one in one million chance of being caused by statistical error.
In physics having enough data to declare 3 Sigma confidence, 99.7%, is considered to be ‘Evidence’ while 5 Sigma, 99.9767% is needed to declare a ‘Discovery’. (Credit: Medium)
So what is going on here? What is causing our models and measurements to differ? Well the simplest answer would be that ‘Dark Energy’ has not been a constant effect throughout the history of the Universe, it’s dynamic, it changes and the results of Pantheon+ can give us some clues as to how it changes with time.
Dynamic simply means changing. For Cosmologists the question of whether ‘Dark Energy’ is dynamic, and if so how it changes, is the Big Question. (Credit: Adam the Automator)
The other possibility is that we’re seeing the first evidence of some completely unknown factor effecting Dark Energy. As you can imagine cosmologists are hoping to avoid that possibility. After all, currently they have no idea what Dark Energy is or if it changes. To assume there’s a yet completely unknown factor effecting Dark Energy would just square the problems we have now.
And then there’s the Dark Matter that astrophysicists first proposed before Dark Energy but which they still have no clear idea of what it is. Dark Matter was supposed to account for why galaxies, like our own Milky Way, are observed to spin faster than they should based on the matter we can see and Newton’s laws of gravity.
As you can see we’ve got a lot of ideas about what Dark Matter could be, and little evidence as to just what it is! (Credit: Physics-APS.org)
Dark Matter therefore was predicted to be some sort of heavy sub-atomic particle that did not react with the electromagnetic field, that is light, and that therefore we could not see. Physicists have been searching for that exotic particle, called a Weakly Interacting Massive Particle or WIMP, since the 1980s and have so far completely failed.
Many experiments, such as Xenon 1T shown here, have tried to discover the elusive Dark Matter particle, none have succeeded so far. (Credit: CERN)
In fact a growing minority of physicists are ready to give up on the whole idea of Dark matter and instead propose that there is something wrong with Newton’s laws of gravity. There are currently many ideas floating around as to how Newton might be wrong and these theories have been given the generic name of MOdified Newtonian Dynamics or MOND.
Modified Newtonian Dynamics or MOND seems to work theoretically but there’s no physical justification for the modifications. It’s all just math that seems to fit the data with no reason as to why! (Credit: Slide Player)
Now a new study of Open Star Clusters in our Milky Way has provided evidence backing some of those MOND theories. The paper comes from researchers at the Helmholtz Institute of Radiation and Nuclear Physics at the University of Bonn in Switzerland.
The Pleiades is an open star cluster that’s easy to see with the naked eye. Known as the seven sisters there are actually hundreds of stars in a family that were born together just a few million years ago. (Credit: Wikipedia)
Open star clusters are the maternity wards of galaxies where gas clouds contract under gravity to give birth to stars. The best-known example of these open clusters are the Pleiades but many are known throughout the Milky Way and neighboring galaxies. After the stellar nursery has given birth to all the stars it can the grouping stays together for a few tens of millions of years as it orbits around the center of the galaxy. Eventually however tidal forces from the billions of other stars in the galaxy cause the stars in an open cluster to drift away, spreading across the galaxy. In fact our own Sun must have once been a member of such a cluster only to have drifted away billions of years ago.
Our Sun follows its own orbit around the center of the Milky Way but once it must have been a part of an open cluster. (Credit: NBC News)
And just as here on earth we have two tides, one rising as the Moon is high in the sky and the other 12 hours later, the tides of the galaxy will pull the stars in an open cluster in a forward direction, relative to its motion around the galactic center, and in a backward direction.
We all know that the tides are caused by the gravity of the Moon and a bit by the Sun but actually every object in the Universe has a gravity that causes a tidal force. (Credit: Time and Date)
Now Newton’s laws predict that the two tides will be of equal strength, with an equal number of stars leaving in each direction. Certain versions of MOND however predict that the forward tide should be just about twice as strong as the backward so that twice as many stars should drift away in that direction.
Newton would predict that the stars leaving an open cluster would do so equally from the front and back but the astrophysicists at the University of Bonn are seeing twice as many leave by the front. Could Newton be wrong? (Credit: Phys.org)
Needless to say trying to determine just which stars that are near an open cluster were actually once members of that cluster is no easy chore but the team from the University of Bonn succeeded with five open clusters and their results, published in the Monthly Notices of the Royal Astronomical Society strongly indicate that some variety of MOND is at work here.
