Astronomy & Science
Initial results from Herschel
Dec 17th
A bigger venue now, for the first scientific results from the Herschel Space Observatory. Not sure how much I can reveal right now (the presentations will be uploaded after the conference, and I think they might be embargoed until then) but the photo above gives you the general idea. In the corner you can just about see the figure of Göran Pilbratt, the Herschel Project Scientist (who refused to stand still for the 8-second exposure), and on the screen he is dazzling us with an overview of the mission.
However, some results were revealed yesterday at a press briefing, and here they are…
Buenos días from Madrid!
Dec 14th
Day 1 of the Herschel Science Demonstration Phase Data Processing Workshop. Until Wednesday we will be based at ESAC, some 20 miles or so outside Madrid (map here). In the photo (click to enlarge) you can see ISO, Herschel’s predecessor, at the left (well, a scale model of it!), and the ruins of a 15th Century castle at the right.
Today: update on the status of the mission, the instruments and the data processing software. This afternoon we’ll be demonstrating the SPIRE photometry pipeline and I’ll be rounding the day off with a brief demonstration of the point source extraction tool. If that made no sense to you, here’s a layman’s description: Herschel makes pictures of thousands of distant galaxies where each galaxy looks like a blob, and the tool automatically spots the blobs and measures how bright they are. And by spotting, counting and measuring blobs, we can learn about how stars formed in the early Universe. Exciting stuff!
Off to Madrid
Dec 12th
Just back from a week at RAL developing software related to the Herschel Space Observatory. I’ll be off again tomorrow, this time to Madrid for a big Herschel conference hosted by ESA(C), where a bunch (a galaxy?) of astronomers will get together to share their brand-new expertise in analysing the brand-new Herschel data (from Monday-Wednesday) before the really exciting bit (Thursday and Friday), when the initial (tentative!) results from the science teams will be presented to the world.
I may post some updates during the week, and I’m sure there will be plenty on the Herschel blog, but for now here are a couple of pictures from a visit to Madrid last December, when I discovered the joys of photo stitching (with Hugin).
First, here’s the Madrid Atocha railway station (spot the trains):
And here’s the Puerto del Sol:
Stand up for research
Nov 5th
The UK government appears to be under the impression that it should preferentially fund scientific research that has direct economic value. This, of course, is rubbish. Industry should preferentially fund scientific research that has direct economic value, because, well, it has direct economic value. The government should fund scientific research that pushes the frontiers of human knowledge, regardless of the direct economic impact.
The Universities and Colleges Union (UCU) is collecting signatures for their Stand up for research campaign, related to this very issue. Follow the link to sign up…
Simon Singh sued
Jun 5th
Chiropractic is all about manipulating the spine to cure various ailments. It’s all over the news at the moment because of something Simon Singh wrote in the Guardian last April:
You might think that modern chiropractors restrict themselves to treating back problems, but in fact they still possess some quite wacky ideas. The fundamentalists argue that they can cure anything. And even the more moderate chiropractors have ideas above their station. The British Chiropractic Association claims that their members can help treat children with colic, sleeping and feeding problems, frequent ear infections, asthma and prolonged crying, even though there is not a jot of evidence. This organisation is the respectable face of the chiropractic profession and yet it happily promotes bogus treatments.
I can confidently label these treatments as bogus because I have co-authored a book about alternative medicine with the world’s first professor of complementary medicine, Edzard Ernst. He learned chiropractic techniques himself and used them as a doctor. This is when he began to see the need for some critical evaluation. Among other projects, he examined the evidence from 70 trials exploring the benefits of chiropractic therapy in conditions unrelated to the back. He found no evidence to suggest that chiropractors could treat any such conditions.
In response to this, the British Chiropractic Association drew attention to the huge number of careful clinical trials that have demonstrated the effectiveness of chiropractic treatment has taken Simon Singh to court to sue him for libel. If you think this is a tad silly, click here to join the Sense About Science campaign.
Six days and counting
May 8th
Herschel (on the left) and Planck (on the right) are scheduled for launch at 2.12pm UK time this coming Thursday…
Credit: ESA
At Sussex we’re busy getting ready for data from both Herschel and Planck, but it’ll be a few months before they reach that distant location known as L2, where they’ll start their proper survey observations. So, in the meantime, here are some links…
- ESA launch page
- Another ESA launch page
- Watch the launch live on the Arianespace webcast page or on the ESA webcast page
John Cleese explains the God gene
Apr 17th
Are we alone in the Universe?
