Category: consciousness

Dan and Lexi

Just a reminder of how we treasure our dogs.

I was speaking two days ago to my friend Dan of many, many years, and also my best man when Jeannie and I were married in 2010, and we were talking of our dogs. In the conversation Dan said this:

You know that Lexi and I are always together for practically twenty-four hours a day!

Dan went on to say that Lexi followed him everywhere and that, literally, they were together for ninety-nine percent of their time.

I asked Dan to send me a photograph of the two of them. Here it is!

Beautiful beyond words.

(And call by tomorrow for some special words about close friends.)

There’s no limit to the care of dogs

For as long as I live I will never stop marvelling at dogs.

Dogs are many things. In a sense they have as many likes and dislikes as us humans. But the one thing that is unique to these beautiful animals is their unconditionality. That, especially, shows through in the way that they care and love the humans and dogs around them.

This story on The Dodo emphasised that special way they care for their fellow dogs. Read it and you will see what I mean.

ooOOoo

Camera Catches Dog Bringing His Bed To His Sick Brother So He’s Comfy

“As he’s dragging it he’s looking at Roman almost to say, ‘This is for you’”

By Caitlin Jill Anders
Published on 6/18/2020

From the moment they became brothers, Spanky has always adored and looked up to his big brother Roman. He follows Roman everywhere he goes, and is always happiest whenever they’re together.

“Roman is definitely Spanky’s security blanket,” Jackie Rogers, Roman and Spanky’s aunt, told The Dodo. “Spanky will do nothing without Roman and always makes sure he is close to him and if he’s not he gets up and goes near him.”

JACKIE ROGERS

About two weeks ago, Roman’s ear started looking a little puffy and infected, so his mom took him to the vet and discovered he has a hematoma on his ear. They scheduled a surgery to take care of it, but unfortunately, while he waited for the surgery, his ear kept getting worse and poor Roman got more and more uncomfortable.

JACKIE ROGERS

At first, Spanky didn’t notice anything was different, but as Roman’s ear got worse, everyone noticed that Spanky was much more gentle and concerned about his best friend.

“We had to take him back to the vet to confirm he could wait five more days for surgery and I brought Spanky along for the ride, but due to COVID we couldn’t go inside with Roman and for 20 minutes Spanky sat in the car crying/whining/barking until Roman got back,” Rogers said.

JACKIE ROGERS

With the surgery set, all the family could do for Roman was to let him rest. During the day while everyone is at work, the family has a Ring camera set up so they can check in on the dogs, which is especially important now so they can make sure Roman is OK. Rogers was checking the camera recently when she noticed Spanky watching his brother lying on the floor, looking very concerned — and then he did the cutest thing.

“I see Spanky pacing for a minute while looking at Roman and then the bed and then I see him dragging the bed to Roman and as he’s dragging it he’s looking at Roman almost to say, ‘This is for you,’ and then the next clip is them snuggling,” Rogers said. “I had to re-watch it multiple times, I was in disbelief that he did that!”

Spanky was worried about his brother and wanted him to be as comfortable as possible, so he brought his bed to him so he wouldn’t have to move — because that’s how much he loves his big brother.

JACKIE ROGERS

Spanky brought the bed over to Roman around 10 a.m., and when Rogers got home that evening, they were still snuggled up there together. Spanky knows his brother isn’t feeling well, and he’s determined to stay by his side until he’s feeling better — and will do anything he can to make sure he’s safe and comfortable in the meantime.

ooOOoo

There’s no real way that words can explain that. It’s beautiful, loving and caring and just goes to show how the loving bond works in practice.

Fabulous creatures!

Picture Parade Three Hundred and Sixty-Seven.

But first this amazing photograph!

