by John Walker Welcome to Your Sky, the interactive planetarium of the Web. You can produce maps in the forms described below for any time and date, viewpoint, and observing location. If you enter the orbital elements of an asteroid or comet, Your Sky will compute its current position and plot it on the map. Each map is accompanied by an ephemeris for the Sun, Moon, planets, and any tracked asteroid or comet. A control panel permits customisation of which objects are plotted, limiting magnitudes, colour scheme, image size, and other parameters; each control is linked to its description in the help file. Your Sky provides three ways to view the sky with links, where appropriate, among the various presentations. Sky Map The sky map shows the entire sky as viewed from a given location at a specified time and date. Horizon Views Horizon Views, showing the stars above the horizon as seen from a specified observing site at a given date and time. The Virtual Telescope Your Sky help Related Software
Related: Universe & Multiverse
Space.comBuy This Infographic as a Full-Size Poster Astronomers have discovered more than 700 alien planets beyond the solar system, and the count is rising all the time. Some are large and hot, and others are smaller and cooler, but scientists are still on the lookout for an Earth twin. They just got closer, with the announcement Dec. 5 of a planet found by NASA's Kepler space telescope to lie in the habitable zone around its star where liquid water, and perhaps life, could exist. You can purchase a 20"x60" poster of this SPACE.com infographic on high-quality 14G Photo Paper from the SPACE.com store here: Buy Poster Embed: Paste the code below into your site. <a href=" alt="Astronomers searching for another Earth are getting closer, thanks to recent discoveries by the Kepler space telescope. " src="
Interactive 3D model of Solar System Planets and Night SkyHubble's Panoramic ViewSeveral million stars are vying for attention in this NASA/ESA Hubble Space Telescope image of a raucous stellar breeding ground in 30 Doradus, located in the heart of the Tarantula nebula. 30 Doradus is the brightest star-forming region in our galactic neighbourhood and home to the most massive stars ever seen. The nebula resides 170 000 light-years away in the Large Magellanic Cloud, a small, satellite galaxy of our Milky Way. No known star-forming region in our galaxy is as large or as prolific as 30 Doradus. The image comprises one of the largest mosaics ever assembled from Hubble photos and consists of observations taken by Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys, combined with observations from the European Southern Observatory’s MPG/ESO 2.2-metre telescope that trace the location of glowing hydrogen and oxygen. The image is being released to celebrate Hubble’s 22nd anniversary. The colours come from the glowing hot gas that dominates regions of the image. Notes
The Elegant Universe: Pt 1The Elegant Universe: Part 3 PBS Airdate: November 4, 2003 NARRATOR: Now, on NOVA, take a thrill ride into a world stranger than science fiction, where you play the game by breaking some rules, where a new view of the universe pushes you beyond the limits of your wildest imagination. This is the world of "string theory," a way of describing every force and all matter from an atom to earth, to the end of the galaxies—from the birth of time to its final tick, in a single theory, a "Theory of Everything." Our guide to this brave new world is Brian Greene, the bestselling author and physicist. BRIAN GREENE (Columbia University): And no matter how many times I come here, I never seem to get used to it. NARRATOR: Can he help us solve the greatest puzzle of modern physics—that our understanding of the universe is based on two sets of laws that don't agree? NARRATOR: Resolving that contradiction eluded even Einstein, who made it his final quest. S. BRIAN GREENE:The atmosphere was electric. S.