Feb 16th
After “Do you want to be the next Patrick Moore?” and “I’m a Capricorn”, the most common response I get when I tell people I work in astronomy is, “Do you think there is life on other planets?” Apparently, according to a talk given by Alan Boss to the American Association for the Advancement of Science in Chicago, the answer should be “Yes”:
If you have a habitable world that is sitting around for four, five or ten billion years around a star, how are you going to stop it from forming life? It’s like taking a refrigerator, unplugging it, shutting the door and then coming back a couple of months later; you’d be amazed to find what’s growing there. … That’s what life’s like. The fridge analogy may not be the same as the origins of life, but life is so tenacious, it’s hard to stop. If you had a planet sitting there at the right temperature with water for a million years, something’s going to come out of it.
The theory of spontaneous generation is alive and well, it seems.
But how many planets have actually formed life? Being extremely simplistic, we could express it as follows:
where 
is the number of planets that have formed life, 
is the probability that a planet will form life, given that it is a habitable planet, and 
is the number of habitable planets. So if there are 100 billion habitable planets in the Milky Way Galaxy, and 
, then we can expect that 1 billion planets in our Galaxy have formed life (whether they would still harbour life today is a different question).
isn’t too difficult to guess, in principle. But if we want to estimate , we need to find . This is more tricky.
One approach is to create life in the laboratory, and then estimate how long it would take for the same processes to take place outside the laboratory. Now, I freely admit that I know almost nothing about current research in this area, except that life has not yet been created in a laboratory. And until it has, we need to proceed in a different way.
The other approach is to estimate given what we know about the existence of life on Earth. Let’s assume for the moment that we know 
, the time it took for life to appear on Earth. This is generally estimated to be perhaps a few hundred million years. Then we assume that for Earth is fairly typical for habitable planets, and then it’s pretty easy to find the result we’re looking for.
But there are a few serious (really serious!) problems with this approach. For example:
- Who says that is a fairly typical length of time? Why is life arising on Earth after however many million years necessarily typical? Maybe it’s extremely unusual. We could even ask this: What part of “planet Earth formed life after ” is inconsistent with life being so improbable that it would not have arisen more than once in the entire Universe?
- How are we supposed to factor out our own existence? This is the issue of anthropic bias in the Drake equation. Why is it reasonable to assume that Earth is a typical habitable planet? Was it chosen at random? Of course not. So when we find for Earth, that is not for any old habitable planet, but for a habitable planet that is home to intelligent life. Why should
, the probability distribution for for habitable planets in general, be the same as 
, the probability distribution of for habitable planets that are (or will become) the home for intelligent life forms, such as our own? - How are we supposed to know that the Earth has ever formed life anyway? Many people believe that life was created by a supernatural being. What scientific experiment could we conduct to distinguish between the two hypotheses, H1, “Life on earth arose from non-living substances by ordinary physical processes”, and H2, “Life on earth was specially created by a divine being”? In order to put a figure on , we have to assume H1, but this not established empirically.
In summary, while there are often good reasons to be optimistic about the number of planets that support life (e.g., to gain funding and/or publicity for your pet project), I would err on the side of caution and argue that we don’t have a clue – scientifically – how many planets have formed life.
Discuss!
Is atheism compatible with belief in evolution?
Feb 3rd
Perhaps not.
