Category: Science

The mystery of Dark Matter

This very interesting article is worth a read.

Patrice Ayme published a post on Wednesday, 25th June, 2025 that is deeply conected to the following post from The Conversation.

His post was called: ‘How Does The Universe Expand? The Way Cosmologists Decided That It Does, FLRW Metric! A Causal Loop Is At The Heart Of Modern ΛCDM Cosmology!’

Thus I recommend that you read that article and then the one that is republished by me, with permission, from The Conversation.

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The Vera C. Rubin Observatory will help astronomers investigate dark matter, continuing the legacy of its pioneering namesake

The Rubin Observatory is scheduled to release its first images in 2025. RubinObs/NOIRLab/SLAC/NSF/DOE/AURA/B. Quint

Samantha Thompson, Smithsonian Institution

Everything in space – from the Earth and Sun to black holes – accounts for just 15% of all matter in the universe. The rest of the cosmos seems to be made of an invisible material astronomers call dark matter.

Astronomers know dark matter exists because its gravity affects other things, such as light. But understanding what dark matter is remains an active area of research.

With the release of its first images this month, the Vera C. Rubin Observatory has begun a 10-year mission to help unravel the mystery of dark matter. The observatory will continue the legacy of its namesake, a trailblazing astronomer who advanced our understanding of the other 85% of the universe.

As a historian of astronomy, I’ve studied how Vera Rubin’s contributions have shaped astrophysics. The observatory’s name is fitting, given that its data will soon provide scientists with a way to build on her work and shed more light on dark matter.

Wide view of the universe

From its vantage point in the Chilean Andes mountains, the Rubin Observatory will document everything visible in the southern sky. Every three nights, the observatory and its 3,200 megapixel camera will make a record of the sky.

This camera, about the size of a small car, is the largest digital camera ever built. Images will capture an area of the sky roughly 45 times the size of the full Moon. With a big camera with a wide field of view, Rubin will produce about five petabytes of data every year. That’s roughly 5,000 years’ worth of MP3 songs.

After weeks, months and years of observations, astronomers will have a time-lapse record revealing anything that explodes, flashes or moves – such as supernovas, variable stars or asteroids. They’ll also have the largest survey of galaxies ever made. These galactic views are key to investigating dark matter.

Galaxies are the key

Deep field images from the Hubble Space Telescope, the James Webb Space Telescope and others have visually revealed the abundance of galaxies in the universe. These images are taken with a long exposure time to collect the most light, so that even very faint objects show up.

Researchers now know that those galaxies aren’t randomly distributed. Gravity and dark matter pull and guide them into a structure that resembles a spider’s web or a tub of bubbles. The Rubin Observatory will expand upon these previous galactic surveys, increasing the precision of the data and capturing billions more galaxies.

In addition to helping structure galaxies throughout the universe, dark matter also distorts the appearance of galaxies through an effect referred to as gravitational lensing.

Light travels through space in a straight line − unless it gets close to something massive. Gravity bends light’s path, which distorts the way we see it. This gravitational lensing effect provides clues that could help astronomers locate dark matter. The stronger the gravity, the bigger the bend in light’s path.

Many galaxies, represented as bright dots, some blurred, against a dark background.
The white galaxies seen here are bound in a cluster. The gravity from the galaxies and the dark matter bends the light from the more distant galaxies, creating contorted and magnified images of them. NASA, ESA, CSA and STScI

Discovering dark matter

For centuries, astronomers tracked and measured the motion of planets in the solar system. They found that all the planets followed the path predicted by Newton’s laws of motion, except for Uranus. Astronomers and mathematicians reasoned that if Newton’s laws are true, there must be some missing matter – another massive object – out there tugging on Uranus. From this hypothesis, they discovered Neptune, confirming Newton’s laws.

With the ability to see fainter objects in the 1930s, astronomers began tracking the motions of galaxies.

California Institute of Technology astronomer Fritz Zwicky coined the term dark matter in 1933, after observing galaxies in the Coma Cluster. He calculated the mass of the galaxies based on their speeds, which did not match their mass based on the number of stars he observed.

He suspected that the cluster could contain an invisible, missing matter that kept the galaxies from flying apart. But for several decades he lacked enough observational evidence to support his theory.

A woman adjusting a large piece of equipment.
Vera Rubin operates the Carnegie spectrograph at Kitt Peak National Observatory in Tucson. Carnegie Institution for Science, CC BY

Enter Vera Rubin

In 1965, Vera Rubin became the first women hired onto the scientific staff at the Carnegie Institution’s Department of Terrestrial Magnetism in Washington, D.C.

She worked with Kent Ford, who had built an extremely sensitive spectrograph and was looking to apply it to a scientific research project. Rubin and Ford used the spectrograph to measure how fast stars orbit around the center of their galaxies.

In the solar system, where most of the mass is within the Sun at the center, the closest planet, Mercury, moves faster than the farthest planet, Neptune.

“We had expected that as stars got farther and farther from the center of their galaxy, they would orbit slower and slower,” Rubin said in 1992.

What they found in galaxies surprised them. Stars far from the galaxy’s center were moving just as fast as stars closer in.

“And that really leads to only two possibilities,” Rubin explained. “Either Newton’s laws don’t hold, and physicists and astronomers are woefully afraid of that … (or) stars are responding to the gravitational field of matter which we don’t see.”

Data piled up as Rubin created plot after plot. Her colleagues didn’t doubt her observations, but the interpretation remained a debate. Many people were reluctant to accept that dark matter was necessary to account for the findings in Rubin’s data.

