Category: Science Blog

I got myself a 3D printer for a Christmas gilt. Well actually, my wife bought it as a gilt but I specified the type and where to buy it from. Before you get all hissy, she specifies her jewelry gifts for me to buy for her so it is a two-way street. The printer I got is an Ender 3 Pro for the 3D printing cognoscenti. For everybody else, it’s possibly the most popular 3D printer at the moment because of its price and capability. I’m pleased with it and I have been busy making things to try it out.

“So what is a 3D printer and why did I want one?” I hear some of you say, well it’s a device that produces 3D objects from a computer modeling program. For most hobby-grade 3D printers it does this by melting plastic string to make the object. The plastic string comes as a reel that is mounted to the printing machine. The string, or filament as it’s properly called, is fed into heated nozzle where it is transformed into a molten thread. This thread is then placed onto the surface of a platform or platen that is moved from front to back by the computer. The nozzle is mounted so that it can be moved from side to side and up or down, also under computer control. By drawing a two-dimensional slice of the object being built onto the platen, then lifting the nozzle up a little bit before drawing the next slice on top of the first, the 3D object can be made, slice by slice.

These printers are used by hobbyists for fun projects. I wanted one to make parts for my model planes and model boats. Simple parts that cost a lot to buy and are hard to find. 3D printers are also used professionally to produce prototypes of new products for consumer testing or complex parts for high technology industries. More complex 3D printers are used to produce prosthetic limbs and other complex structures.

Specialized printers produce sintered metal objects such as jet engine compressor blades. SpaceX makes parts for their rocket motors using a metal deposition 3D printer. Other printers use a bath of metal powder and a laser to produce the 3D print. Yet others use a bath of liquid monomer chemical and a laser that draws on the surface generating a polymer trace to make the 3D object. The applications continue to grow as more and better 3D printers are developed.

The mention of laser 3D printers reminds me of a time long ago and far, far away when I was working as a postdoc researcher in the chemistry department of a large university in England. We were studying the chemical applications of laser technology. We did in fact produce the first laser induced chemical reaction

and the first laser induced reversible isomerization. In our department at that time we had a guest member of staff who was given facilities for his research but was not paid a salary. He earned his living by scientific writing, particularly in writing a weekly column for the UK’s most prestigious popular scientific magazine.

We would often meet over coffee where he would present us with his latest crazy idea for a column. These columns were very amusing and intellectually challenging since they would always have within them a technical flaw that made their claims specious. On one occasion he asked about the possibility of filling an aquarium tank with a monomer that required two different laser colors simultaneously to produce polymer. If we could organize things such that the two different lasers were made to cross inside the tank, they would produce a blob of hardened plastic polymer. By scanning the lasers about we could make a three dimensional object; an early generation 3D printer before they had been invented; we thought. This ‘invention’ was only for the amusement of his readers but when he published the idea little did he anticipate the reaction. He and his publisher were served with a writ to cease and desist by a company claiming contravention of their patent. This writ came from some company in the USA who didn’t seem to have much of a sense of humor and were unable to detect the spoof that it was.

My current interest in 3D printing is focused on my RC sailboat hobby; I want to make a 3D printed model sailboat. I know that others have done this but I’m not interested in copying them so much as learning from their experience to build my own model. Since my printer doesn’t have a print volume large enough to accommodate a complete model, I will have to build it in sections then glue them together, much like most large ships are made today.

To do the design work I use Autodesk Fusion 360 as my CAD program. This is available for free for non-commercial hobbyist use. When I have an object that I want to print I save it as a STL file then I use Ultimaker Cura to slice it. The Cura slicing program does basically what it says; it makes the 2D slices from the 3D model that are then stacked on the printer to produce the 3D object. Once I have the GCODE file made by the slicer, I load it into the printer, load up the printer with the chosen filament, warm it up and set it going. Prints can take a long time. An object about 1cm by 1cm by 1cm will take a bit less than an hour to print but larger objects can take all day.

Luckily I have two sailing buddies who have printers and they have given me lots of tips on how to get the best results. They also made some parts that I wanted before I got my own printer. The most notable of these parts was the mold for a ballast bulb that one of my friends made for me for my US 1M build.