Have a read of this extract from Alvin Plantinga’s entry on Religion and Science in the Stanford Encyclopedia of Philosophy (dealt with at more length here):
In crafting our cognitive faculties, natural selection will favor cognitive faculties and processes that result in adaptive behavior; it cares not a whit about true belief (as such) or about cognitive faculties that reliably give rise to true belief. … What our minds are for (if anything) is not the production of true beliefs, but the production of adaptive behavior: that our species has survived and evolved at most guarantees that our behavior is adaptive; it does not guarantee or even make it likely that our belief-producing processes are for the most part reliable, or that our beliefs are for the most part true. That is because our behavior could perfectly well be adaptive, but our beliefs false as often as true. Darwin himself apparently worried about this question: “With me,” says Darwin, “the horrid doubt always arises whether the convictions of man’s mind, which has been developed from the mind of the lower animals, are of any value or at all trustworthy. Would any one trust in the convictions of a monkey’s mind, if there are any convictions in such a mind?” (Darwin 1887) …
Now naturalism entails that evolution, if it occurs, is indeed unguided. But then, so the suggestion goes, it is unlikely that our cognitive faculties are reliable, given the conjunction of naturalism with the proposition that we and our cognitive faculties have come to be by way of natural selection winnowing random genetic variation. If so, one who believes that conjunction will have a defeater for the proposition that our faculties are reliable—but if that’s true, she will also have a defeater for any belief produced by her cognitive faculties—including, of course, the conjunction of naturalism with evolution. That conjunction is thus seen to be self-refuting. If so, however, this conjunction cannot rationally be accepted, in which case there is conflict between naturalism and evolution …
Simulating the Universe
Jan 20th
Astronomers spend a lot of time making computer simulations of the Universe. Some discussion on The e-Astronomer’s blog has set me thinking about why…
- To help us work out whether the stars and galaxies in the Universe could have arisen from much simpler beginnings. The Universe is quite a complex and diverse place. How did it get like that? Did it start off simple and gradually grow in complexity? Or is that completely implausible? Of course, we’ll never get a definitive answer, but computer simulations can give us some pointers. However, at some point you have to say enough is enough and decide whether the answer is probably “Yes” or “No”. It seems to be “Yes”, so do we really need to keep doing more and more simulations?
- To find or test the laws of physics. If we plug the laws of physics into a computer simulation and find that it reproduces the observed Universe perfectly, then that suggests we were right after all. But if not, maybe we should try tweaking the laws of physics to see if that improves things? Again, this is an exciting question to ask, but simulations are nowhere near good enough to be able to do this – and it’s questionable whether they ever will be.
- To reproduce observations. We know from observations that galaxies have XYZ properties. After N zillion CPU hours, our expensive simulation is able to reproduce XYZ. Wahey! This suggests that the simulations are working, which is good for establishing number 1 above. But there will always be fresh observations for the simulations to replicate, so what’s the point of continuing indefinitely?
- To give observers something to look for. Our simulation of XYZ suggests that galaxies will also have ABC properties. Please Mr Observer, is this the case? Give me a few billion for a shiny new telescope and I’ll tell you… Yes it is! Wahey! (Or, No it isn’t – go back to step 3 and reproduce what we actually found.) Again, this can help to establish whether or not simulations can work (point 1 above). But once that’s been established, it’s another unending road to nowhere…
- To reconstruct the history of the Universe. To my mind, this is by far the best reason to keep on with the simulations. It’s not a competition between simulations and observations, each trying to stay ahead of the other, but it’s both working together (along with a hefty dose of human intuition and creativity) to uncover the sequence of events that made the Universe what it is today. So the aim is not primarily to formulate a simple mathematical description of the Universe or to quantify things with great precision. But astronomers are on a quest more akin to that of a historian, an archaeologist or a forensic scientist – first to figure out what actually happened, and then to communicate the excitement and drama of that story to everyone else.
- To make pretty pictures and animations. Okay, I lied. This (and this) is what simulations are for.
Herschel Space Observatory
Oct 6th
PhD now submitted, I’ve just started a six-month contract working at Sussex on some software for the Herschel Space Observatory, which is due to be launched in 2009. Here it is:
Artist's impression of the Herschel Space Observatory
This week I’m at the Rutherford Appleton Laboratory, near Didcot, Oxfordshire, discussing the nitty-gritty of how the data processing system is going to operate. (Okay, other people are discussing the nitty-gritty, while I’m feeling pretty gormless…)
Confirmation bias
Jul 25th
Professor Aardvark has a theory. His theory predicts X. So he does some experiments and presents a tentative scientific result, suggesting that X might be true.
Dr Bloggs decides to investigate it. Here’s Bloggs’s research diary:
- First preliminary results (finally!): disagreement with Aardvark’s results, but it’s probably something I’ve done wrong.
- New method of analysing the data. Now my results (finally!) agree with Aardvark’s. Still a few issues that need addressing though…
- No progress with the outstanding issues. Getting really bored of this project!
- Paper written:
Aardvark found X. Our results, although tentative, appear to agree with their findings.
Dr Clot-Head investigates the same question and publishes the following:
Aardvark and Bloggs have shown that X is true. Our results agree with their analysis, although we haven’t taken Y and Z into account, so our findings are only tentative.
Dr Dummy joins the bandwagon:
Various authors have found X (Aardvark, Bloggs, Clot-Head). Our findings, although tentative, agree with the general consensus.