A lightning strike over the province of Batangas during the eruption of the Taal volcano in Philippines, January 2020 (Credit: Domcar C Lagto/Pacific Press via Alamy)

From the BBC:

Eruption of Taal Volcano in Philippines, January 2020

Volcanic lightning occurs when fragments of propelled ash (including glass, ice, and rock) spark against each other in the violent plume that rises above an erupting volcano. The First-Century Roman writer Pliny the Younger is credited with recording the earliest-extant account of a so-called ‘dirty thunderstorm’ after witnessing the eruption of Mount Vesuvius in 79 AD. “A dreadful black cloud,” Pliny observed in a letter to Tacitus, “was torn by gushing flames and great tongues of fire like much-magnified lightning.” Photos taken in January 2020 of a similar display near Manila, Philippines when Taal Volcano erupted captured the world’s attention. The intense gnashing of darkness and light preserved by the images recalls the cataclysmic beauty of The Destruction of Pompei and Herculaneum, the Romantic artist John Martin’s 1822 painterly recreation  of the ancient dirty thunderstorm that Pliny the Younger saw with his own eyes.

This is a copyrighted photograph and I may have to remove it pretty damn quickly.

So on to dogs!

Again taken from Pexels.

oooo

oooo

oooo

oooo

oooo

oooo

That’s it, good people, for another week.

It’s all too much, or it could be!

This year, 2020, has been unlike any other year.

I am not saying anything new but just reiterating what has been said before: 2020 is going to go down as the year from hell! And I don’t think that is too strong a word!

Part of it are the news stories that sweep the world: Covid-19; Brexit; Climate change; up until yesterday what was President Trump going to do in his last few weeks; etc; etc.

Also part of it is the way that news and more news and, yes, more news is flashed around the globe. Most of it bad news as we all know that bad news sells!

Finally, part of it is the new world of social media especially messaging on a smartphone. President Trump isn’t the only one to communicate greatly via Twitter.

Now, speaking personally, I couldn’t have got through this year without Jeannie and our dogs.

Pure bliss!

But, nevertheless, something has changed and Mark Satta has written an article that tries to explain things.

ooOOoo

Three reasons for information exhaustion – and what to do about it

By Mark Satta, Assistant Professor of Philosophy, Wayne State University.

November 18th, 2020

An endless flow of information is coming at us constantly: It might be an article a friend shared on Facebook with a sensational headline or wrong information about the spread of the coronavirus. It could even be a call from a relative wanting to talk about a political issue.

All this information may leave many of us feeling as though we have no energy to engage.

As a philosopher who studies knowledge-sharing practices, I call this experience “epistemic exhaustion.” The term “epistemic” comes from the Greek word episteme, often translated as “knowledge.” So epistemic exhaustion is more of a knowledge-related exhaustion.

It is not knowledge itself that tires out many of us. Rather, it is the process of trying to gain or share knowledge under challenging circumstances.

Currently, there are at least three common sources that, from my perspective, are leading to such exhaustion. But there are also ways to deal with them.

1. Uncertainty

For many, this year has been full of uncertainty. In particular, the coronavirus pandemic has generated uncertainty about health, about best practices and about the future.

At the same time, Americans have faced uncertainty about the U.S. presidential election: first due to delayed results and now over questions about a peaceful transition of power.

Experiencing uncertainty can stress most of us out. People tend to prefer the planned and the predictable. Figures from 17th-century French philosopher René Descartes to 20th-century Austrian philosopher Ludwig Wittgenstein have recognized the significance of having certainty in our lives.

With information so readily available, people may be checking news sites or social media in hopes of finding answers. But often, people are instead greeted with more reminders of uncertainty.

As Trump supporters denounce the 2020 election results, feelings of uncertainty can come up for others. Karla Ann Cote/NurPhoto via Getty Images

2. Polarization

Political polarization is stressing many Americans out.

As political scientist Lilliana Mason notes in her book, “Uncivil Disagreement: How Politics Became Our Identity,” Americans have been increasingly dividing politically “into two partisan teams.”