So astronomy and astrophysics today have a couple of really big problems to be solved. Wouldn’t it be interesting if the solution to one problem is also the solution to the other? I mean, what if MOND is that extra factor effecting Dark Energy? We’ll just have to wait and see.
In was during the 1970s that the science of geology was revolutionized by the theory of Plate Tectonics, the idea that the surface of the Earth was cut up into a number of plates that moved relative to each other. As those plates slide past, or butt up against each other mountains rise, volcanoes erupt and earthquakes are generated. There are even places where one plate slides over another causing a ‘subduction zone’ where the deepest parts of the oceans occur. The theory of plate tectonics explains so much of what we see in the rocks around us that it is central to the entire study of geology.
The surface of the Earth is very much like a jigsaw puzzle except that some pieces are getting bigger while others are getting smaller and they’re all pushing and shoving against each other. (Credit: Google Play)
Central perhaps but like most theories plate tectonics is incomplete, there are still some details to be worked out and geologists around the world have been kept busy trying to understand exactly how plate tectonics works. This week’s post is about two such studies.
The major pieces of Earth’s puzzle, the tectonic plates on which the continents ride. (Credit: Earth How)
The first study deals with those subduction zones and how they are generated. The study comes from the Instituto Dom Luiz at the University of Lisbon Portugal along with the supercomputer at the Johannes Gutenberg University in Germany. And, like many scientific studies nowadays, this one uses a computer model to analyze more data than any human being could ever manage to do. In fact the study would not have been possible even with the supercomputer had it not been for the recent development of a much more efficient computational code by the programmers at Johannes Gutenberg.
Modern supercomputers are revolutionizing the way that large scale studies of natural processes are carried out. (Credit: IEEE Spectrum)
Combining the geological expertise of the University of Lisbon with the computing power of Johannes Gutenberg the program was applied to the problem of the development and evolution of subduction zones. For the first time all of the various forces at play at the interface of two plates were taken into account in order to calculate a 3D model of a of how one plate pushes another beneath it down into the Earth’s mantel.
Subduction zones, where one plate is forcing another down into the Earth’s mantel, are regions of great geological activity with earthquakes and volcanoes. (Credit: www.columbia.edu)
Beginning with the many trenches that make up part of the Pacific’s ‘Ring of Fire’ the researchers found that subduction zones follow a rhythmic ebb and flow, with existing trenches slowing in their growth and then being followed by new ones near the same locations. Having used their new model to study the trenches in the Pacific the geologists now hope to apply it to other areas of the Earth like the Caribbean, the Antarctic and even the Atlantic Ocean off of Lisbon. In fact there is evidence that a new subduction zone has started in the waters just off of Portugal, one that may be the beginning of a new ‘Ring of Fire’ that could someday encircle the entire Atlantic Ocean!
The ‘Ring of Fire’ surrounding the Pacific Ocean is formed by all of the plates around the Pacific squeezing in on it! (Credit: National Geographic Society)
Even as one group of geologists learns more about one facet of tectonic activity another, led by scientists at Trinity College in Dublin, Ireland is investigating how plate tectonics contributed to one of the most destructive volcanic events in the history of Earth. Known as the Toarcian period the event happened about 183 million years ago during the Jurassic period. At that time massive volcanic eruptions poured enormous amounts of carbon dioxide into the atmosphere and we all know what that means, global warming and environmental destruction leading to a mass extinction event.
Millions of years after the breakup of the single continent Pangaea, the Toarcian period was marked by a huge increase in volcanic activity releasing enormous amounts of harmful gasses into the atmosphere. (Credit: Nature)
Performing a chemical analysis of samples of mudstone obtained from a 1.5 km deep borehole in Whales researchers were surprised to find that the massive upwelling of magma that triggered the Toarcian event occurred at a time when the movement of the tectonic plates had slowed almost to a stop. That evidence seemed to run counter to common sense, wouldn’t magma pushing up from the Earth’s interior lead to increased tectonic activity?
