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In this issue of SpaceTides

Dear SpaceTides Subscribers

It seems most of South Africa had cloudy weather around the time of the total lunar eclipse of 3 to 4 March 2007. South African photos of the eclipse can however, be found at http://assa.saao.ac.za/news/2007/lunareclipse.htm

The winner of the Sky Guide Africa South 2007 in last issue's lucky draw was H. Lombard - congratulations!

You are invited to take part in the exciting Globe-at-Night project, and contribute to professional research about the state of light pollution on Earth. It is simple and fun and the ideal family activity.
See section 8.

Regards,

Gerrit Penning
Editor

Total subscribers as at 1 March 2007: 733 (-31 due to list cleaning, i.e. removal of dormant addresses)

1. Spaceflight news from around the world

Stunning views of Jupiter's moon Io by the New Horizons probe
From a New Horizons Photo release, NASA/JPL. 28 February 2007. Read full article.

This dramatic image of Jupiter's third largest moon "Io" was taken by the Long Range Reconnaissance Imager (LORRI) onboard the New Horizons space probe on 28 February. This came only about 5 hours after the spacecraft's closest approach to Jupiter. The distance to Io was 2.5 million kilometers. One LORRI pixel shows 12 kilometers on Io.

This is the last of a handful of LORRI images that New Horizons is sending "home" during its busy close encounter with Jupiter - hundreds of images and other data are being taken and stored onboard. The rest of the images will be returned to Earth over the coming weeks and months as the spacecraft speeds along to Pluto.

New Horizons is the first ever space probe to fly to Pluto and the other Kuiperbelt objects.
Arrival at the dwarf planet is slated for 2015. NH homepage: http://pluto.jhuapl.edu/
Image at left shows massive volcanic plume erupting into space (top). NASA-JPL.

A view of Mars from the Rosetta space probe. Credit: ESA

Rosetta takes a special glimpse of Mars
Based on an ESA news release, 25 February 2007. Read full article.

This stunning view, showing portions of the European Space Agency's Rosetta spacecraft with Mars in the background, was taken by the Rosetta Lander Imaging System (CIVA) on board Rosetta’s Philae lander just four minutes before the spacecraft reached closest approach to the Red Planet in February.

Launched three years ago, the Rosetta probe flew just 1 000 km above the Martian surface at a speed of about 36 300 km/h relative to the Red Planet. This Mars flyby created a slingshot-boost for Rosetta, to put the spacecraft on a path to reach Earth on November 13 for a similar maneuver.

Rosetta already made a fly-by of Earth in 2005, and will fly past Earth two more times later this year and in 2009 (both for a speed-boost and to put it on course for its final destination, comet 67P/Churyumov-Gerasimenko in early 2014.

Rosetta homepage at ESA: www.esa.int/SPECIALS/Rosetta/
More info at Spaceflightnow.com: www.spaceflightnow.com/news/n0702/25rosettamars/

2. Astronomy news from around the world

Artist rendering of an exoplanet. Credit: David A. Aguilar (CfA)

An Atmosphere around an Exoplanet?
Extracts from a NASA news release dated 21 February 2007. Read full Article.

NASA's Spitzer Space Telescope has captured for the first time enough light from planets outside our solar system, known as exoplanets, to identify molecules in their atmospheres. It was done using spectrum analysis. This surprise achievement is a significant step toward being able to detect possible life on rocky exoplanets in the future and comes years before astronomers had anticipated. So far, most exoplanets found are similar to the gas giant Jupiter, but dubbed "hot Jupiters" as they orbit very close to their parent stars.

The data indicate the two planets studies are drier and cloudier than predicted. Theorists thought "hot Jupiters" would have lots of water in their atmospheres, but surprisingly none was found around HD 209458b and HD 189733b. According to astronomers, the water might be present but buried under a thick blanket of high, waterless clouds.

A spectrum is created when an instrument called a spectrograph splits light from an object into its different wavelengths, just as a prism turns sunlight into a rainbow. The resulting pattern of light, the spectrum, reveals "fingerprints" of chemicals making up the object.

Artist rendering. NASA/Dana Berry

Integral satellite may have found fastest neutron star yet
Extracted from an ESA News release dated 16 February 2007. Read full article.

