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An absorption feature, the properties of which strongly depend on the pulse phase, has been recently discovered in the X-ray spectrum of the soft gamma repeater SGR0418+5729. If interpreted as a proton cyclotron line, its energy implies a magnetic field ranging from 2× 1014 G to more than 1015 G, which confirms the magnetar interpretation for this source and provides us with the most direct measurement of the magnetic field intensity of an isolated neutron star. The lower value of the dipole field inferred from the timing parameters for SGR 0418+5729 (B = 6× 1012 G) requires that the high magnetic field responsible for the observed feature resides in a strong multi-polar component located close to the neutron star surface, in agreement with the predictions of the magnetar model. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The status and the main results achieved by Project 242 are presented. Project 242 is a programme (funded by ASI—1999/2002 from an idea of Carlo Rubbia) that studied a new concept of space propulsion motor by using direct conversion of the kinetic energy of fission fragments into increasing of enthalpy of a propellant gas. Project 242 studied the application of this propulsion system to a manned mission to Mars. Preliminary results were very satisfactory and it has been observed that a propulsion system with these characteristics could make the mission feasible. Results for other unmanned missions to the outer solar system are also presented.

At the end of the twenty-first century, humanity will have explored out to our solar-system’s boundaries, beyond which many have speculated for centuries about what may exist there. Plato and Aristotle, who dominated the cosmology of the ancient Greeks and Romans, considered the universe to be composed of the five planets visible to the naked eye, plus Earth and the Moon. What lay beyond was left to metaphysical speculation. However, Democritus claimed that countless stars composed the Milky Way and that they appeared as points of light due to their vast distances from Earth. Lucretius thought the universe to be infinite and populated by an infinite number of stars. The Catholic Church adopted Aristotle’s mechanistic ideas (ipse dixit…), which dominated the following centuries.

Astronautics is the theory and practice of navigation beyond the Earth’s atmosphere. Isaac Newton established the mathematical basis of astronautics in his treatise The Mathematical Principles of Natural Philosophy. They are embedded in his laws of motion and gravitation. The reactions in a spaceship’s engine produce enormous pressures. They cause the expulsion of gas and/or radiation at high speed in the direction opposite to travel. It is this reaction force that pushes forward the engine and the spaceship attached to it.

Moving human space exploration beyond the Moon is the next challenge. Mars, the most Earth-like planet in the solar system, is the next target. Table 4.1 summarises the main physical characteristics of the Earth and Mars.

Freeman Dyson once said “there is nothing so great or so crazy that a technological society cannot be moved to do, provided that it is physically possible.” He is one of the few surviving giants among visionaries from the space race of the 1960s. In his book Disturbing the Universe, he presents heretical ideas, such as space colonisation and the exploitation of natural resources in space. He examines two scenarios. The first one explores the feasibility of a habitat around the Sun, which uses its energy to sustain life. Public money would finance this project. The second scenario analyses the activities of small groups of settlers, who use the resources of asteroids to support their operations. His preferences lie with the latter scenario

RX J0822-4300 is the Central Compact Object associated with the Puppis A supernova remnant. Previous X-ray observations suggested RX J0822-4300 to be a young neutron star with a weak dipole field and a peculiar surface temperature distribution dominated by two antipodal spots with different temperatures and sizes. An emission line at 0.8 keV was also detected. We performed a very deep (130 ks) observation with XMM-Newton, which allowed us to study in detail the phase-resolved properties of RX J0822-4300. Our new data confirm the existence of a narrow spectral feature, best modelled as an emission line, only seen in the `Soft' phase interval - when the cooler region is best aligned to the line of sight. Surprisingly, comparison of our recent observations to the older ones yields evidence for a variation in the emission line component, which can be modelled as a decrease in the central energy from ~0.80 keV in 2001 to ~0.73 keV in 2009--2010. The line could be generated via cyclotron scattering of thermal photons in an optically thin layer of gas, or - alternatively - it could originate in low-rate accretion by a debris disk. In any case, a variation in energy, pointing to a variation of the magnetic field in the line emitting region, cannot be easily accounted for.