The recent eruption of the Mauna Loa volcano on Hawaii’s big island is a reminder of the power of molten rock forcing its way up to the Earth’s surface. (Credit: BBC)
But perhaps this is one of those occasions where common sense is simply wrong. Perhaps significant tectonic activity acts as a pressure relief valve releasing energy from beneath so that the magma remains deep below the surface. If that were the case then it would be when the movement of the tectonic plates slows that the magma underneath can build up the pressure to upwell and cause destructive geological events like the Toarcian.
By opening up when the pressure at their intake becomes to high Pressure Relief Valves prevent greater damage from occurring. (Credit: North Ridge Pumps)
The study itself will have to be considered by other geologists but one thing is certain, our planet is a complex, very dynamic place and we still have a great deal to learn from it.
On November 16th, after more than six years of problems, delays and cost overruns, to say nothing of two last minute hurricanes, NASA’s massive Space Launch System (SLS) with it’s Orion man capable capsule was finally launched from Cape Kennedy’s pad 39B. The Artemis 1 mission as the combination is officially designated is an unmanned test of the equipment that will in just a few years take human beings back to the Moon after a more than 50 year absence. In many ways Artemis 1, and its manned successor Artemis 2, are a reboot of the Apollo 8 mission that first took humans to orbit the Moon.
On the Apollo 8 mission Borman (l), Lovell (r) and Anders (c) became the first humans to go to, although they did not land upon, another celestial body as they orbited the Moon. (Credit: National Air and space Museum)
All of this was supposed to happen back in 2016, the huge SLS rocket that serves as the lunch vehicle was going to be easy to design and build. After all the main engines were the same RS25 engines that powered the space shuttle and the solid fuel boosters on each side of the rocket’s core stage were just longer versions of the shuttle’s solid fuel boosters. The problems just kept multiplying however and the delays, and cost overruns caused the program to take twice as long and cost nearly three times what was originally allocated.
The Artemis Program is a scaled back version of the Constellation Program the NASA developed backs in the early 2000s. (Credit: SlidePlayer)
Even once the SLS got to Cape Kennedy the problems continued to pile up with hydrogen fuel leaks alternating with the threat of hurricane winds to cause a series of small delays. Even on the day of launch itself a small hydrogen leak was detected after the SLS had been fueled that required a team of engineers to go out to the pad and tighten some valves on the rocket before liftoff.
As if the engineering problems weren’t enough even the weather caused problems for Artemis 1 as two hurricanes delayed the launch. (Credit: Space Channel)
Still when the countdown went to zero and the engines ignited the SLS, the most powerful rocket ever built, that’s in terms of initial thrust, performed flawlessly, lifting the Orion capsule, its European Service Module (ESM) along with an Interim Cryogenic Propulsion Stage into Earth orbit. So powerful was the takeoff that the mobile launch pad, which had carried Artemis back and forth to the Vehicle Assembly Building several times, was damaged.
Some of the damage sustained by the mobile launch pad used by Artemis 1. (Credit: Florida Today)
Once Orion was in orbit the SLS had completed its task, ten years of costly development for a mere eight minutes of performance. Now the engineers will have to go over the data thoroughly but the big rocket certainly proved that it could do the job it was designed for. Approximately forty minutes after achieving orbit the Interim Cryogenic Propulsion Sage fired its engine for an eight minute burn that sent the Orion capsule and the ESM on an Earth escape trajectory to the Moon.
Years behind schedule and billions over budget at least the Space Launch System (SLS) worked perfectly when it finally did launch. (Credit: Geek Wire)
The rest of the mission is up to the Orion capsule and it’s service module, which was designed and built by the European Space Agency (ESA) as their contribution to the Artemis program. According to the mission plan the spacecraft was to pass behind the Moon and there perform a four minute burn of the ESM’s engine to place Orion in a lopsided retrograde orbit around the Moon that would bring the spacecraft closer than 100 kilometers to the Lunar surface and take it further than 60,000 kilometers. This burn was successfully carried out on the 21st of November.
