Archive for PLATO

It’s Official, it’s PLATO!

Posted in Science Politics, The Universe and Stuff with tags , , , , on February 19, 2014 by telescoper

Just a quick post to pass on the news that the European Space Agency has officially selected the third M-Class mission to form part of its Cosmic Vision Programme (which covers the period 2015-2025). The lucky winner is PLATO (PLAnetary Transits and  Oscillations of stars) and it will detect extra-solar planets by monitoring relatively nearby stars, searching for tiny, regular dips in brightness as planets transit in front of them. It will also study astroseismological activity, enabling a precise characterisation of the host star of each planet discovered, including its mass, radius and age.

plato_satelliteIt is expected that PLATO will find and analyse thousands of  such exoplanetary systems in this way, with an emphasis on discovering and characterizing Earth-sized planets and super-Earths in the habitable zone of their parent star. PLATO will be launched on a Soyuz rocket from Europe’s Spaceport in Kourou by 2024 for an initial six-year mission. It will operate from the Second Lagrange Point, or L2 for short. It’s an intriguing design consisting of 34 small telescopes (left).

PLATO joins Solar Orbiter and Euclid, which were chosen in 2011 as ESA’s first two M-class missions. Solar Orbiter will be launched in 2017 to study the Sun and solar wind from a distance of less than 50 million km, while Euclid, to be launched in 2020, will focus on dark energy, dark matter and the structure of the Universe.

The decision to select PLATO wasn’t exactly a surprise as it was singled out as the leading candidate by an expert panel last month, but there was nevertheless some nervousness among certain senior astronomers at the Royal Astronomical Society on Friday in advance of the formal decision. I suspect they’ll all be out celebrating tonight!

The Meaning of Research

Posted in Uncategorized with tags , , , , , on March 8, 2012 by telescoper

An interesting email exchange yesterday evening led me to write this post in the hope of generating a bit of crowd sourcing.

The issue at hand concerns the vexed question of the etymology and original meaning of the word “research” (specifically in the context of scholarly enquiry). The point is that the latin prefix re- usually seems to imply repetition whereas the meaning we have for research nowadays is that something new is being sought.

My first thought was to do what I always do in such situations, which is reach for the online edition of the Oxford English Dictionary wherein I found the following:

Etymology: Apparently < re- prefix + search n., after Middle French recerche (rare), Middle French, French recherche thorough investigation (1452; a1704 with spec. reference to investigation into intellectual or academic questions; 1815 in plural denoting scholarly research or the published results of this) … Compare Italian ricerca (1470). Compare slightly later research v.1

Interestingly, my latin dictionary gives a number of words for the verb form of research, such as “investigare”, most of which have recognisable English descendants, but there isn’t a word resembling “research”, or even “search”, so these must have been brought into French from some other source. The prefix re- was presumably added in line with the usual treatment of Latin words brought into French.

Most of the brain cells containing my knowledge of Latin died a long time ago, but I do recall from my school days that the prefix re- does not always mean “again” in that language, and alternative meanings have crept into other languages too. In particular, “re-” is sometimes used simply as an intensifier. I remember “resplendent” is derived from “resplendere” which means to shine (splendere) intensely, not to shine again. Likewise we have replete, which means extremely full, not full again.

This led me to my theory, henceforth named Theory A, that the french “recherche” and the italian “ricerca” originally meant “to search intensely, or with particular thoroughness” as in a scholar poring over documents (presumably including the Bible). Support for this idea can be found here where it says

1570s, “act of searching closely,” from M.Fr. recerche (1530s), from O.Fr. recercher “seek out, search closely,” from re-, intensive prefix, + cercher “to seek for” (see search). Meaning “scientific inquiry” is first attested 1630s…

Being a web source, one can’t attest to its reliability and the dates quoted to differ from the OED, but it shows that at least one other person in the world has the same interpretation as me! However, Iin the interest of balance I should also quote, for example,  this dissenting opinion which is also slightly at odds with the OED:

As per the Merriam-Webster Online Dictionary, the word research is derived from the Middle French “recherche”, which means “to go about seeking”, the term itself being derived from the Old French term “recerchier” a compound word from “re-” + “cerchier”, or “sercher”, meaning ‘search’. The earliest recorded use of the term was in 1577.