Rubin continued studying galaxies, measuring how fast stars moved within them. She wasn’t interested in investigating dark matter itself, but she carried on with documenting its effects on the motion of galaxies.

A quarter with a woman looking upwards engraved onto it.
A U.S quarter honors Vera Rubin’s contributions to our understanding of dark matter. United States Mint, CC BY

Vera Rubin’s legacy

Today, more people are aware of Rubin’s observations and contributions to our understanding of dark matter. In 2019, a congressional bill was introduced to rename the former Large Synoptic Survey Telescope to the Vera C. Rubin Observatory. In June 2025, the U.S. Mint released a quarter featuring Vera Rubin.

Rubin continued to accumulate data about the motions of galaxies throughout her career. Others picked up where she left off and have helped advance dark matter research over the past 50 years.

In the 1970s, physicist James Peebles and astronomers Jeremiah Ostriker and Amos Yahil created computer simulations of individual galaxies. They concluded, similarly to Zwicky, that there was not enough visible matter in galaxies to keep them from flying apart.

They suggested that whatever dark matter is − be it cold stars, black holes or some unknown particle − there could be as much as 10 times the amount of dark matter than ordinary matter in galaxies.

Throughout its 10-year run, the Rubin Observatory should give even more researchers the opportunity to add to our understanding of dark matter.

Samantha Thompson, Astronomy Curator, National Air and Space Museum, Smithsonian Institution

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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It is difficult to say anything more as my comment will mean practically nothing compared to Patrice Ayme and Samantha Thompson.

I am just grateful that these fine people publish their research with permission for it to be republished elsewhere. Thank you!

This strange and beautiful place

Pondering on space.

Like so many people, I am fascinated by the universe. Just our own universe is staggering. Here are some items published on the NASA website.

Solar System Facts

Our solar system includes the Sun, eight planets, five officially named dwarf planets, hundreds of moons, and thousands of asteroids and comets.

Our solar system is located in the Milky Way, a barred spiral galaxy with two major arms, and two minor arms. Our Sun is in a small, partial arm of the Milky Way called the Orion Arm, or Orion Spur, between the Sagittarius and Perseus arms. Our solar system orbits the center of the galaxy at about 515,000 mph (828,000 kph). It takes about 230 million years to complete one orbit around the galactic center.

Now to the centre of our universe. And it give me pleasure to republish this account.

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Where is the center of the universe?

In space, there are four dimensions: length, width, height and time. scaliger/iStock/NASA via Getty Images Plus

Rob Coyne, University of Rhode Island

About a century ago, scientists were struggling to reconcile what seemed a contradiction in Albert Einstein’s theory of general relativity.

Published in 1915, and already widely accepted worldwide by physicists and mathematicians, the theory assumed the universe was static – unchanging, unmoving and immutable. In short, Einstein believed the size and shape of the universe today was, more or less, the same size and shape it had always been.

But when astronomers looked into the night sky at faraway galaxies with powerful telescopes, they saw hints the universe was anything but that. These new observations suggested the opposite – that it was, instead, expanding.

Scientists soon realized Einstein’s theory didn’t actually say the universe had to be static; the theory could support an expanding universe as well. Indeed, by using the same mathematical tools provided by Einstein’s theory, scientists created new models that showed the universe was, in fact, dynamic and evolving.

I’ve spent decades trying to understand general relativity, including in my current job as a physics professor teaching courses on the subject. I know wrapping your head around the idea of an ever-expanding universe can feel daunting – and part of the challenge is overriding your natural intuition about how things work. For instance, it’s hard to imagine something as big as the universe not having a center at all, but physics says that’s the reality.

The universe gets bigger every day.

The space between galaxies

First, let’s define what’s meant by “expansion.” On Earth, “expanding” means something is getting bigger. And in regard to the universe, that’s true, sort of. Expansion might also mean “everything is getting farther from us,” which is also true with regard to the universe. Point a telescope at distant galaxies and they all do appear to be moving away from us.

What’s more, the farther away they are, the faster they appear to be moving. Those galaxies also seem to be moving away from each other. So it’s more accurate to say that everything in the universe is getting farther away from everything else, all at once.

This idea is subtle but critical. It’s easy to think about the creation of the universe like exploding fireworks: Start with a big bang, and then all the galaxies in the universe fly out in all directions from some central point.

But that analogy isn’t correct. Not only does it falsely imply that the expansion of the universe started from a single spot, which it didn’t, but it also suggests that the galaxies are the things that are moving, which isn’t entirely accurate.

It’s not so much the galaxies that are moving away from each other – it’s the space between galaxies, the fabric of the universe itself, that’s ever-expanding as time goes on. In other words, it’s not really the galaxies themselves that are moving through the universe; it’s more that the universe itself is carrying them farther away as it expands.

A common analogy is to imagine sticking some dots on the surface of a balloon. As you blow air into the balloon, it expands. Because the dots are stuck on the surface of the balloon, they get farther apart. Though they may appear to move, the dots actually stay exactly where you put them, and the distance between them gets bigger simply by virtue of the balloon’s expansion.

split screen of a green balloon with red dots and a squiggle on the surface, lightly inflated and then much more blown up
It’s the space between the dots that’s growing. NASA/JPL-Caltech, CC BY

Now think of the dots as galaxies and the balloon as the fabric of the universe, and you begin to get the picture.

Unfortunately, while this analogy is a good start, it doesn’t get the details quite right either.

