Astro News
- Recent Updates of Astro News
- Active Mercury(07/09)
- Hubble Status Report: Directly Observes a Planet Orbiting Another Star(01/09)
- A Non-trivial Answer to a Trivial Astronomical Question-The Origin Of Absolute Magnitude(07/08)
- Assault by a Black Hole(04/08)
- New Lakes Discovered on Titan(01/08)
- ˇ§Deviant Behaviourˇ¨ in the Solar System(10/07)
- Cosmic Ripples - Cosmic Microwave Background - CMB(07/07)
- Interplanetary Superhighway(04/07)
- Is Pluto a Planet?(01/07)
- Breathing Moonrocks(10/06)
- My Thoughts on the Theory of Relativity, Quantum Mechanics, Superstring Theory and Dark Matter(07/06)
- Space-time Vortex(04/06)
- Radio Astronomy(01/06)
- Neutrino Astronomy(10/05)
- The Active Earth(07/05)
- What is Dark Energy?(04/05)
- The Mysterious Black Holes(01/05)
- Intermediate-Mass Black Holes And Quasisoft X-Ray Sources(10/04)
- Time Travel: From a Scientific Approach(07/04)
- What is Astrobiology?(04/04)
- Black Hole: From Fantasy To Reality (II)(01/04)
- Black Hole: From Fantasy To Reality (I)(10/03)
- From The Oldest Light In The Universe To The Fate Of The Universe(7/03)
- The Cosmic HERO(4/03)
- Quaoar - the Tenth Member of the Solar System?(1/03)
- The First Chinese Telescope in Space(10/02)
- Diamonds and Other Stardust(7/02)
- Supermassive Black Hole in Andromeda Galaxy(4/02)
- Detection of Solar Neutrinos(1/02)
- Simultaneous Multiple Wavwlength Observation(10/01)
- Celestial Distance(7/01)
- Solar-Terrestrial Relations(7/00)
- Fundamental Particles in Astronomy(4/00)
- The Solar Maximum in 2000(1/00)
- Hubble Constant(10/99)
- New Findings on Cosmology(7/99)
- Strange Stars(4/99)
- How Strong Stellar Magnetic Field Can Be?(1/99)

Important notices

It has been said that "diamonds are a girl's best friend". In fact, women of all times and cultures have always been fascinated by diamonds, attracted by their beauty, glitter and rarity (and therefore value). It is interesting to note that diamond is a form of pure carbon, the fourth most common chemical element of the Universe, after hydrogen, helium, and oxygen. The rarity of diamonds is therefore not due to its chemical composition, but the result of how and where they are made. The diamonds on Earth are believed to have formed under high temperature (~1000ˇC) and pressure (45 kilobar) in the deep (100-300 km) interior of the Earth, and brought to the near surface by volcanic activities. Chemically, diamond is a close cousin to graphite, a natural substance that is used to make pencils. Graphite is the stable form of carbon under low pressures, for example at the natural environment on the surface of the Earth. In fact, if you put a diamond in an oven, the precious diamond will decay into common graphite.

The Chamaeleon dark cloud is one of the most active star formation sites near our Solar System. In the middle of this picture is a reflection nebula.

Astronomers have known since the 1950s that the chemical element carbon is made in old, red giant stars. While it has long been speculated that these freshly made carbon atoms can be brought together to form graphite, it has always been thought the synthesis of diamond in space is impossible. The reason is very simple. The density in the stellar and interstellar environment is extremely low, lower than any vacuum conditions that we can create in the laboratory. Such conditions are a far cry from the hot, dense environment in the great depths of the Earth where diamonds are formed.

The deployment of infrared telescopes in orbiting satellites has opened the new scientific discipline of astromineralogy. The Infrared Astronomical Satellite launched in 1982, followed by the Infrared Space Observatory launched in 1995, have discovered stardust made up of minerals ranging from common rocks of silicates and carbonates, to rare stones similar to rubies and sapphires. These developments greatly surprised astronomers, for there is no theoretical explanation for how such stardust are formed.

This raises the question of diamonds. Although diamonds have been extensively searched for, there was no detection. In 1999, three French astronomers noticed that a pair of mysterious features in the infrared spectra of two stars in the Chamaeleon and Taurus dark clouds resembled the laboratory measurements of diamonds made by Dr. Huan C. Chang of the Institute of Atomic and Molecular Sciences of the Academia Sinica in Taiwan. Based on this comparison, they proposed that these stellar features are due to very small diamonds. Finally, diamonds are positively identified in space.

There is now strong evidence that diamonds are not only made by stars, they are actually delivered to Earth from space. Traces of small diamonds are found in meteorites. Meteorites are extraterrestrial rocks that hit the Earth. Although the bulk of the materials in meteorites are products of the solar system, we now know that they contain traces of stardust. The fact that we can hold in our hands the products of stars thousands of light years away and made probably millions of years ago is one of the most amazing discoveries of modern science. 



The Infrared Astronomical Satellite was a joint mission between US, UK and the Netherlands. It was the first telescope to have performed an all sky survey in the infrared.


Photo credits ˇG
The Chamaeleon dark cloud: VLT, ESO
The Infrared Astronomical Satellite: NASA