My correspondent (and regular commenter on here), Anton, suggested an alternative theory which is based on an idea that can be traced back to Plato. This reminded me of the following explanation of the purpose of scholarship by the Venerable Jorgi in Umberto Eco’s novel The Name of the Rose:

..the preservation of knowledge. Preservation, I say. Not search for… because there is no progress in the history of knowledge … merely a continuous and sublime recapitulation.

Plato indeed argued that true novelty and originality are impossible to achieve. In the Dialogues, Plato has Meno ask Socrates:

“How will you look for it, Socrates, when you do not know at all what it is? How will you aim to search for something you do not know at all? If you should meet with it, how will you know that this is the thing that you did not know? “

And Socrates answers:

“I know what you want to say, Meno … that a man cannot search either for what he knows or for what he does not know. He cannot search for what he knows—since he knows it, there is no need to search—nor for what he does not know, for he does not know what to look for.”

Theory B then is that research has an original meaning derived from this strange (but apparently extremely influential) Platonic idea in which “re-” really does imply repetition.

We scientists think of the scientific method as a means of justifying and validating new ideas, not a method by which new ideas can be generated, but generating new ideas is essential if science can be really said to advance. As one article I read states puts it “We aim for new-search not re-search. It is new-search that advances our understanding of how the world works.”

My research suggests that it’s possible that research doesn’t really mean re-search anyway but I can’t say I have any evidence that convincingly favours Theory A over Theory B. Maybe this is where the blogosphere can help?

I know I have an eclectic bunch of readers so, although it’s unlikely that an expert in 16th Century French is among my subscribers, I wonder if anyone out there can think of any decisive evidence that might resolve this etymological conundrum? If so, please let me have your contributions through the comments box.

In the meantime let’s subject this to a poll…

A Potted Prehistory of Cosmology

Posted in History, The Universe and Stuff with tags , , , , , , , , , , , , , , , , , , , , , on January 26, 2012 by telescoper

A few years ago I was asked to provide a short description of the history of cosmology, from the dawn of civilisation up to the establishment of the Big Bang model, in less than 1200 words. This is what I came up with. Who and what have I left out that you would have included?

–0–

 Is the Universe infinite? What is it made of? Has it been around forever?  Will it all come to an end? Since prehistoric times, humans have sought to build some kind of conceptual framework for answering questions such as these. The first such theories were myths. But however naïve or meaningless they may seem to us now, these speculations demonstrate the importance that we as a species have always attached to thinking about life, the Universe and everything.

Cosmology began to emerge as a recognisable scientific discipline with the Greeks, notably Thales (625-547 BC) and Anaximander (610-540 BC). The word itself is derived from the Greek “cosmos”, meaning the world as an ordered system or whole. In Greek, the opposite of “cosmos” is “chaos”. The Pythagoreans of the 6th century BC regarded numbers and geometry as the basis of all natural things. The advent of mathematical reasoning, and the idea that one can learn about the physical world using logic and reason marked the beginning of the scientific era. Plato (427-348 BC) expounded a complete account of the creation of the Universe, in which a divine Demiurge creates, in the physical world, imperfect representations of the structures of pure being that exist only in the world of ideas. The physical world is subject to change, whereas the world of ideas is eternal and immutable. Aristotle (384-322 BC), a pupil of Plato, built on these ideas to present a picture of the world in which the distant stars and planets execute perfect circular motions, circles being a manifestation of “divine” geometry. Aristotle’s Universe is a sphere centred on the Earth. The part of this sphere that extends as far as the Moon is the domain of change, the imperfect reality of Plato, but beyond this the heavenly bodies execute their idealised circular motions. This view of the Universe was to dominate western European thought throughout the Middle Ages, but its perfect circular motions did not match the growing quantities of astronomical data being gathered by the Greeks from the astronomical archives made by the Babylonians and Egyptians. Although Aristotle had emphasised the possibility of learning about the Universe by observation as well as pure thought, it was not until Ptolemy’s Almagest, compiled in the 2nd Century AD, that a complete mathematical model for the Universe was assembled that agreed with all the data available.