The 4th dimension

Important to any analogy is an understanding of its limitations. Some flaws are obvious: A balloon is small enough to fit in your hand – not so the universe. Another flaw is more subtle. The balloon has two parts: its latex surface and its air-filled interior.

These two parts of the balloon are described differently in the language of mathematics. The balloon’s surface is two-dimensional. If you were walking around on it, you could move forward, backward, left, or right, but you couldn’t move up or down without leaving the surface.

Now it might sound like we’re naming four directions here – forward, backward, left and right – but those are just movements along two basic paths: side to side and front to back. That’s what makes the surface two-dimensional – length and width.

The inside of the balloon, on the other hand, is three-dimensional, so you’d be able to move freely in any direction, including up or down – length, width and height.

This is where the confusion lies. The thing we think of as the “center” of the balloon is a point somewhere in its interior, in the air-filled space beneath the surface.

But in this analogy, the universe is more like the latex surface of the balloon. The balloon’s air-filled interior has no counterpart in our universe, so we can’t use that part of the analogy – only the surface matters.

A blown-up purple balloon on a blue background.
Trying to figure out how the universe works? Start by contemplating a balloon. Kristopher_K/iStock via Getty Images Plus

So asking, “Where’s the center of the universe?” is somewhat like asking, “Where’s the center of the balloon’s surface?” There simply isn’t one. You could travel along the surface of the balloon in any direction, for as long as you like, and you’d never once reach a place you could call its center because you’d never actually leave the surface.

In the same way, you could travel in any direction in the universe and would never find its center because, much like the surface of the balloon, it simply doesn’t have one.

Part of the reason this can be so challenging to comprehend is because of the way the universe is described in the language of mathematics. The surface of the balloon has two dimensions, and the balloon’s interior has three, but the universe exists in four dimensions. Because it’s not just about how things move in space, but how they move in time.

Our brains are wired to think about space and time separately. But in the universe, they’re interwoven into a single fabric, called “space-time.” That unification changes the way the universe works relative to what our intuition expects.

And this explanation doesn’t even begin to answer the question of how something can be expanding indefinitely – scientists are still trying to puzzle out what powers this expansion.

So in asking about the center of the universe, we’re confronting the limits of our intuition. The answer we find – everything, expanding everywhere, all at once – is a glimpse of just how strange and beautiful our universe is.

Rob Coyne, Teaching Professor of Physics, University of Rhode Island

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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That last paragraph says it all: ‘So in asking about the center of the universe, we’re confronting the limits of our intuition.’

Just wonderful!

Keeping one’s garden wild

A great TED Talk.

We live on 13 acres. Even the land near to the house is difficult to keep tidy so when Jean and I saw this TED Talk given by Rebecca McMacin we were overjoyed. For having a tidy garden does much greater harm to wildlife than keeping it wild.

Before I get to the TED video, I just want to show you some photos I took last Saturday.

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Now to the TED Talk

Here is the description of the talk.

Many gardeners work hard to maintain clean, tidy environments … which is the exact opposite of what wildlife wants, says ecological horticulturist Rebecca McMackin. She shows the beauty of letting your garden run wild, surveying the success she’s had increasing biodiversity even in the middle of New York City — and offers tips for cultivating a garden that can be home to birds, bees, butterflies and more.

Here is Rebecca’s background.

Rebecca McMackin is an ecologically obsessed horticulturist who helps people create and care for beautiful gardens that provide habitat for birds, butterflies and soil microorganisms.

Why you should listen

Rebecca McMackin spent a decade as director of horticulture at Brooklyn Bridge Park, where she employed organic principles to manage 85 acres of diverse parkland. During her time overseeing the park’s ecology, stick bugs, rare mantids, threatened bees and lady bugs all returned to the park. The park’s urban biodiversity and successful use of ethical management strategies influenced thousands of people and other urban parks to adopt similar approaches.

In addition to her work designing public gardens, McMackin writes, lectures and teaches on ecological landscape management and pollination ecology. She recently installed an 8,000-square-foot native wildflower garden for the entrance to the Brooklyn Museum. She was a Loeb Fellow at the Harvard Graduate School of Design, while her work has been published by and featured in The New York Times, the Landscape Institute and on NPR and PBS.

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The video is just 12 minutes long and I encourage you to view it.

The blue waters

It was World Oceans Day yesterday.

To my mind, nothing beats the sights of the World’s oceans.

In the past, I spent four years living on a yacht, a Tradewind 33, out in Cyprus. During that time I cruised to Turkey, to Greece, to Algiers, and loved it.

Here’s an extract from World Oceans day website.

Why Earth’s oceans are so important

Earth’s oceans are critical to human survival. Indeed, more than half the oxygen in our atmosphere is generated via photosynthesis by phytoplankton and seaweed in oceans. In addition, millions of people depend on fish and other marine animals for food. Research on some marine organisms has led to the development of new medications. Moreover, ocean currents, known as global conveyor belts, help regulate Earth’s climate. 

Sir David Attenborough has produced a film Ocean and the trailer follows:

There is so much more to view on the World Oceans Day website. Please go to it.

The building blocks of numbers

We are talking of prime numbers.

Science and mathematics have been a long interest of mine and I regret that I did not go to university to study science. But that was a long time ago!

However, thanks to The Conversation I can write about mathematics, in this case Prime Numbers.

