Showing posts with label universe. Show all posts
Showing posts with label universe. Show all posts

22 January 2013

From the beginning to atoms

The universe, Part 4
< In the beginningSeries index | Penzias, Wilson and some noise >

The universe grows larger, cooler and more complex at astonishing speed until it's a few minutes old. Further change is much slower and less dramatic. Fundamental forces and particles are generated, hydrogen and helium are formed and light is released.

The cosmic microwave background radiation
The first few minutes of the universe's existence see a huge increase in volume and a dramatic reduction in temperature. Gravity, light, and atomic forces separate from one another. And finally matter comes into existence in the form of hydrogen and helium nuclei and electrons.

More fundamentally we could say that the universe evolves from a simple, evenly distributed beginning and generates greater and greater complexities confined to smaller and smaller volumes as it expands. We'll explore this concept in a later post.

In Part 3 we discussed the beginning but also understood that we can't directly understand or observe it. A good theory of quantum gravity might help, but we don't have one yet.

So how near the beginning can we claim to have any real understanding? The answer is back to 10-43 of a second. If you want to see that as an ordinary fraction you would need to write 1 at the top with 1 followed by 43 zeroes at the bottom. So we understand the universe (in some sense) back to a very, very tiny part of a second.

What exactly do we know from that very early time?

Gravity and inflation - For one thing, gravity and the other fundamental forces may have all been of equal strength at first, with gravity separating out at 10-43 seconds. There is theoretical support for this. After gravity separated to become the very mild force it is today, the universe entered a time of extremely rapid expansion known as inflation.

This is not just something scientists have dreamed up; the observed properties of the universe can only be explained by such a rapid inflation during which it became unimaginably larger in a tiny, tiny fraction of a second. Before inflation the universe was smaller than a sub atomic particle. Inflation ended between 10-33 and 10-32 seconds, but by this time the universe was spacious (perhaps as large as a football) and packed with elementary particles that still exist in our own time - quarks, antiquarks and gluons.

How do we know all this? There are three important things that constrain what is possible.

  • Theory - Based on what we know of the later universe, theory rules out most hypotheses about the earliest eras. Only an early universe similar to what is described above could have resulted in what we see today.
  • Cosmology - Observations suggest a great deal. The cosmic background radiation (shown above) and the distribution of galaxy clusters, for example, can only be explained by inflation.
  • High energy physics experiments - By creating high energies in particle accelerators we can observe the properties and behaviour of particles in a similar state to these early phases of the universe.

Here's one more thing about inflation. If, as many think, our universe began as a quantum fluctuation, then without inflation it would have been the most transient of fluctuations and the universe would have been snuffed out almost immediately while it was still very tiny.

The electroweak epoch - The next stage in the evolution of the universe involved the strong nuclear force separating from the remaining two fundamental forces. Like the earlier events, this too happened at a very early time, around 10-34 seconds. More particles were able to condense out of the soup of energy at this stage, W bosons, Z bosons and Higgs Bosons became common. These are particles that can be generated in our most powerful accelerators today, so we are able to study them and understand them reasonably well.

The universe continued to expand and cool so that by 10-12 seconds bosons could no longer be created. 10-12 seconds is also called a picosecond (one quadrillionth of a second). Lasers with pulses as short as a picosecond are used for cutting and shaping materials, in medicine, and for removing tatoos. It's still a very brief time, but meaningful enough for real life use. Light travels just 0.3 mm in this time.

The quark, hadron and lepton epochs - The universe continued to expand and cool. After it was a picosecond old the electromagnetic and weak forces separated and the universe at this time was full of a dense quark-gluon plasma.

By the end of this epoch at around a microsecond old (one millionth of a second), the universe was cool enough that the quarks could combine to form protons, neutrons and their anti-particles. At an age of about one second the universe was cool enough for particles and anti-particles to annihilate, leaving a small excess of protons and neutrons.

As the universe expanded and cooled further and aged to about ten seconds, electrons and other leptons were also able to annihilate with their anti-particles leaving a small excess of mostly protons, neutrons, electrons, and photons.

Over the next few minutes conditions cooled to a point where atomic nuclei could form, mostly deuterium and helium with a little lithium. At this point the universe contained these nuclei, protons, electrons, and photons. After a further 380 000 years of cooling and expansion the protons and other nuclei combined with the electrons to form hydrogen and helium atoms (and some lithium atoms). This allowed the photons to move freely (the cosmic microwave background radiation), space became transparent and the earliest structures formed. These structures were simply volumes of slightly varying density and temperature. They are the first things we can 'see' directly and are shown in the illustration at the top of the article.

