Hello SpaceTides Subscribers

First of all, it seems that the Mars Hoax email is doing the rounds again. I couldn't believe what I saw! And people actually tend to believe it. If you get one of these emails claiming "Mars will come very close to the Earth" (and become as big as the full moon), simply ignore it. More info below.

You can now also subscribe to the free ASSA web update service. A short and to-the-point monthly update with internet links to news and events about SA astronomy. All subscribers are invited to make use of this opportunity (click link above or reply to this email with the word "ASSA" in the subject line and I will put you on the list).

I'm sending a separate email with more information about the national ASSA Symposium to be held at Boyden Observatory in Bloemfontein.  You are welcome to attend, hope to see some you of you there! It promises to be a full and exciting event.

All the best,

Gerrit Penning
Editor

Total subscribers as at 1 August: 633 (+78 from previous issue #45)

Beware the Mars Hoax!!

Debunking some really inaccurate data

Many of you might have received it already. The malicious e-mail hoax claiming that, on 27 August, Mars will come extremely close to the Earth. So close in fact, that it will be as large as the "full moon"! It also claims that Mars will easily be visible and only within
56 million km from the Earth. Some of this was true for August 2003. It's totally false now.

Let's quickly set the record straight:
1. For the month of August 2006, Mars will not be easily visible!! It is so close to the western horizon in the glare of the sun as to make it very difficult to discern properly.
2. On 27 August 2006, Mars will not be 56 million km away, it will be 386 million km away. That's pretty much on the other side of the Sun...
3. If Mars is 56 million km from the Earth, it will NOT appear as large as the full moon. In August 2003 Mars came within 56 million km, the closest in 60,000 years, and it was nothing more than a bright speck of light in the sky - the layman wouldn't even have noticed at all.  Just think of what will happen to the tides if Mars came so close to the Earth as to be as large as the "full moon". Total mayhem... So please ignore that hoax!!

Go to this Snopes.com article to read the hoax (green box). 

1. Spaceflight news from around the world

Radar images of Titan's surface. Credit: NASA/JPL

Cassini Finds Lakes on Titan's Arctic Region
From a JPL news release dated 27 July 2006.  Read full article.

NASA's Cassini spacecraft has found lakes on Saturn's largest moon Titan. The lakes are most likely the source of hydrocarbon smog in the frigid moon's atmosphere. Finding the source of these hydrocarbons ("koolwaterstof" in Afrikaans) in Titan's atmosphere has been a major goal for the Cassini mission and is a significant accomplishment.

Scientists have now seen a place other than Earth where lakes are present.

Cassini took radar images of dark patches resembling lakes. At Titan's very cold temperatures, about minus 180 degrees Celsius, the liquids in the lakes are most likely methane or a combination of methane and ethane.  Scientists had predicted, but had no confirmation until now, that pools of liquid were contributing to the high concentration of methane and other hydrocarbons in Titan's atmosphere.

Cassini's next flyby of Titan is on 7 September 2006. In October, Cassini's radar will look even closer to the north pole, searching for more lakes and mapping more of the polar region covered by these features.

Artist impression of SMART-1 near the Moon. ESA.

Lunar Probe to crash into the Moon
From ESA's SMART-1 website, "Approaching the mission end". Link.

After almost 16 months of studying the Moon, the SMART-1 lunar probe is about to end its mission and it is going to make a big impact (literally!)

It  reached the Moon in November 2004 after a long spiraling around Earth. In this initial phase, the spacecraft tested a series of advanced technologies (including an ion engine and gravity assist manoeuvres). After extensively studying the Moon, operators are going to crash the probe into the lunar surface on 3 September. This date allows for further capturing of high resolution data and the opportunity for ground-based telescopes to see the impact from Earth.

The telescopes will try to observe the dust ejected by the impact, hoping to obtain physical and mineralogical data on the surface excavated by the spacecraft.

2. Astronomy news from around the world

Starburst galaxy NGC 908 Credit: ESO

Galaxies with a Twist
Extracted and edited from an ESO press release dated 27 July 2006. Read full article.

ESO's Very Large Telescope has photographed various 'Island Universes', which all have some peculiar characteristics. The galaxy pictured here is NGC 908, located 65 million light-years towards the constellation of Cetus (the Whale).

It is a so-called "starburst galaxy" - a galaxy undergoing a phase where it spawns stars at a frantic rate. The galaxy also displays uneven and thick spiral arms. This indicates that it may have undergone a close encounter with another galaxy in the past.  Clusters of young and massive stars can be seen in the spiral arms.

Computer rendering of rays emitted by a supermassive black hole.  ESA / V. Beckmann (NASA-GSFC)

Those elusive Supermassive Black Holes
Extracted and edited from an ESA news release dated 26 July 2006. Read full article.

Scientists trying to find supermassive black holes hiding in nearby galaxies have found surprisingly few. Either the black holes are better hidden than scientists realised or they are lurking only in the more distant universe.

They might be hiding behind thick clouds of dust. These dusty shrouds allow only the highest energy X-rays to shine through. The X-rays combine into a cosmic background of X-rays that permeates the whole of space. Observations show that there are clearly too few hidden black holes in the nearby Universe to create the observed X-ray background radiation.

The X-ray sky is thousands to millions of times more energetic than the visible sky familiar to our eyes. Much of the X-ray activity is thought to come from black holes violently sucking in gas from their surroundings. The challenge now is to see them...

3. Interesting Space Facts

An H-Alpha view of the Sun with a solar prominence clearly visible. Taken by Jacques van Delft (ASSA Bloemfontein). More info.

Facts about our Sun

-The diameter of the Sun is about 1.4 million kilometers. This is 110 times more the Earth's. The Sun's volume is big enough to hold more than 1.3 million Earths.

