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Perspective in Search of Planets and Life Around Other Stars
Proc. Natl. Acad. Sci. USA Vol. 96, pp. 5353–5355, May 1999 Perspective In search of planets and life around other stars Jonathan I. Lunine* Reparto di Planetologia, Consiglio Nazionale delle Ricerche, Istituto di Astrofisica Spaziale, Rome I-00133, Italy The discovery of over a dozen low-mass companions to nearby stars has intensified scientific and public interest in a longer term search for habitable planets like our own. However, the nature of the detected companions, and in particular whether they resemble Jupiter in properties and origin, remains undetermined. The first detection of a planet orbiting around another star like Table 1. Jovian-mass planets around main-sequence stars our Sun came in 1995, after decades of null results and false Star’s Semi-major Period, alarms. As of this writing, 18 objects have been found with masses Star mass axis, AU days Eccentricity* Mass† potentially less than 12 times that of Jupiter, but none less than 40% of Jupiter’s mass, around main-sequence stars (1) (see Table HD187123 1.00 0.042 3.097 0.03 0.57 1). In addition, several planetary-mass bodies have been detected HD75289 1.05 0.046 3.5097 0.00 0.42 orbiting pulsars. Although these are interesting as well, the exotic Tau Boo 1.20 0.047 3.3126 0.00 3.66 environments around neutron stars make it unlikely that their 51 Peg 0.98 0.051 4.2308 0.01 0.44 companions are abodes for life. It is the success in finding planets Ups And 1.10 0.054 4.62 0.15 0.61 around Sun-like stars that provides a technological stepping stone HD217107 0.96 0.072 7.11 0.14 1.28 ‡ to one of the great aspirations of humanity: to find a world like 55 Cnc 0.90 0.110 14.656 0.04 1.5–3 the Earth orbiting around a distant star. -
Geometry of Some Functional Architectures of Vision
Singular Landscapes: in honor of Bernard Teissier 22-26 June, 2015 Geometry of some functional architectures of vision Jean Petitot CAMS, EHESS, Paris J. Petitot Neurogeometry Bernard and visual neuroscience Bernard helped greatly the developement of geometrical models in visual neuroscience. In 1991 he organized the first seminars on these topics at the ENS and founded in 1999 with Giuseppe Longo the seminar Geometry and Cognition. From 1993 on, he organized at the Treilles Foundation many workshops with specialists such as Jean-Michel Morel, David Mumford, G´erard Toulouse, St´ephaneMallat, Yves Fr´egnac, Jean Lorenceau, Olivier Faugeras. He organised also in 1998 with J.-M. Morel and D. Mumford a special quarter Mathematical Questions on Signal and Image processing at the IHP. He worked with Alain Berthoz at the College de France (Daniel Bennequin worked also a lot there on geometrical models in visual neuroscience). J. Petitot Neurogeometry Introduction to Neurogeometry In this talk I would try to explain some aspects of Neurogeometry, concerning the link between natural low level vision of mammals and geometrical concepts such as fibrations, singularities, contact structure, polarized Heisenberg group, sub-Riemannian geometry, noncommutative harmonic analysis, etc. I will introduce some very basic and elementary experimental facts and theoretical concepts. QUESTION: How the visual brain can be a neural geometric engine? J. Petitot Neurogeometry The visual brain Here is an image of the human brain. It shows the neural pathways from the retina to the lateral geniculate nucleus (thalamic relay) and then to the occipital primary visual cortex (area V 1). J. Petitot Neurogeometry fMRI of human V1 fMRI of the retinotopic projection of a visual hemifield on the corresponding V1 (human) hemisphere. -
What Lies Immediately Outside of the Heliosphere in the Very Local Interstellar Medium (VLISM): What Will ISP Detect?
