Below are some questions you will should be able to answer about how our solar system was formed after reading this page. Further down in the page, there's also a fun 'kitchen table' experiment you can do at home to model the formation of the solar system.
Questions
- Where did the dust and gas that formed our solar system come from?
- Explain what force causes 2 hydrogen atoms "fuse" in the sun? What atom results from this fusion? What is released?
- Looking at the periodic table, write the abbreviation of the heaviest element created by a dying low mass star. Write the abbreviation of the heaviest element created by two neutron stars colliding.
- Watch the video, A Perfect Planet....the Formation of the Earth. It describes a "large planetary object about the size of Mars" colliding with early Earth. What happened after the collision?
- Thinking about our pepper experiment, explain in a stepwise fashion how it helped model how our solar system was formed? [Hint: Use your notes from How the Solar System was formed to help compare the steps with our model.]
ALSO, in this experiment, stirring created a force called centrifugal force. What is the actual force that helped create our solar system? - If the sun is so massive (with enormous gravitational force), why doesn't the earth crash into it?
How our Sun & Planets were Formed
Our sun is a relatively young star. It formed only 4.6 billion years ago, which is about 9 billion years after the Big Bang. It's an "average" star - not too big, not too little. Because stars "are born, live & die", it's nice to have a star that is just right. It is the size that will allow it to "live" for about 8 billion years. Right now, it's about halfway through it's life cycle.
But we should also be glad that there are giant stars (called red giants), whose lifespans can be very short. When they "die" or explode into a supernova, the tremendous force of that explosion is strong enough to overcome the forces that prevent protons from fusing together. This explosion then forces smaller atoms to fuse together, creating all the heavier elements that make up our earth - even us! Indeed, we ourselves are made of the stardust from a supernova explosion of a giant star. So, how is a star "born?" |
To create a star, you need matter and gravity.....
What is gravitational force? Gravity is a force of attraction between any two objects. The greater the mass of the object, the greater the gravitational attraction. But that attraction becomes weaker with distance - the further apart they are, the less they are attracted.
How is a star formed? A star forms when gravity pulls together dust and gases in a nebula (which resulted from a supernova - see below). As the mass gets larger and larger, its gravitational force grows larger and pulls inward towards the core (or center) of the mass. So, at it's center, the pressure is extreme and temperatures become extreme as well. Remember that stars are mostly made of the lightest element, hydrogen, which has only one proton in its nucleus. Now, protons have positive charges that repel each other very strongly (except when they are already in the nucleus of an atom). Think of a magnet as a model. When you place the like ends of a magnet together - such as north and north - they repel each other. When you place two like charges - such as positive and positive - together, they also repel each other. How, then, can protons fuse together? |
As the mass of the growing start gets greater and greater, its gravitational force increases so that the core of the newly forming sun (called a 'protosun') is under extreme pressure. The temperature at the core increases with that increasing pressure. The pressure is so great that the proton of one hydrogen will overcome that repulsion and fuse together with the proton of another hydrogen to make a new element, helium. This "fusion reaction" releases tremendous amounts of energy in the form of radiation (light) and heat. When this happens, the protostar has "ignited," and becomes a star. Our own sun, which is a medium-sized star, creates SO much energy that it would be like releasing 6 trillion atomic bombs per second! This fusion reaction is what provides the light and heat that supports life on Earth. Make sure that you do not confuse this with a star that explodes (supernova, see below).
Where did the elements come from?
A Periodic Table: Remember that elements are the building block of all matter. An element is defined by the number of protons in its nucleus.The periodic table is the list of all the elements known to man. It reads from left to right, like a sentence. As you move to the right, and then to the next row, each element has one more proton than the previous element.
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How elements were made
The periodic table above tells us how scientists think that the elements were made or synthesized (called neucleosynthesis). There is a color key at the top. Note that hydrogen, most of the helium and some lithium was created during the Big Bang (blue). To this day, hydrogen and helium alone make up 98% of the elements in the universe!
Remember that protons, having the same positive charge, repel each other. So, tremendous forces are needed to overcome this repulsion and allow atoms to fuse or join together (called fusion.) Sometimes the force is extreme gravitational force, such as what occurs inside the core of stars as atoms are pushed together (green). We discussed this above in "How is a Star Formed. Sometimes it's explosive collisional force that results from large stars exploding or going supernova (yellow & grey).(see below) And sometimes it's collisional force as when two extremely dense neutron stars collide (purple). Interestingly, collisional force can also cause protons to split apart (called fission), creating smaller elements. This happens when cosmic rays collide with atoms in space (pink). Lastly, humans have made some large elements using explosive collisional force, but there are too many protons in the nucleus of the atom for it to remain stable (brown). So it falls apart (fission) into smaller elements.
Remember that protons, having the same positive charge, repel each other. So, tremendous forces are needed to overcome this repulsion and allow atoms to fuse or join together (called fusion.) Sometimes the force is extreme gravitational force, such as what occurs inside the core of stars as atoms are pushed together (green). We discussed this above in "How is a Star Formed. Sometimes it's explosive collisional force that results from large stars exploding or going supernova (yellow & grey).(see below) And sometimes it's collisional force as when two extremely dense neutron stars collide (purple). Interestingly, collisional force can also cause protons to split apart (called fission), creating smaller elements. This happens when cosmic rays collide with atoms in space (pink). Lastly, humans have made some large elements using explosive collisional force, but there are too many protons in the nucleus of the atom for it to remain stable (brown). So it falls apart (fission) into smaller elements.
