PRESOLAR GRAINS

Jan. 29, 2020

Scientists have discovered the oldest solid material ever found on the Earth, in the form of stardust trapped inside a meteorite that crashed into Australia 50 years ago and predates the formation of our solar system.

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This stardust provides evidence for a ‘baby boom’ of new stars that formed 7 billion years ago, contrary to the theory that star formation happens at a steady, constant rate. The materials the researchers examined are called presolar grains.
Presolar grains are interstellar solid matter in the form of tiny solid grains that originated at a time before the Sun was formed. Presolar stardust grains formed within outflowing and cooling gases from earlier presolar stars.
These bits of stardust became trapped in meteorites where they remained unchanged for billions of years, making them capsules of the cosmic time before the solar system.
However, presolar grains are very tiny and rare, found only in about five per cent of meteorites that have fallen to the Earth. Since presolar grains are formed when a star dies, they can tell us about the history of stars.

Source : Indian Express