The well known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally-powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar and nebula have been considered to be essentially stable. Here we report the detection of strong gamma-ray (100 MeV-10 GeV) flares observed by the AGILE satellite in September, 2010 and October, 2007. In both cases, the unpulsed flux increased by a factor of 3 compared to the non-flaring flux. The flare luminosity and short timescale favor an origin near the pulsar, and we discuss Chandra Observatory X-ray and HST optical follow-up observations of the nebula. Our observations challenge standard models of nebular emission and require power-law acceleration by shock-driven plasma wave turbulence within a ~1-day timescale., Comment: 23 pages (including Supporting On-line Material), 8 figures, 1 table. Version published in Science Express on January 6, 2011 (available at http://www.sciencemag.org/content/early/2011/01/05/science.1200083)

Dati telerilevati e beni pubblici globali - This paper is an initial investigation of the possibility that remote sensing data be regarded as global public goods. Remote sensing data for civil applications may be considered as Moreover products since the marginal cost from an additional use is close to zero. Indeed, remote sensing data are a form of scientific knowledge and as such have an important public good trait. Furthermore, this is also a consequence of the general opinion that regards environmental resources as global public goods and natural disasters as international public bads. To show that remote sensing data have the potential to be considered global public goods has significant implications. Indeed, global public goods provide a rationale for international collective action, which is the only way to produce and share them, given that a global governmental authority does not exist. The paper will recall examples of international initiatives and programs that are based on data sharing principles implying full and open exchange of data and implicitly recognizing that remote sensing data are global public goods. JEL H4

Pulsars are rapidly-rotating, highly-magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently, only seven were observed to pulse in gamma rays and these were all discovered at other wavelengths. The Fermi Large Area Telescope makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics and the energetics of pulsar wind nebulae and supernova remnants., Comment: Corresponding authors: Michael Dormody, Paul S. Ray, Pablo M. Saz Parkinson, Marcus Ziegler

PSR B0540-69 is the Crab twin in the Large Magellanic Cloud. Age, energetic and overall behaviour of the two pulsars are very similar. The same is true for the general appearance of their pulsar wind nebulae (PWNe). Analysis of Hubble Space Telescope images spanning 10 years unveiled significant variability in the PWN surrounding PSR B0540-69, with a hot spot moving at ~0.04c. Such behaviour, reminiscent of the variability observed in the Crab nebula along the counter-jet direction, may suggest an alternative scenario for the geometry of the system. The same data were used to assess the pulsar proper motion. The null displacement recorded over 10 y allowed us to set a 3sigma upper limit of 290 km/s to the pulsar velocity.

We report on the X-ray and optical observation of the two unidentified EGRET sources 3EG J0616-3310 and 3EG J1249-8330. The X-ray coverage performed by the ESA space telescope XMM–Newton provided ∼150 X-ray sources within each of the two γ-ray error-circles. The optical follow-up carried on with the Wide Field Imager at the ESO/MPG 2.2 m telescope have found no candidate counterpart for 125 of these X-ray sources. Among these, we have selected 9 sources with f X/f opt≥100, which we consider promising INS candidates.

1E 161348-5055 (1E) is a compact object lying at the center of the 2000 year old Supernova Remnant (SNR) RCW103. Its original identification as an isolated, radio-quiet neutron star has been questioned in recent years by the observation of a significant long-term variability, as well as by reports of a possible periodicity at ∼6 hours. Here we report conclusive evidence for a strong (nearly 50%) periodic modulation of 1E at 6.67±0.03 hours, discovered during a long (90 ks) XMM-Newton observation performed in August 2005, when the source was in a “low state”. The source spectrum varies along the 6.67 hr cycle. No fast pulsations are seen. 1E could be a very young binary system, possibly composed of a compact object and a low-mass star in an eccentric orbit. This would be the first example of a low-mass X-ray binary (LMXB) associated with a SNR, and thus the first LMXB for which we know the precise birth date, just 2000 years ago. Alternatively, if it is an isolated neutron star, the unprecedented combination of age, period and variability may only fit in a very unusual scenario, featuring a peculiar magnetar, dramatically slowed-down over 2000 years, possibly by a supernova debris disc.

The next logical step in the exploration of space beyond the Earth as we go farther and farther away, after having conquered Sphere +1 once and for all, is to head for the Moon. Indeed, Jules Verne even skipped the intermediate stage and went directly to the Moon in 1865 with one of his best books, From the Earth to the Moon.

