Water Drops and Inverted Images
Photographer: Bertrand Kulik
Summary Author: Bertrand Kulik; Jim Foster
Within these decorative water drops is the inverted image of the flowers in my garden and my house in Paris, France. A liquid drop acts as a simple lens, like a camera lens, so the refracted image is upside-down when viewed through the drop. Note that these drops have more or less spherical shapes because surface tension minimizes the surface area of a drop of water or even a falling raindrop. Photo taken in early September 2011.
Trifid, M20, NGC6514
The Trifid Nebula, M20 or NGC6514, is a familiar sight and an excellent example of an emission and reflection nebula. The red emission nebula contains a bright blue star cluster near its center: it glows red because the ultraviolet light of the stars ionizes the hydrogen gas, which then recombines and emits the characteristic red hydrogen-alpha light. Further out, when the radiation from these hot young stars becomes too weak to ionize hydrogen, the gas and dust instead glows by reflecting the original blue light. M20 is in the constellation of Sagittarius, at a poorly-known distance somewhere between 2200 and 7600 light-years. We also have a deep black and white image from the KPNO Mayall 4-m telescope. M20 is quite close on the sky to the open cluster M21, as shown in this lower resolution but wider field picture.
Minimum credit line: Todd Boroson/NOAO/AURA/NSF
Total Lunar Eclipse
This montage of images taken by skywatcher Kieth Burns shows the Dec. 20, 2010 total lunar eclipse.
What was the first math problem that we needed a computer to solve?
In the 1970s, a remarkable thing was done; a computer was used to solve a math problem. This, in and of itself, was not remarkable. The difference engine could do it. But this problem was the first one that would probably remain unsolved if it weren’t for computers. Find out about the Four-Color Theorem, and why it needed to be turned over to the machines, below.
Hey. What’s one hundred and seventeen thousand six hundred and twenty-two plus three million, four hundred and fifty thousand and twelve?
You just opened up the calculator function on your computer, didn’t you?
Hey. There’s no shame in that. I’m not even going to solve the problem, and I’m the one who wrote it. I’m just saying that we’re used to turning over even relatively easy problems to computers. (Look. Someone programmed that calculator function. If you waste paper trying to figure it out, you’re squandering their hard work.)
Even during the 1970s, when computers were harder to come by and problems were weightier, computers were routinely brought in to solve things for the people who had access to them. But prior to 1976, they weren’t required to prove any math problem. They just made things easier. That is, until Kenneth Appel and Wolfgang Haken used a computer to prove a 124-year-old conjecture. In 1852, Francis Guthrie came up with what’s known as the Four-Color Theorem. That theorem stated that no map needed more than four colors to delineate territories. Generally, different countries, states, or provinces, were given different colors on a map. If a mapmaker were armed with four different colors, there was no territory, or set of them, that could be arranged in such a way that two adjoining territories were the same color.
No one had found anything to contradict Guthrie, but then no one had the time to check. Thousands of different cases would have to be tested before anyone could come to a conclusion. The theorem just wasn’t practically testable, and so not provable, by humans. In 1976, though, a human didn’t need to work through all those cases. Appel and Haken enlisted the help of a machine that worked fast and didn’t mind if its time was being wasted, and proved the Four-Color Theorem. Mapmakers raised a bored eyebrow and continued to use however many colors they felt like using. Computer scientists, though, were impressed.
Eclipses and Transits
The details of celestial mechanics in our own solar system are very predictable and, luckily, not dependent on NASA’s budget cycle. The year 2012 will see one important and rare event with the transit of Venus on June 6. While information from the occurrence was once vital for astronomers looking to calculate the distance between the Earth and the sun, it is now merely a spectacular cosmic show for all to enjoy.
The moon will appear to partially consume the sun on May 20 during an annular solar eclipse. In this type of eclipse, the moon transits in front of the sun, partially blocking it but leaving a small ring of light around the edge. The event will be seen to viewers placed along a path over the Pacific Ocean from southern China to the Western United States.
A total solar eclipse – where the moon will completely block out the sun’s light – will occur on November 13, though will mostly occur over open ocean. The only place on land to see it will be parts of Northern Australia. Two partial lunar eclipses will also occur during the year, on June 4 and November 28, respectively.
Image: An annular eclipse seen from China in 2010. Wikimedia/A013231
Stars Above, Thunder Below
Copyright: Christopher K. Eaton / Terra Photographica
Apollo 14 Moon Rock
Between 1969 and 1972 the National Aeronautics and Space Administration (NASA) successfully landed 12 astronauts on the lunar surface. The astronauts who visited the Moon carefully collected 2,196 documented samples of lunar soils and rocks weighing a total of 382 kilograms (843 pounds) during approximately 80 hours of exploration. It is important to note that these samples were gathered from a harsh lunar environment that included wildly fluctuating temperatures in an almost complete vacuum, dangerous solar radiation, and the uncertainty of return to Earth due to equipment failure.
Kim, New Admin,(expose-the-light).
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Embryonic stem cells
One of the ten Technologies That Congress Tried to Kill
Who Wanted it Killed: Pro-life advocates, mainly. In 1996, Congress passed the Dickey-Wicker amendment, which bans any federal research in which human embryos are created, destroyed or put at risk of harm. This law, which remains on the books, essentially prevented most embryonic stem cell research.
How it Worked Out: In 2001, then-President George W. Bush announced a new policy in which 61 cell lines of existing embryonic stem cells would be allowed for federally-funded research. Congress tried to pass a bill expanding this policy, but Bush vetoed it. Since then, President Obama has tried to abolish the Bush policy, but Obama’s executive order has been tied up in federal courts. (In a related issue, Congress has repeatedly voted to ban human cloning.)
Read all ten here
Want to See Every Tree in America?
We may sing about purple mountains and amber grains, but one of America’s most vital resources is its vast amount of carbon-catching, oxygen-spewing trees. Now, after six years of effort, NASA knows how many we’ve got.
Josef Kellndorfer and Wayne Walker of NASA’s Woods Hole Research Center worked in conjunction with the National Geological Survey and US Forest Service to catalog a mix of data gleaned from space-based radar, satellite sensors, computer models, and old-fashioned tree counting. The map above shows the total amount of woody biomass in the USA. It’s displayed at a 30 meter resolution, where every four pixels constitutes an acre and every ten represents a hectare. In total, Kellendorfer estimates some five million trees reside on US soil. [NASA Earth Observatory via Business Insider via Geekosystem]
The developmental stages of scyphozoan jellyfish’s life cycle.
Tiny Alien Planets, Monster Galaxies And Twin Suns