- 3040 - EARTH - evolution of the Solar System? - To carry our lineage back further this review is about the geological history of our Solar System. We do not have many rocks to work with, a few meteorites, so the history lesson takes more imagination. By studying the rocks, gas , and stars within 6,500 lightyears of Earth with detailed observations.
--------------- 3040 - EARTH - evolution of the Solar System?
- Geological history of our Solar System. The results of astronomy’s 6,500 lightyear survey of the neighborhood.
-
--------------The Sun formed in a nebula of 1,000 to 10,000 other stars. An example can be seen today in the Orion Nebula ( M42 ) in the Constellation Orion the Warrior.
-
------------- One very large star, 25 Solar Mass, exploded in a supernova within the nebula. It was only 1 lightyear from our cluster of dense gas and clouds that became a nursery for stars to be born. An example today is the Star Cluster Pleiades ( M45 ).
-
- The cloud of dust and gas has a temperature of 10 to 20 Kelvin. That is cool, only 18 to 26 F above Absolute Zero temperature. The surrounding interstellar medium has a density of one atom per cubic centimeter but an average temperature of 100 Kelvin. Atoms and particles in the colder cloud pack together to densities of million of atoms per cubic centimeter.
-
- Atoms began to join together to form molecules. The molecular cloud was dozens of lightyears across. Gravity begins to have its effects. The cloud begins contracting as it is brought together by the shockwave of the close exploding supernova.
-
- The cloud does not contract evenly. It fragments into smaller pieces. Over a million years the cloud separates into individual clumps. Each clump is likely to become an individual star looking like the Star Cluster Pleiades.
-
- Our Sun evolved without a binary star. Only 30% of the stars form without a binary. Our star has a higher percentage of the “elements heavier that helium“. Astronomers call all these elements “metals“.
-
- Of the 50 closest stars only Sirius and Procyon are more massive than our Sun. Using the wider survey only 12% of the stars are more massive than our Sun. Only 25% of the stars have a higher percentage of metals.
-
- Our Sun has a solar system with 4 giant gas planets and 4 smaller rocky planets. astronomers have discovered over 4,000 planets around other stars, but, they have to learned enough to define how common our type of solar system is.
-
- Some put the probability at 0.2%. However, this small probability would still mean that amongst the 200 billion stars in the Milky Way Galaxy there would be 400 million Solar Systems like ours.
-
- Evidence for the supernova blast that started the evolution of our Sun and its Solar System comes form meteorites (geology), dating the radioactive isotopes of Nickel-6 and iron-60. Iron-60 has a half-life of 1.5 million years. Therefore, these meteorites had to be delivered form a nearby source during the Solar System’s earliest days.
-
- It takes a massive star to have the gravity and explosive power to create the element iron-60. Other radioactive elements, aluminum-26 and calcium-41 were also found. All this implies that the supernova star was a massive 25 Solar Mass. Such a massive star has a lifetime of 7.5 million years.
-
- The distance away from the supernova could not be too close or too far away. It needed to occur about 1 lightyear away.
-
- A few million years later our Sun began fusing hydrogen and helium. the accretion disk surrounding the Sun began to form planets. This all started 4,600 million years ago.
-
- the Earth’s evolution starts with the planet’s formation 4,600 “million years ago” (MYA) to get to the present day. All learned by studying rocks and minerals. Let’s start with 4,560 MYA and goes to 1,500 MY from now. All learned by studying the atmospheric gases in rocks and ice, and plant and animal fossil records.
-
- What will the Earth by like in the distant future?
-
- The Sun increases luminosity by 10% every 1,000 million years.
-
- Plate tectonics will have ground to a halt just 500 million years from now.
-
- The Earth will grow warmer as the Sun increases in brightness. As temperatures rise more and more water will evaporate into the atmosphere. Clouds will become so thick they will block the infrared light from escaping the planet. The oceans will evaporate away some 1,500 million years from now.
-
- Solar ultraviolet radiation will split the water molecules in the atmosphere allowing the hydrogen to escape. The heavier atmosphere will become corrosive with carbon dioxide and sulfuric acid. To learn what the Earth will be like study the planet Venus. It is 25 million miles closer to the Sun and is 1,000 million years ahead of us.