The Worlds of David DarlingNASA Probe Successfully Orbiting Mercury—A FirstNASA made history tonight as the MESSENGER probe became the first spacecraft to orbit the tiny planet Mercury. Launched in 2004, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging mission marks the first time a craft has gone near Mercury since 1975, when NASA's Mariner 10 probe conducted flybys. (Get MESSENGER facts and figures.) For the past six and a half years MESSENGER has been maneuvering itself into an orbital path via so-called gravity assists, using the tugs from flybys of Earth, Venus, and Mercury itself to speed up and alter course. At 8:45 p.m. The mission control team at the Johns Hopkins Applied Physics Laboratory in Maryland was monitoring MESSENGER's progress from 96 million miles (155 million kilometers) away. At 9:10 p.m. engineers confirmed that the burn had occurred. But the backup plans, he said, didn't involve an immedite retry and would have substantially changed the time line of the mission. Mercury Probe to Fill in Blanks
Nothingness: Why nothing mattersOur pursuit of naught provides profound insights into the nature of reality Read more: "The nature of nothingness" SHAKESPEARE had it right, even in ways he couldn't have imagined. For centuries, scientists have indeed been making much ado about nothing - and with good reason. The modern story of nothing began with a thought experiment dreamed up by Isaac Newton. With that answer, Newton made something out of nothing. The discovery of quantum mechanics took the story of nothing further still. This year's Nobel prize in physics recognises the power of nothing on cosmic scales. The Large Hadron Collider near Geneva, the world's most powerful particle accelerator, is also in the business of probing nothing. Since the time of Newton, we have thus gradually realised that nature has masked the identity of nothing with a Shakespearian deftness. Profile New Scientist Not just a website! More From New Scientist Stuff: A few of your favourite things (New Scientist) More from the web (YouTube)
Neutron Stars, Neutron Stars InformationNeutron stars are ancient remnants of stars that have reached the end of their evolutionary journey through space and time. These interesting objects are born from once-large stars that grew to four to eight times the size of our own sun before exploding in catastrophic supernovae. After such an explosion blows a star's outer layers into space, the core remains—but it no longer produces nuclear fusion. Despite their small diameters—about 12.5 miles (20 kilometers)—neutron stars boast nearly 1.5 times the mass of our sun, and are thus incredibly dense. A neutron star's almost incomprehensible density causes protons and electrons to combine into neutrons—the process that gives such stars their name. Neutron stars pack an extremely strong gravitational pull, much greater than Earth's. When they are formed, neutron stars rotate in space. Pulsing Lights After spinning for several million years pulsars are drained of their energy and become normal neutron stars.
La relativité - 1,2,3,4, dimensionsLa théorie de la Relativité Concepts fondamentaux Corpus théorique (I) Avant de poursuivre cette initiation à la relativité, il est indispensable d'introduire quelques rudiments de mathématiques afin de fourbir votre esprit avec la meilleure arme intellectuelle qui soit pour comprendre la suite du récit. Il faut en effet à présent définir quelques notions fondamentales, quitte à devoir faire usage d’un peu de symbolique mathématique. Mais n'ayez pas d'inquiétudes, le sujet retiendra votre attention. J’ai tout imaginé pour vous éviter cette partie “dure” du sujet , en tous cas sa partie nettement moins littéraire, c’est-à-dire les définitions du cadre relativiste; mais à mesure que je relisais ce passage tout en le rédigeant, je me suis finalement rendu compte que s’il y avait une chose sur laquelle il fallait bien insister quand on apprend une nouvelle matière, c’était par définition les notions de bases. 1,2, 3, 4 dimensions A lire : Flatland, E.Abbott, 1884 (PDF) Vecteur, champ et tenseur
10 Strange Things About The UniverseSpace The universe can be a very strange place. While groundbreaking ideas such as quantum theory, relativity and even the Earth going around the Sun might be commonly accepted now, science still continues to show that the universe contains things you might find it difficult to believe, and even more difficult to get your head around. Theoretically, the lowest temperature that can be achieved is absolute zero, exactly ?273.15°C, where the motion of all particles stops completely. One of the properties of a negative-energy vacuum is that light actually travels faster in it than it does in a normal vacuum, something that may one day allow people to travel faster than the speed of light in a kind of negative-energy vacuum bubble. One prediction of Einstein’s theory of general relativity is that when a large object moves, it drags the space-time around it, causing nearby objects to be pulled along as well. Relativity of Simultaneity This is similar to arranging tiles evenly on a floor.