Many writers have discussed the negative effects of polarization, such as how it can damage democracy. But discussions about the harms of polarization often overlook the toll polarization takes on our ability to gain and share knowledge.

That can happen in at least two ways.

First, as philosopher Kevin Vallier has argued, there is a “causal feedback loop” between polarization and distrust. In other words, polarization and distrust fuel one another. Such a cycle can leave people feeling unsure whom to trust or what to believe.

Second, polarization can lead to competing narratives because in a deeply polarized society, as studies show, we can lose common ground and tend to have less agreement.

For those inclined to take the views of others seriously, this can create additional cognitive work. And when the issues are heated or sensitive, this can create additional stress and emotional burdens, such as sadness over damaged friendships or anger over partisan rhetoric.

3. Misinformation

Viral misinformation is everywhere. This includes political propaganda in the United States and around the world.

People are also inundated with advertising and misleading messaging from private corporations, what philosophers Cailin O’Connor and James Owen Weatherall have called “industrial propaganda.” And in 2020, the public is also dealing with misinformation about COVID-19.

As chess grandmaster Garry Kasparov put it: “The point of modern propaganda isn’t only to misinform or push an agenda. It is to exhaust your critical thinking, to annihilate truth.”

Misinformation is often exhausting by design. For example, a video that went viral,Plandemic,” featured a large number of false claims about COVID-19 in rapid succession. This flooding of misinformation in rapid succession, a tactic known as a Gish gallop, makes it challenging and time-consuming for fact checkers to refute the many falsehoods following one after another.

What to do?

With all this uncertainty, polarization and misinformation, feeling tired is understandable. But there are things one can do.

The American Psychological Association suggests coping with uncertainty through activities like limiting news consumption and focusing on things in one’s control. Another option is to work on becoming more comfortable with uncertainty through practices such as meditation and the cultivation of mindfulness.

To deal with polarization, consider communicating with the goal of creating empathetic understanding rather than “winning.” Philosopher Michael Hannon describes empathetic understanding as “the ability to take up another person’s perspective.”

[Deep knowledge, daily. Sign up for The Conversation’s newsletter.]

As for limiting the spread of misinformation: Share only those news stories that you’ve read and verified. And you can prioritize outlets that meet high ethical journalistic or fact-checking standards.

These solutions are limited and imperfect, but that’s all right. Part of resisting epistemic exhaustion is learning to live with the limited and imperfect. No one has time to vet all the headlines, correct all the misinformation or gain all the relevant knowledge. To deny this is to set oneself up for exhaustion.

ooOOoo

That last section, What to do?, is full of really sensible advice. In fact, the American Psychological Association has an article at the moment that appears to be freely available called Healing the political divide.

I intend to read it.

It finishes up saying:

Scientists must strive to share their research as broadly as possible. And they don’t have to do it alone. Organizations like More in Common work to conduct research and communicate findings to audiences where it can have the greatest impact.

Advocacy is essential as well. Other countries that have made strides in addressing the political divide relied heavily on government-led reconciliation efforts. The Truth and Reconciliation Commission, for example, in South Africa, has been fundamental in addressing disparities and conflict around Apartheid.

Were the United States to consider similar, government-backed efforts, psychologists must be part of the call to do so. And the behavioral expertise of the field would be central to success.

“The collective mental health of the nation is at risk,” says Moghaddam. “Just as we should rely on epidemiological science to tell us when there is a vaccine ready for mass use, we have to rely on psychological science to guide us through these mental health issues.”

And following an election that, for many, has felt like the most polarized of a lifetime, this piece seems critical. “ This is what our profession is all about,” says Moghaddam.

Good advice especially if you can take time off just losing oneself in nature.

Dawn behind nearby Mt. Sexton. Taken from our deck on the 21st August, 2019.

Enough said!

Of dogs and men.

Ancient genomes reveal the common history of human and dog.

At the end of October, 2020 Science magazine published an article about the evolutionary genetics of humans and dogs.

