Wednesday, October 03, 2012
One of the most fascinating and beautiful sites on the internet is the Astronomy Picture of the Day
. It has been online almost since the beginning of the World Wide Web, and is still breathtaking in beauty and simplicity. Each day features a fabulous photograph and sometimes a video, along with a brief description packed with information. This kind of condensed informative and readable information is not easy to write, and the APOD writers make it look graceful and effortless. The scope of the pictures ranges from local to microscopic to cosmic.
Astronomy Picture of the Day (APOD) is originated, written, coordinated, and edited since 1995 by Robert Nemiroff and Jerry Bonnell. The APOD archive contains the largest collection of annotated astronomical images on the internet.
In real life, Bob and Jerry are two professional astronomers who spend most of their time researching the universe. Bob is a professor at Michigan Technological University in Houghton, Michigan, USA, while Jerry is a scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland USA. They are two married, mild and lazy guys who might appear relatively normal to an unsuspecting guest. Together, they have found new and unusual ways of annoying people such as staging astronomical debates. Most people are surprised to learn that they have developed the perfect random number generator.
Here are a selection of recent pictures to give you a taste of the site. The caption follows each picture. It is well worth checking APOD on a daily basis for a bit of inspiration and to expand out from the usual narrow focus of daily life.
M16: Pillars of Creation July 22, 2012
Image Credit: J. Hester, P. Scowen (ASU), HST, NASA Explanation: It was one of the most famous images of the 1990s. This image, taken with the Hubble Space Telescope in 1995, shows evaporating gaseous globules (EGGs) emerging from pillars of molecular hydrogen gas and dust. The giant pillars are light years in length and are so dense that interior gas contracts gravitationally to form stars. At each pillars' end, the intense radiation of bright young stars causes low density material to boil away, leaving stellar nurseries of dense EGGs exposed. The Eagle Nebula, associated with the open star cluster M16, lies about 7000 light years away. The pillars of creation were imaged again in 2007 by the orbiting Spitzer Space Telescope in infrared light, leading to the conjecture that the pillars may already have been destroyed by a local supernova, but light from that event has yet to reach the Earth.
Be Honest: Have you seen this image before?
An Ancient Stream Bank on Mars October 2, 2012Image Credit: NASA, JPL-Caltech, MSSSExplanation: Fresh evidence of an ancient stream has been found on Mars. The robotic rover Curiosity has run across unusual surface features that carry a strong resemblance to stream banks on Earth. Visible in the above image, for example, is a small overhanging rock ledge that was quite possibly created by water erosion beneath. The texture of the ledge appears to be a sedimentary conglomerate, the dried remains of many smaller rocks stuck together. Beneath the ledge are numerous small pebbles, possibly made smooth by tumbling in and around the once-flowing stream. Pebbles in the streambed likely fell there as the bank eroded. Circled at the upper right is a larger rock possibly also made smooth by stream erosion. Curiosity has now discovered several indications of dried streambeds on Mars on its way to its present location where it will be exploring the unusual conjunction of three different types of landscape.
A Solar Filament Erupts September 17, 2012 Image Credit: NASA's GSFC, SDO AIA TeamExplanation: What's happened to our Sun? Nothing very unusual -- it just threw a filament. At the end of last month, a long standing solar filament suddenly erupted into space producing an energetic Coronal Mass Ejection (CME). The filament had been held up for days by the Sun's ever changing magnetic field and the timing of the eruption was unexpected. Watched closely by the Sun-orbiting Solar Dynamics Observatory, the resulting explosion shot electrons and ions into the Solar System, some of which arrived at Earth three days later and impacted Earth's magnetosphere, causing visible aurorae. Loops of plasma surrounding an active region can be seen above the erupting filament in the ultraviolet image. If you missed this auroral display please do not despair -- over the next two years our Sun will be experiencing a solar maximum of activity which promises to produce more CMEs that induce more Earthly auroras.
Other pictures you might enjoy are Hurricane Paths on Planet Earth
that show the path of every known hurricane round the globe since 1851. Or see this dramatic view of a lightning storm around an erupting volcano: Ash and Lightning Above an Icelandic Volcano
, taken during the 2010 volcanic eruption in Eyjafjallajokull glacier Iceland. Also check out the Orion Nebula: The Hubble View
and the Cats Eye Nebula
. The Astronomy Picture of the Day
is always worth a visit.
To learn more visit the Astronomy Picture of the Day's Educational Links
for a variety of sources appealing to every level of interest in astronomy.
To find books and dvds on astronomy in the library look in the section with the Dewey numbers 520 - 529, especially in the 523 section.