From this point on the universe becomes more and more recognisable to us, albeit still far hotter and denser than today. We will be able to see the rest of the story much more in terms of astronomy.


Questions: 
  • Are you surprised at the amount of change that took place in the first second?
  • Is the creation of the universe more complex than you had imagined?
  • How do you feel about a universe that started this way?

See also: 


< In the beginning | Series index | Penzias, Wilson and some noise >

11 January 2013

In the beginning

The universe, Part 3
< How does science work?Series index | From the beginning to atoms >

The beginning of the universe is hidden from us although we know it's about 13.75 billion years old. We can theorise about it using mathematical tools, but we can't see it and we can't measure it. Everything began at that point - space, energy, even time itself.

Maths is an essential tool
We can't see the beginning itself. People sometimes talk about the Big Bang and they imagine a huge explosion crashing out into an empty expanse of endless space.

But that's not right. If you see it in that way you are really not seeing it at all!

Nothing existed before the Big Bang. At least no physical thing that we can see or know inside this universe existed.

There was a singularity, though it's difficult to imagine one of those or what it implies.

  • Time began at the beginning, so before the beginning is meaningless.
  • Space began at the beginning, until then there had been no room in which anything could have existed. There was nowhere to explode into.
  • Energy began then too, beforehand there was no energy.
  • And there was no matter because matter is just condensed energy.
  • Even the laws of physics began at the beginning

Time, space, energy and physics all had their origins at the beginning, and we can't investigate that extraordinary phenomenon - the beginning. We can't see it, we can't visit it, we can't measure it, we can't really imagine it. Not only is it far more extraordinary than we think, it is far more extraordinary than we are able to think.

And perhaps the most amazing thing about the beginning is that eventually we came from it; we are here and are able to think about how extraordinary it all is.

Theoretical problems - It's almost as if the universe doesn't want us to understand its origin. Our best models for the earliest moments of the universe are mathematical. OK, really our only models for this are mathematical.

However there's a serious issue, even with that. If at the beginning the universe was infinitely small then some of the numbers in the models become zero, or they become infinite. Not only does the universe seem to explode, so does the maths.

Maths doesn't always handle zeros and infinities especially well, they can be a problem. It makes mathematical models difficult as we try to apply them closer and closer to the beginning. This is driving some mathematicians and cosmologists to think that there may not be a beginning at all, just a certain minimum size and maximum density before which the universe was larger and, perhaps, time ran the other way. Or something.

Is there room for intelligence? - We can only think about it because we are here. There are no other animals on this planet that even know there was a beginning. We are unique on Earth.

I imagine there must be many other intelligent minds in the universe and it's likely that all of them give some thought to the beginning. Each in their own, unique way no doubt. The fact that there is a beginning is one of the reasons I believe in an even greater intelligence that caused the universe to begin. What is certain is that intelligence is almost inevitable given the properties of the universe, but it couldn't appear until a lot of other things were in place.

But for a moment, let's consider the alternative that the universe has always existed and will always exist with new energy and matter appearing to 'fill the gaps' as it expands. In the 1950s and 60s many cosmologists argued this was the case, it was called the 'Steady State Theory'. But it's since been shown to be incorrect.

But if it was correct I would still feel the need for a first cause, a greater power and intelligence to make it exist. So whether there was a beginning or not, I will still believe in a Creator.

What is the alternative? It's all just causeless?

After the beginning? - But there was a beginning, and we can understand some of the things that happened soon afterwards when the universe, time, space, energy and physics were all very new. And you'll be astounded to learn that we understand some things about it even a tiny fraction of a second after the beginning. A much tinier fraction than you think (unless you're a cosmologist).

It all began roughly 13.75 billion years ago. Our Solar System and this Earth are around 4.5 billion years old or about a third of the age of the universe. The universe was smaller then too.

If you made it this far, congratulations! After this things get easier as the universe grows bigger, older and more familiar. Next time we'll pick up the story at that point where we think we know something, and we'll find out just how awesomely near the beginning that is.


Questions:

  • How comfy are you with the idea of a creative intelligence causing this universe?
  • How comfy are you with the idea of the absence of any such creative intelligence?
  • Does your head hurt yet? Go and get a cup of tea, or coffee, or a glass of wine.

See also:


< How does science work?Series index | From the beginning to atoms >

06 January 2013

How does science work?

The universe, Part 2
< Introducing the universeSeries index | In the beginning >

We need to understand the basis upon which science operates and justifies its findings. Without this basis we would be unable to understand and describe the universe in any meaningful way. We see that science has a rigorous method and underpins reliable technology.