Scientists working with ESA's gamma-ray observatory called Integral, have detected what appears to be the fastest spinning neutron star yet. This tiny stellar corpse is spinning 1122 times every second. If confirmed, the discovery gives astronomers the chance to glimpse the insides of the dead star.

Just because a star dies, it doesn't mean its life is over. A neutron star is the tiny heart of a collapsed star. Measuring about 10 kilometres across, yet containing something like the mass of the Sun, the interior of a neutron star is the most exotic realm that astronomers can imagine. According to their calculations a thumb-sized piece of neutron star material weighs a hundred million tonnes. ESA Integral homepage: www.esa.int/SPECIALS/Integral/index.html

The image at left shows a spinning neutron star sucking in gas from a companion star (artist rendering). More about neutron stars and black holes on Wikipedia.org.

3. Interesting Space Facts

The Threat of Near-Earth Objects

Near-Earth Objects (NEOs) are meteoroids, asteroids, and comets whose orbits lie close to Earth's. They can also sometimes cross our planet's orbit.

NEOs pose a potential threat to life on Earth. It has gained much public attention in recent years, partly due to Hollywood movies, but also through increased scientific understanding of NEOs and their potentially destructive consequences.

The crash of Comet Shoemaker-Levy 9 into Jupiter in 1994 showed that collisions are still happening even today in our solar system.

More than 3,400 Near-Earth Asteroids (NEA's) have been found to date, which is only a fraction of their suspected total population. "1036 Ganymed", with an approximate diameter of 41 kilometers, is the largest NEA. It is currently estimated that there are about 1 100 NEAs with diameters larger than 1 kilometer; they are large enough to produce global catastrophe if they were to hit Earth...

More information: http://www.planetary.org/explore/topics/near_earth_objects/

4. The Solar System

The Planet Saturn.
Credit: NASA/JPL/SSI

The Ringed Planet Saturn

Saturn is the 6th planet from the Sun and second largest. It has an impressive ring system that clearly distinguishes it from the other planets in our solar system.

The planet is mostly gaseous, consisting primarily of hydrogen and helium. Its volume is 755 times greater than that of the Earth. Saturn has very fast winds: combined with heat rising from within the planet's interior, the winds cause the yellow and gold bands visible in the atmosphere. It is the only planet that is less dense than water.

Saturn's interior is similar to Jupiter's: it also has a rocky core at the center, a liquid metallic hydrogen layer above that, followed by a layer of molecular hydrogen.

The ring of Saturn consists mostly of iced particles, rocks and dust. Although it is over
250 000 km in diameter, it is only a few kilometers thick! It is not one solid ring: various ringlets make up the total ring structure.

Image left: "State of beauty". Saturn's visual colours appear through filters on Cassini cameras, from 1 million km distant. More info on Saturn.

5. Sky Observation Log

Naked eye Planets - March 2007
Mercury is visible in the morning skies and is best viewed at month-end.
Venus shines bright in the evening skies just after sunset in the west - a beautiful sight.
Earth is still spinning round and round and round...
Mars rises in the mornings at about 3h30. 
Jupiter rises after midnight and is visible throughout the morning.
Saturn can be seen all night, located in Leo in the north-east in the evenings.

The planets move through the sky on an imaginary line, called the ecliptic. The ecliptic represents the plane (disc) on which the planets revolve around the Sun. Can you think why the ecliptic makes an angle of about 23 degrees with the equator?

Refer to the Sky Guide 2007 for detailed planetary rise and set times.

Other celestial events - March 2007
- Full Moon on 4 March 2007.  New Moon on 19 March 2007
- The Moon will occult the M4 globular star cluster on 11 March 2007 from 4h30, 0.7 degrees
  from the bright red star Antares.
- 21 March is time for the autumn equinox again.

Take a binocular and scan through the milky way - especially in the south-east (even from city skies!) You'll be surprised to see how many stunning deep sky objects you can see. More about them next month in SpaceTides...