Currently (3 December) the Orion Spacecraft is in a distant retrograde orbit around the Moon. This orbit was chosen in order to more fully test the capabilities of the Orion capsule and its European built Service Module. (Credit: The Coalition for Deep Space Exploration)
O’k, so what’s a retrograde orbit and why it that important for Artemis? Well if you take your right hand, point your thump up while wrapping your fingers around, see image, and imagine that your thumb is the Sun’s north pole then virtually everything in our Solar System orbits, rotates, spins around the Sun in the direction your fingers point, their angular momentum is counter-clockwise.
Spin can occur in two directions, like your right hand, seen above, or left hand. Because most people are right handed that direction has been defined as positive while left handed is negative. It just so happens that our Solar System as a whole is righted handed. (Credit: Rolling Motion)
Only a few objects, like the spin of Venus on its axis and several of Jupiter’s smallest, and farthest moons rotate in the opposite direction, clockwise and are said to have a retrograde motion. Now the engineers at NASA wanted Orion to be put into this unusual orbit in order to push it a bit, to see if the spacecraft and the ground systems tracking it, could handle the extra strain. This mission is intended to test the equipment after all.
At the farthest point in its orbit from Earth the Orion capsule takes a selfie with the Earth and Moon in the background. (Credit: Friends of NASA)
So the plan was for Orion, with its ESM to orbit the Moon until the 1st of December when a final burn of the ESM’s engine set the spacecraft on a return path back to Earth. Reentry and splashdown are scheduled for December eleventh off the California coast in the Pacific Ocean.
The splashdown of Apollo 11. It’s been a long time since a man capable capsule has returned from the Moon but hopefully that’s about to change. (Credit: DesignNews.com)
If the mission ends as successfully as its gone so far then the Artemis 2 mission is scheduled for sometime in 2024. That mission will be manned and for the first time in fifty humans will return to Lunar Orbit although not actually land on the Lunar surface. That event is going to have to wait for Artemis 3 and the development of a landing module.
While changes could still be made it is expected that the Artemis lander will look something like this. How long its development will take is the big question. (Credit: Space.com)
It’s been along time since humans last walked on the Moon but the Apollo program that put men on the Moon had no plan for a follow up, no intention of staying on the Moon. Artemis may be slower but it is designed as a step-by-step program leading to a permanent base on the Moon. This time we plan on staying.
Paleontology is the science that’s all about origins. Whether it be the origin of life itself or the beginnings of a certain aspect of some living creatures, let’s say warm bloodiness, paleontology seeks to understand when and how the different characteristics that living creatures possess came to be. In this post I’ll be discussing three such important characteristics and as usual I’ll begin in the distant past and work my way forward in time.
O’k ‘The Cambrian Explosion’ is really just a metaphor but the sudden appearance of so many different life forms at the same time was a unique event in the history of life. (Credit: Think Big)
I have mentioned the Cambrian period several times in these posts, see posts of 16 June 2018 and 2 December 2020. The Cambrian is unique in the history of life because that is the time when a large diversity of living creatures first appears in the fossil record, a phenomenon known as the Cambrian explosion. In the fossils from the Cambrian however we can already recognize animals that are clearly molluscs, or echinoderms, or worms, or arthropods. In other words the major groups of animals known as phyla are already distinct, which means a lot of evolution has already happened. If we want to study the relationships between those major groups, say that between the segmented worms and arthropods, we need fossils that are either from before the Cambrian or from a creature in the Cambrian that contains features unique to two or more distinct phyla.
In order to understand how the various phyla of animals are related to each other we either need evidence from before the Cambrian or ‘missing links’ that share characteristics of two or more phyla. (Credit: ResearchGate)
A recent fossil from China falls into that latter category. The creature is a one centimeter long worm like animal covered with both armoured plates and hair like bristles that has been given the name Wufengella. This creature packs a lot of anatomy into its tiny frame linking three different phyla, the brachiopods (bivalved animals that are not related to clams), bryozoans (known as moss animals) and phoronids (horseshoe worms).
Wufengella, from the late Cambrian, appears to be one of those Missing Links, having features of several very different types of creatures. (Credit: Wikipedia)
Brachiopods (l) may superficially look like clams (r) but the animal inside the bivalve shell is completely different, from a different phyla. (Credit: Wikipedia)
The fossil has been dated to 518 million years ago, near the end of the Cambrian period and so therefore it is not a ‘missing link’ ancestor to those three phyla but rather a now extinct cousin of the brachiopods, bryozoans and phoronids who possessed features of them all. The paper describing Wufengella was published in the journal Current Biology and was written by a large group of paleontologists from a number of universities in both China and the United Kingdom illustrating once again the value to science of cooperation between nations no matter what the quarrels created by their governments.