Much of the knowledge acquired by the Greeks was lost to Christian culture during the dark ages, but it survived in the Islamic world. As a result, cosmological thinking during the Middle Ages of Europe was rather backward. Thomas Aquinas (1225-74) seized on Aristotle’s ideas, which were available in Latin translation at the time while the Almagest was not, to forge a synthesis of pagan cosmology with Christian theology which was to dominated Western thought until the 16th and 17th centuries.

The dismantling of the Aristotelian world view is usually credited to Nicolaus Copernicus (1473-1543).  Ptolemy’s Almagest  was a complete theory, but it involved applying a different mathematical formula for the motion of each planet and therefore did not really represent an overall unifying system. In a sense, it described the phenomena of heavenly motion but did not explain them. Copernicus wanted to derive a single universal theory that treated everything on the same footing. He achieved this only partially, but did succeed in displacing the Earth from the centre of the scheme of things. It was not until Johannes Kepler (1571-1630) that a completely successful demolition of the Aristotelian system was achieved. Driven by the need to explain the highly accurate observations of planetary motion made by Tycho Brahe (1546-1601), Kepler replaced Aristotle’s divine circular orbits with more mundane ellipses.

The next great development on the road to modern cosmological thinking was the arrival on the scene of Isaac Newton (1642-1727). Newton was able to show, in his monumental Principia (1687), that the elliptical motions devised by Kepler were the natural outcome of a universal law of gravitation. Newton therefore re-established a kind of Platonic level on reality, the idealised world of universal laws of motion. The Universe, in Newton’s picture, behaves as a giant machine, enacting the regular motions demanded by the divine Creator and both time and space are absolute manifestations of an internal and omnipresent God.

Newton’s ideas dominated scientific thinking until the beginning of the 20th century, but by the 19th century the cosmic machine had developed imperfections. The mechanistic world-view had emerged alongside the first stirrings of technology. During the subsequent Industrial Revolution scientists had become preoccupied with the theory of engines and heat. These laws of thermodynamics had shown that no engine could work perfectly forever without running down. In this time there arose a widespread belief in the “Heat Death of the Universe”, the idea that the cosmos as a whole would eventually fizzle out just as a bouncing ball gradually dissipates its energy and comes to rest.

Another spanner was thrown into the works of Newton’s cosmic engine by Heinrich Olbers (1758-1840), who formulated in 1826 a paradox that still bears his name, although it was discussed by many before him, including Kepler. Olbers’ Paradox emerges from considering why the night sky is dark. In an infinite and unchanging Universe, every line of sight from an observer should hit a star, in much the same way as a line of sight through an infinite forest will eventually hit a tree. The consequence of this is that the night sky should be as bright as a typical star. The observed darkness at night is sufficient to prove the Universe cannot both infinite and eternal.

Whether the Universe is infinite or not, the part of it accessible to rational explanation has steadily increased. For Aristotle, the Moon’s orbit (a mere 400,000 km) marked a fundamental barrier, to Copernicus and Kepler the limit was the edge of the Solar System (billions of kilometres away). In the 18th and 19th centuries, it was being suggested that the Milky Way (a structure now known to be at least a billion times larger than the Solar System) to be was the entire Universe. Now it is known, thanks largely to Edwin Hubble (1889-1953), that the Milky Way is only one among hundreds of billions of similar galaxies.

The modern era of cosmology began in the early years of the 20th century, with a complete re-write of the laws of Nature. Albert Einstein (1879-1955) introduced the principle of relativity in 1905 and thus demolished Newton’s conception of space and time. Later, his general theory of relativity, also supplanted Newton’s law of universal gravitation. The first great works on relativistic cosmology by Alexander Friedmann (1888-1925), George Lemaître (1894-1966) and Wilhem de Sitter (1872-1934) formulated a new and complex language for the mathematical description of the Universe.