I am not allowed to republish the full text, despite being an AAAS member, but I am sure that selected quotes will be alright.

The article was written by Pavlos Pavlidis and Mehmet Somel.

Dogs likely evolved from a wolf population that self-domesticated, scavenging for left-overs from Palaeolithic hunter-gatherers in Eurasia. However, the exact timing and geographic location where the dog lineage started remain unknown, owing to the scarcity of Palaeolithic dogs in the archaeological record. Analyses of genetic data suggest that dog-wolf divergence took place ~25,000 to 40,000 years ago, providing an earliest possible date for dog domestication.

The last paragraph in the short article is as follows:

For example, there is evidence that pigs were domesticated in both Anatolia and China. For dogs, however, the story is different. Dogs and modern-day Eurasian grey wolves appear as monophyletic groups; that is, any dog is genetically closer to another dog than to a wolf, and vice versa, Monophyly supports a single origin of dogs from a possible extinct wolf lineage.

Absolutely fascinating!

A couple of photographs, courtesy of Pexels, to close the piece.

The wolf

oooo

The dog.

See you tomorrow.

Picture Parade Three Hundred and Sixty-Four

There’s a theme to this week’s Picture Parade.

First of all I must again thank Pexels for providing these photographs. They are from a grouping called Man’s Best Friend.

This is the theme. That dogs are our closest and longest animal companions by far. Indeed, the era that humans befriended wolves is so long ago that an exact time is far from settled. Here’s a piece in the August 2020 issue of Scientific American magazine:

In the 14,000 to 40,000 years during which this domestication process occurred, wild wolves were probably doing better than dogs in terms of numbers – after all, our dogs were probably another food source for humans when times became lean. The first written record of a wolf hunt was recorded in the sixth century B.C.E., when Solon of Athens offered a bounty for every wolf killed.

So in all these photographs today there is a human with the dog!

oooo

oooo

oooo

oooo

oooo

oooo

oooo

Fabulous even though I say it myself!

Ageing gracefully applies to our dogs as well.

Another guest post from John Brooks.

This is an argument from John to consider dogs that are well past their prime.

It’s a good article. You will enjoy reading it and may learn something; I certainly did!

ooOOoo

Here’s Why Senior Pets Have Lots To Offer

As you may or may not know, we’ve recently celebrated Adopt a Less-Adoptable Pet Week. During this week, animal rescues around the globe join together to raise awareness about the benefits of adopting pets that society deems as ‘less adoptable’ – and sadly, senior pets make the list.

We think that senior pets are just as loving, sweet and great companions as their ‘adoptable’ counterparts. But despite the many benefits of owning a senior pet, most families choose younger pets when adopting. With that in mind, here’s why we believe seniors deserve a second look and a fur-ever home.

Why you should consider a senior pet
Since the onset of the pandemic, the number of families adopting and fostering pets since the enforcement of COVID-19 restrictions has risen dramatically across the globe. Near the commencement of stay at home orders, RSPCA received 1,600 adoption applications in a single week of April—a 45% increase in dog adoptions and a 20% increase in cat adoptions compared to 2019.

Senior pets (and other less-adoptable animals) typically spend four times as long in a shelter as a healthy, younger pet. In the U.S. alone, about 400,000 senior pets die in a shelter. Though most people do seek a puppy or kitten when adopting, families would benefit in many ways from choosing an older pet. Here’s why.

Better manners
Older pets are well past the playful, chew-everything, get-into-anything stage. Older dogs and cats sleep for 20 hours a day or more, rousing just long enough for a conversation, to greet visitors, or have a meal. They are also probably house-trained, dog-door trained, and have formal or informal obedience training.

They are much more likely to come when called, which means they are at less risk of danger younger pets encounter when escaping their yard and wandering the streets.

Easier to train
For the older dog with less than perfect manners, training is typically more straightforward. They are more focused and eager to please than puppies with short attention spans. Senior animals are smarter and more experienced, and this can mean they acclimate more quickly to the house and how the household operates.

