[AstroNet] What's up at the Observatory next Saturday

[Thembela Mantungwa]

Hi there, 

South African Astronomical Observatory in Cape Town will have a free public lecture on Saturday, 24 September at 20:00. Dr. Christian Hettlage will talk about " Measuring the Universe"

There will be tours of the library, the McClean telescope and stargazing weather permitting.

Visitors are advised to arrive at least at 19:30, this will give them time to park and find the venue. 

Abstract: 
Using simple yet ingenious reasoning, astronomers in ancient Greece were not only able to estimate the Earth's size, but also the distance of the Moon and even that of the Sun. The distance of the Stars remained elusive, however, until telescopes allowed the detection of minuscule motions of nearby stars throughout the year. The story of this success is closely linked to Cape Town. Knowing the distance to stars and applying the laws of physics gave astronomers an unprecedented insight into the nature of stars. Using the variability of certain stars, Edwin Hubble went one step further and established that there are galaxies other than our own Milky Way. The study of the distance and speed of these galaxies led to the conclusion that our Universe expands and must have had a beginning in time. Pushing the distance measurements even further, astronomers found evidence that what we are made of may constitute only 4 percent of the Universe.

Regards
Thembela Mantungwa
Tel: 021 460 9319
Web: www.saao.ac.za
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