The famous Miller-Urey experimentBefore we look at the story of the universe, there's some groundwork we need to put in place. In the previous part I explained why I wanted to embark on this project and why I thought I'm suited to it. But this time I want to address science itself.

How do we know science works? Why should we accept its claims, for the universe or for anything else?

There are two lines of argument that should encourage us to accept the ability of science to produce valid conclusions. One is theoretical and is based on how science works. The other is practical and looks for evidence that science has worked.

How does science work? - At its most basic, science is pretty straightforward. It's really just good observation, making a best guess as to what might account for the observation, devising an experiment to test the guess, and then either rejecting the guess because it failed or making a new guess and trying again.

When a guess (science calls it an hypothesis) has been tested for a prolonged period of time and has passed every single test thrown at it, we become convinced it really is correct and then science calls it a theory. And we're not talking about ten tests, or a hundred. It may take fifty years or more of serious effort before a theory is widely accepted.

The words 'observation', 'hypothesis', 'experiment' and 'theory' are scientific jargon and should not be taken to have their everyday meanings. In the area of science they have precise definitions that we must keep in mind if we want to understand scientific debate and writing. 'Theory' in particular is commonly misunderstood.

(That is a simplified description of science, for a more thorough version read the Wikipedia article on the scientific method.)

The image above is a diagram of the apparatus used in the famous Milley-Urey experiment. This experiment disproved the hypothesis that organic chemicals could not form naturally in early planetary atmospheres.

So what does science look like in practice? - An example will help.

Let's say we notice that grass doesn't grow well underneath mature trees. That's an observation.

We might guess that grass doesn't like to be covered in dead leaves. That's an hypothesis.

We decide to grow grass in pots and then cover some of the pots with dead leaves gathered from the woods. That's an experiment.

We let the experiment run for some time and then come to look at the results. All the grass is still growing happily. So it looks as if the hypothesis was wrong, there must be some other reason that grass doesn't grow under trees. The hypothesis can't become a theory because we've shown it was wrong.

Suppose instead that we had guessed that grass needs plenty of light to grow. This time we'd find we couldn't disprove the guess. We might do dozens of different experiments and find grass always dies if it doesn't get plenty of light. We could now make a theory - 'grass needs plenty of light to grow'.

We can now say that grass almost certainly needs plenty of light to grow, and dead leaves definitely don't prevent it from growing. That's an advance in scientific knowledge.

Because of the way science works there is little room for argument. A single negative result kills an hypothesis stone dead. Hypotheses become reliable theories when they have passed many unsuccessful challenges. For example general relativity, evolution, quantum mechanics and electro-magnetism are regarded as theories. They have very, very high likelihoods of being correct and long histories of passing experimental tests.

Technology stands on the shoulders of science - Technology also gives us great confidence in the results of science. Technology often depends on the results of scientific understanding in order to make something useful or to make it more efficiently. If the underlying science was wrong, the technology based on it would fail.

The fact that technology works as well as it does is strong, additional evidence that the scientific method produces reliable and correct results. We are surrounded by proof that science is trustworthy. Cars, ships, computers, TV sets, radio communications, plastics, medicines, heart pacemakers, electricity, fridges, washing machines, microwaves, air conditioning, central heating, felt pens, emulsion paint, rubber, plant and animal breeding - all these technologies and many, many more depend on the reliability of science.

There are also examples of technology that failed because it was not based on sound science. The best example is plant breeding in the Soviet Union during the cold war. It was based on Lysenkoism, a falsified theory of inheritance.

If we can be sure science is reliable and produces correct results, then we can also be confident about what it tells us about the universe.

Questions:
  • If science is purely well-tested observation, on what grounds can we question it?
  • The nature of the universe makes technology possible, what can we conclude from that?
  • Can you imagine a world in which there were no underlying rules?

See also:



< Introducing the universeSeries index | In the beginning >

03 January 2013

The universe - INDEX

(See indexes on other topics)

This is the index page for a major series on the story of the universe. I'll be adding sections from time to time and provide links to all the parts below.

Where does it begin and end?I would like to attempt a major project in which I'll do my best to describe and explain the universe as we understand it in 2012 and 2013. The first part of the series is an introduction and explains why and how I am doing this.

The list below will expand as fresh parts are written. It's a story with no beginning as we cannot currently investigate the state of the universe right at the start (assuming 'the start' has any rational meaning for the universe). And it's a story with no end because it seems unlikely that the universe will have an ending in the sense of ceasing to exist.

Besides, time itself might be seen as part of the universe. In that case we would be talking about the beginning and end of time. What would that mean?