He took the airfoil shape that we wanted and modeled it using Fusion 360. The CAD software gave an estimate of the volume of the torpedo shape and we combined that with our best estimate of the density of the material we would use until we got close to the 4lbs weight I was looking for. He then printed out the half mold in two sections on his printer. I glued the two parts together to get a mold of the lower (or upper) half of the bulb shape. This I filled with epoxy resin and #7 lead shot. When it set, I removed the shape, made a second piece and epoxied the two together. A little filling and filing, a couple of coats of primer, a coat of black paint and some clear lacquer, and I had a perfect bulb weight for the keel of the boat.

As I said earlier, I’m having fun with my printer. If you want to know more just Google 3D printing and you will get a huge list of information about them including places that will make a 3D print for you as a service, albeit not a cheap one.

When I was a kid living in Scotland, I remember my dad getting us out of bed in the middle of the night to show us a comet in the sky out of our bedroom window. This occurred in the 1950s. The comet was easily visible with the naked eye and had a very distinctive tail. I don’t know for sure which comet it was but a little research suggests it was either Arend-Roland or Mrkos. My money is on Mrkos.

Both these comets were visible from Earth months apart in 1957 and both were non-periodic comets; so they won’t be back. I have never seen another comet so clearly since then.

There’s a lot of fuss today about comets and asteroids and their possibility of impacting our planet. It turns out that we are struck by at least 6000 asteroids per year, most of which are small and burn up in the atmosphere. It’s estimated that about 100 tons of dust/sand-sized debris impact our atmosphere every day.

It seems that asteroid impacts are quite common so I think the fuss is really about those that are large enough to cause a threat to life and property. Asteroid impacts of this size are rare. Impacts that are large enough to cause damage and some loss of life happen about every 2000 years on average with those large enough to threaten our civilization occurring every few million years.

Most asteroids orbit the sun in a belt, the Asteroid Belt, between Mars and Jupiter. This belt lies in the plane of the ecliptic, the disk around the sun within which all the planets orbit. Now and again one of these asteroids is disturbed in its orbit, usually by a collision with another asteroid, and fall inward toward the sun in the plane of the ecliptic.

As it falls toward the sun it gains speed, swapping its potential energy for kinetic energy. When it gets close to the Earth it can be moving at up to 150,000 miles per hour. The law of gravity means that the speed of the falling asteroid does not depend on its mass, but its kinetic energy does. A large mile wide asteroid weighing millions of tons and traveling at 150,000 miles an hour will be an extinction-level event if it hits our planet; the planet will recover, we will not.

Comets are thought to come from either the Kuiper Belt, a disk-shaped cloud of objects and lies beyond the orbit of Neptune, or the Oort Cloud that is thought to be a spherical cloud far beyond Pluto that contains up to a trillion comet-like objects. Unlike asteroids, comets typically travel toward the sun on a path that is not in the plane of the ecliptic.

These more random trajectories and the relative infrequency of comets compared to asteroids makes them less of a threat. Although it might have been a comet that caused the impact 65 million years ago that is attributed to the extinction of the dinosaurs, it was more likely to have been an asteroid, if for no other reason than the abundance of Iridium that it seems to have left behind.

I do hear people worrying about the destruction of the planet; they should not fret about the Earth being destroyed. Our planet has survived many extinction events and come through it, changed to be sure, but still a vibrant home to new life forms to thrive. The human species may be exterminated by a comet or asteroid impact, but the planet will continue to spin on its axis and orbit the sun as before, it will just do so less a number of the species currently living upon it. When folks claim to be trying to ‘save the planet’ they aren’t, they are trying to save themselves in the manner that they find comfortable. I don’t hear them consulting cockroaches and ants for their opinion on planet-saving.

Our planet is about 4.5 billion years old. During that time it has gone through many changes. The late heavy bombardment is thought to have happened about 4 billion years ago and is thought to have been a time when Earth was hammered by a deluge of asteroids leaving the surface molten lava. Life would not have been possible during this time. As the Earth cooled the early atmosphere consisted mostly of nitrogen and carbon dioxide, 200 times what is in the atmosphere today, with an abundance of methane, ammonia, water vapor, hydrogen sulfide, and neon, but no oxygen. The oxygen-rich atmosphere occurred about 3 billion years ago and was caused by the emissions of oxygen by cyanobacteria, using photosynthesis, that thrived in the CO2 rich atmosphere. This was chemical warfare on the global scale as the planet was changed forever. The arrival of free oxygen kick-started the evolution of life on Earth. But it would not last as life on Earth endured a sequence of mass-extinctions beginning with the Ordovician-Silurian Extinction some 440 million years ago.

