The discovery of an opal-embedded meteorite in Antarctica was announced on Monday at the National Astronomy Meeting, which took place in Nottingham, England.
Opal is frequently associated with water, due to it being a hydrated form of silica. Its water content may range from 6 up to 30 percent, and its presence on a meteorite indicates that there is a high probability of other meteorites and asteroids carrying significant amounts of water in the form of ice. This is the first time opal has been found in an asteroid.
Water in a meteorite
Professor Hilary Downes from the Birkbeck Institute of Earth and Planetary Sciences at the University of London announced the finding and reinstated the theory that asteroids “may have brought the water to the earth and helped it become the world teeming with life that we live in today.”
The meteorite was classified as EET 83309, and scientists believe that it came from the surface of an asteroid. The difference between these bodies is that asteroids behave much like minor planets since they orbit around the sun. Meteoroids are much smaller objects that also orbit around the sun, and as they enter earth’s atmosphere, they combust and evaporate, so they become meteorites.
Asteroids colliding with earth
Asteroids can reach almost 600 miles (940 km) across, while the smallest to ever be discovered was only 20 feet (6 m) across. Some asteroids are so massive that can have up to two companion moons. There are also cases of binary and triple asteroids that orbit around each other. Other asteroids have also been able to become moons as they are captured by a planet’s gravity, such as it is the case of some moons of Mars and Jupiter.
It is estimated that every 1,000 to 10,000 years, an asteroid is almost sure to strike the earth, which could cause devastating effects to humans through earthquakes, tsunamis, or by just hitting a city and destroying everything in its path. Asteroids are often tracked due to their predictable orbits, which is why at least ten asteroids have been classified as “potentially hazardous” by astronomers. There is a chance that in a couple of decades, an asteroid will eventually collide with Earth. But luckily, there would be enough time to react. Some proposed solutions would include to explode the asteroid or divert its trajectory.
It seems that EET 83309 was still part of its parent asteroid as it was exposed to the sun’s radiation. But it is not the meteorite itself what’s interesting.
“The pieces of opal we have found are either broken fragments, or they are replacing other minerals,” according to Professor Downes.
This means that previous impacts on the parent asteroid by objects from different parts of the solar system were the events that brought water ice to its surface in the first place.
There was no question regarding the meteorite’ origin. Isotope analysis on the meteorite’s pieces has shown that the minerals do share the same extra-terrestrial origin.
The National Astronomy Meeting of 2016 is set to take place from June 27 to July 1, and the Royal Astronomical Society sponsors it. Users can follow the meeting’s latest announcements through their Twitter account.
Source: NAM2016