Tag: NASA

Why is intelligent life so rare?

Maybe it is because of a ‘Great Filter‘.

Like so many others I read many items online. One of the websites that I follow is the EarthSky site because for a long time I have been interested in space.

So when I saw an article on why intelligent life is so rare in our Milky Way I read it fully. And hoped it would be of interest to others.

Here it is:

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What is the Great Filter, and can we survive it?

Posted by

Kelly Kizer Whitt and Deborah Byrd

November 17, 2022

This graphic depicts intelligent civilizations as stars. The vertical lines represent Great Filters that civilizations do or don’t survive. This graphic depicts Earth’s human population (the yellow “star”) approaching its own Great Filter. How would we surpass it, and keep going? Image via NASA/ arXiv.

What is the Great Filter?

Is intelligent life common, or rare in our Milky Way galaxy? If it’s common, why haven’t we encountered it? While discussing UFOs on a walk to lunch in the year 1950, the physicist Enrico Fermi is famously said to have asked, “But where is everybody?” Scientists today call that riddle Fermi’s Paradox. Now a new paper by NASA scientists explores one possible answer to the paradox. The answer may be what’s called the Great Filter.

Economist Robin Hanson first proposed the Great Filter, in the late 1990s. It’s the idea of that – even if life forms abundantly in our Milky Way galaxy – each extraterrestrial civilization ultimately faces some barrier to its own survival. The barrier might come from without (for example, an asteroid striking a planet, and wiping out all life forms). Or it might come from within (for example, all-out nuclear war).

Hanson proposed that a Great Filter might be at work within our Milky Way galaxy. He argued – from what we can see here on Earth – life expands to fill every niche. And so, he argued, we should see signs of intelligent life beyond Earth in nearby star systems, perhaps even in our solar system. But we don’t see this.

Is humanity facing a Great Filter?

The authors of the new paper take Hanson’s idea further. They explore the idea that humanity may now be facing a Great Filter. The authors wrote:

We postulate that an existential disaster may lay in wait as our society advances exponentially towards space exploration, acting as the Great Filter: a phenomenon that wipes out civilizations before they can encounter each other … In this article, we propose several possible scenarios, including anthropogenic and natural hazards, both of which can be prevented with reforms in individual, institutional and intrinsic behaviors. We also take into account multiple calamity candidates: nuclear warfare, pathogens and pandemics, artificial intelligence, meteorite impacts, and climate change. 

And they offer solutions, beginning with, as they say:

… a necessary period of introspection, followed by appropriate refinements to properly approach our predicament, and addressing the challenges and methods in which we may be able to mitigate risk to mankind and the nearly 9 million other species on Earth.

In a sense, the authors of the new paper – including lead author Jonathan H. Jiang of NASA’s Jet Propulsion Laboratory in Pasadena, California – are engaging in a “necessary period of introspection” by the act of writing their paper.

And, with their paper, they’re laying out the challenges we’re facing and methods of addressing them.

We’ve already survived some ‘filters’

The scientists point to life’s resilience. Life on Earth has already survived a number of filters in the form of mass extinction events. The Permian-Triassic extinction – aka the Great Dying – occurred 250 million years ago and nearly ended all life on the planet. This extinction event wiped out about 96% of marine life and 70% of land species. The exact cause of the Great Dying is still a matter of study, but some scientists have said it was a combination of warming temperatures and decreasing oxygen.

But these previous filters, or extinction events, have been natural, arising from the evolution of our planet and solar system, including volcanic eruptions and asteroid impacts. 

A Great Filter of our own making

But now, clearly, humanity may be facing a Great Filter of our own making, and one that other intelligent civilizations in the galaxy have faced … and failed to withstand. Perhaps it’s no surprise that the technological advancements humans have achieved might ultimately lead to our undoing. Perhaps that’s nature’s way. As the new paper said:

It seems as though nearly every great discovery or invention, while pushing back the borders of our technological ignorance, is all too quickly and easily turned to destructive ends. Examples such as splitting the atom, biomedical innovations and resource extraction and consumption come to mind with disconcerting swiftness. Still, some have suggested artificial intelligence (AI) as yet another factor, which, pending substantial technical hurdles, may yet have its chance to prove friend or foe.

Here’s a look at some of the issues that might compose Earth’s Great Filter.

Unchecked population growth

One of the factors Earth faces, according to the paper, is unchecked population growth. Earth just passed a milestone on November 15, 2022, when it reached 8 billion human inhabitants. The paper said with our current population figures, Earth has experienced:

… an exponential rise from about 1.6 billion [people] at the start of the 20th century.