The original fossil of Wufengella (l) and an artists rendering (r). (Credit: Sci.ners)
One anatomical structure that is of critical importance to many animals is the one with which they eat, their jaw. Different types of animals built their jaws in different ways, arthropods for example built their jaws from modified legs, that’s why close ups of insects eating look so creepy to us. Humans and other vertebrates however developed our jaws from bones that originally held our gills in place, that’s why human fetuses still develop gills about five weeks after fertilization, if we didn’t we wouldn’t have either a jaw or an inner ear.
Human Embryos do in fact develop gills and gill slits. That’s where our jawbones came from and where they first appear. (Credit: Vedantu)
In a previous post I discussed how the early jaws of vertebrates evolved and diversified in the Devonian period, some 400 million years ago, see my post of 30 April 2022, but how the very first vertebrate jaw evolved is still a subject of debate among paleontologists. The one thing that was agreed upon was that, since there were so many different vertebrates with so many different sizes and shapes of jaws during the Devonian, the first jaw must have developed before that time, perhaps during the preceding Silurian period, around 440 million years ago.
By the Devonian period many species of fish possessed jaws. This guy’s are quite impressive. In order to find the first fish with a jaw paleontologists have had to go further back, into the Silurian period. (Credit: The applied Ecologist)
Now a series of four papers in the journal Nature have described a series of early species of jawed fish from the Silurian that are so diverse that they may force paleontologists to look even further back for the first jaw, perhaps as far as the Ordovician period some 480 million years ago. The Silurian fossils were unearthed in a pair of fossil beds outside of Chongqing in southern China and contain both cartilaginous fish, like modern sharks and rays, along with bony fish.
The species discovered represent not only a variety of different types of jaws but different body types, from the wide flat bottom dwelling shape of Xiushanosteus mirabilis and Tujiaspis vividus to the sleek, fast swimming shark like shape of Shenacanthus vermiformis and Fanjingshania renovata. With so much diversity it is obvious that the fish unearthed in China have a lot of evolution behind them, meaning that paleontologists will have to look even further back in time, to the Ordovician period in order to understand how the earliest members of our own phyla came into being.
With a life style that probably resembled a founder’s Xiushanosteus mirabilis already had a well developed jaw when it lived during the Silurian. (Credit: The New York Times) Shenacanthus vermiformis was a very different kind of fish but, like X mirabilis it too had a well developed jaw. So the common ancestor of this two species, the first jawed vertebrate, must have lived even earlier. In the Ordovician perhaps? (Credit: The New York Times)
Moving forward in time another important innovation in vertebrate animals is the wing, which has allowed thousands of different species to fly. Nowadays when we think of wings we think of birds or bats but they weren’t the first vertebrates to fly, that honour belongs to the family of lizard-like contemporaries of the dinosaurs known as the Pterosaurs.
The Pterosaurs were a large and diverse group of flying reptiles during the age of the dinosaurs but they were not themselves dinosaurs. (Credit:Wikipedia)
Now a reexamination of fossils discovered a hundred years ago in Scotland may have identified the pre-flying ancestors of the pterosaurs. Known as Scleromochlus taylori the small reptile went unappreciated in part because of the incredibly hard 237 million year old limestone blocks in which it was encased.
Not a very impressive creature the small 237 million year old reptile Scleromochlus may have been the common ancestor of the pterosaurs. (Credit: The Indian Express)
The question of how the pterosaurs evolved to fly has been debated as long as how the birds first flew and with pretty much the same arguments. Most paleontologists thought that tree climbing reptiles who began gliding from branch to branch eventually developed leathery wings which they starting flapping for powered flight. The fossils of S taylori however tell the story of a small, fast running ground runner.