6. Global Warning

Credit: WMO, Christian Morel

World Meteorological Day 2007 - 23 March

Excerpt from the WMO's information brochure: "The WMO Executive Council decided that the theme for World Meteorological Day in 2007 would be “Polar meteorology: understanding global impacts”. In recent decades, great advances have been made in our understanding of the role of the polar regions in the global climate system. Shrinking sea-ice, melting ice sheets, the discharge of glaciers and thawing of permafrost are all dramatic changes that have been taking place in those regions owing to an increase in global average temperature."

  "It is evident that the increased average rate of sea-level rise resulting from the melting of ice of land origin would be dangerous for lowlands and some islands whatever their geographical location. Ocean circulation changes may have an impact on the distribution of temperature, salinity and organic substances in tropical areas. This would have a crucial impact on fish stocks and therefore on national economies, livelihoods and our eating habits".  Source: more information on the WMO's website: http://www.wmo.ch/wmd/

7. Astronomy events in Bloemfontein

Boyden Sterrewag Ope-aand vir die publiek, Bloemfontein

Datum: Saterdag, 24 Maart 2007
Tyd: 18h45 vir 19h00
Koste: R30 per voertuig
Plek: Boyden Sterrewag op Harvard koppie langs Maselspoort, Bloemfontein
Spreker: Dr. Peter Martinez van SAAO in Kaapstad/Sutherland
Tema: "Wetenskap met SALT: Hoe die Suider-Afrikaanse Groot Teleskoop sal help om sterrekunde se groot vrae te beantwoord".
Aangebied deur: Die Vriende van Boyden Sterrewag, in samewerking met ASSA Bloemfonteintak
Bespreking is noodsaaklik. Besprekings open egter eers 19 Maart 2007. Skakel reeds daardie Maandag 051-401 2561 om jou plek te verseker, aangesien plekke baie vinnig opgeneem word.

Verversings sal te koop wees.

Boyden Observatory Open Evening for the public, Bloemfontein

Date: Saturday, 24 March 2007
Time: 18h45 for 19h00
Cost: R30 per vehicle
Venue: Boyden Observatory on Harvard Hill next to Maselspoort, Bloemfontein
Speaker: Dr. Peter Martinez of the SAAO in Cape Town/Sutherland
Topic: "Science with SALT: How the Southern African Large Telescope will help to answer astronomy's big questions".
Organised by: The Friends of Boyden with assistance from ASSA Bloemfontein Centre
Reservation is essential. Bookings open on Monday 19 March 2007. Phone 051-401 2561 on that Monday, as seats go fast. Refreshments will be for sale.

8. Astronomy in Southern Africa

South Africans invited to participate in the International Globe-at-Night Project
All you need to do is go outside for one evening during the period 8 to 21 March 2007 and compare YOUR view of the Orion star field with star maps supplied by Globe at Night. Easy and simple. Visit Globe-at-Night's website and download the family pack with full instructions. You can also send your results to SpaceTides for recognition of your name on the internet. This is your opportunity to help fight light pollution: a growing concern that is busy destroying our precious night skies for next generations. In the process you can also do something fun and educational together with your children.


Satellite Tracking and Video Astrophotography
Interested in satellite tracking and video astrophotography? See fascinating pictures of satellites and other objects on national ASSA's Video Astrophotography page.

Scope-X in Johannesburg on 21 April 2007
The well-known annual telescope and astronomy expo called Scope-X, organized by the Johannesburg Centre of ASSA, will take place on Saturday, 21 April 2007 in Johannesburg. Download PDF Information brochures in Afrikaans or English by visiting the Johannesburg Centre's website.
Main theme: Astrophotography. International guest speaker Richard Berry from the USA will deliver the keynote talk.  You can also attend a special dedicated workshop on 20 April presented by Richard.

9. Promotion section (non-profit)

Scared of Speaking in Public? Need more self-assurance to talk in front of an audience?

Toastmasters International is a non-profit organisation that started in 1924. Since then it has helped millions of men and women to become more confident when speaking in front of an audience. Find the nearest club to you.

Bloemfonteiners can visit the local club's website here or phone Gerrit Penning for more information (051-522 2536 all hours). Die "Toastmasters" is ook 'n uitstekend geleentheid om jou Engels te verbeter. Dit het reeds talle lede gehelp om met meer selfvertroue in Engels voor gehore te praat.