Technological advancements in farming, energy production and distribution have made such a large population possible on Earth. But, as the paper said, these advancements cannot:

… indefinitely offset the multifaceted stresses imposed by an ever-escalating population.

When will Earth’s human population reach its peak size? Some projections report that education in developing nations might allow Earth’s population to peak at 10 billion in the 2060s. But, of course, no one really knows.

Nuclear war

While warfare has long been a factor of life on Earth, only in the past century has humanity had a weapon that could destroy all nations, not just those participating in a nuclear war. The scientists said the greater the number of democracies in the world, the better our chances for avoiding nuclear war. The scientist also saw other encouraging signs, including:

Peace agreements in the historically troubled Middle East, a vast reduction in nuclear warheads since the height of the Cold War and a wide coalition of nations rallying their support for the besieged in Eastern Europe.

Pathogens and pandemics

The threat of illness and pandemics continues to grow simply because our world is so interconnected. Spreading diseases have a much easier time in our global society. But on the positive side, advancements in medicine have also given us an edge. The scientists said that having current and reliable data is crucial:

… in predicting how future pandemics will spread, how deadly they will be and how quickly and effectively we will be able to leverage our knowledge of the life sciences to counter this manifestation of the Great Filter.

Artificial intelligence

While true artificial intelligence as a separate sentient being is not yet reality, the authors of the paper urge a proactive plan to peacefully share Earth. They project that computer sophistication will one day rival that of the human mind. The scientists said:

As for whether AI would be benign or otherwise, self-imposing a Great Filter of our own invention, that will depend on the evolving nature and disposition of Earth’s first high-tech species.

Asteroid and comet impacts

Here’s an extinction event from the past that could still spell our doom in the future. While large impacts are exceedingly rare, there is, as the scientists said:

… a non-zero percentage [of asteroids or comets] which are large enough to survive passage through the atmosphere and, impacting the surface, cause catastrophic destruction to our sensitive biosphere.

The odds of a mass extinction level event in the coming years is vanishingly small. But, over time periods extending into the very distant future, the odds increase toward 100%. Meanwhile, with projects such as the DART mission, and given enough lead time, humanity has a way of defending itself.

Climate change

Climate change has become one of the most studied threats to life on Earth. Because the threats from climate change happen on a slower time scale than, say, the time it takes to launch a nuclear weapon, the efforts to curb these effects have not been as rapid as they could have been. The scientists said:

The major impediment to taking more decisive actions, however, are the challenges imposed by transitioning to non-carbon-based energy sources such as solar, wind, nuclear power. Here again, rapidly advancing technologies in areas such as modularized nuclear power plants and carbon capture and sequestration (CCS) are among the best hopes for avoiding slow-motion ensnarement by this lulling but lethal Great Filter.

Avoiding the Great Filter

So you see there’s not just one possible Great Filter for Earth, but many. Any one of them could be our downfall. These scientists are suggesting something that sounds simple on its face, but is (apparently) hard to do. That is, in order to avoid the Great Filter, humans must work together and recognize the big picture. As the paper said:

History has shown that intraspecies competition and, more importantly, collaboration, has led us toward the highest peaks of invention. And yet, we prolong notions that seem to be the antithesis of long-term sustainable growth. Racism, genocide, inequity, sabotage … the list sprawls.

Meanwhile, we continue to look outward, peering at the dark depths between the stars, hoping for a sign that we aren’t alone in the universe. Ultimately, our quest to find life beyond Earth is part of trying to understand life on our planet and where we fit in. As Carl Sagan said:

In the deepest sense, the search for extraterrestrial intelligence is a search for ourselves.

Bottom line: Scientists say the reason we haven’t found intelligent civilizations in the galaxy is that they may not have survived the Great Filter. And they say we may be facing down our own Great Filter.

Source: https://arxiv.org/ftp/arxiv/papers/2210/2210.10582.pdf

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We are a funny bunch! As was said just a couple of paragraphs ago we humans must work together and recognise the big picture. But we do not!

Why do we not do that?

I wish I knew the answer to that conundrum! Nevertheless, I hope you enjoyed the article.

Far, far back in time.

Nasa’s James Webb telescope is awesome beyond words.

The recent launch of this telescope, as a successor to Hubble, can see right back more than 13.5 billion years. The universe was formed 13.78 billion years ago. The reach of the James Webb telescope is therefore 98% (97.96) of the life of the universe. But the superlatives about this telescope are almost never-ending. For example it will, in time, be able to explore the tiny planetary worlds far, far away. We may in time see signs of life, as in water, vegetation, or industrialisation, connected with those planets.