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Prime numbers, the building blocks of mathematics, have fascinated for centuries − now technology is revolutionizing the search for them

Prime numbers are numbers that are not products of smaller whole numbers. Jeremiah Bartz

Jeremiah Bartz, University of North Dakota

A shard of smooth bone etched with irregular marks dating back 20,000 years puzzled archaeologists until they noticed something unique – the etchings, lines like tally marks, may have represented prime numbers. Similarly, a clay tablet from 1800 B.C.E. inscribed with Babylonian numbers describes a number system built on prime numbers.

As the Ishango bone, the Plimpton 322 tablet and other artifacts throughout history display, prime numbers have fascinated and captivated people throughout history. Today, prime numbers and their properties are studied in number theory, a branch of mathematics and active area of research today.

A history of prime numbers

A long, thin shard of bone with small lines scratched into it.
Some scientists guess that the markings on the Ishango bone represent prime numbers. Joeykentin/Wikimedia Commons, CC BY-SA

Informally, a positive counting number larger than one is prime if that number of dots can be arranged only into a rectangular array with one column or one row. For example, 11 is a prime number since 11 dots form only rectangular arrays of sizes 1 by 11 and 11 by 1. Conversely, 12 is not prime since you can use 12 dots to make an array of 3 by 4 dots, with multiple rows and multiple columns. Math textbooks define a prime number as a whole number greater than one whose only positive divisors are only 1 and itself.

Math historian Peter S. Rudman suggests that Greek mathematicians were likely the first to understand the concept of prime numbers, around 500 B.C.E.

Around 300 B.C.E., the Greek mathematician and logician Euler proved that there are infinitely many prime numbers. Euler began by assuming that there is a finite number of primes. Then he came up with a prime that was not on the original list to create a contradiction. Since a fundamental principle of mathematics is being logically consistent with no contradictions, Euler then concluded that his original assumption must be false. So, there are infinitely many primes.

The argument established the existence of infinitely many primes, however it was not particularly constructive. Euler had no efficient method to list all the primes in an ascending list.

a diagram showing prime numbers as dots in rows, with composite numbers as dots arranged in rectangles of at least two rows of dots, with the same number of dots in each row.
Prime numbers, when expressed as that number of dots, can be arranged only in a single row or column, rather than a square or rectangle. David Eppstein/Wikimedia Commons

In the middle ages, Arab mathematicians advanced the Greeks’ theory of prime numbers, referred to as hasam numbers during this time. The Persian mathematician Kamal al-Din al-Farisi formulated the fundamental theorem of arithmetic, which states that any positive integer larger than one can be expressed uniquely as a product of primes.

From this view, prime numbers are the basic building blocks for constructing any positive whole number using multiplication – akin to atoms combining to make molecules in chemistry.

Prime numbers can be sorted into different types. In 1202, Leonardo Fibonacci introduced in his book “Liber Abaci: Book of Calculation” prime numbers of the form (2p – 1) where p is also prime.

Today, primes in this form are called Mersenne primes after the French monk Marin Mersenne. Many of the largest known primes follow this format.

Several early mathematicians believed that a number of the form (2p – 1) is prime whenever p is prime. But in 1536, mathematician Hudalricus Regius noticed that 11 is prime but not (211 – 1), which equals 2047. The number 2047 can be expressed as 11 times 89, disproving the conjecture.

While not always true, number theorists realized that the (2p – 1) shortcut often produces primes and gives a systematic way to search for large primes.

The search for large primes

The number (2p – 1) is much larger relative to the value of p and provides opportunities to identify large primes.

When the number (2p – 1) becomes sufficiently large, it is much harder to check whether (2p – 1) is prime – that is, if (2p – 1) dots can be arranged only into a rectangular array with one column or one row.

Fortunately, Édouard Lucas developed a prime number test in 1878, later proved by Derrick Henry Lehmer in 1930. Their work resulted in an efficient algorithm for evaluating potential Mersenne primes. Using this algorithm with hand computations on paper, Lucas showed in 1876 that the 39-digit number (2127 – 1) equals 170,141,183,460,469,231,731,687,303,715,884,105,727, and that value is prime.

Also known as M127, this number remains the largest prime verified by hand computations. It held the record for largest known prime for 75 years.

Researchers began using computers in the 1950s, and the pace of discovering new large primes increased. In 1952, Raphael M. Robinson identified five new Mersenne primes using a Standard Western Automatic Computer to carry out the Lucas-Lehmer prime number tests.

As computers improved, the list of Mersenne primes grew, especially with the Cray supercomputer’s arrival in 1964. Although there are infinitely many primes, researchers are unsure how many fit the type (2p – 1) and are Mersenne primes.

By the early 1980s, researchers had accumulated enough data to confidently believe that infinitely many Mersenne primes exist. They could even guess how often these prime numbers appear, on average. Mathematicians have not found proof so far, but new data continues to support these guesses.

George Woltman, a computer scientist, founded the Great Internet Mersenne Prime Search, or GIMPS, in 1996. Through this collaborative program, anyone can download freely available software from the GIMPS website to search for Mersenne prime numbers on their personal computers. The website contains specific instructions on how to participate.

GIMPS has now identified 18 Mersenne primes, primarily on personal computers using Intel chips. The program averages a new discovery about every one to two years.

The largest known prime

Luke Durant, a retired programmer, discovered the current record for the largest known prime, (2136,279,841 – 1), in October 2024.

Referred to as M136279841, this 41,024,320-digit number was the 52nd Mersenne prime identified and was found by running GIMPS on a publicly available cloud-based computing network.

This network used Nvidia chips and ran across 17 countries and 24 data centers. These advanced chips provide faster computing by handling thousands of calculations simultaneously. The result is shorter run times for algorithms such as prime number testing.