-
- Looking backwards in time, “million years ago” (MYA):
-
- 100 MYA: The first flowering plants occurred.
-
- 300 MYA: Thick layers of dead plant material built up in the wetlands creating coal, drawing down the carbon dioxide levels, and leading to the ice age 300 MYA
-
- Over 10’s of millions of years plants spread across the land and grew taller.
-
- 380 MYA: Forests covered large areas and pumped more oxygen into the air, up to 34% concentration.
- 450 MYA: The atmosphere was nitrogen, oxygen, and argon. But, the concentration levels of oxygen was varying:
-
------------------------------------ 450 MYA ---------- 12% concentration level
-
----------------------------------- 300 MYA ---------- 34%
-
----------------------------------- 250 MYA ----------- 15%
-
----------------------------------- 100 MYA ---------- 30%
-
----------------------------------- Today ---------- 21%
-
- The origin of animal life occurred. reptiles , amphibians, dinosaurs and mammals coexisted. Mass extinctions occurred devastating life on the planet several times.
-
------------------------------------- 450 MYA extinctions
-
------------------------------------- 375 MYA extinctions
-
----------------------------------- 251 MYA extinctions
-
----------------------------------- 205 MYA extinctions
-
----------------------------------- 65 MYA extinctions
-
- 450 MYA: Plate tectonics slowly pushes more land above sea level.
-
- 543 MYA: Rapid diversification of animal life began. The first fishes were 500 MYA. Fossils of animals have been dated back to 585 MYA. Fungi and simple plants spread on to the land.
-
- 600MYA: The atmosphere was nitrogen, oxygen water vapor and methane. The Sun is 90% its present luminosity.
-
- 600 MYA and 800 MYA and 2,400 MYA the Earth froze over almost completely. Called “ Snowball Earth” occurring soon after the rise in oxygen levels.
-
- 2,450 MYA Oxygen first became an important constituent of the atmosphere. The luminosity of the Sun was 85% what we experience today. Positive feedback occurred when oxygen level produced ozone (O3) layers in the upper atmosphere blocking the Sun’s ultraviolet light. This in turn slowed the UV reactions with methane that limited the concentration of oxygen
-
- More oxygen produced more ozone slowing oxygen destruction even more. Oxygen tolerant microbes evolved in this oxygen rich atmosphere paving the way for the evolution of plants and animals. Modern algae evolved during this period.
-
- 2,700 MYA: The first organisms were single cells that ingested compounds dissolved in seawater. Photosynthesis evolved.
-
- 3,800 MYA: The oldest evidence of life is from the ratio of carbon isotopes in sedimentary rock. Metabolism of living cells prefers carbon-12 isotope compared with carbon-13 isotope.
-
- 3,900 MYA: Saturn and Jupiter hit a 2 to 1 orbiting resonance that shifted planetary positions throughout the Solar System. This disrupted orbiting comets and asteroids that rained down on the inner planets.
-
- 4,200 MYA: The first oceans formed.
-
- 4,500 MYA: A giant impact formed the Moon and melted the young planets. Metals sank to the core and a froth of molten rock floated to become the mantle. There was a thick steam atmosphere over the molten rock that lasted for 300 million years. The oldest rocks dated so far were formed 4,000 MYA.
-
- Use your binoculars to look at the surface of the Moon. The Great Bombardment is still in evidence there because the Moon has no erosion or tectonic activity.
-
- 4,560 MYA: Earth and the other planets formed in the accretion disk orbiting the Sun, the star in the neighborhood. The Sun was only 70% that of today’s luminosity. The atmosphere on Earth was nitrogen, carbon monoxide, and water vapor.
-
- 4,600 MYA: The Orion Nebula in the Star Constellation Orion the Hunter gives you a picture back in time. What you see is what it was like 1,400 years ago. The Orion Nebula is 1,400 lightyears away.
-
February 10, 2021 EARTH’S evolution 1507 1510 3040
----------------------------------------------------------------------------------------
----- 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” -----------
--------------------- --- Wednesday, February 10, 2021 ---------------------------
No comments:
Post a Comment