The James Webb is in orbit some million miles away from Earth and will, in fact, be orbiting the sun.

One could go on and on speaking about this achievement but I will resist. I want to share a three things with you.

First the release of this early image and a portion of the associated text:

NASA’s James Webb Space Telescope has delivered the deepest and sharpest infrared image of the distant universe so far. Webb’s First Deep Field is galaxy cluster SMACS 0723, and it is teeming with thousands of galaxies – including the faintest objects ever observed in the infrared.

Webb’s image is approximately the size of a grain of sand held at arm’s length, a tiny sliver of the vast universe. The combined mass of this galaxy cluster acts as a gravitational lens, magnifying more distant galaxies, including some seen when the universe was less than a billion years old. This deep field, taken by Webb’s Near-Infrared Camera (NIRCam), is a composite made from images at different wavelengths, totaling 12.5 hours – achieving depths at infrared wavelengths beyond the Hubble Space Telescope’s deepest fields, which took weeks. And this is only the beginning. Researchers will continue to use Webb to take longer exposures, revealing more of our vast universe.

Second, why is it named after James E. Webb (1906- 1992)? James Webb was NASA’s second administrator and known for leading Apollo, the series of lunar exploration programs that landed the first humans on the Moon. (A good Q&A is here: https://www.jwst.nasa.gov/content/about/faqs/faq.html )

Last thing to share is some music! ‘Floating in Heaven’ by Graham Gouldman and Brian May

It is indeed wonderful to be alive at this time!

The James Webb Space Telescope (JWST)

A beautiful example of humans in the supreme invention and deployment of JWST.

(A reminder that Tuesday is a ‘non-doggie’ day.)

JWST is astounding. It will look back to the beginnings of the universe, just 200 million light-years after the Big Bang, or possibly further back in time. Because of the way that the universe stretches out and causes light to go red, as it were, JWST will be searching for images from the cosmos in the infrared.

I recently listened to a 30-minute programme on BBC Sounds. It was a BBC Discovery episode about the JWST. Recorded before the launch it was, nonetheless, a deeply fascinating programme about what JWST will be looking for.

Now the link is here:

https://www.bbc.co.uk/sounds/play/w3ct1m8t

Please listen to it!

Then there is the NASA website that has many videos about the progress of JWST. I selected this one.

Finally, YouTube also have many videos and I selected this one to share with you.

I feel very grateful to be alive when this is happening.

Well done the team at NASA.

What an outstanding feat.

Many, many congratulations!

On Feb. 18, 2021, NASA’s Mars Perseverance rover makes its final descent to the Red Planet.

A little more information:

Landed: Feb. 18, 2021, 12:55 p.m. PST (3:55 p.m. EST), (20:55 UTC)

Landing Site: Jezero Crater, Mars

Mission Duration: At least one Mars year (about 687 Earth days)

Main Job: The Perseverance rover will seek signs of ancient life and collect rock and soil samples for possible return to Earth.

As someone who watched the television non-stop in 1969 to see man’s remarkable achievement, NASA has been an organisation of considerable interest all my life.

At 10:56 p.m. EDT Armstrong is ready to plant the first human foot on another world. With more than half a billion people watching on television, he climbs down the ladder and proclaims: “That’s one small step for a man, one giant leap for mankind.“

What an achievement!

The dark of the night!

This recent post from EarthSky is a fascinating read!

By some amazing luck when we came to Merlin, Oregon some eight years ago we found these acres distant from any form of light pollution. Frankly, light pollution at night never crossed our mind at the time.

But almost every evening, when it is dark, I go outside to call in the dogs and look up at the night sky. At this time of the year the Big Dipper is high in the sky. Also the Milky Way can be seen as a faint ‘smudge’ of light. It is a glorious sight and one that I will never, ever tire of seeing.

Which is my introduction to today’s post Why we need darkness.

And, please watch this TED Talk given by Paul.

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Paul Bogard on why we need darkness

Posted by in ASTRONOMY ESSENTIALS, October 29, 2020

Light at night may be a sign of life on Earth, but the darkness will proclaim our true intelligence. Check out this video on why we need darkness, from Paul Bogard. In his captivating talk Paul describes what we call “light pollution,” the overuse and misuse of artificial light at night. In cities and towns, in suburbs and villages all over the world, we are using more light than we need, and we are using it ways that waste money and energy, harm our physical health, harm the environment, and yes — rob us of the stars. What are the solutions for this problem? A native Minnesotan, Paul Bogard loves night’s natural darkness. So much so that he wrote two successful books about it. He is author of The End of Night: Searching for Natural Darkness in an Age of Artificial Light and editor of Let There Be Night: Testimony on Behalf of the Dark. He also likes to walk through the woods, surrounded by the trees and birds and hidden animals. For 15 years he had a dog who would come with him on these walks. Her name was Luna, like the moon. He misses her a lot. He loves coffee in the morning and red wine at night. Paul is now an assistant professor at James Madison University in Harrisonburg, Virginia, where he teaches creative writing and environmental literature.

