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To Mars or not to Mars?

Posted in Science Politics, The Universe and Stuff with tags , , , , , on April 17, 2010 by telescoper

Amongst  the news this week was President Obama’s announcement of a new space exploration policy for NASA. Out goes the Constellation program, including the Orion crewship, its Ares launch rocket, and the rest of the project’s Moon-bound architecture. Obama says NASA were on an unsustainable path, costing too much money and taking too long to develop. Instead he’s given them extra funds ($6 billion, modest by the standards of space exploration) and told them to find new ways of putting people into space. Obama’s particular goal is to send someone to Mars by the mid 2030s and return them safely to Earth. I think Obama’s plans have ruffled a few feathers, especially among those longing for a return to the Moon, but it seems to me to be both bold and intelligent. 

The European Space Agency also has a programme – called Aurora – which includes components involved with both robotic and human exploration. This programme is a kind of optional extra within the ESA budget and countries that wanted to join in were asked to pay an extra contribution. The UK opted in so now we pay a top-up on our subscription to ESA in order to participate. This will be one of the things that transfers to the new UK Space Agency, when it’s up and running properly, from the Science and Technology Facilities Council (STFC).

Thus far the UK policy has been not to get involved in human space exploration. There are a lot of reasons behind that, but one of the most important is sheer cost. Space exploration is expensive by its very nature, but involving human beings creates enormous extra costs connected with keeping them alive and keeping them safe while they are in space. Since our national expenditure on space exploration has largely been channelled through STFC (or its predecessor PPARC) where it has had to compete for funds with “pure” science activities in the areas of particle physics and astronomy (and, more recently, nuclear physics).

I think the scientific argument against funding human exploration has always been as follows. There aren’t many things that people could do on Mars that a robot couldn’t – here I’m talking just about scientific experiments and the like. Human space exploration is much more expensive than the robotic variety. The scientific value for money is consequently much higher for robotic missions ergo, since money is tight, we don’t do human space exploration. Plus, we couldn’t afford it anyway…

The other factor is that there aren’t many feasible targets for manned spaceflight in the first place. The Moon and Mars are basically it. Other objects in the solar system are either too distant or too inhospitable (or both) to be considered. Unmanned probes haven’t all been successful, but some certainly have paid off enormously in scientific terms. I give the Cassini-Huygens mission to Saturn (and its extraordinary moon Titan) as an example that has turned out, in my opinion, to be nothing short of sensational. The images of Titan’s surface sent back by Huygens were gobsmackingly amazing, for instance.

Before going on let me point out that I’m a cosmologist, not a planetary scientist. There’s a tendency among scientists to think that their own field is more important than the others with which it has to compete for funding. It’s perfectly natural that someone working on galaxy formation should find galaxies more interesting than planets, and vice-versa. We all pick what we want to work on, and obviously we pick what interests us most.  But any scientist worth his/her salt should have enough of a grasp of the big picture to recognize outstanding work in disciplines other than their own.  I don’t want anyone to think that the following comments are intended to suggest that there isn’t excellent work going on in the UK and rest of the world in the field of planetary exploration.

I do think, however, that there is a big difference in character between fundamental science (especially particle physics and cosmology) and planetary exploration. In fundamental physics we are attempting to uncover the nature of basic constituents of the universe and the general laws that govern the structure of matter and how it interacts and evolves – in other words, its scope is (or at least tries to be) universal. It’s certainly this aspect – trying to unravel an enormous cosmic puzzle – that drew me into cosmology. By contrast, the study of a particular planet – even a fascinating one, such as Saturn with all the beautiful orbital dynamics going on in its ring system – lacks this aspect of universality. That’s why cosmology interests me more than planetary exploration does. This is nothing more than a statement of personal interest.

Having said that – and pointing out  again that I’m no particular expert on the Solar System – I don’t find the Moon and Mars very  interesting from a scientific point of view compared with, say,  the outer planets which I find fascinating. Others – a great many others, in fact – obviously do see a lot of interest in Mars. I’m not at all convinced about the scientific merit of some other space probes either, especially the planned Mercury orbiter BepiColombo. But there we are. We can’t all expect to agree on everything. What I’m trying to say, though, is at the moment these different types of activity are funded from the same pot. In order to draw up an order of priority, STFC has to compare apples with oranges with predictably bizarre outcomes.

Moreover, space exploration – especially human space exploration – isn’t just about science. There are definite commercial opporunities in space, in both short and long term.  Space missions often  provide results that are fairly easily accessible to non-scientists, so has considerable popular appeal as well as inspiring young people to take up science and engineering subjects. It has immense cultural impact too, altering the way we think about ourselves and our place in the Universe. But these aren’t unique to space exploration. Particle physics and astronomy do this too.