EPSC Abstracts Vol. 14, EPSC2020-68, 2020 https://doi.org/10.5194/epsc2020-68 Europlanet Science Congress 2020 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. What lies immediately outside of the heliosphere in the very local interstellar medium (VLISM): What will ISP detect? Jeffrey Linsky1 and Seth Redfield2 1University of Colorado, JILA, Boulder CO, United States of America ([email protected]) 2Wesleyan University, Astronomy Department, Middletown CT, United States of America ([email protected]) The Interstellar Probe (ISP) will provide the first direct measurements of interstellar gas and dust when it travels far beyond the heliopause where the solar wind no longer influences the ambient medium. We summarize in this presentation what we have been learning about the VLISM from 20 years of remote observations with the high-resolution spectrographs on the Hubble Space Telescope. Radial velocity measurements of interstellar absorption lines seen in the lines of sight to nearby stars allow us to measure the kinematics of gas flows in the VLISM. We find that the heliosphere is passing through a cluster of warm partially ionized interstellar clouds. The heliosphere is now at the edge of the Local Interstellar Cloud (LIC) and heading in the direction of the slighly cooler G cloud. Two other warm clouds (Blue and Aql) are very close to the heliosphere. We find that there is a large region of the sky with very low neutral hydrogen column density, which we call the hydrogen hole. In the direction of the hydrogen hole is the brightest photoionizing source, the star Epsilon Canis Majoris (CMa). -
The Interstellar Medium
The Interstellar Medium http://apod.nasa.gov/apod/astropix.html THE INTERSTELLAR MEDIUM • Total mass ~ 5 to 10 x 109 solar masses of about 5 – 10% of the mass of the Milky Way Galaxy interior to the suns orbit • Average density overall about 0.5 atoms/cm3 or ~10-24 g cm-3, but large variations are seen • Composition - essentially the same as the surfaces of Population I stars, but the gas may be ionized, neutral, or in molecules (or dust) H I – neutral atomic hydrogen H2 - molecular hydrogen H II – ionized hydrogen He I – neutral helium Carbon, nitrogen, oxygen, dust, molecules, etc. THE INTERSTELLAR MEDIUM • Energy input – starlight (especially O and B), supernovae, cosmic rays • Cooling – line radiation and infrared radiation from dust • Largely concentrated (in our Galaxy) in the disk Evolution in the ISM of the Galaxy Stellar winds Planetary Nebulae Supernovae + Circulation Stellar burial ground The The Stars Interstellar Big Medium Galaxy Bang Formation White Dwarfs Neutron stars Black holes Star Formation As a result the ISM is continually stirred, heated, and cooled – a dynamic environment And its composition evolves: 0.02 Total fraction of heavy elements Total 10 billion Time years THE LOCAL BUBBLE http://www.daviddarling.info/encyclopedia/L/Local_Bubble.html The “Local Bubble” is a region of low density (~0.05 cm-3 and Loop I bubble high temperature (~106 K) 600 ly has been inflated by numerous supernova explosions. It is Galactic Center about 300 light years long and 300 ly peanut-shaped. Its smallest dimension is in the plane of the Milky Way Galaxy. -
Size and Scale Attendance Quiz II
Size and Scale Attendance Quiz II Are you here today? Here! (a) yes (b) no (c) are we still here? Today’s Topics • “How do we know?” exercise • Size and Scale • What is the Universe made of? • How big are these things? • How do they compare to each other? • How can we organize objects to make sense of them? What is the Universe made of? Stars • Stars make up the vast majority of the visible mass of the Universe • A star is a large, glowing ball of gas that generates heat and light through nuclear fusion • Our Sun is a star Planets • According to the IAU, a planet is an object that 1. orbits a star 2. has sufficient self-gravity to make it round 3. has a mass below the minimum mass to trigger nuclear fusion 4. has cleared the neighborhood around its orbit • A dwarf planet (such as Pluto) fulfills all these definitions except 4 • Planets shine by reflected light • Planets may be rocky, icy, or gaseous in composition. Moons, Asteroids, and Comets • Moons (or satellites) are objects that orbit a planet • An asteroid is a relatively small and rocky object that orbits a star • A comet is a relatively small and icy object that orbits a star Solar (Star) System • A solar (star) system consists of a star and all the material that orbits it, including its planets and their moons Star Clusters • Most stars are found in clusters; there are two main types • Open clusters consist of a few thousand stars and are young (1-10 million years old) • Globular clusters are denser collections of 10s-100s of thousand stars, and are older (10-14 billion years -
Arxiv:1910.06396V4 [Physics.Pop-Ph] 12 Jun 2021 ∗ Rmtv Ieeitdi H R-Oa Eua(Vni H C System)
