A
couple of weeks ago, we learned about the origin of life on earth both through
watching an educannon video and a video in class. We learned that the earth was
formed 4.5 billion years ago and that the origin of life could be traced
through molecular evidence, geological evidence, and chemistry evidence.
According
geological evidence, life most likely began 3.5 - 3.8 billion years, traceable through
absolute and relative dating. Chemically, Miller and Urey performed an experiment
to simulate the conditions of early earth, adding early atmospheric gases and
an electrical charge equivalent to lightning, forming amino acids. Molecular
evidence shows that the tree of life branched from a universal common ancestor
that most likely had DNA, RNA intermediates, proteins, ATP, a lipid membrane,
and cell division since every other form of life uses these today.
The
most currently accepted idea is that life came from non-life or chemistry in
shallow pools of water with the elements H, O, C, and N. However, the earth
melting repeatedly due to collisions with meteorites would have wiped out any
form of life developing immediately. Therefore, some scientists are suggesting
that some chunks of earth flew into space after collision, containing the newly
formed primitive chemistry, which could have survived the trip into space and
back home through the same meteorite landing back on earth.
This
idea of life coming from earth into space, surviving in space, and coming back
to earth in meteorites blew me away. I was dumb struck to think that life could
survive in space. This lead me to think that if life could survive in space,
could life on earth have originated in space entirely and come to earth only by
chance that a meteorite with life land on earth?
I
researched this topic further and found that scientists from Cornell University
have found that some amino acids and sugars exist inside of meteorites using
the Alma Observatory in Chile (O’Callaghan 2014). Not only that, but they also
discovered the presence of carbon 27,000 light years away, suggesting the
possibility that life came from outer space (O’Callaghan 2014). In addition,
they found hints of the molecule isopropyl cyanide (a complex molecule common
in life-essential molecules) in the form of emitted radio waves from a giant
gas cloud near the center of the Milky Way (O’Callaghan 2014). This means that
the building blocks of life may have originated somewhere else in space and
could have been brought to earth via meteorites. Their research has me
questioning that if life did originate from space (I’m not solidifying that
this is how life rose about on earth) and come to earth in meteorites, what is
to say that these meteorites did not carry life to other planets as well? Could
the same basic organic chemistry that evolved into life as we know it today be
present on other planets?
Work Cited:
O'Callaghan, J. (2014, September 29). Did life on Earth come
from outer space?
Discovery of carbon 27,000 light-years away suggests
building blocks came from
elsewhere in the Milky Way. Retrieved October 29, 2014.
It is a very interesting topic. The origin of Earth has been questioned for such a long time, and this information from Cornell University could possibly bring light to another possible explanation. I think that it would be so interesting if other planets could support life. If meteorites could carry life to our planet, it is not wrong to say that they could possibly carry life to other planets. I found some further evidence to show that life was possibly brought to Earth by meteorites. It also blows my mind that life organic molecules could travel all that way to a planet! In 2011, a meteorite named Sutter’s Mill meteorite fell in California. Researchers believe that most meteors come from asteroids in between Mars and Jupiter. One researcher, Sandra Pizzarello, said that since the “origins of life are utterly unknown, the idea has its merits”(Choi, 2013). At first, I was confused about how scientists could look at the organic molecules. However, Pizzarello said that the organic molecules are able to be extracted with solvents. When the researchers attempted to dissolve the fragments in conditions similar to those of Earth (ex-hydrothermal vents) they found that there were many organic molecules in the meteorite(Choi, 2013). It is funny as at first they assumed that there were many less organic molecules! Yet, continuous research shows that life could arise from the organic molecules within meteorites.
ReplyDeleteThank you for bring this topic up, as I learned that there is a lot more evidence out there to support your original topic!
Choi, C. (2013, September 9). California Meteorite Carried Rare Life Ingredient : DNews. Retrieved November 5, 2014
I was also very intrigued by the video we watched in class about the origin of life on Earth! I love reading different theories, no matter how crazy or far out they seem, because it's so interesting to think about what possibly could have cause the Earth to be what it is today. I remember in the video in class they mentioned the idea that life had already existed on Earth but was wiped out during a mass extinction and organic molecules were released into outer space and eventually made their way back to Earth, creating life again. I think that's so crazy to think that maybe the Earth was inhabited way before we think, and that maybe this is a cycle we are going through. The video also mentioned the theory that a meteor carried amino acids from life on another planet, suggesting that we actually share a common ancestor with organisms living somewhere out there in the universe. Again, this seems outlandish but there is strong evidence that supports it so it is completely possible!
ReplyDeleteI was really curious to see what other theories there are out there regarding how life began on Earth so I read an article discussing 7 different theories of how life began. The first of course was the idea that Earth's atmosphere was plentiful of ammonia, water, hydrogen and methane and that constant lighting was able to create the first building blocks of life (Live Science, 2011). This theory is widely known because of the Urey Miller experiment that tried to mimic this. I thought I would share with you the theory I found the most interesting because it is similar to the theory you discussed in your post. So the theory is that billions of years ago the all of the Earth's oceans were covered in ice which preserved organic molecules that had impacted the Earth's surface through comets (Live Science, 2011). This was the only theory I hadn't heard of all the ones in the article so I thought it was really interesting! The 7 theories in the article I read are actually really cool, so here's the link if you want to check it out: http://www.livescience.com/13363-7-theories-origin-life.html.
Citations
Q, Charles. "7 Theories on the Origin of Life." LiveScience. TechMedia Network, 22 Mar. 2011. Web. 03 Nov. 2014. .