Life has thrived then been extinguished at least five times in the history of our planet. It seems that more than 99% of all species that ever lived on Earth are now extinct. The first mass extinction, the Ordovician-Silurian Extinction, occurred about 440 million years ago and killed off about 85% of all species, mostly small marine organisms. It is thought that the cause was the rapid swing of the global temperature from very much colder to a very much warmer bounce, with changes in sea levels and atmospheric CO2 concentration. It doesn’t seem that comet or asteroid impacts were responsible.

Life thrived again on Earth until the next mass extinction killed 75% of all species, falling hardest of marine organisms including corals and trilobites. This Late Devonian Extinction happened over a 20 million year span starting about 380 million years ago. It is thought that this extinction was caused by mass volcanism, probably in what is now Siberia, that resulted in lower oxygen levels in the atmosphere.

The Permian-Triassic Extinction, 252 million years ago, is also called the Great Dying. It killed off 96% of all marine species and 75% of all land species. The world’s forests were wiped out as well as large numbers of insect species. The largest contributor to this global calamity was the Siberian Traps, a complex of super volcanos that spewed 14.5 trillion tons of carbon into the atmosphere. The global temperature rose about 30F with the result that the oceans lost up to three-quarters of their oxygen.

Life on Earth got busy recovering from the Great Dying but only 50 million years later, about 201 million years ago, some 80% of all species were wiped out in the Triassic-Jurassic Extinction. The causes of this extinction event are the subject of much debate. Some contend that the cause was global warming caused by the release of CO2 into the atmosphere by volcanism associated with the break up of the super-continent Pangea. Others blame the release of methane into the atmosphere while a third group of scientists blames a combination of volcanism and the impact of a large comet or asteroid. What is not debated is that this extinction event cleared the way for the dinosaurs to rule the Earth.

The dinosaurs prospered for 150 million years until they were wiped out along with 76% of all species by the Cretaceous-Tertiary Extinction 65 million years ago. The causes of this extinction have been long debated but the majority view nowadays is that it was caused by a large asteroid impact off the coast of the Yucatan Peninsula. The jury is still out on the verdict on the cause with a vocal minority blaming global warming caused by volcanism and other tectonic effects. What is not in doubt is that land dinosaurs were profligate before this event and non-existent afterward, leaving the planet free for the rise of the Mammals, including us.

What can we conclude from this history of the evolution of life on our planet and the mass extinctions that eliminated most of the life at five times in our history? I think that the first obvious conclusion is that our planet is very robust and can shake off these calamitous events as can be seen by the average global temperature over the last 500 million years.

Life too seems to be very robust in the abstract if not the specific.After each annihilation of species, new life evolves and thrives on our planet. It seems therefore that while the life of humanity may be fragile and in danger of extinction from one calamity or another, life on planet Earth is not subject to the same danger. When we are gone, our planet will keep spinning and orbiting the sun and new life will keep evolving until our sun goes red giant and consumes it. I will not be here to see that event but I wish I could.

Many people are curious about the universe they live in. Many of them are afraid to ask obvious questions in case they are accused of asking stupid questions. When it comes to matters of science there are no stupid questions; it’s the simple questions that reveal the most interesting findings. Here I want to pose some of the most obvious questions that people might ask. These questions, it turns out, are not simple but reveal some of the deepest and most complex properties of our universe. Here I am reviewing some of the questions that people ask together with my understanding of how science answers them. Remember that I could be wrong in my explanations but I think I’m mostly right.

One of the first questions people ask is ‘how old is the universe?’ This is a very non-stupid question. Scientists and philosophers have been staring at the night sky for centuries and more, contemplating this very question. Now we have an answer that has been a long time coming. As best we can tell our universe is about 13.8 billion years old.

Your next question should be, ‘how do you know that?’ That too is not a stupid question. Our first clue came from the work of the famous American astronomer, Edwin Hubble and the Belgian astronomer Georges Lemaitre. Hubble found that distant galaxies were moving away from each other at a speed that increased with distance, Hubble’s Law. That being the case, turning the clock backward would find all of the galaxies in one place at one time. This finding was initially greatly resisted by other astronomers who insisted that the universe was static and infinite in time and space. It was one of them, Fred Hoyle, who coined the phrase Big Bang as a derogatory epithet. The phrase stuck as did the expansion theory with its conclusion of a finite age to the universe.

Modern estimates of the age of the universe depend less on Hubble’s Law and more on the precise measurement of the Cosmic Background Radiation (CMB).