Nebula-Relay Hypothesis: Primitive Life in Nebula and Origin of Life on Earth Lei Feng1,2, ∗ 1Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023 2Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing University – Purple Mountain Observatory, Nanjing 210093, China Abstract A modified version of panspermia theory, named Nebula-Relay hypothesis or local panspermia, is introduced to explain the origin of life on Earth. Primitive life, acting as the seeds of life on Earth, originated at pre-solar epoch through physicochemical processes and then filled in the pre- solar nebula after the death of pre-solar star. Then the history of life on the Earth can be divided into three epochs: the formation of primitive life in the pre-solar epoch; pre-solar nebula epoch; the formation of solar system and the Earth age of life. The main prediction of our model is that primitive life existed in the pre-solar nebula (even in the current nebulas) and the celestial body formed therein (i.e. solar system). arXiv:1910.06396v4 [physics.pop-ph] 12 Jun 2021 ∗Electronic address: [email protected] 1 I. INTRODUCTION Generally speaking, there are several types of models to interpret the origin of life on Earth. The two most persuasive and popular models are the abiogenesis [1, 2] and pansper- mia theory [3]. The modern version of abiogenesis is also known as chemical origin theory introduced by Oparin in the 1920s [1], and Haldane proposed a similar theory independently [2] at almost the same time. In this theory, the organic compounds are naturally produced from inorganic matters through physicochemical processes and then reassembled into much more complex living creatures. -
The Perception of Color from Motion
UC Irvine UC Irvine Previously Published Works Title The perception of color from motion. Permalink https://escholarship.org/uc/item/01g8j7f5 Journal Perception & psychophysics, 57(6) ISSN 0031-5117 Authors Cicerone, CM Hoffman, DD Gowdy, PD et al. Publication Date 1995-08-01 DOI 10.3758/bf03206792 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Perception & Psychophysics /995,57(6),76/-777 The perception of color from motion CAROLM. CICERONE, DONALD D. HOFFMAN, PETER D, GOWDY, and JIN S. KIM University ofCalifornia, Irvine, California Weintroduce and explore a color phenomenon which requires the priorperception of motion to pro duce a spread of color over a region defined by motion. Wecall this motion-induced spread of colordy namic color spreading. The perception of dynamic color spreading is yoked to the perception of ap parentmotion: As the ratings of perceived motion increase, the ratings of color spreading increase. The effect is most pronounced ifthe region defined by motion is near 10 of visual angle. As the luminance contrast between the region defined by motion and the surround changes, perceived saturation of color spreading changes while perceived hue remains roughly constant. Dynamic color spreading is some times, but not always, bounded by a subjective contour. Wediscuss these findings in terms of interac tions between color and motion pathways. Neon color spreading (see, e.g., van Tuijl, 1975; Varin, Mathematica (Version 2.03) program used for generating 1971) shows that the colors we perceive do not always such frames is given in Appendix A. -
Important Processes Illustrated September 22, 2021
Important Processes Illustrated September 22, 2021 Copyright © 2012-2021 John Franklin Moore. All rights reserved. Contents Introduction ................................................................................................................................... 5 Consciousness>Sense .................................................................................................................... 6 space and senses ....................................................................................................................... 6 Consciousness>Sense>Hearing>Music ..................................................................................... 18 tone in music ........................................................................................................................... 18 Consciousness>Sense>Touch>Physiology ................................................................................ 23 haptic touch ............................................................................................................................ 23 Consciousness>Sense>Vision>Physiology>Depth Perception ................................................ 25 distance ratio .......................................................................................................................... 25 Consciousness>Sense>Vision>Physiology>Depth Perception ................................................ 31 triangulation by eye .............................................................................................................. -
A Review of Local Interstellar Medium Properties of Relevance for Space Missions to the Nearest Stars
Project Icarus: A Review of Local Interstellar Medium Properties of Relevance for Space Missions to the Nearest Stars (Accepted for publication in Acta Astronautica) Ian A. Crawford* Department of Earth and Planetary Sciences, Birkbeck College, University of London, Malet Street, London, WC1E 7HX, UK *Tel: +44 207 679 3431; Email: [email protected] Abstract I review those properties of the interstellar medium within 15 light-years of the Sun which will be relevant for the planning of future rapid (v ≥ 0.1c) interstellar space missions to the nearest stars. As the detailed properties of the local interstellar medium (LISM) may only become apparent after interstellar probes have been able to make in situ measurements, the first such probes will have to be designed conservatively with respect to what can be learned about the LISM from the immediate environment of the Solar System. It follows that studies of interstellar vehicles should assume the lowest plausible density when considering braking devices which rely on transferring momentum from the vehicle to the surrounding medium, but the highest plausible densities when considering possible damage caused by impact of the vehicle with interstellar material. Some suggestions for working values of these parameters are provided. This paper is a submission of the Project Icarus Study Group. Keywords: Interstellar medium; Interstellar travel 1 Introduction The growing realisation that planets are common companions of stars [1,2] has reinvigorated astronautical studies of how they might be explored using interstellar space probes. The history of Solar System exploration to-date shows us that spacecraft are required for the detailed study of planets, and it seems clear that we will eventually require spacecraft to make in situ studies of other planetary systems as well. -
