Welcome to the latest newsletter and we hope that you will enjoy reading it.
CLUB MEETING – 02 OCTOBER
Club member Johan Retief gave an informative presentation full of useful and practical information on how and when to observe the moon, and identify some of its major features with the naked eye, binoculars or a small telescope. The practical tips included having something ‘warming’ at hand to drink when observing on chilly winter nights and cool early mornings in addition to a comfortable chair!
Johan stated that it is best to avoid observing lunar features when the moon is full because the more direct light makes features difficult to identify. Features are ‘sharper’ when the moon is waxing or waning. The dark areas on the moon are seas (maria) whose darkness is produced by basalt lava which lies on their floors. From the southern hemisphere, the seas form the shape of the side view of a rabbit looking left and sitting on its haunches.
One of the easiest light coloured features to identify is Crater Tychos. It is a large white crater with clearly visible radiating ejecta (debris) which looks like a bird’s eye view of a volcano on earth. It is just to the right of the bunny’s ears and identifies the northern pole of the moon when viewing it from the southern hemisphere.
OBSERVATORY COMMITTEE REPORT.
Further meetings and discussions have been taking place to find a suitable location for the Hermanus Astronomical Observatory. These are serving to move the process forwards in an informed and productive way, both for the Astronomy Club and other potential stakeholders.
MEETING DATES AND SPEAKERS FOR 2009
Planning for the 2009 programme continues. If any member wishes to give a presentation or knows someone who may be interested in doing so, please contact a committee member.
A reminder that club meetings for 2009 will be changed to coincide with the phases of the ‘New Moon’ in order to allow better star-gazing visibility. From January through June it will be the fourth Thursday in the month and from July to December it will be the third Thursday evening. Once these dates have been secured with the Botanical Society for the use of the Fernkloof Hall, you will be advised.
ASTRONOMY NEWS FROM STEVE KLEYN
1. Spitzer finds a Solar System very similar to our own. New observations from NASA’s Spitzer Space Telescope indicate that the nearest planetary system to our own has two asteroid belts. Our own solar system has just one.
The star at the center of the nearby system Epsilon Eridani, is a younger, slightly cooler and fainter version of the sun. Previously, astronomers had uncovered evidence for two possible planets in the system, and for a broad, outer ring of icy comets similar to our own Kuiper Belt.
Now, Spitzer has discovered that the system also has dual asteroid belts. One sits at approximately the same position as the one in our solar system. The second, denser belt, most likely also populated by asteroids, lies between the first belt and the comet ring. The presence of the asteroid belts implies additional planets in the Epsilon Eridani system.”This system probably looks a lot like ours did when life first took root on Earth,” said Dana Backman, an astronomer at the SETI Institute, in Mountain View, Calif., and outreach director for NASA’s Sofia mission. “The main difference we know of so far is that it has an additional ring of leftover planet construction material.”
Get the full story at http://www.spitzer.caltech.edu/Media/releases/ssc2008-19/release.shtml
2. Gamma Ray Bursts.
When stars die they do so with great fanfare. The most massive stars leave with the greatest fanfare of all – blasting out gamma-ray bursts (GRBs), tremendous explosions that rock the Universe like nothing else. These spectacular blasts, second in power only to the Big Bang, occur when stars 50 to 100 times more massive than our sun use up all their fuel and collapse.
Andrew Fruchter of the Space Telescope Science Institute clarifies that there are two types of gamma-ray bursts: long ones, produced by the explosion of supermassive stars as described above, and short ones, produced by stars of high metalicity. “Metals in a star produce strong stellar winds — the metals’ atoms reflect the star’s light and act like a solar sail, getting an extra push that hydrogen and helium alone would not get,” says Fruchter. This activity causes some of the star’s mass to flow out into space and the remaining energy just disappears into a black hole. The biggest bang is produced by stars of great mass, low metallicity, and rapid spin.
When rapidly rotating stars of low metalicity collapse there is no hindrance to the infall of material. “The centrifugal force of rotation causes the infalling material to form a torus and makes a less dense region form along the axis of rotation. This provides a channel for the some of the matter and energy to blast out along the poles instead of being absorbed by the black hole.” Mystery solved? Maybe.
3. Problems with a spare part for the Hubble Space Telescope – which has been stored for years at a NASA centre – may further delay a shuttle mission to repair and upgrade the telescope now targeted for launch in February.