As the universe expanded after the Big Bang, the universe cooled from the almost unimaginable temperatures that it started with. That cooling continues to this day. By measuring the temperature of the CMB today we can estimate for how long the initial fireball has been cooling, leading to the most accurate estimate of the age of the universe of 13.8 billion years.

The next question people might ask is, ‘how big is the universe?’ That too is not a stupid question and it has multiple answers. We can see up to 13.8 billion years away, almost back to the beginning of the universe, but it has expanded since then. Because of this expansion, what was 13.8 billion light-years away is now estimated to be 46 billion light-years away. Thus the diameter of the observable universe is estimated to be 93 billion light-years and still expanding.

There is no sure answer to the question, ‘what existed before the Big Bang?’ There have been many attempts to answer this question with no completely convincing theory. These attempts continue today with some claims that the CMB shows signs of ‘bruising’ caused by contact with an adjacent universe together with other indications of a life before the Big Bang. Steven Hawking and James Hartle suggested in a famous scientific paper that the evolution of the universe was shaped like a shuttlecock, with no beginning. They claimed that asking what came before the Big Bang was like asking what was south of the South Pole.

This answer is very unsatisfactory since it avoids an answer. This drives scientists to strive even harder to find a theory that explains the facts and is satisfying.

Perhaps the next question people ask is, ‘what will happen to the universe over time?’ Again there is no clear answer, it all depends on the nature of space and time. We once thought that the future of the universe depended on how much matter (stuff) was in it. It’s a bit like throwing a baseball straight up into the air. Since you can’t throw it fast enough it will fall back down to you. The faster you throw it the higher it will go before slowing down, coming to a stop, and falling back down for you to catch. Imagine if you could throw it really fast, fast enough that it would never slow down enough to come to a stop; it would be gone forever. There are three conditions in this baseball throwing challenge; not fast enough; just fast enough; and more than fast enough. In the first condition, the ball falls back to the thrower. In the second the ball slows to a stop at infinity and stays there. In the third condition, the ball is still moving away when it gets infinitely distant from the thrower. Using Newton’s gravity, these conditions were labeled, elliptic, parabolic, and hyperbolic.

Getting back to the universe. Depending on how much stuff is in the universe, we once thought it could fly apart forever, stop moving at infinite distance, or fall back together into a big crunch. By estimating how much mass we could see in the universe it looked like it would fly apart forever.

Then we discovered Dark Matter, and later Dark Energy. When we look at the planets in our solar system as they orbit the sun we notice that those farther away take longer to complete an orbit.

The closer planets complete their orbits more quickly. When astronomers looked at stars orbiting the centers of spiral galaxies they got a shock; the outer stars were all orbiting at more or less the same speed. This behavior, and that of orbiting galaxies in galactic clusters, did not obey the rules of gravity as we knew them.

One way to make this orbital behavior fit was to propose that these galaxies contained much more matter than we could see; Dark Matter.

To confirm the Dark Matter theory, astronomers started to look for other signs of its existence. One major confirmation was when they saw that individual galaxies could act as a gravitational lens to distort the view of galaxies farther away. When astronomers computed how much gravity was needed to do this it was much more than was visible in the galaxy that formed the lens.

In addition, when astronomers plotted the positions of galactic clusters in a three-dimensional map of the universe, they discovered that they were distributed in strings and sheets with voids between them much like Swiss cheese or a sponge. It seems that it was Dark Matter that formed the structure of the universe around which ordinary matter such as stars and galaxies coalesced.

Astronomers then calculated how much Dark Matter was in the universe and got another shock. It seems that Dark Matter accounts for about 85% of the matter in the universe while ordinary matter like stars and galaxies, accounts for the other 15%.

However, even adding the Dark Matter estimate did not provide enough stuff to slow down the expansion enough to stop the universe from expanding forever. Another shock came when astronomers checked on the expansion rate of the universe using more powerful and more accurate techniques than before; the expansion was accelerating.