Fossils in Limestone can be almost perfectly preserved, but are a bitch to get out of the rock. No wonder it took a long time to discover just exactly what S taylori was. (Credit: Wikimedia Commons)
The researchers at Edinburgh University discovered the connection between S taylori and pterosaurs only when they performed CT scans of the limestone encased fossils revealing for the first time some of more delicate details of the animal’s anatomy. Details like a head too large for its body and a femur with a hook to it that fits into a slot in the hip so that the animal’s legs go straight downward instead of sidewards like a lizard’s or crocodile’s.
Nowadays paleontologists use advanced technology in order to learn everything they can about their fossils. (Credit: Rapid City Journal)
S taylori was a runner, catching insects near the ground and maybe it started using flaps on its forearms to help it catch its prey. Flaps that got larger and larger until the creature took off like…well, like a pterosaur!
The pterosaurs were the largest animals to ever fly. The sight of one of these babies soaring overhead would have put an eagle to shame! (Credit: Biosphere Magazine)
By studying the anatomy of ancient life paleontologists not only learn about the lives of creatures of the past but of how different species relate, the family tree of life on Earth.
Nowadays we’re all used to seeing beautiful images of astronomical objects, whether from Hubble or now James Webb or from some other observatory. To my mind however, nothing beats seeing the planet Saturn with your own eyes through even a small telescope. Somehow looking through a telescope is different; maybe it’s the movement of the air causing a little shimmer that makes it seem different from an image.
A beautiful image of the planet Saturn even showing a ring of Aurora around the south pole. (Credit: Hubble Space Telescope)
Of course it’s the rings that make Saturn the most beautiful planet to see. They just seem so unreal, fairy like in a sense. And in a telescope they seem to be as solid as the planet they circle, even though in your mind you know that they are actually made up of trillions, hey millions of trillions of small snowballs. Each snowball a separate moon with its own orbit around Saturn.
From here on Earth it looks like Saturn only has a few rings but up close it’s easy to see hundreds if not thousands of small ringlets in this enhanced image taken by Voyager 2. (Credit: NASA Space Place)
Back before the space age it was thought that only Saturn had rings, you couldn’t see any around any other planet using the telescopes of the 1950s or earlier. Some astronomers claimed to see faint rings around Uranus but it wasn’t until 1977 that observations by James Elliot, Jessica Mink and Edward Dunham convinced the astronomical community that Uranus did indeed have rings. Then in 1979 as the Voyager 1 space probe was flying by Jupiter a couple of its images of the giant planet showed a faint ring system, a discovery that Voyager 2 would confirm a few months later. Finally in 1989 Voyager 2 found that the last of the solar systems gas giants, Neptune also had a set of rings. Since all of the solar systems giant planets are now known to have rings astronomers have begun to wonder if there is some connection, do all gas planets, even those in other solar systems, have rings.
After Saturn the planet Uranus has the best set of rings as seen in this Hubble image. (Credit: Universe Today)
Which of course begs the questions, why do any planets have rings? How do rings form, and how long do they last. Since we’ve never actually seen a ring system forming we really only have theories and educated guesses and astronomers have argued for decades over the details.
One thing we do know about planetary rings is that they are not solid but made up of billions and billions of small moonlets. (Credit: Shutterstock)
For a big ring system like Saturn’s the leading theory has always been that one of the planet’s moons got too close and was disintegrated by tidal forces generating the trillions of particles making up the rings. As I said that theory has been around for nearly a hundred years but now a new analysis by a team of astrophysicists at MIT is using data collected by the Cassini spacecraft that studied the Saturn system between 200 and 2017.
Two major models for how Saturn’s rings formed. Either a moon got to close to Saturn and was pulled apart by tidal forces or an object from the Kuiper belt got to close. (Credit: Science)
As you may remember, NASA ended the Cassini mission by taking the space probe closer and closer to the giant planet until it finally burned up in Saturn’s atmosphere. By tracking Cassini’s path as it got closer and closer the researchers were able to actually measure the distribution of Saturn’s mass within its body, in other words how much of Saturn’s mass was deep in the planet’s core, how much near the surface etc.