But while these conceptual developments paved the way, the final steps towards the modern era were taken by observers, not theorists. In 1929, Edwin Hubble, who had only recently shown that the Universe contained many galaxies like the Milky way, published the observations that led to the realisation that our Universe is expanding. That left the field open for two rival theories, one (“The Steady State”, with no beginning and no end)  in which matter is continuously created to fill in the gaps caused by the cosmic expansion and the other in which the whole shebang was created, in one go, in a primordial fireball we now call the Big Bang.

Eventually, in 1965, Arno Penzias and Robert  Wilson discovered the cosmic microwave background radiation, proof (or as near to proof as you’re likely to see) that our Universe began in a  Big Bang…

Cosmic Vision

Posted in Science Politics, The Universe and Stuff with tags , , , , , , , , , on February 20, 2010 by telescoper

It’s nice to have a bit of science stuff to blog about for a change. Just this week the European Space Agency (ESA) has  announced the results of its recent selection process for part of its Cosmic Visions programme, which represents ESA’s scientific activity for the period 2015-2025.

The selection process actually began in 2007, with over 50 proposals. This list was then whittled down so that there were six candidate missions under consideration for the so-called M-class launch slots (M meaning medium-sized), and three in the L-class list of larger missions. The latest exercise was to select three of the M-class missions for further study. They succeeded in selecting three, but have also kept another, much cheaper, mission in the frame.

As far as I understand it, only two M-class missions are actually envisaged so the race isn’t over yet, but the missions still in the running are:

PLATO.  The PLATO mission is planned to study planets around other stars. This would include terrestrial planets in a star’s habitable zone, so-called Earth-analogues. In addition, PLATO would probe stellar interiors by through stellar seismology. In some sense, this mission is the descendant of a previous proposal called Eddington. (PLATO stands for PLAnetary Transits and Oscillations of stars – I’ll give it 3/10 for quality of acronym).

EUCLID. Euclid would address key questions relevant to fundamental physics and cosmology, namely the nature of the mysterious dark energy and dark matter. Astronomers are now convinced that these substances dominate ordinary matter. Euclid would map the distribution of galaxies to reveal the underlying ‘dark’ architecture of the Universe. I don’t think this is meant to be an acronym, but I could be wrong. Perhaps it’s European Union Cosmologists Lost in Darkness?

SOLAR ORBITER. Disappointingly, this is neither an acronym nor a Greek person. It would take the closest look at our Sun yet possible, approaching to just 62 solar radii. It would deliver images and data that include views of the Sun’s polar regions and the solar far side when it is not visible from Earth.

These are the three main nominations, but the panel also decided to endorse another mission, SPICA, because it is much cheaper than the approximately 500 Million Euro price tag on the other contenders. SPICA would be an infrared space telescope led by the Japanese Space Agency JAXA. It would provide ‘missing-link’ infrared coverage in the region of the spectrum between that seen by the ESA-NASA Webb telescope and the ground-based ALMA telescope. SPICA would focus on the conditions for planet formation and distant young galaxies.

Many of Cardiff’s astronomers will be very happy if SPICA does end up being selected as it is the one most directly related to their interests and also their experience with Herschel which is, incidentally,  continuing to produce fantastic quality data. If SPICA is to happen, however, extra money will have to be found and that, in the current financial climate, is far from guaranteed.

Which of these missions will get selected in the end is impossible to say at this stage. There are dark mutterings going on about how realistic is the price tag that has been put on some of the contenders. Based on past experience, cost overruns on space missions are far from unlikely and when they happen they can cause a great deal of damage in budgets. Let’s hope the technical studies do their job and put realistic figures on them so the final selection will be fair.

Whatever missions fly in the end, I also hope that the Science and Technology Research Council (STFC) – or whatever replaces it – remembers that these are science missions, and its responsibility extends beyond the building of instruments to fly on them. Let’s to hope we can count on their support for research grants enabling us to answer the science questions they were designed to address.

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