According to the usual theory of gravity, Einstein’s General Relativity, the expansion rate must slow down over time due to the pull of the totality of matter in the universe; but it wasn’t. It seemed that another force was at work, much like gravity but this time a repulsive force rather than an attractive one. This force was named Dark Energy, mainly because no one knows what it is or how it works. Most people have heard of Einstein’s most famous equation, E-mc², and understand that it means that mass can turn into energy and vice versa, but it also means that energy can act just like mass to cause a gravitational pull. In the case of Dark Energy, it seems to cause a change in the overall force of gravity in the universe over time to accelerate the expansion. When astronomers added up the total energy in the universe from Dark Energy, Dark Matter, and ordinary matter, they found that Dark Energy contributed an estimated 69% of it, with Dark Matter contributing 26% and ordinary matter only 5%. It seems then that 95% of our universe is made up of stuff we can neither see nor understand as yet. It also seems that the Dark Energy contribution sends our universe on a one-way journey, expanding forever until all the stars go out and it becomes a cold and dark, and lonely place. We shall be long gone by then.

There’s a current push to encourage girls to become better represented in the STEM studies; Science, Technology, Engineering and Mathematics. While I’m more than happy to see this encouragement I do hope it’s what the girls want to do and not herding them into areas they don’t prefer because of some political vision held by non-STEM types. That having been said I do think that there are plenty of unsung women scientists of the past who deserve the recognition they were denied my a misogynist culture that happily used their work while ignoring their contribution. I have chosen to introduce you to two of them who you may or may not have heard of.

  Amalie Emmy Noether, was born on March 23, 1882, Erlangen, Germany and died on April 14, 1935, Bryn Mawr, Pennsylvania, U.S. She is the first woman scientist I want to introduce you to. She is also the poster child for misogynist intellectual oppression. Her specialty was abstract algebra where she made some of the most creative and fundamental contributions of the 20th century. Einstein said of her after she died, “Noether was the most significant creative mathematical genius thus far produced since the higher education of women began.” Noether’s Theorem which connects conservation laws in physics to the symmetry of the system. This law remains at the cornerstone of modern physics of elementary particles and forces.
When she first went to the university of Erlangen in 1900 to study mathematics, women were not allowed to matriculate as students so she had to audit her classes with the permission of the professor. In 1903 she studied for a year at Gottingen under Hilbert, Klein, Minkowski and Schwarzchild, four pillars of mathematics and theoretical physics at that time. In 1904 Erlangen admitted women as students and she returned there to complete he studies before obtaining a PhD there in 1907.
She stayed at Erlangen working on her own research and to work with her father Max Noether without pay until 1915 when she moved back to Gottingen to work under David Hilbert, much against the objections of the rest of the male faculty. While working on the mathematics of Einstein’s recently published theory of General Relativity, Noether discovered the relationship between the laws of conservation in a system and its symmetry. Thus she explained the foundational mathematics of the conservation laws we learn in high school physics class; conservation of energy, conservation of momentum and conservation of angular momentum.
In 1919 she received an appointment as a lecturer (professor in American) at the university of Gottingen. She continued her work in abstract algebra that includes the mathematics of sets, groups, rings and fields. She made major contributions to mathematics in the field of non-commutative algebras. However dark clouds were on the horizon and after the Nazis came to power many of the academic staff at Gottingen were dismissed because they were Jews.
Emmy Noether found her way to Bryn Mawr College in the USA where she continued her research both there and at Princeton. Sadly she died suddenly and unexpectedly after an operation for an ovarian cyst in 1935. The world lost one of its most perceptive and creative mathematicians and although her findings are widely used today she is mostly forgotten by the world of science and almost completely unknown by our chattering classes.

For more about Emmy Noether:

1. https://en.wikipedia.org/wiki/Emmy_Noether
2. https://www.britannica.com/biography/Emmy-Noether

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Rosalind Elsie Franklin was born 1920 in London, England and died in the same city in 1958. Her most famous and controversial contribution to science was her work on the structure of DNA for which Watson and Crick received the Nobel Prize after using her research findings without her knowledge or permission.
She graduated from The University of Cambridge with a degree in physical chemistry. In 1941 she received a Cambridge fellowship to conduct research in physical chemistry but it was interrupted by WWII. She found work with the Coal Research organization where she studied the physical chemistry of coal and carbon. This work led to her being awarded her PhD in 1945. From 1947 to 1950 she studied the applications of X-ray diffraction technology. This led to her taking up a position as a research fellow in King’s College, London in 1951 where she used X-ray crystallography to study the structure of DNA in collaboration with Maurice Wilkins.
It was during this period that she produced the crucial X-ray diffraction photographs that led to the structure of DNA being identified as a double helix after her supervisor Max Perutz showed her photographs to Watson and Crick. Her colleague Wilkins later shared the Nobel Prize with Watson and Crick.
In 1953 Franklin’s relationship with her director John Randall and with Wilkins had deteriorated so badly that she left Kings College and took up a position at Birkbeck College. Where in addition to working on DNA and RNA she studied the structure of viruses including the Polio virus. She died of ovarian cancer in 1958 four years before Watson, Crick and Wilkins were awarded the Nobel Prize for deducing the double helix structure of DNA. It has long been claimed that Franklin was not included in the Noble Prize because they typically do not award to more than three recipients or posthumously. However the story of how Watson and Crick got a peek at Franklin’s work and published without including her as an author has caused controversy ever since. She certainly did not receive the recognition she so richly deserved.

