Meteorite with abundant nitrogen for life on Earth?

04 March 2011

A chemical essential for building the first life forms on Earth has been found in abundance in an Antarctic meteorite, say scientists in the journal Proceedings of the National Academy of Sciences this week.

Grave Nunataks 95229 meteorite

Research on the Grave Nunataks 95229 meteorite produced unexpected amounts of ammonia, containing nitrogen, a building block of life © NASA

The team from Arizona State University and the University of California analysed powder from the Grave Nunataks meteorite. Using high temperatures and pressures, they were able to release ammonia gas in quantities much higher than the team had expected, and higher than any reported before.

Ammonia is made up of nitrogen, one of the crucial elements needed for making the building blocks of life, such as DNA, proteins and amino acids, which are present in all living things.

First life on Earth

But how did life first form on our planet and where did these elements come from? 

Nitrogen would have had a crucial role. It is the 4th most abundant element in the sun and our universe. When it is in the form of ammonia, it is more reactive and useful for combining with other chemicals.

However, most evidence suggests there was not enough ammonia around in the early Earth’s atmosphere for life to form. The conditions were not right and ammonia gas is destroyed by sunlight. So where did it come from?

Antarctica is the best place in the world to find meteorites.

Antarctica is the best place in the world to find meteorites. 90% of all meteorites found come from here.

Ammonia could have been delivered to Earth as it was showered with meteorites, the team says. The ammonia was protected within the meteorite, and then released on impact, ready to help kick-start life on Earth.

Meteorite expert at the Natural History Museum Dr Caroline Smith comments on the research, 'This is an interesting study and the fact that so much ammonia has been found in this meteorite could be quite important.  

'We know that the early Earth was bombarded by meteoritic and cometary material, which could well have delivered the chemical elements and molecular building blocks needed for life to start.'

Smith says that it will be good to find out if any other meteorites contain similar amounts of ammonia. 

'This is a result from just one meteorite so it will be very interesting to see whether similar abundances of ammonia are found in similar meteorites. Results like this all add pieces of the jigsaw puzzle of how life began on our planet.'

Meteorites
A stony meteorite, the most common type of meteorite found

A stony meteorite. These are the most common type of meteorite found and include the carbonaceous chondrites, such as the Grave Nunataks used in this research.

Most meteorites found on Earth are fragments of asteroids - ancient rocks that formed during the creation of the solar system about 4.56 billion years ago.

There are many different types of meteorite. The Grave Nunataks (full name CR2 Grave Nunataks 95229), is a type of stony meteorite called carbonaceous chondrite, one of the most primitive rocks in the solar system. They are rich in water, sulphur and organic material and haven't changed much from the asteroid they came from.

The Grave Nunataks meteorite was found in Antarctica in 1995. Antarctica is the best place in the world to find meteorites as the cold and dry conditions preserve them well and they are easy to find on the ice.

The Museum looks after a collection of approximately 5,000 meteorites, including rare specimens from the Moon and Mars. They are part of the world-class mineralogy collection and are studied by scientists worldwide.

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