-
-
----------------- 2588 - SOLAR SYSTEM - how did chemistry arrive for life ?
-
- The "Great Divide" is a well-known schism of mountains that divides North America. There is another Great Divide that may have separated the solar system just after the Sun first formed.
-
- The Great Divide phenomenon is a like how the Rocky Mountains divide North America into east and west. For the solar system’s great divide one side has "terrestrial" planet, such as Earth and Mars. They are made up of fundamentally different types of materials than the more distant planets from the Sun such as Jupiter and Saturn.
-
- The theory is that the early solar system was partitioned into at least two regions by a ring-like structure that formed a disk around the young Sun. This disk holds the major implications for the evolution of planets and asteroids, and even the history of life on Earth.
-
- The Great Divide today is a relatively empty stretch of space that sits near Jupiter, just beyond what astronomers call the “asteroid belt“.
-
- Its presence can be detected throughout the solar system. Move sunward from that line, and most planets and asteroids tend to carry relatively low abundances of organic molecules. Go the other direction toward Jupiter and beyond and a different picture emerges: Almost everything in this distant part of the solar system is made up of materials that are rich in carbon.
-
- As you move out from the Sun the chemistry changes. Different minerals and chemical compounds formed depending on changing radiation, temperature, gravity, and a multitude of other differing conditions.
-
- Astronomers first assumed that Jupiter was the giant planet responsible for that grest divide. The thinking went that the planet is so massive that it may have acted as a gravitational barrier, preventing pebbles and dust and different minerals from the outer solar system spiraling toward the sun.
-
- Computer simulations were used to explore Jupiter's role in the evolving solar system. The results found that while Jupiter is big, it was probably never big enough early in its formation to entirely block the flow of rocky material from moving sunward.
-
- Young stellar systems are often surrounded by disks of gas and dust that, in infrared light, look a bit like a tiger's eye. If a similar ring existed in our own solar system billions of years ago it could theoretically be responsible for this Great Divide.
-
- That's because such a ring would create alternating bands of high- and low-pressure gas and dust. Those bands, in turn, might pull the solar system's earliest building blocks into several distinct sinks. One that would have given rise to Jupiter and Saturn, and another Earth and Mars.
-
- That barrier in space likely was not perfect. Some outer solar system material may still have climbed across the divide. And those fugitives could have been important for the evolution of our own world. Those materials that might go to the Earth would be those volatile, carbon-rich material. And that gives you water. That gives you organics."
-
- Water is not the only material that arrived on Earth to bring us life. Then there was phosphorous. Phosphorus, present in our DNA and cell membranes, is an essential element for life as we know it.
-
- Astronomers have now traced the journey of phosphorus from star-forming regions to comets. Their research shows where molecules containing phosphorus form, how this element is carried in comets, and how a particular molecule may have played a crucial role in starting life on our planet.
-
- Life appeared on Earth about 4 billion years ago, but we still do not know the processes that made it possible. The new results show that phosphorus monoxide is a key piece in the origin-of-life puzzle.
-
- A detailed look into the star-forming region astronomers could pinpoint where phosphorus-bearing molecules, like phosphorus monoxide, form. New stars and planetary systems arise in cloud-like regions of gas and dust in between stars, making these interstellar clouds the ideal places to start the search for life's building blocks.
-
- The observations showed that phosphorus-bearing molecules are created as massive stars are formed. Flows of gas from young massive stars open up cavities in interstellar clouds. Molecules containing phosphorus form on the cavity walls, through the combined action of shocks and radiation from the infant star. The astronomers have also shown that phosphorus monoxide is the most abundant phosphorus-bearing molecule in the cavity walls.
-
- If the cavity walls collapse to form a star, particularly a less-massive one like the Sun, phosphorus monoxide can freeze out and get trapped in the icy dust grains that remain around the new star. Even before the star is fully formed, those dust grains come together to form pebbles, rocks and ultimately comets, which become transporters of phosphorus monoxide.
-
- The sighting of phosphorus monoxide on a comet helps astronomers draw a connection between star-forming regions, where the molecule is created, all the way to Earth. Data has revealed a sort of chemical thread during the whole process of star formation, in which phosphorus monoxide plays the dominant role.
-
- Phosphorus is essential for life as we know it. As comets most probably delivered large amounts of organic compounds to the Earth, the phosphorus monoxide found in comets may strengthen the link between comets and life on Earth."
-
- If it weren’t for comets I would not be writing this. And, it were not for astronomy I would not learn about these wondrous miracles.
-
- January 17, 2020 2588
----------------------------------------------------------------------------------------
----- Comments appreciated and Pass it on to whomever is interested. ----
--- Some reviews are at: -------------- http://jdetrick.blogspot.com -----
-- email feedback, corrections, request for copies or Index of all reviews
--- to: ------ jamesdetrick@comcast.net ------ “Jim Detrick” -----------
- https://plus.google.com/u/0/ -- www.facebook.com -- www.twitter.com
--------------------- Friday, January 17, 2020 --------------------
-----------------------------------------------------------------------------------------
No comments:
Post a Comment