Done growing
One of the best parts about adopting a senior is they have finished growing, and the new family knows exactly how large the pet is. When adopting a puppy, owners are often surprised at how large the dog becomes or how little it grows. With an older dog, there will be no surprises.

Seniors make better companions for seniors
Senior pets usually move at a slower pace, which makes them a better choice for older people, especially those with limited mobility or disabilities. The new owner is less likely to be toppled by a dog jumping up. It’s also safer for those that allow their pets to sleep with them. An older dog is less likely to be rambunctious and cause injury to a sleeping adult.

Laid-back company
Senior pets are content to stay close to home or in the house for the majority of the day. They are more likely to be found soaking up a sunbeam on a cosy patch of carpet than barking wildly at everything and everyone crossing past the front window.

Senior dogs are also far less distracted when out for a walk. Though they may perk up at the sight of another dog, they are less likely to drag the owner down the sidewalk in pursuit. They also walk slower, and at a pace their owner matches.

Gratitude and devotion
Senior dogs spend up to four times as long in a shelter, so when they finally find a furever home, their gratitude runs deep, and it shows. They give unconditional love and devotion and look after their families. Often they will attach to a family member and stay close at all times, moving with them from room to room. They take full responsibility for their welfare and provide comfort with a warm, wet kiss.

Years of happiness
At seven years old, most dogs and cats are considered senior. Cats often live to be 15 or even 20 years so that the owner can expect a long life with their new friend. Depending on the breed and size, dogs too can live 15 or more years. So while adopting a senior dog will mean you may spend slightly less birthdays together, you’ll still be blessed with some wonderful years and memories.

Despite the many benefits of owning a senior pet, families also worry about the costs associated with maintaining their pet’s health. Dental cleanings, blood work, and annual shots can quickly add up, but younger animals have just as many health risks and are more likely to be involved in accidents.

Final thoughts
Fostering helps many people feel fulfilled because they are making a significant contribution to a pet’s life. For them, seeing their foster move on to their forever family is reward enough. Don’t be surprised though if fostering leads to adoption. That’s always a great outcome for all involved.

ooOOoo

In the U.S. alone, about 400,000 senior pets die in a shelter.

Among the many interesting aspects of this post, for me the statement above that I have put into italics jumped off the page at me. What an appalling waste!

But coming back to the complete article it offers many aspects of something that I had hitherto not thought about. I suspect that I am not the only one!

We, too, have a senior foster dog. She is Sheena and is 12 years of age. We love her and there is no question of Sheena going back to the kennels.

Once again, let me offer a bit of background on John.

John Brooks is the Professional Content Marketer. He writes a lot of articles on his carrier. Last one year he is working with Orbeen.com as a digital marketing expert. The company provides various types of Digital Marketing services i.e, Search Engine Optimisation (SEO), Search Engine Marketing (SEM), Social Media Optimization (SMO), Web design & development, Link Building, Content Marketing & blogger outreach.

Fabulous!

 

Simply in awe!

It’s both beautiful and yet beyond comprehension.

When we have a clear night there are two occasions for me to gaze upwards and become lost in thought. One is in the evening when the dogs are outside just before going to bed. The other is in the morning because we are usually awake well before sunrise.

We are very lucky in that there is no light pollution locally.

So, in the evening, while I look at the broad expanse of stars, my eyes are drawn to the Big Dipper and to Orion.

In the morning, when we look to the East there is Venus sparkling bright in the night-sky over the hills.

I still vividly remember all those years ago when I was sailing in the Western Mediterranean coming on deck in the middle of the night to find the stars down to the horizon all 360 degrees about me. I am sure it will be one of the last memories of mine just before I die! I hope so!

But I speak of the solar system. Here’s an article that was recently published by EarthSky that goes way beyond the solar system. It is a wonderful essay and almost mystical.

ooOOoo

What is a galaxy?