For more about Rosalind Franklin:

1. https://en.wikipedia.org/wiki/Rosalind_Franklin
2. https://www.britannica.com/biography/Rosalind-Franklin
   
   

I am and have always been an unapologetic scientist. Worse than that, I’m a hard scientist, a physicist. No soft ‘science’ for me. What’s more, I’m not a person of faith. I’m not a believer that a sentient being created the universe as a playpen for humans. I also do not believe that such a being exists, or cares in any way about the evolution of the universe or of humankind. I am therefore an atheist, albeit with a lowercase ‘a’ rather than being a member of the American Atheist religion, for religion it is.

Before going further a discussion of my perception of faith. To me faith is a belief in an ontology absent proof. I also believe that faith is strongest when proof is not sought or expected. It seems to me that those who claim faith but keep searching for proof or justification of their faith are in the process of weakening their faith in that search. To me it seems that those who claim a faith should quit looking for proof that they are right and others are wrong. Perhaps in this way we can have a few less wars in the world and a lot more harmony.

Having said all that, what does a scientist like me understand of the origin and evolution of the universe and why do I care; why should you care? What you believe and how you believe it is up to you but science is a bit different. In science belief is limited to what can be proved to be true without ambiguity particularly if that belief provides an explanation or prediction of what could not be explained or be seen before. Scientific beliefs are tested against observations and experiment. If they fail to pass muster they are rejected, replaced or modified to better fit reality.

Within the framework of science there exists an intertwined philosophy that requires that science provide an explanation for both how things work and why things work that way. This is the reason that Newton’s laws of gravity are superseded by Einstein’s General Relativity.  Even though Newton’s laws are adequate for most purposes they do not explain why gravity works the way it does.

To see how science works let’s start with a simple observation with profound implications. Imagine primitive man looking up at the sky at night wondering why it is dark.  Today we notice the same thing but most of us just take it for granted that it should get dark at night. If asked, most people will say it’s because the sun drops below the horizon and does not rise again until dawn. While this observation is undoubtedly true it is completely wrong in explaining the dark sky and obscures a profound finding about the universe that cannot be discovered unless one puts aside complacency and thinks more deeply about this question.

From the Greek philosophers onward many observed that an infinite static universe containing an infinite number of stars is incompatible with a dark night sky. This conflict is described as the “dark night sky paradox” or more commonly “Olbers Paradox” after Heinrich Olbers (1758 – 1840) who wrote about it in 1823. https://en.wikipedia.org/wiki/Olbers%27_paradox. Put simply, if the universe is infinite in time and place with an infinite number of stars then wherever you look at the sky you would be looking at the surface of a star. This would be like looking at the surface of the sun everywhere you looked.

Even the primitive humanoid staring at the night sky noticed that it wasn’t as bright as the sun. The question arises why this is so. There have been many suggested ideas why the sky is dark and not bright at night but fundamentally the only theory that works well is that the universe is expanding. In this model of the universe the whole of our existence started at a moment in time when the universe came into an explosive being; a Big Bang. Since then the universe has expanded with stars, galaxies planets and us coming into being as it did so. As a result the universe has a finite age, about 13.8 billion years, with space expanding at a rate that increases with distance from the observer; Hubble’s parameter . The consequence of this model of the universe is that the sky will be dark at night because of the finite number of stars, finite speed of light and the expansion of the space between us and distant stars.

We can therefore see that science sometimes provides profound findings about the nature of reality from the most basic observations; the night sky is dark leads us to the Big Bang model of the universe. Today we can observe the remnants of the fireball of the Big Bang , the Cosmic Microwave Background (CMB), that occurred about 380,000 years after the Big Bang. As we observe this background of microwave radiation we are able to find clues about how the Big Bang happened and how our universe will develop into its old age. Sometimes the universe is even stranger than our imaginings.