3D Solar System Cell Size and Scale Some cells are visible to the unaided eye The smallest objects that the unaided human eye can see are about 0.1 mm long. That means that under the right conditions, you might be able to see an ameoba proteus, a human egg, and a paramecium without using magnification. A magnifying glass can help you to see them more clearly, but they will still look tiny. Smaller cells are easily visible under a light microscope. To see anything smaller than 500 nm, you will need an electron microscope. Adenine The label on the nucleotide is not quite accurate. How can an X chromosome be nearly as big as the head of the sperm cell? No, this isn't a mistake. The X chromosome is shown here in a condensed state, as it would appear in a cell that's going through mitosis. A chromosome is made up of genetic material (one long piece of DNA) wrapped around structural support proteins (histones). Carbon The size of the carbon atom is based on its van der Waals radius.
What Will First Photos of Black Holes Look Like? | Event Horizon Telescope A giant black hole is thought to lurk at the center of the Milky Way, but it has never been directly seen. Now astronomers have predicted what the first pictures of this black hole will look like when taken with technology soon to be available. In particular, researchers have found that pictures of a black hole ― or, more precisely, the boundaries around them ― will take a crescent form, rather than the blobby shape that is often predicted. By modeling what these pictures will look like, scientists say they are preparing to interpret the photos that will become available from telescopes currently under construction. "No one has been able to image a black hole," said University of California, Berkeley student Ayman Bin Kamruddin, who presented a poster on the research last week in Long Beach, Calif., at the 221st meeting of the American Astronomical Society. Black holes themselves are invisible, of course, as not even light can escape their gravitational clutches. 0 of 9 questions complete
FlowingData Your Help Needed to Study Andromeda Galaxy | PHAT Crowdsourcing Project A group of astronomers is inviting the public to join their star-hunting team in a search of the bright Andromeda Galaxy. The project aims to identify star clusters in our neighboring galaxy, also known as M31. All it takes to find the clusters in Andromeda is an Internet-enabled computer and a desire to help, said Anil Seth, the team's lead investigator. "No special training is required," he said. The so-called "Andromeda Project," which began Wednesday (Dec. 5), will generate the largest sample of clusters from a single spiral galaxy when it is completed. Scientists expect the project could identify 2,500 new star clusters when finished. "The general benefit is to better understand how spiral galaxies form," said Seth, an assistant professor of physics and astronomy at the University of Utah. "Andromeda is the nearest example of a [spiral] galaxy, except for the Milky Way," he said. PHAT science But when the team asked the software to do the same thing, difficulties arose.
Farthest Known Galaxy in the Universe Discovered A new celestial wonder has stolen the title of most distant object ever seen in the universe, astronomers report. The new record holder is the galaxy MACS0647-JD, which is about 13.3 billion light-years away. The universe itself is only 13.7 billion years old, so this galaxy's light has been traveling toward us for almost the whole history of space and time. Astronomers spotted the object using NASA's Hubble and Spitzer space telescopes, with the aid of a naturally occurring cosmic zoom lens as well. This lens is a huge cluster of galaxies whose collective gravity warps space-time, producing what's called a gravitational lens. As the distant galaxy's light traveled through this lens on its way to Earth, it was magnified. "This cluster does what no manmade telescope can do," Marc Postman of the Space Telescope Science Institute in Baltimore, Md., said in a statement unveiling the discovery today (Nov. 15).
New telescope array reveals death spiral of old star As stars like our Sun die, they swell to a huge size and shed much of the gas in their outer layers. This process seeds the galaxy with raw material for the next generation of stars and planets. Studying the last stages of stellar evolution helps astronomers model the process by which heavier elements are distributed through interstellar space (and incidentally provides some of the most beautiful astronomical images). New observations of one of these dying stars revealed both a fascinating spiral structure in the ejected gas and that about three times the expected mass has been jettisoned into space. Astronomers using the Atacama Large Millimeter Array (ALMA) in Chile constructed a three-dimensional view of the giant red star R Sculptoris. Millimeter and submillimeter astronomy straddles the (admittedly arbitrary) boundary between the infrared and microwave portions of the spectrum. Spiral patterns like that exhibited by R Sculptoris are generally due to a companion star.
nineplanets.org introduction The Nine Planets is a collection of information about our Solar System intended for a general audience with little technical background. No special expertise or knowledge is needed; all technical and astronomical terms and proper names are defined in the glossary. The bulk of this material should be familiar to planetary scientists and astronomers but they may find a few interesting tidbits, too. This site consists of about 100 pages, one page for each major body in the Solar System. a large picture of its object and usually several smaller thumbnail images (all linked to their full-size originals) some scientific and historical facts about it, if the object has satellites then its page has a table of data on them and links to their pages, links to more images and information about the object elsewhere on the Web, and a list of open issues for which we as yet have no answers. To truly justify the title of "Multimedia Tour", I've also included: Frequently Asked Questions Home ...
International Astronomical Union | IAU March 2013 (SA Jewellery News,January 2013, pp. 12-13) For a brief moment during the mid 1970’s, a number of local goldsmiths came together to create a better structured environment in which they could work. They formed the Goldsmiths Guild of S.A. It was a time of hope and enthusiasm, but it did not last long. Even though all of the founder members enjoyed national recognition for their work, their technical and creative brilliance were not strong enough to withstand the forces that were working against them. Late in 1973, under Peter Cullman’s leadership, the Goldsmiths Guild of South Africa was born in Johannesburg. A three page constitution was adopted at the founding meeting of the Guild. Figure 1: Founder members of the SA Goldsmiths Guild in 1973: Peter Cullman, Hartmut Jaeger, Ilse Jaeger, Kurt Donau, Liz Bezuidenhout-Kratz, Ewald Kratz & Jochen Kessel No jewellery of repetitive or ordinary nature may bear the logo stamp of the guild. Figure 3: Cecil skotnes and Kurt Donau collaboration.
IVS Home Page Factsheets : Global Positioning Systems Directorate The Global Positioning Systems Directorate is a joint service effort directed by the United States Air Force and managed at the Space and Missile Systems Center, Air Force Space Command, Los Angeles Air Force Base, Calif. The directorate is the Department of Defense acquisition office for developing and producing Global Positioning System (GPS) satellites, ground systems and military user equipment. GPS is a space-based dual use radio navigation system nominally consisting of a minimum of 24-satellite constellation that provides positioning, velocity and timing to military and civilian users worldwide. GPS provides the following: 24-hour, worldwide service Highly accurate, three-dimensional location information Precision velocity and timing services Accessibility to an unlimited number of global military, civilian, and commercial users Related fact sheets: Pseudorandom Noise Code Assignments GPS Public Interface Control Documents GPS IIR/IIR-M Satellite GPS IIF Satellite