The Cassini spacecraft studied Saturn and its moons for thirteen before plunging itself into the giant planet’s atmosphere and burning up! (Credit: Jet Propulsion Labouratory)
That distribution, technically known as the ‘moment of inertia’ was the missing piece of the puzzle to carry out hundreds of computer simulations of an ancient moon of Saturn, which has been given the name of ‘Chrysalis’ being torn apart by the planet’s gravity to form the rings. According to the simulations Chrysalis was about the size and mass of Saturn’s remaining moon Iapetus, about 700 km in diameter. What happened to Chrysalis is that roughly 160 million years ago the gravity of Saturn’s big moon Titan sent Chrysalis too close to the planet where it broke up. So our best estimate now is that Saturn’s big, beautiful ring system probably formed during the age of the dinosaurs!
The beginning of the end for Chrysalis? That’s the leading model for where Saturn’s rings came from. (Credit: PBS Learning Media)
The same thing may happen before too long, cosmically speaking with another moon around planet in our solar system. Phobos, the larger, closer moon of Mars is getting ever closer because of tidal forces drawing it towards the planet. It has been estimated that in about 50 million years Phobos will start to break apart giving Mars a ring system of its own.
Phobos, the bigger, and closer moon of Mars. Are those lines stretched across the moon’s surface signs that Phobos is being pulled apart? Astronomers think that may be so! (Credit: NASA)
Before I go I would like to mention several news stories that have been circulating about the eventual fate of our own planet Earth. According to the stories, based on a paper published in the Astrophysical Journal, as the Sun uses up its hydrogen fuel its core will shrink and grow hotter until it begins to burn helium as a fuel. As the core gets hotter the outer surface of the Sun will expand turning the Sun into a red giant star like Betelgeuse or Antares. As the Sun’s atmosphere expands it will engulf the planets Mercury and Venus and perhaps even our Earth. the news stories hasten to assure their readers that these events will not occur for another 4-5 billion years.
When a star runs out of its hydrogen fuel it begins to burn helium. That causes the star to puff up and become a red giant star. The familiar stars Betelgeuse and Antares are both red giants. (Credit: Forbes)
Well actually that’s all been known since about the 1950s when astrophysicists combined the data from the Hertzprung-Russell diagram with nuclear research to determine the life cycle of stars. That was when the idea that our Sun was a ‘main sequence’ star with a life span of about 10 billion years and was about half way through that span was developed. After the main sequence our Sun will have just about one billion years as a red giant. The question of whether or not the Sun will expand enough to devour the Earth has been debated now for more than 60 years.
The Hertzprung-Russell diagram of star absolute brightness versus surface temperature. This diagram was instrumental in understanding the life cycle of stars. (Credit: Center for Astrophysics and Supercomputing)
What the new study was actually about was what would happen to those planets, Mercury and Venus and maybe Earth, that are engulfed by the Sun as it grows. Once again computer simulations were carried out giving a range of possible fates for those planets but anyway you look at it the planets will certainly be destroyed.
Astronomers think that about 5 billion years from now, as the Sun becomes a red giant, there’s about a 50-50 chance that our Earth will be devoured. In either case our planet won’t be a pleasant place to live anymore! (Credit: Forbes)
The first season of HBO’s new series ‘House of the Dragon’ has finished and so I’ll take this opportunity to give my two cents worth. As I’m sure everyone reading this post knows ‘House of the Dragon’ (HOD) is a prequel to HBO’s massively successful series ‘Game of Thrones’ (GOT) and the network hopes to capitalize on the popularity of its biggest ever hit.
HBO’s House of the Dragon (HOD) is the prequel to the network’s hugely successful Game of Thrones (GOT) with much of the same production staff and even input from the creator of GOT George R. R. Martin. (Credit: IGN Nordic)
As a prequel HOD is more constrained in what new ideas can be portrayed than could be done in a sequel. For example, since in the final season of GOT the supernatural creatures the ‘White Walkers’ were totally defeated and destroyed a sequel could replace them by introducing a completely new supernatural foe, maybe some sort of amphibious creature or bat like people. A prequel on the other hand cannot introduce anything too important that’s completely new without explaining why that new thing never got mentioned in the original show.
As a prequel HOD cannot introduce any new ideas or important characters that would cause anachronisms (literally out of time) in the already broadcast GOT. (Credit: IMDB)
HOD definitely succeeds in not going outside the bounds of a prequel. In fact it may succeed too well because whereas GOT is a sprawling tapestry of many stories woven into one, HOD is much more narrow in theme, too narrow in my opinion.