Posted by in ASTRONOMY ESSENTIALS, September 25, 2020

We live in a galaxy called the Milky Way. But there is so much more to know about these grand and glorious star islands in space! Click in here, and prepare to have your mind expanded.

This is a giant galaxy cluster known as Abell 2744, aka Pandora’s Cluster, located in the direction of the constellation Sculptor. The cluster is about 4 million light-years across and has the mass of 4 trillion suns. It appears to be the result of a simultaneous pile-up of at least 4 separate, smaller galaxy clusters that took place over a span of 350 million years. Read more about this image at HubbleSite. Image via NASA/ ESA/ J. Lotz/ M. Mountain/ A. Koekemoer/ the Hubble Frontier Fields Team.

A galaxy is a vast island of stars in an ocean of space. Galaxies are typically separated from one another by huge distances measured in millions of light-years. Galaxies are sometimes said to be the building blocks of our universe. Their distribution isn’t random, as one might suppose: galaxies are strung out along unimaginably long filaments across the universe, a cosmic web of star cities.

A galaxy can contain hundreds of billions of stars and be many thousands of light-years across. Our own galaxy, the Milky Way, is around 100,000 light-years in diameter. That’s about 587,900 trillion miles, nearly a million trillion kilometers.

Galaxies are of widely varying sizes, too.

There are an estimated two trillion galaxies in the universe.

Illustration showing snapshots from a simulation by astrophysicist Volker Springel of the Max Planck Institute in Germany. It represents the growth of cosmic structure (galaxies and voids) when the universe was 0.9 billion, 3.2 billion and 13.7 billion years old (now). Image via Volker Springel / MPE/ Kavli Foundation.

Galaxies group together in clusters. Our own galaxy is part of what is called the Local Group, for example: a cluster comprising 55 galaxies that we know of so far.

In turn, galaxy clusters themselves group into superclusters. Our Local Group is part of the Virgo Supercluster.

The “glue” that binds stars into galaxies, galaxies into clusters, clusters into superclusters and superclusters into filaments is – of course – gravity, the universe’s construction worker, which sculpts all the structures we see in the cosmos.

Distances from the Local Group for selected groups and clusters within the Local Supercluster, which is called the Virgo Supercluster.

There are several basic types of galaxy, each containing sub-types. Galaxies were first systematically classified, based on their visual appearance, by the famous astronomer Edwin P. Hubble in the late 1920s and 30s, during years of painstaking observations. Hubble’s Classification of Galaxies, as it is known, is still very much in use today, although, since Hubble’s time, like any good classification system it has been updated and amended in the light of new observations.

Before Hubble’s study of galaxies, it was believed that our galaxy was the only one in the universe. Astronomers thought that the smudges of light they saw in their telescopes were in fact nebulae within our own galaxy and not, as Hubble discovered, galaxies in their own right. It was Hubble who demonstrated, by measuring their velocities, that they lie at great distances from us, millions of light-years beyond the Milky Way, distances so huge that they appear tiny in all but the largest telescopes. Moreover, he demonstrated that, wherever he looked, galaxies are receding from us in all directions, and the further away they are, the faster they are receding. Hubble had discovered that the universe is expanding.

A diagrammatic representation of Edwin Hubble’s “tuning fork diagram.” In the late 1920s and 30s, Hubble conducted the laborious observations needed to begin to classify galaxies. His original classification scheme was published in 1936 in a book called “The Realm of the Nebulae.” His original scheme is – like all scientific work – continually being modified. But his idea of a “tuning fork diagram” has continued to be useful. Image via Las Cumbres Observatory.

The most common type of galaxy is the one most people are familiar with: the spiral galaxy. The Milky Way is of this family. Spiral galaxies have majestic, sweeping arms, thousands of light years long, made up of millions upon millions of stars. Our solar system is situated about 2/3 of the way out from the galactic center towards the periphery of the galaxy, embedded in one of these spiral arms.

