Posted on October 14, 2005 by Afarensis, FCD
Scientists associated with NASA’s Spitzer Telescope have discovered polycyclic aromatic hydrocarbons:
“NASA’s Spitzer Space Telescope has shown complex organic molecules called polycyclic aromatic hydrocarbons (PAHs) are found in every nook and cranny of our galaxy. While this is important to astronomers, it has been of little interest to astrobiologists, scientists who search for life beyond Earth. Normal PAHs aren’t really important to biology,” Hudgins said. “However, our work shows the lion’s share of the PAHs in space also carry nitrogen in their structures. That changes everything.”
This is important because:
“Much of the chemistry of life, including DNA, requires organic molecules that contain nitrogen,” said team member Louis Allamandola, an astrochemist at Ames. “Chlorophyll, the substance that enables photosynthesis in plants, is a good example of this class of compounds, called polycyclic aromatic nitrogen heterocycles, or PANHs. Ironically, PANHs are formed in abundance around dying stars. So even in death, the seeds of life are sewn,” Allamandola said.
Looking back over the years it is totally amazing to me how many different types of organic chemicals have been found in outer space. Once upon a time it used to be thought that outer space was barren of organic chemicals and origins of life research focused on chemicals believed to be present on early earth. It seems the picture is changing…
Filed under: Astronomy, Space Science | Tagged: Organic Chemicals | 1 Comment »
Posted on September 7, 2005 by Afarensis, FCD
Deep Impact collision ejected the stuff of life
Millions of kilograms of fine dust particles and water and a “surprisingly high” amount of organic molecules sprayed into space when NASA crashed its Deep Impact spacecraft into Comet 9P/Tempel 1 on 4 July 2005, reveal a trio of new studies.
The observations bolster theories that comets may have seeded Earth with the raw materials for life and suggest they may be sponge-like – rather than hardened – at their cores.
Observers estimate the impact released about 5 million kilograms of water from beneath the comet’s surface and between two and five times as much dust. There was so much dust, in fact, that mission members have not been able to see the impact crater with the high-resolution camera on the mission’s flyby spacecraft, about 500 km away.
But here is the interesting part:
The team estimates the impact blasted away a crater about 100 metres wide and up to 30 m deep. Crucially, organic molecules were among the material ejected. Neither the full range of molecules nor their abundances have been determined yet, but researchers say they have found a surprisingly high amount of methyl cyanide, a molecule seen in large quantities in another comet.
This supports theories that comets may have brought water and the building blocks of life to Earth, and the team hopes to eventually “identify all the species comets brought in abundance to early Earth”, says A’Hearn.
Filed under: Astronomy, Space Science | Tagged: Organic Chemicals, Origin of life | Comments Off on Comets and Organic Molecules
Posted on April 27, 2005 by Afarensis, FCD
From New Scientist Cassini has found complex organic chemicals on Titan.
Some complex organic molecules – such as benzene and diacetylene – had already been picked up on an earlier approach to Titan, but the latest encounter has yielded an even wider range.
It includes nitriles and scores of different hydrocarbons, some with up to seven carbon atoms. And the results suggest that Titan’s upper atmosphere holds even heavier and more complex organics, which are beyond the instrument’s mass range.
Scientists do have some idea about how they are formed, however. Methane and molecular nitrogen are thought to be smashed apart by ultraviolet radiation from the Sun and by high energy particles trapped in Saturn’s magnetic field. That creates highly reactive radicals that can combine to form more complex molecules.
Similar processes might have operated on the Earth a few hundred million years after it formed, generating the raw materials for life. On the other hand, Earth’s organics may have been created in deep space and then delivered by comets.
Filed under: Astronomy, Space Science | Tagged: Organic Chemicals, Origin of life | 2 Comments »