The dark is good for our sleep, our biology, and the health of our ecosystems. It’s good for our creativity and our spirits, and, yes, it’s even good for our safety and security. That’s the message of Paul Bogard, who has written extensively on the importance of darkness. His book is titled “The End of Night.” His TEDx Talk – above – focuses on why we need darkness. I’ve spent time mulling over both the book and this video and recommend them highly. In this pandemic year – as many wondered whether lockdowns gave us darker skies – you might enjoy thinking about it, too.

Bogard researched night-shift workers, those who are exposed to light during the hours that most bodies crave darkness and sleep. Humans have a circadian trough from approximately midnight to 6 am. The absence of darkness and sleep during this trough contributes to night-shift work being labeled a probable carcinogen, with workers more likely to suffer from obesity, diabetes, cardiovascular issues, depression, substance abuse, and especially breast and prostate cancer. Light at night disrupts the body’s production of melatonin, which is thought to be needed to keep these types of cancers at bay.

But it’s not just night-shift workers who suffer from exposure to lights at night. Any quick look at a photo of the Earth at night shows the great glows of cities and suburbs spilling across the land and down highways into the edges of the countryside. Even when we keep the lights dark outside our own home, the light from our neighbors’ homes seeps around the cracks in our blinds and splashes across our back patio.

Earth at night, via NASA.

The light we see on maps of Earth at night isn’t just interrupting our sleep or blinding us on a late-night walk with our dog. It’s also wasting money. Bogard claims that billions of dollars are wasted each year throughout the world on light that illuminates nothing on the ground, but instead points straight up.

He points out that proper lighting directs illumination toward the ground, away from the sky and out of the eyes of those nearby. Bright lights near someone’s front door create an illusion of safety, but not true safety, according to Bogard. That’s because the glare shining into our eyes makes it difficult to impossible to see what is hiding in the deep shadows cast by the light.

Policing in some communities has been made much easier with the replacement of constant lighting by motion lights. For example, Bogard recounts how Loveland, Colorado, changed their schoolyard lighting to motion detectors, which made it simple for patrols to see if someone was present or not determined by whether or not the area was dark or light.

The issue with safety and lighting isn’t black or white, or darkness or light. It’s choosing proper lighting for each situation, which helps to make an area safer, saves money, preserves sleep, and protects the dark night sky.

When we protect the night sky, Bogard says, we’re also protecting not just ourselves and our biology but those of the ecosystem around us. In his book “The End of Night,” Bogard writes:

I remember Pierre Brunet arguing in Paris that the presence of an astronomer was the sign of a healthy ecosystem; that when the sky grows too bright for astronomy and the astronomers go away, you know you have a light-polluted sky, and whatever has polluted that sky will eventually pollute other resources, given time.

Countless animals are dependent on darkness, Bogard points out. More than 60% of invertebrates and 30% of vertebrates are nocturnal, having evolved to find food and mates in uninterrupted darkness.

Sea turtles are a well-known example of animal life that needs darkness to survive. Anyone who has been to the oceanfront has seen the lighting adapted to help the sea turtles find their way back to the sea. At my parents’ condo in Florida, the ocean-facing side of lamps have been blacked out so that the newly-hatched sea turtles, upon leaving their nests, are not lured onshore by false light but find their right paths into the water.

When you examine the night sky map of the United States and consider where most of the population lies, it’s not hard to believe, as Bogard tells us, that more than 80% of Americans can no longer see the Milky Way from their home. I live in the suburbs of a large city, for example, and my location on a map of light pollution is nearly bright white.

Recently, I spent some time about three hours west of Chicago in a quiet patch of countryside that is a rare blue shade of darkness on light pollution maps. When I stepped out onto the deck on a crystal-clear evening, I looked up at the stars and was immediately lost.

I’ve been observing and writing about the night sky for two decades, but my familiarity with the sky is linked to recognizing what I see nightly above me, which is usually a dim cousin to the depth and wonder of a truly dark sky. None of the conventional patterns were popping out at me like I was used to: the Big Dipper, the Summer Triangle, the V-shape of Taurus’s head. Instead, a brilliant orange Mars was bright enough to wash out the stars around it, yet the lush Milky Way held her own and a thousand normally unseen stars twinkled in a chorus.