HOD is really just a family squabble played out across the background of seven kingdoms. Nevertheless by concentrating on a single family it loses much of the complexity and variety that made GOT so interesting. (Credit: IMDB)
Season one of HOD concerns itself with the political intrigue between two branches of the Targaryen dynasty that rules the ‘Seven Kingdoms of Westeros’. In HOD the Targaryen family rules Westeros because they control the dragon’s that are by far the most fearsome weapon in the whole GOT Universe.
Since their power comes from their dragons the Targaryen family has taken to revering, almost deifying the creatures. By the way many people have begun to criticize the cinematography of HOD as simply being so dark it’s hard to see what’s happening! (Credit: NPR)
King Viserys Targaryen is the fifth king of that line and when his wife dies in childbirth Viserys names his daughter Rhaenyra as his heir rather than his hot-tempered brother Daemon. Things get even more complicated when Viserys marries a second time to the lady Alicent Hightower who bears the king two sons. The marriage between the old king and the young noblewoman was the contrivance of Alicent’s father Ser Otto Hightower, the king’s first minister, known as ‘the Hand’. Ser Otto seeks to increase his own power by putting his grandson on the iron throne as king. It’s in episode 9, when King Viserys dies that the peace of Westeros unravels as the various claimants grab for power.
As HOD begins the young noblewomen Rhaenyra Targaryen and Alicent Hightower are the best of friends. That doesn’t last long however, not when there’s the throne to be taken. (Credit: Vanity Fair)
And so we have a tale of political intrigue worthy of GOT, but GOT was about a lot more than just than just political intrigue. In GOT in addition to the fight over the iron throne after the death of King Robert Baratheon between House Stark and House Lannister there were the adventures of Daenerys Targaryen across the narrow sea in Pentos, there were the adventures of Jon Snow beyond the Wall in the north, and there were the adventures of Arya Stark with the Assassins, plus a lot more.
George R. R. Martin freely admits that much of his inspiration for GOT came from England’s ‘War of the Roses, a war for the English throne between two branches of the same family. GOT however also went beyond that simple conflict to explore a unique and interesting world while HOD is just a family quarrel. (Credit: Ancient Origins)
There was also a lot more magic, whether it be Bran Stark with the Raven’s eye, or the witch Melisandre along with the religious fanaticism of the High Sparrow, and I’ve already mentioned the demonic White Walkers. In other words there were a lot of things going on at once, I haven’t mentioned a tenth of everything that happened in GOT and trying to keep it all straight was part of the fun. If one story ever got a little boring there were a half dozen other stories to keep your interest.
In GOT the gift of clairvoyance was represented by the three eyed raven (r). Bran Start (l) had it. Aside from dragons there’s a lot less magic in HOD. (Credit: Diply)
HOD isn’t that complicated, and therefore it just isn’t that fascinating. It also isn’t as surprising as GOT was, remember the Red Wedding! A lot of things happened in GOT that were totally unexpected, but that certainly isn’t true of HOD where everything is pretty much predictable. In fact we’re told about Ser Otto Hightower’s plans to put his grandson on the throne at least a dozen times over five episodes before the king dies.
GOT’s ‘Red Wedding’ just before the blood starts to flow. GOT made a point of killing off major characters suddenly and sometimes almost pointlessly, in a sense almost like real life. HOD hasn’t shown that same spontaneity however. Everything that happens is is pretty much telegraphed well ahead of time. (Credit: Herald Sun)
I’ll add one more criticism, at the beginning of GOT we’re told that the Night’s Watch who guard the northern wall are just a shadow of their former glory and at the same time GOT starts with no dragons still alive. Well, when I heard that they were doing a prequel I was hoping to see the Night’s Watch at full strength and learn a little about what happened to the dragons. So far I’ve been disappointed on both counts.
Winter is Coming. In GOT the Night’s Watch were tasked with guarding ‘The Wall’ that kept the wild peoples and supernatural creatures of the north out of the ‘Seven Kingdoms of Westeros’. (Credit: winteriscoming.net)
Now this is only the first season of HOD, and to be honest GOT got a lot better in season 2. Still HOD seems to be much more committed to its main story and when that story sags the whole show becomes uninteresting. And that’s one thing Game of Thrones never was.
