Learning Resources for Students, Families and Teachers

Search over 100,000 research quality URLs

StudySphere provides fast, easy and free access to a wide variety of research-quality child-safe websites organized for education online from home, school, study abroad and home school. StudySphere’s goal is to help students, teachers, librarians, and other researchers find both highly targeted and closely related information quickly.

Dark Matter

/Home/Sciences/Earth & Space/Astronomy/Astro-Physics/Dark Matter


		Chandra :: Field Guide to X-ray Astronomy :: Dark Matter Mystery ^Votes:0 Dark Matter Mystery While carefully measuring the speed of rotation of galaxies, astronomers stumbled upon a profound cosmic mystery. They could estimate what the rotation speed should be by calculating the mass of all the visible stars and gas, thereby determining the gravity of the galaxy. Much to their surprise, the measurements showed that most galaxies are rotating faster than they should. Not a little faster. Much faster! More than twice as fast. This meant that, according to Einstein's theory of gravity, these galaxies should be flying apart. Yet clearly, they are not. Page 1 \| 2 \| 3 \| 4 CXC Home \| Search \| Help \| Site Map \| Image Use Policy \| Privacy & Accessibility \| Downloads & Plugins Latest Images \| New & Noteworthy \| Multimedia \| Flash Ecards \| Glossary \| Q&A \| Guestbook RSS F Read More Go to Site


		Cosmological Issues for Theorists ^Votes:0 The Observers Universe The Theorists Universe Cosmological Issues: Particle Generation and Their Masses Baryon Content of the Universe Matter (light + dark) Density in the Universe Nature of the Dark Matter Formation of Galaxies Large Scale Structure Determination of Cosmological Parameters Particle Generation and Their Masses: Masses of quarks endowed during some phase transistion? --> sets the entropy of the Universe is well? SU(10), SU(16), SU(??) --> how will we ever know which one is correct? Baryon Content of the Universe: Places where Baryons can reside: Easy to detect Galaxies Hard to detect Galaxies Cosmological Backgrounds --> QSO absorption lines Constraints on Baryon Density: Abudances of helium, lithium --> 0.04 -- 0.07 (for h =1) Number density of galaxies Observations of Deu Read More Go to Site

		MACHO Project Home Page ^Votes:0 The MACHO Project Welcome to the MACHO Project WWW Home Page! We are maintaining two identical sites: http://wwwmacho.anu.edu.au/ (Australia) and http://wwwmacho.mcmaster.ca/ (North America) New! Microlensing Optical Depth Toward the Galactic Bulge New! Final Catalog of Bulge Microlensing Events Novae in the LMC and SMC Cataclysmic Variables The Project Overview The MACHO Collaboration and Science Team Candidate Microlensing Events Affiliate Programme Systems MACHO Camera Systems MACHO Data System Search Fields Field Centers LMC R-band GIF showing fields [606 kb] SMC R-band GIF showing fields [649 kb] LMC R-band FITS image with WCS [1.284 Mb] SMC R-band FITS image with WCS [1.284 Mb] Original images were obtained by Greg Bothun with his "Parking Lot" camera. Versions of saoimage more recen Read More Go to Site

		CyberSpace! - dark matter ^Votes:0 During the early part of this century, astronomers believed that the distribution of mass in the universe followed the distribution of light. In other words, more light meant more stars , which in turn meant more mass. Unfortunately, things aren't that simple. In 1938, Fritz Zwicky and Sinclair Smith discovered a cluster of galaxies that, according to theory, shouldn't exist. According to Kepler's third law of planetary motion, the speed (linear, not angular) of a body revolving around another decreases as the distance between them increases. This is evidenced by the speed of the planets revolving around the Sun; Mercury moves at 48 km/sec, while Pluto's speed is 4.7 km/sec. This law also applies to stars revolving around the galactic core and galaxies revolving around each other. What Zwi Read More Go to Site

		UKDMC default. ^Votes:0 UKDMC Home Page UKDMC default. UKDMC Intranet Transferring to http://hepwww.rl.ac.uk/ukdmc/ukdmc.html You should be transferred there automatically; if not, click link above. Read More Go to Site

		What is Dark Matter? ^Votes:0 [Physics FAQ] - [Copyright] Updated 1993 by SIC. Original by Scott I. Chase. What is Dark Matter? The story of dark matter is best divided into two parts. First we have the reasons that we know that it exists. Second is the collection of possible explanations as to what it is. Why the Universe Needs Dark Matter We believe that that the Universe is critically balanced between being open and closed. We derive this fact from the observation of the large scale structure of the Universe. It requires a certain amount of matter to accomplish this result. Call it M. We can estimate the total baryonic matter of the universe by studying Big Bang nucleosynthesis. This is done by connecting the observed He/H ratio of the Universe today to the amount of baryonic matter present during the early hot phas Read More Go to Site

StudySphere is an outstanding resource for homework help, special education, music school, cooking school, charter schools, art schools, technical schools, traffic school, film schools, catholic schools, etc.