For the first time ever, I witnessed the fuzzy oval glow of the Andromeda Galaxy with nothing more than my eyes. I saw star clusters dig out patches of sky and anchor their surroundings instead of having to hunt them down with binoculars. Cassiopeia and Perseus were nearly swallowed up by the sea of stars flowing from the Milky Way behind them.

We need darkness for moments like that. We need darkness to feed our spirit, protect our health and protect the health of our planet. Light at night may be a sign of life on Earth, but the darkness will proclaim our true intelligence.

Bottom line: A video on why we need darkness from Paul Bogard, author of the book “The End of Night.” The video explains why light pollution is detrimental and why darkness is good for our bodies, our world and our spirits.

Via Paul Bogard

Via YouTube

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Yes, we need darkness!

So, please, take a moment to view the night sky. If you are somewhere where there is excessive light pollution then plan at some point to get away to the darkness. Also make sure you sleep in a dark room. It’s too easy to let a light or two get in the way of a properly darkened room.

Finally, amongst my many photographs I do not have is one of the night sky. And, frankly, if I did it wouldn’t be as fantastic as the one below. So let me close with a Pexels photograph of the Milky Way by Sam Kolder.

Photo by Sam Kolder from Pexels

Stunning and what a brilliant photograph.

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.

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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.

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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!

Hubble into music.

Back to the space telescope!

I cannot stop engaging in Hubble stories and republishing them in this place.

The latest is an account, published here, of how scientists turned an image of a galaxy into music! Or rather added music to the video.

Here it is!

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Cool! A Hubble photo translated to music

Posted by in Human World | Space | May 10, 2020

There’s no sound in space. But – working with NASA – musicians and scientists turned a Hubble Space Telescope image of a galaxy cluster into music.

We stumbled on this video via a May 3, 2020, re-post at ScienceAlert. Matt Russo and Andrew Santaguida of System Sounds in Toronto – which calls itself “a sci-art outreach project” – created the video. It’s part of NASA’s Astrophysics Visualizations series. NASA explained the video this way:

Space becomes sonified in this visualization of a cluster of galaxies imaged by NASA’s Hubble Space Telescope. Time flows left to right, and the frequency of sound changes from bottom to top, ranging from 30 to 1,000 hertz. Objects near the bottom of the image produce lower notes, while those near the top produce higher ones. Most of the visible specks are galaxies housing countless stars. A few individual stars shine brightly in the foreground. Stars and compact galaxies create short, clear tones, while sprawling spiral galaxies emit longer notes that change pitch. The higher density of galaxies near the center of the image – the heart of this galaxy cluster, known as RXC J0142.9+4438 – results in a swell of mid-range tones halfway through the video. Hubble’s Advanced Camera for Surveys and Wide Field Camera 3 acquired this image on August 13, 2018.

Cool!

Here’s the original Hubble image of galaxy cluster RXC J0142.9+4438, later “sonified” by Russo and Santaguida. NASA wrote: “Galaxies abound in this spectacular Hubble image; spiral arms swirl in all colors and orientations, and fuzzy ellipticals can be seen speckled across the frame as softly glowing smudges on the sky. Each visible speck of a galaxy is home to countless stars. A few stars closer to home shine brightly in the foreground, while a massive galaxy cluster nestles at the very center of the image; an immense collection of maybe thousands of galaxies, all held together by the relentless force of gravity.” Read more about this image, which is via ESA/ Hubble & NASA, RELICS.

Here’s the original Hubble image of galaxy cluster RXC J0142.9+4438, later “sonified” by Russo and Santaguida. NASA wrote: “Galaxies abound in this spectacular Hubble image; spiral arms swirl in all colors and orientations, and fuzzy ellipticals can be seen speckled across the frame as softly glowing smudges on the sky. Each visible speck of a galaxy is home to countless stars. A few stars closer to home shine brightly in the foreground, while a massive galaxy cluster nestles at the very center of the image; an immense collection of maybe thousands of galaxies, all held together by the relentless force of gravity.” Read more about this image, which is via ESA/ Hubble & NASA, RELICS.

Bottom line: Musicians and scientists turned a Hubble Space Telescope image – of galaxy cluster RXC J0142.9+4438 – into music.

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That is so lovely.

It’s only just over half a minute long but is still precious!

And I learnt a new word: sonification!

Wow! What a stupendous sight!

Mars!

I’m not going to do anything other than launch straight into this post. Taken from EarthSky.