One of the truly astonishing things about the universe is that it contains tiny blobs of matter (us) that are capable, in some sense, of comprehending it. This should seem far more extraordinary than it does to most people most of the time.

Here's the list of parts so far.
  1. Introducing the universe - Why am I attempting this project?
  2. How does science work? - So, why should we accept the claims of science?
  3. In the beginning - Even time and space began at the beginning.
  4. From the beginning to atoms - Forces and particles condense from energy
  5. Penzias, Wilson and some noise - How the cosmic background was found.

Questions:

  • Do 'beginning' and 'end' in science and in religion refer to the same thing?
  • Scientific and religious - do they overlap or conflict or are they distinct?
  • What lies beyond the universe? How could we know?

See also:

11 December 2012

Introducing the universe

The universe, Part 1
< No earlier items | Series index | How does science work? >

This is the first post in a series on the story of the universe, insofar as we know it in the first eighth of the twenty-first century. In this introduction I provide a little background about my reasons for tackling this subject and my own training and experience in science.

The Hubble extreme deep field view
I have a new project, and this post is the very first part of it. What I'd like to attempt is a sweeping review of the development of the entire universe, from the earliest moments right up to the present. It goes without saying that this is a rather ambitious task.

Why would I want to do this? - There are several reasons. One is the current battle of ideas between science on the one hand and people who think they know better on the other. And here I include creationists, the detractors of the evidence for global warming, deniers of human causes of global warming, those who are anxious about the side effects of inoculations and all sorts of other groups denying that scientific understanding of this or that topic is correct. I'll refer to these disparate groups as deniers and disbelievers (DDs).

DDs have a variety of reasons for their views. Some are genuinely concerned that science has a wrong view that is dangerous or harmful. Others may have some kind of hidden agenda. DDs of both kinds can be extraordinarily resistant to logical argument. Some (a small minority) can be manipulative and a few have been abusive.

Another reason is simply to share what are to me profound and amazing truths about the nature of existence. When you see something astonishing and beautiful, don't you want to share it with others?

Fun along the way - I have a scientific background (I was a professional biologist for many years) and I enjoy explaining things. I don't know a whole lot about fields other than my specialist area of biology, but I do have a science education and I possess the basic tools needed to understand scientific arguments and the principles by which science progresses.

I expect we can have a lot of fun along the way. Get ready for some amazing images and videos. Prepare to meet some extraordinary characters. And don't be surprised if some of the things we see are truly beautiful and awe inspiring - that's the way the universe is. To see some of these now, click on the photo of distant galaxies for a more detailed view, and take a look at the scale of the universe, an interactive journey up and down from the scale of our normal environment.

Not all my blog posts will be devoted to this journey of discovery. They'll be interspersed with much else besides - all the other topics I've posted on in the past. But every so often I plan to slip in another post in this series on the story of the universe. I'll link the posts together so you can easily browse back and forth between them, and there's an index to help you jump straight to a particular topic.

Questions:

  • Broadly speaking, is your inclination to trust or distrust science and scientists?
  • Do you find the natural world beautiful, perplexing, and thought provoking?
  • In your opinion, does the existence of the universe demand an ultimate cause?
  • If not, would you say it's enough to assume that there is no cause?

See also:


< No earlier itemsSeries index | How does science work? >

02 November 2012

Why is life dangerous?

Why is there so much danger in the world? We examine how random chance is necessary if we are to have a choice and how choice is necessary if we are to be capable of love. The most surprising thing is that there are not many more disasters.

Mount Pinatubo in 1991
What underlies the fact that life is dangerous and the Earth is such a dangerous place? Wherever we look we see danger and catastrophe lying in wait for us. Road accidents, volcanic eruptions, storms (like Hurricane Sandy), diseases of all kinds, violent crime; there's no denying the risks we face daily.

Some of these hazards can blamed on human wrongdoing or failure. Violent crime is an example of wrongdoing and most road accidents result from failures of judgement, design, construction or maintenance. But what of a volcanic eruption? Who is to blame for that?

Let's put dangers into three broad categories - deliberate human action or inaction, unintended human action or inaction, and natural events. Of the three, natural events form the category we want to consider in this article. We need to begin by understanding that the universe has always been open to the effects of chance.

Let's elaborate a little. We don’t know how the universe came into being, all we can say is that we have a pretty good idea how it developed after the first tiny fraction of a second (10-35 s). But we do know that since that first fraction of a second, randomness and chance have been (and remain) fundamental to its development. Sub-atomic particles flashed into existence and then, just as suddenly vanished again. They still do that today, what we regard as a perfect vacuum can be shown to be a sea of churning activity.