Breaking through Sphere +2 and going beyond the Moon sending probes to the planets, starting with Mars, is something that not even Jules Verne imagined or wrote about. Instead, the proof that reality always beats imagination was already contained in the programmes and capabilities of the very first generation of space explorers, from Korolyov with his Soviet school, to that of von Braun and Carl Sagan at NASA.

Having reached the borders of the solar system, there is bound to be a desire to lean on the fence, even if there is no one out there, and to look outwards, and, while having a look around, to wonder what might lay beyond. After all, this is the first time we have arrived at this spot.

In 1953, the same year that Everest was conquered, Auguste Piccard and his son Jacques made a record dive with the bathyscaphe Trieste to a depth of −3150 mt. in the sea off the coast of Ponza, an Italian island off Naples. A few years later, in 1958, the first nuclear-powered submarine of the US Navy, Nautilus, made its way to the arctic, reached the North Pole and surfaced off Greenland. Thus began the era of ocean exploration from within, or from below, rather than from above. Then, two years later, in 1960 (the same year Triton completed its submerged circumnavigation of the globe), the Trieste, with Jacques Piccard again on board, and with US naval support, reached a depth of 10,916 mt.: the deepest point of all the Earth oceans, at the bottom of the Mariana Trench. It is just one more courageous example of what it means to explore: this time it is the depths of the ocean and its floor, which no one then had yet seen; and even now, those few who have seen it have only seen a small part.

It is a fact that within a few tens of thousands of years after leaving Africa, that is about 70,000 years ago, sapiens came to supersede all other species in the genus Homo, driving them to extinction, but not before cohabiting for a while and acquiring a bit of genetic material, let us say that 2 % of Neanderthal that is in all of us and which can still occasionally leap out rather unexpectedly.

We consider the largest observed sample including all intermediate-frequency peaked (IBL) and high-frequency peaked (HBL) flaring blazars above 100 GeV up to redshift $z = 0.6$. We show that the best-fit regression line of the emitted spectral indices $\Gamma_{\rm em} (z)$ is a concave parabola decreasing as $z$ increases, thereby implying a statistical correlation between the $\{\Gamma_{\rm em} (z) \}$ distribution and $z$. This result contradicts our expectation that such a distribution should be $z$-independent. We argue that the above correlation does not arise from any selection bias. We show that our expectation naturally emerges provided that axion-like particles (ALPs) are put into the game. Moreover, ALPs can also explain why flat spectrum radio quasars emit up to 400 GeV, in sharp contradiction with conventional physics. So, the combination of the two very different but consistent results -- taken at face value -- leads to a hint at an ALP with mass $m = {\cal O} (10^{-10} \, {\rm eV})$ and two-photon coupling in the range $2.94 \times 10^{- 12} \, {\rm GeV}^{- 1} < g_{a \gamma \gamma} < 0.66 \times 10^{- 10} \, {\rm GeV}^{- 1}$. As a bonus, the Universe would become considerably more transparent above energies $E \gtrsim 1 \, {\rm TeV}$ than dictated by conventional physics. Our prediction can be checked not only by the new generation of observatories like CTA, HAWC, GAMMA-400, LHAASO, TAIGA-HiSCORE and HERD, but also thanks to the planned laboratory experiments ALPS II (upgraded), STAX, IAXO and with other techniques now being developed by Avignone and collaborators., Comment: 13 pages, 14 figures. This version matches the published paper: MNRAS 493, 1553 (2020)

In Jules Verne’s Journey to the Centre of the Earth (1864) its protagonist, Professor Otto Lidenbrock seemed to find everything easy. In an old book, he had discovered a loose sheet of paper, written in ancient runic by the Arne Saknussemm, in which the great Scandinavian explorer of the past claimed (in Latin) to have been to the centre of the Earth.

As far as crowning achievements in physics go, discovering a fundamental particle of nature is hard to beat. Why else, for example, would physicists be spending billions of Euros on the Large Hadron Collider at CERN to look for the famous Higgs boson and other new particles? But such discoveries are rare, which is why an anomalous signal reported by physicists at the National Institute for Nuclear Physics in Legnaro, Italy, last year is generating such excitement. As renowned theorist Andreas Ringwald put it recently in Science magazine: "If you believe the signal to be real, then the interpretation is a new particle."