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Curiosity rover on Mars snags highest-resolution panorama yet

Posted by in Space | Today’s Image | March 5, 2020
This just in … a new super-cool composite from Curiosity on Mars. The panorama contains more than 1,000 images taken last Thanksgiving and assembled over the past few months … 1.8 billion new pixels of Martian landscape!

Yesterday (March 4, 2020) NASA released a panoramic image of the Martian surface captured by the Curiosity rover. It’s the highest-resolution panorama yet of the planet’s surface.

NASA said:

Composed of more than 1,000 images taken during the 2019 Thanksgiving holiday and carefully assembled over the ensuing months, the composite contains 1.8 billion pixels of Martian landscape. The rover’s Mast Camera, or Mastcam, used its telephoto lens to produce the panorama; meanwhile, it relied on its medium-angle lens to produce a lower-resolution, nearly 650-million-pixel panorama that includes the rover’s deck and robotic arm.

The panorama showcases Glen Torridon, a region on the side of Mount Sharp that Curiosity is exploring. They were taken between November 24 and December 1, 2019, when the mission team was out for the Thanksgiving holiday. NASA said:

Sitting still with few tasks to do while awaiting the team to return and provide its next commands, the rover had a rare chance to image its surroundings from the same vantage point several days in a row.

| NASA’s Curiosity rover captured its highest-resolution panorama of the Martian surface between November 24 and December 1, 2019. Image via NASA/ JPL-Caltech/ MSSS.

| Along with an almost 1.8-billion-pixel panorama that doesn’t feature the rover, NASA’s Curiosity also captured a 650-million-pixel panorama that features the rover itself. Image via NASA/ JPL-Caltech/ MSSS.

It required more than 6 1/2 hours over the four days for Curiosity to capture the individual shots. Mastcam operators programmed the complex task list, which included pointing the rover’s mast and making sure the images were in focus. To ensure consistent lighting, they confined imaging to between noon and 2 p.m. local Mars time each day.

In 2013, Curiosity produced a 1.3-billion-pixel panorama using both Mastcam cameras; its black-and-white Navigation Cameras, or Navcams, provided images of the rover itself.

Bottom line: Highest-resolution yet panorama of Martian surface by Mars Curiosity rover.

Via NASA

Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.

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When one stops and reflects one can’t hide the scale of progress that humans have achieved. It is incredible!

It is also a struggle to take the situation so expertly spoken about by George Monbiot in yesterday’s post and square it with the achievement covered in today’s post.

Oh well!

A leap into the unknown!

A slight tongue-in-cheek title to today’s post.

Because it is a leap day!

So I’m going back a long time.

I was born towards the tail end of 1944; six months before the end of WWII in Europe.

As such I was in my early twenties when NASA came to the wider attention of millions of people with their effort to put a man on the moon. It was enthralling to look up at the night sky when a moon was present and think that in time there would be a man standing on the moon’s surface.

Now that I am 75 many things have changed. But one of them has not: Staring up at the night sky and getting lost in thought. Luckily we live in a rural location without artificial light anywhere nearby and the night skies are very clear.

All of which takes me back to my days of sailing. From 1986 until 1991 I lived on a deep-water ketch, a Tradewind 33, based in Larnaca, in Cyprus. Each Spring, I would solo across to the Turkish coast, or the Greek coast, and meet up with friends, or my son and daughter, and go coastal cruising. Then in the last year I sailed for England. I well recall seeing the night sky all around me with the stars practically down the watery horizon.

But more of that some other day. Now back to the moon.

All of which is to republish this post and I do hope you will be able to read it fully.

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NASA video reconstructs the harrowing lunar journey of Apollo 13

By Michael d’Estries, February 26, 2020

NASA’s reconstruction of the moon’s far side is based off images received by its Lunar Reconnaissance Orbiter spacecraft. (Photo: NASA/Snapshot from video/YouTube)

On April 15, 1970, NASA astronauts Jim Lovell, Jack Swigert and Fred Haise aboard Apollo 13 set a Guinness World Record for the highest absolute altitude attained by a crewed spacecraft at a distance of 248,655 miles from Earth. Nearly 50 years later, that unplanned record still stands as part of a mission beset by technical glitches and saved by engineering heroism.

“We didn’t slow down, unlike the others, when we got to the moon because we needed its gravity to get back, so we hold the altitude record,” Lowell told the Financial Times in 2011. “I never even thought about it. Records are only made to be broken.”

Gliding by the moon’s far side at an altitude of only 158 miles, the crew of Apollo 13 were, at the time, one of only a handful of humans to ever gaze upon this strange and relatively-unknown terrain of our closest neighbor. Because the moon is tidally locked, a phenomenon in which an orbiting body takes just as long to rotate around its own axis as it does to revolve around its partner, only one side ever faces the Earth.