Actually, X is not true and Professor Aardvark’s theory is wrong. However, due to the complexity of the issue, the lack of any credible alternative theory and constraints on the researchers’ time, X soon becomes part of common knowledge. Everyone knows X is true!
My question: does this actually happen in astronomy?
Stellarium
Sep 17th
If, like me, you know virtually nothing about astronomy, wouldn’t know which way to look through a telescope, but would quite like to be able to identify more than three objects in the sky, then Stellarium is just what you’ve been looking for. (Much more suitable than Google Earth-Sky or Sky-map.org for this particular purpose, if you ask me.)
As a very slightly geeky person, I found it easiest to navigate Stellarium using the keyboard: press ‘H’ for help, and ‘M’ to change the settings (location, time, etc.).
Galaxy Zoo
Jul 12th
Galaxy Zoo is a project to get ordinary people (that’s you) to help look through pictures of a million galaxies, labelling each one as a spiral galaxy, elliptical galaxy, etc. (People are better than computers at doing this sort of task.)
They’ll have to be careful about drawing conclusions from this project, but it seems an excellent way to get the public to appreciate the vastness of the Universe and the beauty and diversity of some of the billions of galaxies that populate it. (And bear in mind that each galaxy contains billions of stars.)
Go on, join in!
Questions for the standard cosmological model
Mar 30th
…it seems probable that most of the grand underlying principles have been firmly established…
The words of Albert Michelson, Nobel Prize-winning physicist, in 1894.
But these words would have fit comfortably into many of the 60-70 presentations I sat through this week as part of “Outstanding Questions for the Standard Cosmological Model” at Imperial College, London.
Cosmological research has within the last few decades been converging towards a certain “standard model”. The Universe is now taken to be flat, expanding and accelerating, composed of ordinary matter, dark matter and dark energy, and filled with structures that grew out of small fluctuations in the early Universe.
So is this model right? That, I suppose, was the question behind this conference.
The “standard model” is not without its successes. Douglas Scott summarized a few of these in his talk: for example, years before observations were able to offer confirmation, it was predicted that both the cosmic microwave background and the spatial distribution of galaxies would display the signature of acoustic oscillations (sound waves).
But nor is it without its challenges. These are mainly related to dark matter and dark energy: can we really claim to have a firm model for the Universe when we know almost nothing about 96% of it?
So what’s the verdict?
There’s clearly something in it – the successful predictions of the model aren’t just coincidences. But, as Albert Stebbins pointed out in his conference summary, paraphrasing Einstein, “The most problematic thing about the universe is that it is too explainable” (or words to that effect). This is because there is often more than one plausible explanation for any given set of observations. Scientific models are always tentative – our best guess until someone thinks of a better idea. So have we discovered the true model? We can’t say. All we can do is look for consistency (the data are consistent with Model A) and make comparisons (the data suggest that Model B is to be preferred over Model C).
So as the jury gets to work on this task, here’s my advice to them:
- The first stage is to come up with some ideas. Our models are no better than our imaginations. Reflect long and hard on the evidence. Make just a few really basic assumptions, and stare at the hard facts to see what they suggest to you. Be creative. (Science is one of the arts, you know!)
- Established models will always need refining. But resist the urge to bolt on appendages whenever you encounter difficulties. Keep going back to the foundations of the model – don’t treat it as a black box that can’t be taken to pieces. For example, as several of this week’s speakers suggested, is it possible to re-formulate general relativity in such a way that dark energy and dark matter are no longer required?
Fortunately, the jury doesn’t have to return a definitive verdict (although the individual members of the jury will feel compelled before too long to champion their personal favourite model – sitting on the fence is not comfortable – but that’s another story).
On faith and reason
Dec 4th
Religious knowledge is about faith, but scientific knowledge is about reason, right?
Well, no.
At least, not according to this talk (MP3) by Andrew Fellows. After examining various views of the interplay between reason and faith, he argues (convincingly) that “true understanding is always preceded by faith” because “we cannot arrive at knowledge until we first make a commitment to a starting point” (following Polanyi). In science this starting point is the tradition we inherit, which both shapes and moulds our understanding and also tells us which questions we should be asking.
A cautionary note to those who think that science is objective but religion is subjective.
Not convinced? Have a listen! Great thing to do while on the bus, walking home or washing up.
I am a research fellow in 
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