October 23, 2017

17.03.10: A Hadean Simulation.

 

A pahoehoe lava flow on Hawaii. (Credit: Art Explosion).

A pahoehoe lava flow on Hawaii. (Credit: Art Explosion).

 

 

One of the key mysteries in science is how life began on Earth. In the 1950s, the landmark Urey-Miller experiments gave tantalizing evidence of how organic compounds may have formed on ancient Earth. Recently, scientists at the University of Hohenheim in Stuttgart have shed more light on the subject.  Using an artificial solution of primordial seawater interacting with atmospheric nitrogen and CO2, they subjected the mixture to temperatures of up to 662° Fahrenheit, similar to conditions that existed in the early Hadean era, 3.8 to 4.5 billion years ago. The Earth was much more volcanically active in its early history, and the baking process observed allowed amino acids to be “cooked” into the resulting salt crust. Amino acids are the key building blocks to proteins. Specifically, the team found essential compounds such as pyrroles, which function as the oxygen carrying component in the haemoglobin in your blood, were easily formed. Pyrroles also play a role in plant chlorophyll. This all points to the conjecture that life soon arose on Earth once the conditions were ripe for it. The initial seeding of amino acids may have occurred via cometary impacts in what is known as the panspermia process, which may be common place throughout the galaxy even today.

28.01.10: A Key Organic Compound Found in Space.

The Stardust aerogel detector. (Credit: NASA/JPL).

The Stardust aerogel detector. (Credit: NASA/JPL).

 

Stardusters rejoice; one of the largest citizen scientist projects has borne fruit. In 2004, NASA’s Stardust spacecraft passed through the outer envelope of comet Wild 2, allowing its sticky aerogel detectors to capture samples of gas and dust. Ever since the detectors parachuted safely to Earth on January 15, 2006, scientists, bloggers, and school kids have been pouring over the aerogel microscope scans looking for tell-tale dust tracks in a project known as Stardust@home, a vast citizen science project that might well be dubbed as the greatest science project done before bedtime.  Scientists at Goddard Space Flight Center announced late in 2009 that the molecule glycine has been detected in the aerogel detector. A key amino acid used in the construction of proteins, glycine is represented by the formula NH2CH2COOH. Scientists actually detected the molecules trapped in the foils at the rim of the detectors. Terrestrial glycine was ruled out due to the isotopic structure of the carbon atoms seen; Earth bound carbon tends to be of the Carbon 12 variety, while the glycine in the sample is the heavier Carbon 13, just what would be expected if the compound had come from the nucleus of a comet. It should be pointed out that the discovery of organic compounds is not the same as the discovery of life, but rather the key building blocks of such. This does, however, provide evidence that the raw materials to get life going may indeed be prevalent in the cosmos.