Chance is absolutely necessary in a universe where there is to be some freedom of choice. Why? Because we can only choose if we live in a universe where things are not normally determined in advance. My understanding is that Yahweh created a universe in which intelligence would arise and in which any intelligent life forms would be able to know him and choose to love and follow him.

Perhaps we see a glimpse of this in 1 Kings 19:11-13. We'll be exposed to many things during our lives, but Yahweh is not present in the outward tumult and danger; he communicates quietly. We may fail to notice him if we are focussed on the loud and dangerous things.

Let's put it very simply. Love requires a universe in which things are not directed. Volcanoes can erupt, earthquakes can shatter cities and hurricanes can flood coastal plains. The chain of  dependency is that love depends on the ability to choose, and choice depends on the existence of chance. In other words chance makes choice possible and choice makes love possible.

It seems to me that the real wonder is not that bad things sometimes happen, but that they happen so rarely. We certainly shouldn't blame Papa for random disasters, but we should thank him for such an exquisite combination of personal freedom and relative day to day safety. This supreme balancing act is something worthy of great praise, awe and gratitude.

In conclusion we have to take a small amount of rough with the surprisingly large dollop of smooth. Thank you, Father, for doing such a great job of designing this universe! Truly you are worthy of praise.

(This article is based on a comment I left on an article on the Jesus Creed blog.)

Questions:
  • People sometime ask, 'If there's a God, why does he allow suffering?' How do you answer this?
  • Has this blog post provided any unfamiliar arguments about suffering?
  • Do you believe a creator is free to create things without regard to logic?
  • Is a universe possible in which something could be simultaneously true and false?

See also:

25 April 2010

Science and faith - war or peace?

The origin of the universe, the origin of life, evolution - these are some of the topics that seem to be endlessly debated across the science/faith divide. Molecules of lifeWhy does this happen, what are the root causes of the sometimes strongly-worded arguments? Perhaps it's time to take a fresh look.

Science is based on such things as reason, deduction, inference, and testing by experiment. At the most fundamental level science is simply a formal way of observing how things are. And it has an excellent track-record. We depend daily on the technologies that science has made possible. We drive our cars, watch TV, depend on medical help when we are sick or injured. All of these things and many more are rooted in generations of observation, hypothesis, and testing.

On the other hand faith is not based on observation and experiment but on assertion, often about matters that are untestable and are unknowable in the scientific sense. The existence of a powerful personality outside the universe and this personality's influence within it are not things science can investigate. Science doesn't reject faith (indeed it might investigate faith as a phenomenon) but it does not (and cannot) investigate the claims of faith.

There is therefore no reason for science and faith to do battle with one another, but historically this has happened repeatedly. An example of past 'warfare' concerns whether the earth or the sun is the centre of the solar system, one current skirmish centres on the origin of life and on evolution, another one on theories about the origin of the universe.

The usual pattern is that science draws a conclusion that offends people of faith in some way. Instead of understanding the scientific arguments and accommodating them within the framework of faith, believers often try to find holes in the science. Scientists continually refine our understanding in a formal way, believers sometimes lash out at new ideas they don't like.

How can we take this forward? Here is some advice for scientists and believers who have become embroiled in debates of this sort.

Scientists - Don't become angry, recognise that if the science is sound you have demonstrable facts on your side. State these straightforwardly and point detractors to the evidence calmly. If you are vilified and your integrity is questioned, recognise that these are the actions of desperate people who have not yet understood that facts are a form of truth. The battle will rarely centre on those facts, instead it will usually focus on attempts to discredit the people involved. Don't engage with these attempts.

Believers - Don't interpret statements from scientists as provocation, they are simply sharing factual information. Respect the people even if you don't like their thinking. Christ called you to love so speak in love, not in anger. Look at the scientific claims calmly, facts about the world cannot possibly contradict truth. Look for ways of accepting the science within your framework of faith. Remember the battles about the place of the earth in astronomy, why is that no longer an issue? Understand that if the Almighty exists, scientific and spiritual truth will be able to coexist, because he is the author of both.

Where there appear to be contradictions there is an opportunity for mutual understanding. Science deals with the realm of materials and energy, faith deals with the realm of the spirit. There is no overlap in subject matter and there is no clash of ideas that can't be accommodated.

Copyright

Creative Commons Licence

© 2002-2017, Chris J Jefferies

This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License. A link to the relevant article on this site is sufficient attribution. If you print the material please include the URL. Thanks! Click through photos for larger versions. Images from Wikimedia Commons will then display the original copyright information.
Real Time Web Analytics