 But the overriding factor is the politics. When NASA put a man on the Moon 40 years ago, it was never about science – it was a political statement made right at the height of the Cold War. We no longer have a Cold War, but nations still feel the need to show off to each other. It’s called national pride. Politicians know how this works, and how it can turn into votes…

So we shouldn’t think of the plan to put a man on Mars as being primarily a scientific thing anyway. I’m quite comfortable with that.  My worry – if the UK decides to take part in manned Mars exploration – is that the money will come from the already dwindling pot allocated to fundamental science. Particle physics and astronomy research in the UK is on the ropes after the recent devastating cuts. Any more blows like this and we’ll be on the floor. I’m deeply worried that far worse is already on the way – a combination of public spending cuts after the general election and political directives to devote more to space exploration.

The new UK Space Agency could be either a hero or a villain, and I don’t know how it will turn out. On the one hand, the creation of this organization may prevent the fundamental sciences from being squeezed further by expensive space projects. In this way it might represent a recognition of the different characteristics I talked about above. The industrial and commercial aspects of space exploration are present in the new outfit too.  On the other hand, the result of hiving off the “glamorous” space parts of STFC may lead to further cuts in what is left behind. I’m also nervous about the future relationship between UKSA and STFC, especially the extent to which the former can demand research grant funding from the latter.

I’m sorry this has been such a long and rambling post, but this has been on my mind for quite some time and I wanted at last to put something together about it. I could summarise what I’m saying as follows:

  •  I’m not convinced about the scientific case for Mars exploration – particularly if it involves manned missions
  • BUT it’s not my field so it’s not my decision to make
  • AND there’s more to Mars than science anyway
  • SO by all means do it if there’s a will
  • BUT for heavens sake don’t pay for it by killing off the rest of astronomy

This is something that I’d be genuinely interested in hearing other views on. What is stated above is my opinion and is not intended to be representative of anyone, but I’d be very interested in hearing other views through the comments box.

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Hubble Flash

Posted in The Universe and Stuff with tags , , , , , on September 9, 2009 by telescoper

Just a quick post to point out that brand new “Early Release” images have just appeared following the recent refurbishment of the Hubble Space Telescope.

You can read the accompanying press release here, so I’ll just post this brief description:

These four images are among the first observations made by the new Wide Field Camera 3 aboard the upgraded NASA Hubble Space Telescope.

The image at top left shows NGC 6302, a butterfly-shaped nebula surrounding a dying star. At top right is a picture of a clash among members of a galactic grouping called Stephan’s Quintet. The image at bottom left gives viewers a panoramic portrait of a colorful assortment of 100,000 stars residing in the crowded core of Omega Centauri, a giant globular cluster. At bottom right, an eerie pillar of star birth in the Carina Nebula rises from a sea of greenish-colored clouds.

My own favourite has to be Stephan’s Quintet, but they all look pretty fantastic.

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Everyone’s Gone to the Moon

Posted in Uncategorized with tags , , , , on July 16, 2009 by telescoper

Since the media have been banging on about it all week, as have various other bloggers, I suppose I should at least mention that today (16th July 2009) is the fortieth anniversary of the launch of NASA’s  Apollo 11 mission which put the first man on the Moon. I’m reliably informed that the picture on the left shows the second man on the Moon, Buzz Aldrin, although I don’t think the costume gives much clue to the identity of the wearer.

My response to the media furore  is muted because I’m decidedly ambivalent about the whole business of manned space exploration. I’m not going to be churlish and say that all the Apollo missions did was provide America with a much-needed propaganda victory during the Cold War. I think it’s true that putting a man on the Moon was a great achievement in terms of ingenuity and organization. It’s  probably also true that it inspired many people to go into science who otherwise wouldn’t have done so. I’d even say that the sight of Earth from the Moon marked the beginning of a new age of awareness of the fragility of our own existence on our home planet and, perhaps even a step towards our coming-of-age as a species.

The reason I am ambivalent, however, is that the scientific returns from the Apollo missions were entirely negligible, at least in terms of value for money,  partly because the Apollo missions weren’t really designed to do science in the first place and partly because the Moon just isn’t very interesting…

Mankind hasn’t returned to the Moon since the Apollo series came to an end. That’s not a matter for regret, just a reflection of the fact that there isn’t much to be found there. In those forty years  astronomy and space science have moved on immeasurably through spaceborne observatories and unmanned probes. We have learned far more about the Universe  those ways than could ever be achieved by sending a few people to collect rocks from a dull piece of rubble in our backyard. In the process, the Universe has grown in size relative to the scale possible to reach by human engineering projects. The last forty years has shown us that, in retrospect, going to the Moon wasn’t really all that impressive compared to what we can find out by remote means.

Unfortunately there appears to be an increasingly vocal lobby in favour of diverting funds from fundamental science into manned space exploration, much of it aimed at the goal of putting a person on Mars.  This has not yet resulted in a commitment by the United Kingdom government to join in manned space exploration, but it is worrying that the Chief Executive of the Science & Technology Facilities Council is a failed astronaut who I fear sees this as an attractive option. Even more worryingly, Science Minister Lord Drayson seems to be keen too. It’s up to  scientists to present the case to government for maintaining investment in fundamental science and against having the budget plundered to play Star Trek.