Spiral galaxies are also characterised by having a bright center, made up of a dense concentration of stars, so tightly packed that from a distance the galaxy’s center looks like a solid ball. This ball of stars is known as the galactic bulge. At the center of the Milky Way – within the galactic bulge – the density of stars has been calculated at 1 million per 34 cubic light-years, for example.

Meanwhile, in the vicinity of our sun, the stellar density has been estimated as 0.004 stars per cubic light-year. Big difference!

A stunning view of the center of our Milky Way galaxy as seen by the Murchison Widefield Array (MWA) telescope in Australia in 2019. Image via Natasha Hurley-Walker (ICRAR/ Curtin)/ GLEAM Team/ Phys.org.

The Milky Way is, in fact, in one of Hubble’s spiral galaxy sub-types: it’s a barred spiral, which means it has a bar of stars protruding out from either side of the center. The ends of the bar form the anchors of the spiral arms, the place from where they sweep out in their graceful and enormous arcs. This is a fairly recent discovery: how the bar forms in a galaxy is not yet understood.

Also established recently is the fact that the disk of the Milky Way is not, as most diagrams depict, flat: it is warped, like a long-playing vinyl record left too long in the sun. Exactly why is not known, but it is thought to be the result of a gravitational encounter with another galaxy early in the Milky Way’s history.

Artist’s illustration of our warped Milky Way. Image via Ogle/ Warsaw University/ BBC.

Elliptical galaxies are the universe’s largest galaxies. They are huge and football-shaped.

They come to be because – although most galaxies are flying apart from each other – those astronomically close to each other will be mutually gravitationally attracted. Caught in an inexorable gravitational dance, eventually they merge, passing through each other over millions of years, eventually forming a single, amorphous elliptical galaxy. Such mergers may result in the birth of new generations of stars as gravity’s shock-wave compresses huge clouds of interstellar gas and dust.

The Milky Way is caught in such a gravitational embrace with M31, aka the Andromeda galaxy, which is 2 1/2 million light-years distant. Both galaxies are moving toward each other because of gravitational attraction: they will merge in about 6 billion years from now. However, both galaxies are surrounded by huge halos of gas which may extend for millions of light-years, and it was recently discovered that the halos of the Milky Way and M31 have started to touch.

The two galaxies have had their first kiss.

Galaxy mergers are not uncommon: the universe is filled with examples of galaxies in various stages of merging together, their structures disrupted and distorted by gravity, forming bizarre and beautiful shapes.

Galaxies may take billions of years to fully merge into a single galaxy. As astronomers look outward in space, they can see only “snapshots” of this long merger process. Located 300 million light-years away in the constellation Coma Berenices, these 2 colliding galaxies have been nicknamed The Mice because of the long tails of stars and gas emanating from each galaxy. Otherwise known as NGC 4676, the pair will eventually merge into a single giant galaxy. Image via Wikimedia Commons.

At the lower end of the galactic size scale, there are the so-called dwarf galaxies, consisting of a few hundred to up to several billion stars. Their origin is not clear. Usually they have no clearly defined structure. Astronomers believe they were born in the same way as larger galaxies like the Milky Way, but for whatever reason they stopped growing. Ensnared by the gravity of a larger galaxy, they orbit its periphery. The Milky Way has around 20 dwarf galaxies orbiting it that we know of, although some models predict there should be many more.

The two most famous dwarf galaxies for us earthlings are, of course, the Small and Large Magellanic Clouds, visible to the unaided eye in Earth’s Southern Hemisphere sky.

Eventually, these and other dwarf galaxies will be ripped apart by the titanic maw of the Milky Way’s gravity, leaving behind a barely noticeable stream of stars across the sky, slowly dissipating over eons.

Lynton Brown captured this beautiful image of the Milky Way over Taylor’s Lake near Horsham, Australia, on April 22, 2019. The 2 objects on the right are the Magellanic Clouds. Thank you, Lynton!