A small rectangle metal chip reading 'nVIDIA'
New and increasingly powerful computer chips have allowed prime-number hunters to find increasingly larger primes. Fritzchens Fritz/Flickr

The Electronic Frontier Foundation is a civil liberty group that offers cash prizes for identifying large primes. It awarded prizes in 2000 and 2009 for the first verified 1 million-digit and 10 million-digit prime numbers.

Large prime number enthusiasts’ next two challenges are to identify the first 100 million-digit and 1 billion-digit primes. EFF prizes of US$150,000 and $250,000, respectively, await the first successful individual or group.

Eight of the 10 largest known prime numbers are Mersenne primes, so GIMPS and cloud computing are poised to play a prominent role in the search for record-breaking large prime numbers.

Large prime numbers have a vital role in many encryption methods in cybersecurity, so every internet user stands to benefit from the search for large prime numbers. These searches help keep digital communications and sensitive information safe.

Jeremiah Bartz, Associate Professor of Mathematics, University of North Dakota

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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I find it unbelievable that there are prizes for the first 100 million-digit prime number and also the first 1 billion-digit prime number. It is so far away from my understanding of these numbers that all I can say is: I find it unbelievable!

Artificial Intelligence and Mars

NASA hasn’t landed humans on Mars yet. But thanks to robotic missions, scientists now know more about the planet’s surface than they did when the movie, The Martian, was released.

Our human knowledge is constantly growing. In many, many directions. Here is a fascinating (well it is to me!) article from The Conversation.

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A decade after the release of ‘The Martian’ and a decade out from the world it envisions, a planetary scientist checks in on real-life Mars exploration

‘The Martian’ protagonist Mark Watney contemplates his ordeal. 20th Century Fox

Ari Koeppel, Dartmouth College

Andy Weir’s bestselling story “The Martian” predicts that by 2035 NASA will have landed humans on Mars three times, perfected return-to-Earth flight systems and collaborated with the China National Space Administration. We are now 10 years past the Hollywood adaptation’s 2015 release and 10 years shy of its fictional timeline. At this midpoint, Mars exploration looks a bit different than how it was portrayed in “The Martian,” with both more discoveries and more controversy.

As a planetary geologist who works with NASA missions to study Mars, I follow exploration science and policy closely. In 2010, the U.S. National Space Policy set goals for human missions to Mars in the 2030s. But in 2017, the White House Space Policy Directive 1 shifted NASA’s focus toward returning first to the Moon under what would become the Artemis program.

Although concepts for crewed missions to Mars have gained popularity, NASA’s actual plans for landing humans on Mars remain fragile. Notably, over the last 10 years, it has been robotic, rather than crewed, missions that have propelled discovery and the human imagination forward.

A diagram showing the steps from lunar missions to Mars missions. The steps in the current scope are labeled 'Human presence on Moon,' 'Practice for Mars Exploration Demo' and 'Demo exploration framework on Mars.' The partial scope step is labeled 'Human presence on Mars.'
NASA’s 2023 Moon to Mars Strategy and Objectives Development document lays out the steps the agency was shooting for at the time, to go first to the Moon, and from there to Mars. NASA

Robotic discoveries

Since 2015, satellites and rovers have reshaped scientists’ understanding of Mars. They have revealed countless insights into how its climate has changed over time.

As Earth’s neighbor, climate shifts on Mars also reflect solar system processes affecting Earth at a time when life was first taking hold. Thus, Mars has become a focal point for investigating the age old questions of “where do we come from?” and “are we alone?”

The Opportunity, Curiosity and Perseverance rovers have driven dozens of miles studying layered rock formations that serve as a record of Mars’ past. By studying sedimentary layers – rock formations stacked like layers of a cake – planetary geologists have pieced together a vivid tale of environmental change that dwarfs what Earth is currently experiencing.

Mars was once a world of erupting volcanoes, glaciers, lakes and flowing rivers – an environment not unlike early Earth. Then its core cooled, its magnetic field faltered and its atmosphere drifted away. The planet’s exposed surface has retained signs of those processes ever since in the form of landscape patterns, sequences of layered sediment and mineral mixtures.

Rock shelves layered on top of each other, shown from above.
Layered sedimentary rocks exposed within the craters of Arabia Terra, Mars, recording ancient surface processes. Photo from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment. NASA/JPL/University of Arizona

Arabia Terra

One focus of scientific investigation over the last 10 years is particularly relevant to the setting of “The Martian” but fails to receive mention in the story. To reach his best chance of survival, protagonist Mark Watney, played by Matt Damon, must cross a vast, dusty and crater-pocked region of Mars known as Arabia Terra.

In 2022 and 2023, I, along with colleagues at Northern Arizona University and Johns Hopkins University, published detailed analyses of the layered materials there using imagery from the Mars Reconnaissance Orbiter and Mars Odyssey satellites.

By using infrared imagery and measuring the dimensions of surface features, we linked multiple layered deposits to the same episodes of formation and learned more about the widespread crumbling nature of the terrain seen there today. Because water tends to cement rock tightly together, that loose material indicates that around 3.5 billion years ago, that area had a drying climate.

To make the discussions about this area easier, we even worked with the International Astronomical Union to name a few previously unnamed craters that were mentioned in the story. For example, one that Watney would have driven right by is now named Kozova Crater, after a town in Ukraine.

More to explore

Despite rapid advances in Mars science, many unknowns remain. Scientists still aren’t sure of the precise ages, atmospheric conditions and possible signatures of life associated with each of the different rock types observed on the surface.