On 27 September, errors turned up in Hubble’s science data formatter, which relays data between Earth and the probe’s science instruments. The failure has prevented the telescope from making observations.There is an identical formatter – known as ‘Side B’ – on the telescope, and NASA is planning to boot up that backup system next week. If all goes according to plan, that would restore the telescope to life.
However, there is no backup for Side B, so last week NASA decided to delay its mission to service the telescope from October to no earlier than February in order to prepare a replacement part for flight. Now, preliminary checks into the history of the spare, which has been stored at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, suggest the device might not be ready to fly in February.
4.The Milky Way’s spiral arms could have cast the Sun far from its birthplace, a new simulation suggests. The results could help explain why stars near the solar system vary widely in their chemical composition.
A new simulation suggests the Milky Way’s arms could actually launch stars thousands of light years from their birthplaces, while still preserving their circular orbits.”Our results imply that a star like our Sun could have originated in an entirely different place in the galaxy than where it presently resides,” says astronomer Rok Roškar of the University of Washington in Seattle.
5. Hopes for large lakes of frozen water at the Moon’s poles have taken another bashing, with new images of a prominent crater revealing dull lunar dust instead of shiny pools of ice.
A decade ago, NASA’s Lunar Prospector spacecraft suggested the Moon’s poles could have water deposited by comets. The Japanese spacecraft Kaguya, which launched in September 2007, contains a highly sensitive camera that can capture images of the Moon’s surface even in the near-total darkness of its south pole. The images provided a full profile of the crater – including details of tiny craters on its floor and two landslides from the inner wall. But the most striking feature was what was missing. If there had been nice, clean ice, we’d have seen brighter reflections from its surface – but none was visible.
DID YOU KNOW?
We continue our overview of planets in the solar system. This month, we focus on Mars, the red planet, and its moons.
Named after the Roman Warrior God also known as The God of War, Mars is often called the Red Planet as due to the colour of its surface it appears red in the night sky. Mars has been the subject of many myths and science fiction stories of the centuries.
In 1877 Italian astronomer Giovanni Schiaparelli looked at Mars through his telescope and saw many dark lines which he interpreted to be artificial canals and thus believed that they must be the work of Martians. Maps of Mars were produced showing these long and intricate canals as he saw them. From this began the wonderful stories of ‘little green’ Martians and it spawned a huge interest in ‘Life on Mars’. Schiaparelli was actually a very successful astronomer and he has a Martian crater named after him for all his work studying the planet. We now know that there were once rivers of lava and even possibly of water which are now dried up but not canals.
You may have heard the story of how on October 30th 1938 (Halloween Night) in New York when Orson Welles narrated an adaptation of the H.G. Wells story “War of the Worlds” on the radio and hundreds of terrified New Yorkers ran out of their houses into the street believing that the Martians had landed. Although Martians, as such, do not exist, scientists continue to search for evidence for lif on Mars, albeit microscopic in size.
Mars has many interesting features such as Valles Marineris which is a huge canyon system which stretches a quarter of the way round the entire planet.
Endurance Crater is a small and somewhat inconspicuous Martian crater which has been the subject of more investigation than any other crater on the planet, largely due to the successful lander Endurance, (named after the explorer Ernest Shackleton’s ship) and its robototic rover Opportunity which spent approximately six months exploring the crater.
Olympus Mons is the largest volcano in the Solar System. Its height is approximately 24 km’s high and is probably the most well known landmark on the planet.
Mars has two small moons, named Phobos and Deimos. Both have near circular orbits of the planet and were discovered in 1877 by American astronomer Asaph Hall, the same year as Schiaparelli saw the ‘canals’.
The Phoenix lander spacecraft which successfully landed on the planet in May this year is still sending out remarkable pictures and carrying out soil excavation for ‘on board’ analysis.
Rotation Period: 24 hours and 37 minutes. Temperature: -140 to 20 degrees Celsius Length of Year: About 1 Earth-year and ten and a half months. Diameter: 6796 Kms Atmosphere: Mainly Carbon Dioxide
FUTURE CLUB EVENINGS 2008.
6th Nov – The Astronomers enemy – Light Pollution, Loom & Glare. Presenter
CliffTurk from the Cape town ASSA.
11th Dec – Christmas Party
John Saunders (Chairman) 028 314 0543
Steve Kleyn (Technical Advisor) 028 312 2802
Pierre de Villiers (Treasurer) 028 313 0109
Irene Saunders (Secretary) 028 314 0543
Piet Daneel 028 314 0947
Pierre Hugo 028 312 1639
Jenny Morris 071 350 5560