Panspermia theory

The Panspermia theory - the roots of which go back at least as far as the 5th century BCE - was popularized in the 1980s by Fred ('Big Bang'plugin-autotooltip__plain plugin-autotooltip_bigBig Bang theory

There is now a large body of evidence (from different sources) to support the Big Bang Theory for the origin of the universe, but the problem remains as to the origin of the material or energy which initialised it.

As the UK’s Astronomer Royal Martin Rees has put it :) Hoyle and Chandra Wickramasingh.

The idea is that the building-blocks of life (e.g. DNA/RNA fragments, or Amino Acid protein-components) may exist and travel through deep space. Thus, such compounds may have arrived on Earth as 'space dust', or by comet impact, and could have provided triggers for the origin of Lifeplugin-autotooltip__plain plugin-autotooltip_bigPrimordial Soup

"In 1953 an iconic set of experiments showed that some of the chemical building blocks of life, such as amino acids, could form spontaneously in the atmospheric conditions thought to prevail on the primordial Earth. This gave rise to the idea that the early oceans were a "primordial soup" from which life somehow emerged. on the planet.

Since the 1980s, many discoveries have been made which make the Panspermia theory appear less improbable.

For example :

• Amino acids have now been confirmed in deep space.(example ref.)
• It's now known that some viruses and bacteria can survive in space (ref.)
• Uracil - one of the base-pair compounds of RNA - had been found in a meteorite (ref.).

Although there is now a growing body of evidence appearing to support the theory - or at least not contradict it - it's still not widely accepted by experts in the field.

Further reading Advances in Genetics, Volume 106, pp.101-107

Note : Wikipedia maintains a list of chemical compounds, including amino acids, which have been detected in Space.