The radio quiet neutron star 1E1207.4-5209 has been the target of a 260 ks XMM-Newton observation, which yielded, as a by product, an harvest of about 200 serendipitous X-ray sources above a limiting flux of 2E-15 erg/cm2/s, in the 0.3-8 keV energy range. In view of the intermediate latitude of our field (b~10 deg), it comes as no surprise that the logN-logS distribution of our serendipitous sources is different from those measured either in the Galactic Plane or at high galactic latitudes. Here we shall concentrate on the analysis of the brightest sources in our sample, which unveiled a previously unknown Seyfert-2 galaxy., Comment: 8 pages, 7 figures, 2 tables. Accepted for publication by Astronomy & Astrophysics

Everyone knows Galileo Galilei as an astronomer, physicist and writer of books that changed our perception of the world. Few people know that Galileo also wrote poetry in elegant XVI century Italian. In 1590, aged 26, Galileo was a lecturer of mathematics at the University of Pisa, the poorest paid of the faculty. He dutifully taught Euclid, but quickly ran into trouble: he despised and openly challenged Pisa's strict academic traditions. Especially the rule by which all professors had to wear their gown at all times, under penalty of a stiff fine. To chastise and mock such rule, he wrote his longest poem, the 301-line Capitolo "Against the Donning of the Gown".

Il mito della vita extraterrestre e antico quanto l’umanita, ma prende uno slancio speciale negli ultimi 400 anni della storia dell’astronomia, da quando Galileo ci ha dato il telescopio. Nel 1835, la piu grande bufala lunare della storia, oggi dimenticata, viene perpetrata dalNew York Sun afruttando la fama del telescopio di Herschel, il VLT dell’epoca. Pulcinella, a Napoli, legge la traduzione del quotidiano americano, ma non ci crede e decide di andare lui stesso sulla Luna, con una nave a ruote. Sette anni prima di Jules Verne, Capocci, direttore dell’Osservatorio di Capodimonte, descrive il primo viaggio di una donna sulla Luna, colpendo perfino la fantasia del razionalismo francese di Flammarion. Schiaparelli scopre i «canali» di Marte, dando inizio al mito dei marziani, intelligenti per necessita poiche devono sopravvivere in un ambiente ostile. Mito sopravvissuto da Lowell fino a Carl Sagan e che, in fondo, non si e ancora spento. Gli ultimi 40 anni di astronomia dallo spazio stanno riuscendo, dal Mariner 4 al Mars Express, a cambiare il nostro modo di concepire la possibilita di vita su un pianeta come Marte. Viviamo un momento storico della scienza: potremmo avere risposte definitive in un futuro molto prossimo. Piu probabilmente, avremo solo nuove domande. Nell’ultimo decennio, l’astronomia ci ha dato piu di 100 pianeti extrasolari, anche se forse nessuno di tipo «abitabile». Solo negli ultimi anni e stata pero intrapresa una ricerca seria, con i dati europei di Hipparcos; il risultato e la scoperta di 17.129 «Habstars» a meno di 500 anni luce da noi, cioe dietro l’angolo di casa nella nostra galassia. Non possiamo andarci, certo, ma sono i migliori bersagli per ascoltare possibili messaggi intelligenti. Anche la Terra si fa sentire, con la sua «bolla Marconi» in espansione alla velocita della luce e con le sonde planetarie che, lanciate 30 anni fa, stanno ora uscendo dal sistema solare, portando messaggi, immagini e suoni del pianeta Terra nello spazio interstellare.

Isolated neutron stars are seen in x-rays through their nonthermal and/or surface thermal emissions. XMM-Newton observations of the Geminga pulsar show a 43 electron volt spectrum from the whole neutron star surface, as well as a power-law component above 2 kiloelectron volts. In addition, we have detected a hot (170 electron volts) thermal emission from an 60-meter-radius spot on the pulsar s surface. Such a thermal emission, only visible at selected phase intervals, may be coming from polar hot spot(s), long thought to exist as a result of heating from magnetospheric accelerated particles. It may provide the missing link between the x-ray and gamma-ray emission of the pulsar., Comment: Published in Science, 16 July 2004

LEGEND has it that when word reached Copenhagen of the discovery of the neutron in 1932, Niels Bohr threw a great party at his home. Among his guests was a young Russian named Lev Landau, who is said to have quietly remarked that "stars could be made with this new particle". Astronomers like to think that this was said in earnest – and not under the influence of Danish hospitality – because we now know that neutron stars really do exist.