It is believed that all galaxies rotate: the Milky Way takes 226 million years to spin around once, for example. Since its birth, therefore, the Earth has travelled 20 times around the galaxy.

At the center of most galaxies lurks a supermassive black hole, of millions or even billions of solar masses. The record holder, TON 618, has a mass 66 billion times that of our sun.

The origin and evolution of supermassive black holes are not well understood. A few years ago, astronomers uncovered a surprising fact: in spiral galaxies, the mass of the supermassive black hole has a direct linear relationship with the mass of the galactic bulge. The more mass the black hole has, the more stars there are in the bulge. No one knows exactly what the significance of this relationship is, but its existence seems to indicate that the growth of a galaxy’s stellar population and that of its supermassive black hole are inextricably linked.

This discovery comes at a time when astronomers are beginning to realize that a supermassive black hole may control the fate of its host galaxy: the copious amounts of electromagnetic radiation emitted from the maelstrom of material orbiting the central black hole, known as the accretion disk, may push away and dissipate the clouds of interstellar hydrogen from which new stars form. This acts as a throttle on the galaxy’s ability to give birth to new stars. Ultimately, the emergence of life itself may be tied to the activity of supermassive black holes. This is an area of much ongoing research.

While astronomers still know very little about exactly how galaxies formed in the first place – we see them in their nascent forms existing only a few hundred million years after the Big Bang – the study of galaxies is an endless voyage of discovery.

Less than a hundred years after it was realized that other galaxies beside our own exist, we have learned so much about these grand, majestic star cities. And there is still much to learn.

Bottom line: What is a galaxy? Learn about these starry islands in space.

ooOOoo

There are an estimated two trillion galaxies out there. It is beyond comprehension. Well it is to this mind sitting in front of his Mac in a rural part of Oregon. Two trillion! I can’t even get my mind around the fact that our local galaxy, our Milky Way, is 100,000 light years across. Although some would say that it is even larger; about 150,000 light years across. And what is a light year?

Here’s NASA to answer that:

A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More precisely, one light-year is equal to 9,500,000,000,000 kilometers.

Why would you want such a big unit of distance? Well, on Earth, a kilometer may be just fine. It is a few hundred kilometers from New York City to Washington, DC; it is a few thousand kilometers from California to Maine. In the universe, the kilometer is just too small to be useful. For example, the distance to the next nearest big galaxy, the Andromeda Galaxy, is 21 quintillion km. That’s 21,000,000,000,000,000,000 km. This is a number so large that it becomes hard to write and hard to interpret. So astronomers use other units of distance.

In our solar system, we tend to describe distances in terms of the Astronomical Unit (AU). The AU is defined as the average distance between the Earth and the Sun. It is approximately 150 million km (93 million miles). Mercury can be said to be about 1/3 of an AU from the Sun and Pluto averages about 40 AU from the Sun. The AU, however, is not big enough of a unit when we start talking about distances to objects outside our solar system.

For distances to other parts of the Milky Way Galaxy (or even further), astronomers use units of the light-year or the parsec . The light-year we have already defined. The parsec is equal to 3.3 light-years. Using the light-year, we can say that :

  • The Crab supernova remnant is about 4,000 light-years away.
  • The Milky Way Galaxy is about 150,000 light-years across.
  • The Andromeda Galaxy is 2.3 million light-years away.

So here we are. In a remote part of our galaxy, the Milky Way, far, far from everywhere, on a pale blue dot. As Carl Sagan put it in his talk from The Age of Exploration given in 1994:

On it, everyone you ever heard of… The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every young couple in love, every hopeful child, every mother and father, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there on a mote of dust, suspended in a sunbeam. …
Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot.

Carl Sagan, Cornell lecture in 1994

It all seems impossible for us mortals to understand.

But it won’t stop me from peering up into the night sky and wondering about the universe with total awe.

And thank goodness for dogs!