For instance, the Perseverance rover recently drilled into and analyzed a unique set of rocks hosting organic – that is, carbon-based – compounds. Organic compounds serve as the building blocks of life, but more detailed analysis is required to determine whether these specific rocks once hosted microbial life.

The in-development Mars Sample Return mission aims to address these basic outstanding questions by delivering the first-ever unaltered fragments of another world to Earth. The Perseverance rover is already caching rock and soil samples, including ones hosting organic compounds, in sealed tubes. A future lander will then need to pick up and launch the caches back to Earth.

Sampling Mars rocks could tell scientists more about the red planet’s past, and whether it could have hosted life.

Once home, researchers can examine these materials with instruments orders of magnitude more sensitive than anything that could be flown on a spacecraft. Scientists stand to learn far more about the habitability, geologic history and presence of any signs of life on Mars through the sample return campaign than by sending humans to the surface.

This perspective is why NASA, the European Space Agency and others have invested some US$30 billion in robotic Mars exploration since the 1960s. The payoff has been staggering: That work has triggered rapid technological advances in robotics, telecommunications and materials science. For example, Mars mission technology has led to better sutures for heart surgery and cars that can drive themselves.

It has also bolstered the status of NASA and the U.S. as bastions of modern exploration and technology; and it has inspired millions of students to take an interest in scientific fields.

The Perseverance rover and the Ingenuity helicopter on the Martian surface, with the rover's camera moving to look down at Ingenuity.
A selfie from NASA’s Perseverance Mars rover with the Ingenuity helicopter, taken with the rover’s extendable arm on April 6, 2021. NASA/JPL-Caltech/MSSS

Calling the red planet home?

Colonizing Mars has a seductive appeal. It’s hard not to cheer for the indomitable human spirit while watching Watney battle dust storms, oxygen shortages and food scarcity over 140 million miles from rescue.

Much of the momentum toward colonizing Mars is now tied to SpaceX and its CEO Elon Musk, whose stated mission to make humanity a “multi-planetary species” has become a sort of rallying cry. But while Mars colonization is romantic on paper, it is extremely difficult to actually carry out, and many critics have questioned the viability of a Mars habitation as a refuge far from Earth.

Now, with NASA potentially facing a nearly 50% reduction to its science budget, the U.S. risks dissolving its planetary science and robotic operations portfolio altogether, including sample return.

Nonetheless, President Donald Trump and Musk have pushed for human space exploration to somehow continue to progress, despite those proposed cuts – effectively sidelining the robotic, science-driven programs that have underpinned all of Mars exploration to date.

Yet, it is these programs that have yielded humanity’s richest insights into the red planet and given both scientists and storytellers like Andy Weir the foundation to imagine what it must be like to stand on Mars’ surface at all.

Ari Koeppel, Postdoctoral Scientist in Earth and Planetary Science, Dartmouth College

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Nothing to add from yours truly except to say that this quote is highly relevant: “Challenges are what make life interesting and overcoming them is what makes life meaningful.” – Joshua J. Marine

(And this was the result of me looking online for quotes and coming across 50 quotes from USA Today.)

Light speed

There is more to this topic that many of us do not know.

Photons are massless. They travel at a speed that 99% of us do not really comprehend. But over to Prof. Jarred Roberts who does comprehend the subject.

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Do photons wear out? An astrophysicist explains light’s ability to travel vast cosmic distances without losing energy

Light, whether from a star or your flashlight, travels at 186,000 miles per second. Artur Debat/Moment via Getty Images

Jarred Roberts, University of California, San Diego

My telescope, set up for astrophotography in my light-polluted San Diego backyard, was pointed at a galaxy unfathomably far from Earth. My wife, Cristina, walked up just as the first space photo streamed to my tablet. It sparkled on the screen in front of us.

“That’s the Pinwheel galaxy,” I said. The name is derived from its shape – albeit this pinwheel contains about a trillion stars.

The light from the Pinwheel traveled for 25 million years across the universe – about 150 quintillion miles – to get to my telescope.

My wife wondered: “Doesn’t light get tired during such a long journey?”

Her curiosity triggered a thought-provoking conversation about light. Ultimately, why doesn’t light wear out and lose energy over time?

Let’s talk about light

I am an astrophysicist, and one of the first things I learned in my studies is how light often behaves in ways that defy our intuitions.

A photo of outer space that shows a galaxy shaped like a pinwheel.
The author’s photo of the Pinwheel galaxy. Jarred Roberts

Light is electromagnetic radiation: basically, an electric wave and a magnetic wave coupled together and traveling through space-time. It has no mass. That point is critical because the mass of an object, whether a speck of dust or a spaceship, limits the top speed it can travel through space.

But because light is massless, it’s able to reach the maximum speed limit in a vacuum – about 186,000 miles (300,000 kilometers) per second, or almost 6 trillion miles per year (9.6 trillion kilometers). Nothing traveling through space is faster. To put that into perspective: In the time it takes you to blink your eyes, a particle of light travels around the circumference of the Earth more than twice.

As incredibly fast as that is, space is incredibly spread out. Light from the Sun, which is 93 million miles (about 150 million kilometers) from Earth, takes just over eight minutes to reach us. In other words, the sunlight you see is eight minutes old.

Alpha Centauri, the nearest star to us after the Sun, is 26 trillion miles away (about 41 trillion kilometers). So by the time you see it in the night sky, its light is just over four years old. Or, as astronomers say, it’s four light years away. Imagine – a trip around the world at the speed of light.