In the framework of a five year plan the Italian Space Agency has started a national program of small scientific satellites. The first two, AGILE and DAVID are already at an advanced stage of development. The former is dedicated to Gamma Ray Astrophysics, the latter to communication technology and engineering development. A third mission, to be devoted to Earth Science and exploration is in the process of being defined. A general view of the program and some specific features of the missions selected so far are given

The distance to the Vela pulsar (PSR B0833-45) has been traditionally assumed to be 500 pc. Although affected by a significant uncertainty, this value stuck to both the pulsar and the supernova remnant. In an effort to obtain a model-free distance measurement, we have applied high-resolution astrometry to the pulsar V ~ 23.6 optical counterpart. Using a set of five Hubble Space Telescope Wide Field Planetary Camera 2 observations, we have obtained the first optical measurement of the annual parallax of the Vela pulsar. The parallax turns out to be 3.4 ± 0.7 mas, implying a distance of 294 pc, i.e., a value significantly lower than previously believed. This affects the estimate of the pulsar absolute luminosity and of its emission efficiency at various wavelengths and confirms the exceptionally high value of Ne toward the Vela pulsar. Finally, the complete parallax database allows for a better measurement of the Vela pulsar proper motion [μα cos(δ) = -37.2 ± 1.2 mas yr-1; μδ = 28.2 ± 1.3 mas yr-1 after correcting for the peculiar motion of the Sun], which, at the parallax distance, implies a transverse velocity of ≈65 km s-1. Moreover, the proper-motion position angle appears especially well aligned with the axis of symmetry of the X-ray nebula as seen by Chandra. Such an alignment allows us to assess the space velocity of the Vela pulsar to be 81 km s-1.

The European Photon Imaging Camera (EPIC) consortium has provided the focal plane instruments for the three X-ray mirror systems on XMM-Newton. Two cameras with a reflecting grating spectrometer in the optical path are equipped with MOS type CCDs as focal plane detectors (Turner 2001), the telescope with the full photon flux operates the novel pn-CCD as an imaging X-ray spectrometer. The pn-CCD camera system was developed under the leadership of the Max-Planck-Institut fur extraterrestrische Physik (MPE), Garching. The concept of the pn-CCD is described as well as the dierent operational modes of the camera system. The electrical, mechanical and thermal design of the focal plane and camera is briefly treated. The in-orbit performance is described in terms of energy resolution, quantum eciency, time resolution, long term stability and charged particle background. Special emphasis is given to the radiation hardening of the devices and the measured and expected degradation due to radiation damage of ionizing particles in the rst 9 months of in orbit operation.

Nowadays are we already able to operate a connection between the Universe and our “living” selves, that is to follow the fil rouge from Big Bang to humankind? More or less, in the sense that there are at least a couple of gaps in the fil rouge, albeit regrettably important ones. The first we already saw: it is that initial moment, brief (10−43 s) but crucial, in which the whole of physics was born and we don’t know how. Then, and here we are faring much better, matter was born, and cosmological nucleosynthesis among lighter elements in the first 3 min took place, as it did a little later (a few hundreds of millions of years later? Not so very little), when stars were turned on. From such stellar nucleosynthesis (the final explosive stage included) come the elements we know, such as Iron, Calcium, Uranium and so on. Including the mythical CHNOPS cocktail included (Carbon [C], Hydrogen [H], Nitrogen [N], Oxygen [O], Phosphorus [P] and Sulphur [S]), upon which our own chemistry is based.

A little girl who is born today in a “rich” country has more than a 50 % chance of living for a 100 years. Also many boys, albeit fewer than girls, will make it to a century. In a few dozen years, we will have more great-grandparents than great-grandchildren. A proper way of attacking the ageing process remains to be discovered; maybe we could even try and understand the maximum possible life expectancy for a human being—either man or woman.

Until very recently, it was taken for granted that there would be somebody else out there, not just elementary forms of life, such as the bacteria that had lorded over Earth for billions of years (and which today still make up the bulk of our biomass). No, when we said ‘somebody’, we meant developed and intelligent life.

Before we begin thinking of our future, giving a quick look at our past should teach us something, if anything not to fall into the same mistakes. Because now we know that if someone had written a book like this one a hundred years ago or, so much the more, a thousand years ago (when books were few and far between) he would have been mistaken all along.