-The Sun is about 4.6 billion years old. It has already used up almost half of its hydrogen supply in its core and will "run out of gas" in about 5 billion years. It will then expand and engulf all of the inner planets. After its destruction, a planetary nebula will most probably be left over, with the Sun as a white dwarf in the centre.

-The Sun contains more than 99.8% of the total mass of the whole solar system (with Jupiter taking up most of the rest).

-If you travel to the Sun at 120 km/h (as with a car), it will take you 142 years to reach  the Sun!

4. The Solar System: Our Sun

The Sun - courtesy SOHO Consortium
(ESA / NASA). More SOHO images.

Our nearest star, the Sun

The Sun is on average 150 million km from the Earth. This is actually very close in cosmic terms. We thus have a star close to us which we can study directly. Much research is performed on the Sun, but equally many questions still remain.

Scientists are only now beginning to understand the impact that the Sun have on the environmental and climatical systems here on Earth. We are very fortunate to have such a stable and ordinary Sun - without such characteristics, intelligent life on Earth would have been in grave danger, or might never have existed at all.

The Sun’s energy is created deep down in its core.  The temperature here is estimated to be 15 million° C! (surface temperature approaches 6 000° C).  These reactions are so intense that nuclear fusion takes place. When hydrogen particles fuse together to form helium, energy is emitted. Every second, 700 million tons of hydrogen are converted into helium.

The Sun makes one rotation around its own axis in just over 25 days.  It is being studied by orbital satellites as well as Earth-based observatories. More about amateur solar observations on ASSA Bloemfontein's solar page.

5. Sky Observation Log

Credit: Stellarium

Planets - August 2006
Mercury is in the morning sky for the first 3 weeks of the month.
Venus is also in the morning sky, visible for the entire month.
Earth is probably the best place for intelligent life in the solar system. It's not too hot, not too cold, geologically pretty stable and if you don't live in the largest its cities, the atmosphere is also quite breathable.
Mars is visible just after the Sun sets, but is very close to the western horizon in the Sun's glare.
Jupiter shines bright overhead in the evening sky, setting shortly after midnight.
Saturn only reappears in the morning sky at the end of August.

Constellations and stars - evenings of August 2006
To the North: Hercules (the Hero) are fully visible in all its mythological splendour. To its "right" is Lyra (the Lyre), with the star Vega monopolising the northern sky with its brightness.
Mid-sky: Sagittarius (the Archer) is now well-situated for observation and Aquila is rising in the east.
To the South: Ara (the Altar) is still the perfect hunting-ground for deep sky objects while Triangulum Australis, Apus (the bird of Paradise) and Pavo (the Peacock) dominates the southern-most skies.

Have you tried to find Sigma Octantis yet? It is the star closest to the south celestial pole. You can attempt to locate it with a binocular.

Deep sky Objects - August 2006
Sagittarius deep sky objects: Use a telescope to find the numerous Messier objects in this superb constellation. Look at M25 (Open Cluster), M8 (bright "Lagoon" nebula), M22 (large Globular Cluster), M17 (Swan nebula!!), M20 (Triffid Nebula). Recommended: a telescope with 6 to 8 inch aperture and up.

Other night sky events
- Full Moon on 9 August 2006. New Moon on 23 August 2006.
- The moon occults Antares as seen from Cape Town on 4 August 2006. Observers more north should still watch - they will be very close to each other. Actually something not to miss!

6. Astronomy & Science in Southern Africa

SKA South Africa and KAT news updates

Visit the newsletter site of the Square Kilometer Array / Karoo Array Telescope for up to date information pertaining to these exciting projects. 

Website: http://www.ska.ac.za/newsletter/

You can also join the mailing list free of charge. The competition runs high between the countries hoping to host the mega SKA project. South Africa - let's wish the representatives good luck. If SA wins the bid, we can say that we have the world's most powerful, largest radio telescope!

7. Observatories of the World

McDonald Observatory and the Hobby-Eberly Telescope
The McDonald Observatory is located in the Davis Mountains, some 720 km west of Austin, Texas in the United States. The Observatory is equipped with various state-of-the-art instrumentation for imaging and spectroscopy in the optical and infrared, and operates one of the first and most productive lunar ranging stations.  Currently, the Observatory operates four research telescopes:

9.2m Hobby-Eberly Telescope
2.7m Harlan J. Smith Telescope
2.1m Otto Struve Telescope
0.8m Telescope

The South African Large Telescope (SALT) is based on the design of the Hobby-Eberly Telescope.

Left: Dome of the Hobby-Eberly 9.2 m telescope (souce).
Website: http://www.as.utexas.edu/mcdonald/

8. Photo Sense

A night photo taken at Boyden Observatory on 17 June 2006 by Gerrit Penning. The image shows one of the numerous telescope buildings on the Boyden hill, "painted" red by a flashlight while the photo was exposed for 30 seconds. The fast-moving clouds are evident and the trees display a vivid green colour.

9. Web Links

Global Dimming: BBC Horizon documentary - and you thought Global Warming was the only problem we're sitting with? Think again... http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml

NASA Astrophysics Data system - The Digital Library for Physics, Astrophysics, and Instrumentation:  http://www.adsabs.harvard.edu/

Earth Observatory, NASA - a collection of Earth imagery: http://earthobservatory.nasa.gov/

Open Directory Project (dmoz.org) - a vast directory of websites: http://www.dmoz.org/

Lamont-Doherty Earth Observatory - where scientists seek to obtain fundamental knowledge about the origin, evolution and future of the natural world: http://www.ldeo.columbia.edu/

S*T*A*R Astronomy Telescope making links - http://www.starastronomy.org/TelescopeMaking/Links/

Celestia space simulator - hours of fun in space in front of your computer!