Cybernetique D'une Theorie De La Connaissance
Trivium Revue franco-allemande de sciences humaines et sociales - Deutsch-französische Zeitschrift für Geistes- und Sozialwissenschaften 20 | 2015 Réflexivité et Système. Le débat sur l'ordre et l'auto- organisation dans les années 1970 Cybernetique d’une theorie de la connaissance Heinz von Foerster Traducteur : Didier Renault Édition électronique URL : http://journals.openedition.org/trivium/5178 ISSN : 1963-1820 Éditeur Les éditions de la Maison des sciences de l’Homme Référence électronique Heinz von Foerster, « Cybernetique d’une theorie de la connaissance », Trivium [En ligne], 20 | 2015, mis en ligne le 11 juin 2015, consulté le 08 septembre 2020. URL : http://journals.openedition.org/ trivium/5178 Ce document a été généré automatiquement le 8 septembre 2020. Les contenus des la revue Trivium sont mis à disposition selon les termes de la Licence Creative Commons Attribution - Pas d'Utilisation Commerciale - Pas de Modification 4.0 International. Cybernetique d’une theorie de la connaissance 1 Cybernetique d’une theorie de la connaissance Heinz von Foerster Traduction : Didier Renault NOTE DE L’ÉDITEUR Nous remercions la maison d’édition Suhrkamp de nous avoir accordé l’autorisation de traduire ce texte pour le présent numéro. Wir danken dem Suhrkamp Verlag für die freundliche Genehmigung, diesen Artikel in französischer Übersetzung zu publizieren. 1 Lorsque j’ai accepté de prononcer ici ma conférence1 en allemand, je ne soupçonnais pas les difficultés auxquelles je me verrais confronté. Au cours des vingt dernières années, dans mon activité scientifique, j’ai exclusivement pensé et parlé en anglais. Nombre de concepts et de résultats de recherches ont été baptisés en anglais lors de leur naissance, et se montrent rétifs à toute traduction. -
Subject Index
Subject Index Absence, 47, 79, 83, 87, 89, 131, 143, 204, Appearances, 8, 10, 11, 17, 19, 51, 96, 112, 227, 230, 232, 265, 267, 268, 271, 272, 279, 121, 123, 127, 128, 130, 159, 162, 180, 315, 317, 318, 320–325, 354, 373 184–192, 224, 242, 261, 288, 289, 292, Abstraction, 6, 172, 174, 176, 178, 187, 194, 322–325, 335, 350–352, 356, 357, 359, 361, 338, 354, 368, 369, 373, 375, 400, 402, 404, 365, 373, 406 412 Art, 17, 20, 31, 93, 131, 338, 399–404, 411– Accident, 128, 144, 145, 189, 204, 212, 213, 420 234, 360, 364 abstract art, 20, 401–405, 411, 412 Accommodation, 203, 211, 224–226 color, 402, 403–404 Action-perception synergies, 131, 132, 133 compositional techniques, 399–404 Activation zone, 375 constructivism, 396, 398, 406, 407, 412, Active vision, 131 418 Adaptive strategies, 85, 96, 97 generative art, 20, 411, 412, 414–418 Additive scanning, 364 history, 184, 393 Aesthetics, 2, 9, 16, 17, 85, 90, 91, 93, 97, 113, modulation, 83, 402–403 121, 413 Pop/Op, 31, 113, 124, 352 Affine distortion, 220, 223 Artificial intelligence, 1, 28, 31 Affordance, 14, 15, 186, 338, 356, 359 Artistic expression, 83, 85, 90, 91, 97 Afterimage, 112, 149, 150 Astigmatism, 112 Alphabet, 271, 347, 351, 367 Attention, 6, 51, 84, 96, 99, 100, 125, 174, Amodal, 47, 315, 336 190, 355, 356, 375, 376, 394, 396, 397 boundaries, 263, 266 Attneave points, 5, 125, 129 completion, 175, 261, 265, 270, 273, 315, Auditory objects, 340 318, 322–324, 328, 329, 374, 376 Auffälligkeit, 375 contours, 8, 15, 19, 263, 280 Automatic processes, 4, 32, 85, 96, 97, 100, perception, -
Optical Illusion - Wikipedia, the Free Encyclopedia
Optical illusion - Wikipedia, the free encyclopedia Try Beta Log in / create account article discussion edit this page history [Hide] Wikipedia is there when you need it — now it needs you. $0.6M USD $7.5M USD Donate Now navigation Optical illusion Main page From Wikipedia, the free encyclopedia Contents Featured content This article is about visual perception. See Optical Illusion (album) for Current events information about the Time Requiem album. Random article An optical illusion (also called a visual illusion) is characterized by search visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a percept that does not tally with a physical measurement of the stimulus source. There are three main types: literal optical illusions that create images that are interaction different from the objects that make them, physiological ones that are the An optical illusion. The square A About Wikipedia effects on the eyes and brain of excessive stimulation of a specific type is exactly the same shade of grey Community portal (brightness, tilt, color, movement), and cognitive illusions where the eye as square B. See Same color Recent changes and brain make unconscious inferences. illusion Contact Wikipedia Donate to Wikipedia Contents [hide] Help 1 Physiological illusions toolbox 2 Cognitive illusions 3 Explanation of cognitive illusions What links here 3.1 Perceptual organization Related changes 3.2 Depth and motion perception Upload file Special pages 3.3 Color and brightness