To begin with we ask: what remains to be discovered in the sky? The answer is easy, and we already know it: the greatest majority of the Universe, or rather almost all of it. And on Earth? In this case the answer is harder, if we talk physics, that is the nature of matter and energy. But we should make no mistakes if we start, as Mr. Qfwfq says (he who always treats me as a bit of silly), from the simple observation that the Earth is a part of the Universe and its only real difference from the rest of the Universe is that it is the only part of it that we can easily study.

The discoveries that change everything are those that have a deep social impact; those discoveries of thought, of science and of technology which, after being made in a lab or elsewhere by chance, fortune or scheming, in the end find their own way inside society and become an integral part of it. It’s their entry into society, their acceptance as discoveries and then the use of them, be it practical or conceptual, to build scientific advancement. From history we learn that often some time goes by between a discovery and its entry into society. Famous examples are legions, from electricity to the internal combustion engine, from the lamp bulb to the understanding of the relation between germs and infections and many more.

You rightly never dared to dream it, because you were afraid it wasn’t clean and it could release zillions of tons of CO2 or more into the atmosphere, damaging irreversibly our poor planet.

If seen from the outside, how does our brain work? We know it makes use of the inputs from our five senses that are at the moment the only interface between our brain and the rest of the world to accumulate data, feel emotions, make decisions and work out strategies. Furthermore, we know that, as a result of the analysis of the inputs coming from the senses and of decisions taken, it is able to produce an output in the shape of orders sent to the rest of the organism in the most various forms: a movement of the arm to catch a tennis ball, but also a watering mouth, an erection, a blush, words and much, much else.

Pythagoras (575–495 bc), the one who became famous for his theorem, had been the first, according to tradition, who would declare: “The secret language of the created world is all locked up in numbers”. More than 2,000 years later, Galileo Galilei in his Il saggiatore (1623) wrote: “Philosophy is written in this very great book that all the time lies open in front of our eyes (I say the Universe), but it cannot be understood if first you do not learn how to understand the language and know the characters it is written in. It is written in a mathematical language and the characters are triangles, circles and other geometrical figures, without which means it is impossible for any human being to understand one single word of it; it is like wandering aimlessly in a dark labyrinth”.

Extreme astrophysical sources, those where the largest energy transfers occur, give all way to gravity's fatal attraction to sustain their unrivalled power. With a special emphasis on space observations, we present an inventory of extreme astrophysical sources which follows the filiation supernovae, neutron stars and black holes, before ending with supermassive black holes. This ill-assorted population of cosmic sites has some traits in common, the black-hole relativistic-jet connection being commonplace, from solar-mass specimens up to supermassive ones.

The effort made in 2004/2005 by the European Space Science community to bring about the Cosmic Vision long-term programme set a standard to spacefaring Agencies for the third time in history. We think that the long-term space science programme of ESA is the only example of planned and formalized cooperation between a whole scientific community and an agency, in this case a multinational organization. It is easier said than done, but Europe did it, already three times. It is nice to think that there is now the chance to hand over to posterity, in printed form as a complement to the original ESA report, the present collection of 41 refereed papers. They are a representative sample of the 49 proposals originally submitted by the space science community, and on which the Cosmic Vision programme is based. The selection procedure for this volume was first of all related to the willingness of authors to actually put in scientific paper form their original proposals, secondly for them to accept the idea of rendering their work public and finally to enforce a particularly scrutinous refereeing process. However, this is only one part of the picture. Having participated (one of us as Chair of the ESA Space Science Advisory Committee) to the Cosmic Vision exercise, we would like to briefly outline here three other important elements, which were, and still are, at the heart of the programme. First of all, there is the idea itself of a long term programme, conceived from the start to be as binding as any plan can be. One does so consciously, in spite

In the panorama of Isolated Neutron Star (INS) optical astronomy new data are rapidly accumulating, especially on the recently discovered “middle age” (≥ 10 5 y) emitters. For Geminga, wide band photometry has led to the discovery of a spectral feature superimposed to the thermal continuum. Its most natural interpretion is that of emission at the ion cyclotron frequency, leading to a B-field value of ≈ 3–5 10 11 G. This is the first “in situ” measurement of an INS surface magnetic field. Other relevant characteristics of Geminga are reviewed.