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  Night Sky
 

PLEASE Turn off or shield your outside lights downward 
Left unshielded, they ruin the starry night sky and annoy your neighbors. Light glare going upward doesn’t help deter crime. Keep the night sky available for everyone.

December Night Sky

~Charlie Christmann

There is a hypothesis floating among the astrobiologists, called “panspermia,” which says that life on Earth actually began elsewhere. In one version of this hypothesis, comets and asteroids crashed into the young Earth bringing all the essential materials needed to build biology. A second version believes that actual bacterial life hitchhiked on these asteroids and meteorites and gained a foothold here.

For many years, science did not believe that organic molecules could form in the cold vacuum of space. The distance between the chemical elements floating in space were too far apart; and, even if they did get close enough, it was much too cold for them to react and form complex molecules. Then, even if that actually happened, ultraviolet radiation from the star would break up any that actually formed. However, the first version of this hypothesis has some legs. Astronomers have detected several of the building blocks of life in space.

It turns out that organic molecules are everywhere: stellar nebulae, interstellar dust, planetary disks, asteroids, comets, and even meteorites found here on Earth. Complex organics fill the space between the planets, the stars, and the galaxies.

Researchers at the University of Hong Kong observed stars at different evolutionary phases and found that they are able to produce complex organic compounds and eject them into space, filling the regions between stars. The compounds are so complex that their chemical structures resemble the makeup of coal and petroleum, the study’s lead author Sun Kwok of the University of Hong Kong, said [Nature, Oct 26, 2011].

It seems stars and the radiation that was thought to split organic molecules apart were the very mechanism that provided the energy to create them. Stars everywhere were creating organics and spewing them into interstellar and even intergalactic space.

In the early history of our solar system, there was a heavy bombardment of the planets with meteors and comets. Since our sun and planets were likely formed after some long dead star exploded in a nova, the gas cloud that gave rise to our system likely had organic material already embedded in its dust. This dust went on to create the sun, planets, asteroids, and comets. As they crashed into the young Earth, we were seeded with the ingredients of life.

The second panspermia hypothesis says microscopic life formed elsewhere and hitched a ride on comets and meteors to Earth. We know that meteorites have been found that are believed to be from Mars, blasted off the planet by a large impact. These chinks of Mars floated around the solar system until intersecting Earth’s orbit and crashing to the ground.

The most intriguing, and still very controversial, case is that of the meteorite called ALH84001. Discovered in the Antarctic, it was found to have structures that could possibly have been created by fossilized bacteria. This space rock was linked to Mars. Others say the structures could have a geologic origin. Could life have evolved on Mars and then been thrown toward Earth? Are we actually Martians?

Now, there is the real possibility that life on Earth could have interstellar origins. October 19, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) telescope in Hawaii picked up the first interstellar asteroid, named 1I/2017 U1. It has been named “`Oumuamua” meaning “first” in the Hawaiian language. Dr. Karen Meech of the Institute for Astronomy in Hawaii, said, “`Oumuamua is unlike any other asteroid we’ve ever seen.”

Further studies by Dr. Meech and her team, using the Very Large Telescope in Chile, showed this unusual visitor had already rounded the sun in September of 2017 and was on a hyperbolic trajectory, meaning it was only visiting our solar system and was already speeding back into interstellar space. Those observations, according to a European Space Agency press release, said, “This unusually large variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape. We also found that it has a dark red color, similar to objects in the outer Solar System, and confirmed that it is completely inert, without the faintest hint of dust around it.”

The report also said the asteroid is believed to be dense and rocky with a high metal content and little in the way of water ice. Its dark and reddened surface is also an indication of tholins, which are the result of organic molecules (like methane) being irradiated by cosmic rays for millions of years.

Projecting backwards, `Oumuamua came from the direction of Vega and had been traveling for over 300,000 years. There is a chance that Vega was not its origin, and the space rock may have been wandering the Milky Way for millions of years.

While this is the first extra solar visitor to be discovered, telescopes are now advanced enough to make findings more likely. On average, one extrasolar visitor is expected to pass the sun each year.


 
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