The Hong Kong Space Museum's latest Sky Show "Stars: The Powerhouses of the Universe", screening from tomorrow (January 1) until June 30, will take audiences on a journey to understand the life of stars. They will witness the stars' evolution phases of birth, ageing and death, and learn from the human progress of scientific understanding of the universe.
Most of the star lights we see in the night sky came from "Stars". Stars like our Sun emit light and heat constantly. They look eternal but actually they are not. Stars have evolution phases of birth, ageing and death - just like human life. However, these phases are lengthy; as long as millions or even hundreds of millions of years.
The life-cycle of the stars begins in nebulae. Interstellar cloud within a nebula contracts by its own gravity may form a "protostar". If the protostar is massive enough, the gas in the protostar continues to heat up until the temperature of the central portion reaches about 15 million degree celsius. Nuclear fusions then take place and a star is then born.
Our very own star, the Sun, is a typical star right at its meridian of life, also known as "main sequence". The Sun is made mostly of hydrogen and helium with a surface temperature of nearly 6,000 degree celsius. Deep within its core, the temperature rises to 15 million degrees. Every second, nuclear fusion reactions convert more than four million tonnes of hydrogen into helium, releasing the energy that may keep on powering the Sun for the next five billion years.
The ageing of a star consumes hydrogen fuel and produces more and more helium. When there is no hydrogen left in the core, the helium core of the star starts to collapse. The envelope will be heated up and the star will be expanded, becoming very big in size with high luminosity. This big red star will then be at the "red giant" phase.
For a small mass star like the Sun, its luminosity decreases gradually during the short red giant phase. Eventually the star becomes a "white dwarf". As there is no more nuclear reaction in the white dwarf, the star is actually said to be dead at this phase. When a massive star with more than eight solar masses has exhausted most of its fuel, the core of the star will collapse dramatically. Incredible energy triggered by the core collapse will be released instantly and send off shock waves outwards and throw off the outer layers of the star. It is a "supernova" explosion. The brightness of a supernova can rapidly increase by more than one million times. Various elements created during the explosion will be dispersed into interstellar space and trigger the birth of the next generation of stars.
Our knowledge of the universe and stars is based on a journey of discovery that started thousands of years ago when humans first tried to make sense on the night sky and understand the connection with the stars. We found from the journey that every star has a story. But the most incredible story is of our star, the Sun, that keeps a small jewel in its orbit. It provides just enough light, warmth and energy for life to flourish on this unique and fragile oasis.
The 40-minute Sky Show, "Stars: The powerhouses of the Universe", also features a 14-minute seasonal planetarium show. It will be screened daily at 2.40pm and 6.10pm at the museum's Stanley Ho Space Theatre. There will be an additional screening at 11.10am on Sundays and public holidays. On Chinese New Year's Eve, it will be closed at 5pm. It is closed on Tuesdays (except public holidays) and the first two days of the Chinese New Year.
Tickets are available at the Space Museum Box Office and at all URBTIX outlets for $24 (front stalls) and $32 (stalls). Full-time students, senior citizens and people with disabilities will receive a half-price concession.
The Space Museum is located at 10 Salisbury Road, Tsim Sha Tsui, Kowloon. For further information, call 2721 0226 or visit the website at http://hk.space.museum .
Ends/Thursday, December 31, 2009