UPSC Express

In brief: Meteorites

Introduction

• Meteoroids are chunks of rocks in space just like asteroids. (only difference is size)
• When these meteoroids strikes the earth’s atmosphere, they appear are flash of light called meteor.
• In its travel to earth it the meteor survives it is called as meteorite.
• Thus meteorites are inter-planetary rocks that have been formed elsewhere in the solar system but have reached the earth.

Significance of Meteorites

• Since the meteorites have note undergone the geological processes on earth or any other planet, they are said to be pristine objects formed at the beginning of solar system.
• Thus Meteorites are significant in revealing the origin and evolution of Solar System.
• This is done by studying the elements they contain.

Basics

Origin of elements

• Any star including our own sun basically survives on the fusion reaction in its core.
• Different elements we see in nature are formed by different processes.
• In our Sun, hydrogen atoms are undergoing fusion reaction to form helium at extremely high temperatures.
• In massive stars (1000 times bigger than sun), the heaviest element formed due to fusion reaction is Iron.
• Note: The maximum temperatures that can be achieved in the core of the star is only enough to make iron.
• Elements heavier than Iron are formed are formed in various other events such as
• Super nova explosion
• This is because due to high pressure of explosion leads to higher temperatures making fusion of heavier elements possible
• Solar flares
• These are high energy pulses released by sun’s corona.
• The solar flares are violent eruptions of sun that occur at intense magnetic fields at the corona. (called sunspots)
• A solar flare can have as much energy as 100 trillion nuclear bombs.
• Such high energy can result in fusion of heavier elements.

The study of Efremovka Meteorite

• The meteorite found in Efremovka is known to be the one of the most pristine meteorites formed during early stages of solar system.
• The early elements formed during solar flare eruptions during early ages of sun (about 5 lakh years old) are calcium and aluminium.
• The study shows how meteorites ended up containing beryllium-10.
• Beryllium-10 is known to form due to fission of oxygen or carbon.
• The study of the Efremovka meteorite has revealed how beryllium-9 decayed into beryllium-7 which in turn fused to form beryllium-10 in the meateorite.

Conclusion

• So far this was believed that beryllium-10 formed only during a supernova event.
• Now the study has confirmed that the Solar flares of early sun had so much energy that it fused lighter elements into heavier ones