The European Space Agency‘s Aurora programme is intended to culminate with a manned trip to Mars, at an overall cost of over £30 billion. One of the arguments I hear over and over again in favour of this programme is that it will inspire young people to take up science, especially physics. Well, maybe. But people can’t become scientists unless they have the opportunity to learn science at School and there is a drastic shortage of physics teachers these days. What’s the point of being inspired if you can’t get the education anyway? You could train an awful  lot of school teachers for  a small fraction of the Aurora budget.  And what’s the point of inspiring people to take up astronomy and space science when you’re also busy slashing the budget for research and ending the careers of those excellent scientists we’ve already got?

So by all means let’s celebrate the marvellous achievements of 1969, but let’s move on and not pretend that there is any good scientific reason for repeating them.

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What’s all the Noise?

Posted in Science Politics, The Universe and Stuff with tags , , , , on January 18, 2009 by telescoper

Now there’s a funny thing…

I’ve just come across a news item from last week which I followed up by looking at the official NASA press release. I’m very slow to pick up on things these days, but I thought I’d mention it anyway.

The experiment concerned is called ARCADE 2, which is an somewhat contrived acronym derived from Absolute Radiometer for Cosmology, Astrophysics and Diffuse Emission. It is essentially a balloon-borne detector designed to analyse radio waves with frequencies in the range 3 to 90 Ghz. The experiment actually flew in 2006, so it has clearly taken considerable time to analyse the resulting data.

Being on a balloon that flies for a relatively short time (2.5 hours in this case) means that only a part of the sky was mapped, amounting to about 7% of the whole celestial sphere but that is enough to map a sizeable piece of the Galaxy as well as a fairly representative chunk of deep space.

There are four science papers on the arXiv about this mission: one describes the instrument itself; another discusses radio emission from our own galaxy, the Milky Way; the third discusses the overall contribution of extragalactic origin in the frequency range covered by the instrument; the last discusses the implications about extragalactic sources of radio emission.

The thing that jumps out from this collection of very interesting science papers is that there is an unexplained, roughly isotropic, background of radio noise, consistent with a power-law spectrum. Of course to isolate this component requires removing known radio emission from our Galaxy and from identified extragalactic sources, as well as understanding the systematics of the radiometer during its flight. But after a careful analysis of these the authors present strong evidence of excess emission over and above known sources. The spectrum of this radio buzz falls quite steeply with frequency so appears in the two long-wavelength channels at 3 and 8 GHz.

So where does this come from? Well, we just don’t know.

The problem is that no sensible extrapolation of known radio sources to high redshift appears to be able to generate an integrated flux equivalent to that observed. Here is a bit of the discussion from the paper:

It is possible to imagine that an unknown population of discrete sources exist below the flux limit of existing surveys. We argue earlier that these cannot be a simple extension of the source counts of star-forming galaxies. As a toy model, we consider a population of sources distributed with a delta function in flux a factor of 10 fainter than the 8.4 GHz survey limit of Fomalont et al. (2002). At a flux of 0.75 μJy, it would take over 1100 such sources per square arcmin to produce the unexplained emission we see at 3.20 GHz, assuming a frequency index of −2.56. This source density is more than two orders of magnitude higher than expected from extrapolation to the same flux limit of the known source population. It is, however, only modestly greater than the surface density of objects revealed in the faintest optical surveys, e.g., the Hubble Ultra Deep Field (Beckwith et al. 2006).  The unexplained emission might result from an early population of non thermal emission from low-luminosity AGN; such a source would evade the constraint implied by the far-IR measurements.

The point is that ordinary galaxies produce a broad spectrum of radiation and it is difficult to boost the flux at one frequency without violating limits imposed at others. It might be able to invoke Active Galactic Nuclei (AGN) to do the trick, but I’m not sure. I am sure there’ll be a lot work going on trying to see how this might fit in with all the other things we know about galaxy formation and evolution but for the time being it’s a mystery.

I’m equally sure that these results will spawn a plethora of more esoteric theoretical explanations, inevitably including the ridiculous as well as perhaps the sublime. Charged dark matter springs to mind.

Or maybe it’s not even extragalactic. Could it be from an unknown source inside the Milky Way? If so, it might shed some light on the curiosities we find in the cosmic microwave background that I’ve mentioned here and there, but it seems to peak at too low a frequency to account for much of the overall microwave sky temperature.

But it does have a lesson for astronomy funders. ARCADE 2 is a very cheap experiment (by NASA standards). Moreover, the science goals of the experiment did not include “discovering a new cosmic background”. It just goes to show that even in these times of big, expensive and narrowly targetted missions there is still space for serendipity.

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