With those enormous distances in mind, consider Cristina’s question: How can light travel across the universe and not slowly lose energy?

Actually, some light does lose energy. This happens when it bounces off something, such as interstellar dust, and is scattered about.

But most light just goes and goes, without colliding with anything. This is almost always the case because space is mostly empty – nothingness. So there’s nothing in the way.

When light travels unimpeded, it loses no energy. It can maintain that 186,000-mile-per-second speed forever.

It’s about time

Here’s another concept: Picture yourself as an astronaut on board the International Space Station. You’re orbiting at 17,000 miles (about 27,000 kilometers) per hour. Compared with someone on Earth, your wristwatch will tick 0.01 seconds slower over one year.

That’s an example of time dilation – time moving at different speeds under different conditions. If you’re moving really fast, or close to a large gravitational field, your clock will tick more slowly than someone moving slower than you, or who is further from a large gravitational field. To say it succinctly, time is relative.

An astronaut floats weightless aboard the International Space Station.
Even astronauts aboard the International Space Station experience time dilation, although the effect is extremely small. NASA

Now consider that light is inextricably connected to time. Picture sitting on a photon, a fundamental particle of light; here, you’d experience maximum time dilation. Everyone on Earth would clock you at the speed of light, but from your reference frame, time would completely stop.

That’s because the “clocks” measuring time are in two different places going vastly different speeds: the photon moving at the speed of light, and the comparatively slowpoke speed of Earth going around the Sun.

What’s more, when you’re traveling at or close to the speed of light, the distance between where you are and where you’re going gets shorter. That is, space itself becomes more compact in the direction of motion – so the faster you can go, the shorter your journey has to be. In other words, for the photon, space gets squished.

Which brings us back to my picture of the Pinwheel galaxy. From the photon’s perspective, a star within the galaxy emitted it, and then a single pixel in my backyard camera absorbed it, at exactly the same time. Because space is squished, to the photon the journey was infinitely fast and infinitely short, a tiny fraction of a second.

But from our perspective on Earth, the photon left the galaxy 25 million years ago and traveled 25 million light years across space until it landed on my tablet in my backyard.

And there, on a cool spring night, its stunning image inspired a delightful conversation between a nerdy scientist and his curious wife.

Jarred Roberts, Project Scientist, University of California, San Diego

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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This remark jumped out at me when I first read the article: ‘In the time it takes you to blink your eyes, a particle of light travels around the circumference of the Earth more than twice.’

The following photograph is the Milky Way.

The image is from Geography Realm.

Despite the fact that the article is far from me understanding it, it doesn’t reduce the wonder and the awe for me of outer space.

Making your vet clinic profitable

The second guest post from Penny Martin.

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Image: Freepik

Vision to Reality: Building a Profitable Vet Clinic

Launching a veterinary clinic is a significant endeavor that requires meticulous planning and strategic decision-making. This venture combines a passion for animal care with the intricacies of managing a successful business. Aspiring clinic owners must navigate several critical steps to lay a strong foundation and ensure operational excellence. Starting your own clinic promises not only to fulfill a dream of helping animals but also to establish a thriving enterprise in the community.

Build a Strong Foundation with an Effective Marketing Strategy

A robust marketing strategy is essential to attract potential clients in the digital era. Establishing a professional online presence through a user-friendly website that details your services, team, and location builds trust among pet owners. Engage actively on social media with regular updates and client testimonials to showcase your expertise and commitment to animal care. Forge partnerships with local pet-related businesses to increase visibility and drive traffic to your clinic, enhancing both your and your partners’ customer bases.

Craft a Clear and Detailed Business Plan

A well-constructed business plan acts as your clinic’s roadmap, detailing your mission, services offered, and the specific target market. Identify your niche early—whether it’s specializing in certain animals or treatments—to attract the appropriate clientele. Include comprehensive financial projections and a marketing budget in your plan to ensure financial preparedness and support your clinic’s promotional activities.

Enhance Your Business Knowledge by Pursuing an MBA

Running a veterinary clinic demands a blend of clinical and business expertise. Pursuing a master’s of business administration online can boost your proficiency in key business areas such as strategy, management, and finance. An MBA not only deepens your understanding of business operations but also enhances leadership skills and self-assessment capabilities. These competencies are essential for balancing the medical and business demands of your clinic, ensuring its long-term success.

Safeguard Your Business with Proper Insurance

Operating a veterinary clinic comes with inherent risks, making comprehensive insurance coverage essential. Essential policies include malpractice insurance to handle legal issues and general liability insurance for accidents on your premises. Property insurance is crucial to protect your clinic’s infrastructure and equipment against unexpected events. Consulting with an insurance expert can ensure that you have thorough coverage to protect against potential financial setbacks.

Invest in High-Quality Veterinary Equipment

Providing top-tier care necessitates investing in high-quality veterinary equipment. Essential tools like X-ray machines, surgical instruments, and lab equipment should be of the highest standard to ensure accurate diagnoses and treatments. Modern technologies, such as digital imaging systems, not only enhance patient care but also improve operational efficiency. While the initial cost may be higher, investing in quality equipment pays off in the long run by boosting efficiency and minimizing errors.

Secure the Necessary Funding for Your Clinic

Securing sufficient funding is critical when starting a veterinary clinic. Estimate your startup costs accurately to understand your financial needs, including equipment, premises, staffing, and marketing. Explore diverse financing options, such as bank loans, private investors, and specialty medical practice loans that might offer favorable terms. Adequate initial funding prevents cash flow problems and supports your clinic’s growth trajectory.