Using imagery collected by its Lunar Reconnaissance Orbiter spacecraft, NASA has recreated views observed by Apollo 13 during the crew’s harrowing 25-minute journey around the moon’s far side.

“This video showcases visualizations in 4K resolution of many of those lunar surface views, starting with earthset and sunrise, and concluding with the time Apollo 13 reestablished radio contact with Mission Control,” the agency said in a release. “Also depicted is the path of the free return trajectory around the Moon, and a continuous view of the Moon throughout that path. All views have been sped up for timing purposes — they are not shown in ‘real-time.'”

This video uses data gathered from the Lunar Reconnaissance Orbiter spacecraft to recreate some of the stunning views of the Moon that the Apollo 13 astronauts saw on their perilous journey around the farside in 1970. These visualizations, in 4K resolution, depict many different views of the lunar surface, starting with earthset and sunrise and concluding with the time Apollo 13 reestablished radio contact with Mission Control. Also depicted is the path of the free return trajectory around the Moon, and a continuous view of the Moon throughout that path. All views have been sped up for timing purposes — they are not shown in “real-time.” Credits: Data Visualization by: Ernie Wright (USRA) Video Produced & Edited by: David Ladd (USRA) Music provided by Universal Production Music: “Visions of Grandeur” – Frederick Wiedmann

According to Lowell, despite the astronauts’ extremely close proximity, the moon was not the most awe-inspiring scene outside the spacecraft window.

“The impression I got up there wasn’t what the moon looked like so close up, but what the Earth looked like,” he said.

“The lunar flights give you a correct perception of our existence. You look back at Earth from the moon and you can put your thumb up to the window and hide the Earth behind your thumb. Everything you’ve ever known is behind your thumb, and that blue-and-white ball is orbiting a rather normal star, tucked away on the outer edge of a galaxy. You realize how insignificant we really all are. Everything you’ve ever known — all those arguments and wars — is right behind your thumb.”

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Did you watch the video? It’s amazing and is literally the dark side of the moon!

I will close by republishing a Wikipedia entry for Apollo 13.

Apollo 13 was the seventh crewed mission in the Apollo space program and the third meant to land on the Moon. The craft was launched from Kennedy Space Center on April 11, 1970, but the lunar landing was aborted after an oxygen tank in the service module (SM) failed two days into the mission. The crew instead looped around the Moon, and returned safely to Earth on April 17. The mission was commanded by Jim Lovell with Jack Swigert as command module (CM) pilot and Fred Haise as lunar module (LM) pilot. Swigert was a late replacement for Ken Mattingly, who was grounded after exposure to rubella.

Accidental ignition of damaged wire insulation inside the oxygen tank as it was being routinely stirred caused an explosion that vented the tank’s contents. Without oxygen, needed both for breathing and for generating electric power, the SM’s propulsion and life support systems could not operate. The CM’s systems had to be shut down to conserve its remaining resources for reentry, forcing the crew to transfer to the LM as a lifeboat. With the lunar landing canceled, mission controllers worked to bring the crew home alive.

Although the LM was designed to support two men on the lunar surface for two days, Mission Control in Houston improvised new procedures so it could support three men for four days. The crew experienced great hardship caused by limited power, a chilly and wet cabin and a shortage of potable water. There was a critical need to adapt the CM’s cartridges for the carbon dioxide removal system to work in the LM; the crew and mission controllers were successful in improvising a solution. The astronauts’ peril briefly renewed interest in the Apollo program; tens of millions watched the splashdown in the South Pacific Ocean by television.

An investigative review board found fault with preflight testing of the oxygen tank and the fact that Teflon was placed inside it. The board recommended changes, including minimizing the use of potentially combustible items inside the tank; this was done for Apollo 14. The story of Apollo 13 has been dramatized several times, most notably in the 1995 film Apollo 13.

That pale blue dot!

Carl Sagan’s legacy!

Last Friday saw the thirtieth anniversary of Carl Sagan’s iconic photograph, or rather NASA’s photograph, of Planet Earth. Carl persuaded NASA to turn Voyager 1, as it left the Solar System, and take the photo. It became famous almost instantly and became known as the pale blue dot.

Here’s a shortened Wikipedia account of Carl Sagan’s book:

Pale Blue Dot: A Vision of the Human Future in Space is a 1994 book by Carl Sagan. It is the sequel to Cosmos and was inspired by the famous 1990 Pale Blue Dot photograph, for which Sagan provides a poignant description. In this book, Sagan mixes philosophy about the human place in the universe with a description of the current knowledge about the Solar System. He also details a human vision for the future.

