Showing posts with label Big Bang. Show all posts
Showing posts with label Big Bang. Show all posts

04 March 2013

Penzias, Wilson and some noise

The universe, Part 5
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Penzias and Wilson discovered an unknown microwave signal that turned out to be evidence for the origin of the universe. The story involves inconvenient pigeon droppings and more than a little serendipity. It ends with a Nobel Prize for physics and fame.

The Holmdel Horn Antenna
In part 4 of the series we saw how the cosmic microwave background radiation (CMBR) provides the earliest visible image of structure in the universe.

This time we're going to follow the curious story of its accidental detection by Penzias and Wilson.

The Holmdel microwave antenna in the image is at Bell Labs in New Jersey and was built in 1959 for early radio experiments with the Echo satellites (reflective balloons in earth orbit).

The horn antenna was being used by Arno Penzias and Bob Wilson in 1964. They were building sensitive, low noise, microwave radio receivers for use with the Echo satellites and had a serious problem with unexplained radio noise. They ruled out several possible causes, including a build-up of pigeon droppings in the horn, but nothing they could think of seemed to reduce the frustrating noise. Eventually they concluded it was not noise, but a genuine signal from an unknown source.

The noise explained - Another physicist, Robert Dicke had been searching for a signal just like the one that had caused Arno and Penzias so much trouble. Dicke had failed in his search but he heard about Penzias and Wilson's results and recognised it as relic light from the early universe, the elusive CMBR! The Penzias and Wilson paper and another by Dicke and three others were published together in July 1965. There's a lot more about this story in the book 'Genesis of the Big Bang' by Ralph A Alpher and Robert Herman who remembered the events well.

This is an interesting example of the way science progresses. Dicke, like George Gamow before him, had predicted the CMBR based on cosmological theory. Now that it had been found, the credibility of the theory was greatly strengthened.

Dicke was soon able to observe the CMBR himself, and later the COBE satellite would observe it in much greater detail, finding small irregularities in temperature. These too had been theoretically predicted.

When experimental results bear out theoretical predictions like this, scientists can be confident the theory is on track and more likely to be reliable.

WMAP, Planck and other instruments have refined the detail still further and strongly support the current Standard Model of Cosmology known as the Lambda-CDM Model..

Penzias and Wilson were awarded the Nobel Prize for physics in 1978 for their discovery.


Questions: 
  • Which interests you the most, the science itself or personal stories like this one?
  • Can you imagine the amount of dedicated effort involved in doing science?
  • Do you sense the determined search for truth in the hearts of dedicated scientists?

See also: 


< From the beginning to atoms | Series index | No later items >

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 >

16 October 2012

Debating science and faith

Science and faith sometimes appear to be at war. But is that inevitable? A conference in Switzerland is examining these issues and draws together influential scientists, theologians and philosophers.

The Whirlpool Galaxy
A conference is underway as I write, a conference with a difference. The whole affair is very refreshing and encouraging and exciting.

It brings together influential scientists, theologians and philosophers to discuss the nature of science and faith, and focusses on the Big Bang theory and the discovery of the Higgs boson.

The conference is being held in Switzerland and is called 'The Big Bang and the interfaces of knowledge: towards a common language?' The aim is to explore questions around the interface between science and faith and whether a common framework of knowledge might be possible.

You can download the programme as a PDF file (165 kB) or read brief details online from the website of the organisers, Wilton Park in collaboration with CERN in Geneva. There's also a very useful BBC News article about the conference 'Big Bang and religion mixed in Cern debate'.

Here's the introduction from the full programme...

The Big Bang theory is the prevailing cosmological model for explaining the genesis of the universe. To date it has the wide support of the scientific community because if offers the most accurate and comprehensive explanation for a broad range of observations. It leads to a dating of the universe as 13.7 billion years old.

The purpose of this conference is to enable scientists from a range of disciplines to dialogue with philosophers and theologians from the world religions about the nature of the Big Bang Theory. What understandings might scientists and theologians share in common? How are their paradigms shaped and developed? Is it possible to develop a common framework or language?

Why is this conference so exciting? Simply because it's an unusual opportunity to discuss and (perhaps) reconcile views that are often perceived to be irreconcilable. And it's exciting because the conference involves experts who would rarely meet together. When a record of the meeting becomes available it will make very interesting reading and should spark further debate in the wider community.

We might borrow the words of Pontius Pilate and simply describe the topic of this meeting as 'What is truth?' Pilate was caught in a dilemma between religion and politics. The dilemma this meeting is discussing is quite different - it's examining two different kinds of truth.

How do you see the debate? Is it possible for science and faith to agree about anything at all? Are the two views truly irreconcilable or do they actually threaten one another? Is there an unbridgeable gulf between the two?

See also
  • Relationship between religion and science - Wikipedia, undated - Encyclopaedic article on the topic with further references.
  • Science and faith archive - Patheos, undated - A collection of links and book titles on the topic, updated from time to time.
  • Science and faith - again - Journeys of heart and mind, 22nd August 2012 - How do science and faith stack up against one another as ways of knowing the truth? Science provides truth about the physical universe while faith provides truth about spiritual things. Is there any overlap?
  • Science and faithJourneys of heart and mind, 7th January 2012 - Can I have faith and accept science too? Is that an unreasonable position to hold? Recent discussions on Jesus Creed have provoked me to write on this topic again.
  • Science and faith - war or peace? - Journeys of heart and mind, 25th April 2010 - 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. Why does this happen, what are the root causes of the sometimes strongly-worded arguments? Perhaps it's time to take a fresh look.
  • Science and faith: The conflict - The Telegraph, 16th March 2009 - A new film opening at the Cambridge Science Festival this evening attempts to demonstrate that the divide between religion and science is not as great as it has been portrayed.

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