Choose the Right Location for Your Clinic

The location of your clinic is pivotal to its success, necessitating a spot with a high demand for veterinary services. Conduct thorough market research to choose a community rich in pet owners who need your services. Select a location that is accessible, visible, and has ample parking to ensure convenience for your clients. Proximity to complementary services like pet groomers or dog trainers can further enhance client traffic and provide expansion opportunities.

Opening a veterinary clinic is both challenging and rewarding, demanding a careful blend of dedication and strategic foresight. Success in this field not only enhances the well-being of pets but also contributes positively to the local community. It requires ongoing commitment to adapt and grow in a dynamic environment. Ultimately, the fulfillment of running a successful veterinary clinic comes from both the impact on animal health and the achievement of entrepreneurial goals.

Discover the timeless wisdom that dogs offer at Learning from Dogs, where integrity and living in the present are celebrated. Dive into our content and embrace the lessons from our four-legged friends.

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This is all very sound advice. Thank you, Penny.

Starting a Veterinary Clinic

A guest post.

This post, and the next one, are submitted by Penny Martin.

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Image: Freepik

Vision to Reality: Building a Profitable Vet Clinic

Launching a veterinary clinic is a significant endeavor that requires meticulous planning and strategic decision-making. This venture combines a passion for animal care with the intricacies of managing a successful business. Aspiring clinic owners must navigate several critical steps to lay a strong foundation and ensure operational excellence. Starting your own clinic promises not only to fulfill a dream of helping animals but also to establish a thriving enterprise in the community.

Build a Strong Foundation with an Effective Marketing Strategy

A robust marketing strategy is essential to attract potential clients in the digital era. Establishing a professional online presence through a user-friendly website that details your services, team, and location builds trust among pet owners. Engage actively on social media with regular updates and client testimonials to showcase your expertise and commitment to animal care. Forge partnerships with local pet-related businesses to increase visibility and drive traffic to your clinic, enhancing both your and your partners’ customer bases.

Craft a Clear and Detailed Business Plan

A well-constructed business plan acts as your clinic’s roadmap, detailing your mission, services offered, and the specific target market. Identify your niche early—whether it’s specializing in certain animals or treatments—to attract the appropriate clientele. Include comprehensive financial projections and a marketing budget in your plan to ensure financial preparedness and support your clinic’s promotional activities.

Enhance Your Business Knowledge by Pursuing an MBA

Running a veterinary clinic demands a blend of clinical and business expertise. Pursuing a master’s of business administration online can boost your proficiency in key business areas such as strategy, management, and finance. An MBA not only deepens your understanding of business operations but also enhances leadership skills and self-assessment capabilities. These competencies are essential for balancing the medical and business demands of your clinic, ensuring its long-term success.

Safeguard Your Business with Proper Insurance

Operating a veterinary clinic comes with inherent risks, making comprehensive insurance coverage essential. Essential policies include malpractice insurance to handle legal issues and general liability insurance for accidents on your premises. Property insurance is crucial to protect your clinic’s infrastructure and equipment against unexpected events. Consulting with an insurance expert can ensure that you have thorough coverage to protect against potential financial setbacks.

Invest in High-Quality Veterinary Equipment

Providing top-tier care necessitates investing in high-quality veterinary equipment. Essential tools like X-ray machines, surgical instruments, and lab equipment should be of the highest standard to ensure accurate diagnoses and treatments. Modern technologies, such as digital imaging systems, not only enhance patient care but also improve operational efficiency. While the initial cost may be higher, investing in quality equipment pays off in the long run by boosting efficiency and minimizing errors.

Secure the Necessary Funding for Your Clinic

Securing sufficient funding is critical when starting a veterinary clinic. Estimate your startup costs accurately to understand your financial needs, including equipment, premises, staffing, and marketing. Explore diverse financing options, such as bank loans, private investors, and specialty medical practice loans that might offer favorable terms. Adequate initial funding prevents cash flow problems and supports your clinic’s growth trajectory.

Choose the Right Location for Your Clinic

The location of your clinic is pivotal to its success, necessitating a spot with a high demand for veterinary services. Conduct thorough market research to choose a community rich in pet owners who need your services. Select a location that is accessible, visible, and has ample parking to ensure convenience for your clients. Proximity to complementary services like pet groomers or dog trainers can further enhance client traffic and provide expansion opportunities.

Opening a veterinary clinic is both challenging and rewarding, demanding a careful blend of dedication and strategic foresight. Success in this field not only enhances the well-being of pets but also contributes positively to the local community. It requires ongoing commitment to adapt and grow in a dynamic environment. Ultimately, the fulfillment of running a successful veterinary clinic comes from both the impact on animal health and the achievement of entrepreneurial goals.

Discover the timeless wisdom that dogs offer at Learning from Dogs, where integrity and living in the present are celebrated. Dive into our content and embrace the lessons from our four-legged friends.

ooOOoo

Opening a vet clinic is well beyond me even though many years ago I was an entrepreneur.

However, one hopes that somewhere a person or two find this very useful.

Talking dogs!

And that title is not a joke!

Want to know whether “talking” dogs like Bunny are for real? When UC San Diego Professor Federico Rossano first saw Bunny’s videos, he was a skeptic. After all, he knows all about the complicated and messy history of animal communication studies – like the woman who tried to teach a dolphin to speak. But after studying these button-pushing pups for years, his team has published some research that will make you rethink just how much dogs are capable of telling us. Federico’s study is still looking for participants! Sign up here: https://cclab.ucsd.edu/pet-cognition-…