Here’s the latest from NASA.

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’Pale Blue Dot’ Revisited

February 12th, 2020

This updated version of the iconic “Pale Blue Dot” image taken by the Voyager 1 spacecraft uses modern image-processing software and techniques to revisit the well-known Voyager view while attempting to respect the original data and intent of those who planned the images.
Credits: NASA/JPL-Caltech

For the 30th anniversary of one of the most iconic views from the Voyager mission, NASA’s Jet Propulsion Laboratory in Pasadena, California, is publishing a new version of the image known as the “Pale Blue Dot.”

The updated image uses modern image-processing software and techniques while respecting the intent of those who planned the image. Like the original, the new color view shows Planet Earth as a single, bright blue pixel in the vastness of space. Rays of sunlight scattered within the camera optics stretch across the scene, one of which happens to have intersected dramatically with Earth.

The view was obtained on Feb. 14, 1990, just minutes before Voyager 1’s cameras were intentionally powered off to conserve power and because the probe — along with its sibling, Voyager 2 — would not make close flybys of any other objects during their lifetimes. Shutting down instruments and other systems on the two Voyager spacecraft has been a gradual and ongoing process that has helped enable their longevity.


This simulated view, made using NASA’s Eyes on the Solar System app, approximates Voyager 1’s perspective when it took its final series of images known as the “Family Portrait of the Solar System,” including the “Pale Blue Dot” image. Move the slider to the left to see the location of each image. (You have to go here to see the full image. Ed.)
Credits: NASA/JPL-Caltech

This celebrated Voyager 1 view was part of a series of 60 images designed to produce what the mission called the “Family Portrait of the Solar System.” This sequence of camera-pointing commands returned images of six of the solar system’s planets, as well as the Sun. The Pale Blue Dot view was created using the color images Voyager took of Earth.

The popular name of this view is traced to the title of the 1994 book by Voyager imaging scientist Carl Sagan, who originated the idea of using Voyager’s cameras to image the distant Earth and played a critical role in enabling the family portrait images to be taken.

Additional information about the Pale Blue Dot image is available at:

https://solarsystem.nasa.gov/resources/536/voyager-1s-pale-blue-dot/

The original Pale Blue Dot and Family Portrait images are available at:

https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00452

https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA00451

The Voyager spacecraft were built by JPL, which continues to operate both. JPL is a division of Caltech in Pasadena. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington. For more information about the Voyager spacecraft, visit:

https://www.nasa.gov/voyager

https://voyager.jpl.nasa.gov

Calla Cofield​
Jet Propulsion Laboratory, Pasadena, Calif.
626-808-2469
calla.e.cofield@jpl.nasa.gov

Written by Preston Dyches

2020-030

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Voyager 1 is now nearly 14 billion miles from Planet Earth and still going strong. It has a plutonium battery that will last for eighty years. A one-way radio signal from Earth takes about twenty hours to reach the probe.

And now for something different but still to do with space.

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NASA astronaut Christina Koch recently returned to Earth after 328 days in space, breaking the record for the longest single spaceflight by a woman. She completed six spacewalks while on the International Space Station, including the first all-female spacewalk with astronaut Jessica Meir.

When she finally made it home, her beloved pup, LBD (Little Brown Dog), couldn’t contain her excitement.

Koch shared a video on Twitter of the moment she walked through her front door and LBD pounced to shower her with kisses.

“Not sure who was more excited,” she captioned the video. “Glad she remembers me after a year!”

“We call her LBD, little brown dog, she’s from the Humane Society and she couldn’t be sweeter,” Koch told Insider on a phone call with reporters from the Johnson Space Centre.

“And yes, she was very excited, I was very excited, I’m not sure who was more excited! … You know it’s just a symbol of coming back to the people and places that you love, to see your favourite animal.”

This article was originally published by Business Insider.

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Now I can’t disappear without acknowledging the fantastic work of Carl Sagan.

And I can’t do better than republish the first bit of a wonderful piece on Carl put out by Wikipedia.

Carl Edward Sagan (/ˈseɪɡən/; November 9, 1934 – December 20, 1996) was an American astronomer, cosmologist, astrophysicist, astrobiologist, author, science popularizer, and science communicator in astronomy and other natural sciences. He is best known as a science popularizer and communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space: the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the now accepted hypothesis that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect.[

He died far too young in my opinion!

But not without leaving a tremendous legacy – The Pale Blue Dot.