A supernova created the heavier elements that now make up our solar system
Our solar system and all of the elements that make up the sun and planets was created from the debris of a massive star that exploded. The debris that exploded out into space created a nebula, which had all the elements needed to make a new star (our sun) and our planets. This is how a supernova happens...
Stars much more massive than our sun have such extreme gravitational force that within them fusion reactions make heavier and heavier elements (with more and more protons) - all the way up to Iron (Fe), which has 26 protons. Once most of a super-massive star's original hydrogen has fused to ultimately form iron in its core, that star will eventually explode into a supernova. This explosion sends out the "guts" of the star with such explosive force that the colliding atoms fuse to make even larger elements such as gold (Au-79), lead (Pb-82), uranium (U-92) and even heavier elements. Look again at the color-coded (yellow and grey) periodic table to see which elements could be created by atoms that collide together in a supernova explosion.
Our solar system and all of the elements that make up the sun and planets was created from the debris of a massive star that exploded. The debris that exploded out into space created a nebula, which had all the elements needed to make a new star (our sun) and our planets. This is how a supernova happens...
Stars much more massive than our sun have such extreme gravitational force that within them fusion reactions make heavier and heavier elements (with more and more protons) - all the way up to Iron (Fe), which has 26 protons. Once most of a super-massive star's original hydrogen has fused to ultimately form iron in its core, that star will eventually explode into a supernova. This explosion sends out the "guts" of the star with such explosive force that the colliding atoms fuse to make even larger elements such as gold (Au-79), lead (Pb-82), uranium (U-92) and even heavier elements. Look again at the color-coded (yellow and grey) periodic table to see which elements could be created by atoms that collide together in a supernova explosion.
Above is a short video documenting a star that went supernova in the year 1650.
Below is a wonderful view of an exploding star taken January 2014. It's the best known image of a supernova that shows the formation of the dust during the earliest stages after the explosion. The image on the left is the actual photo, while the image on the right is an artist's illustration of that photo.
Telescopes have been looking at another red giant star for several years, and below you can see the images of that red giant after it sent off an explosion (although the whole star did not explode or go supernova) and created light "flashes". You can see the dust from previous explosions expanding away from the red giant over time. This red giant will eventually collapse as more of its atoms fuse into iron and explode into a supernova...but hasn't yet.
As our star formed, so did our planets....
Newly forming stars (or protostars) are created from clouds of hydrogen gas and dust made of other elements. Our own sun, created 9 billion years after the Big Bang, is made up of the remains of a much larger star that exploded (or went supernova). When a part of the dust cloud becomes large enough, it begins to collapse under its own gravity. As this collapsing cloud, called a solar nebula, becomes more tightly packed together, the gas begins to rotate and flatten out, and takes the form of a disk—much like forming a flat pizza out of dough—, called a protoplanetary disk.
The gases in this disk start to gather together ( like our pepper demonstration) to form the beginnings of small young planets, called planetesimals while the hydrogen particles gather in the center to form the protostar. As the planetesimals orbit the newly forming protostar, they gather more gas and dust and other small planetesimals in their path around the protostar by gravitational attraction. The larger the planetesimals and protostar become, the greater their gravitational attraction, the more they 'sweep up' the debris in their path. When the protosun becomes large enough and hot enough from the gravitational pressure, the hydrogen atoms in its core (where the pressure is greatest) begin fusing together. This fusion reaction releasing tremendous amounts of energy, thus igniting into a star. Here is a website that further explains this process |
The Story of our solar system
Please watch these videos , which explain how a star is formed within a nebula, and how planets such as Earth then form around the star.
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III. How the Solar System was Formed
"Kitchen Table" Model of the Formation of the Solar SystemOn the right you can try making a model of the formation of our solar system using pepper and a bowl of water. Models are representations of events or phenomenon that help us understand that phenomenon. Think of a world globe. It's a model of our earth. It helps us see the positions of the oceans and the continents more easily.
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IV. Our Solar System
If the solar system were drawn to scale, you would not be able to picture the planets as close as they are in this image. To get a better idea of the true scale, click on the picture to go to an interactive that helps demonstrate this.
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A. Order of Planets from the Sun
1. Mercury 2. Venus 3. Earth 4. Mars a. Asteroid belt i. Ceres (dwarf planet) 5. Jupiter 6. Saturn 7. Uranus 8. Neptune a. Pluto (considered a dwarf planet) b. Kuiper belt 9. Planet 9? (strong evidence discovered in 2016 suggests another planet 60 billion miles from the sun that takes 10-20,000 Earth years to revolve around the sun) a. Oort cloud B. Age of the sun and earth 1. Our sun was formed 4.60 billion years ago 2. Earth was formed about 4.56 billion years ago Scale of the Solar System
On the left is a video where they used a desert in Nevada to show the solar system to scale. There is another one towards the end of this webpage where they use a drone and also show where Planet 9 is. Both are interesting videos. You should watch one of the two videos, but you may watch both.
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Why do the planets orbit the sun, instead of crash into it?
We'll use a tetherball as a model. Imagine that the pole is the sun and the ball is a planet. The rope is the "gravity" keeping the ball in orbit around the sun. Remember that when the solar system was formed from the protoplanetary disc, the gases and dust was spinning - it had motion! As long as the tetherball or planet is in motion, it will continue moving around the pole or the sun. Imagine if the tetherball was not in motion - it would simply fall back to the pole. If our Earth was not in motion, it, too, would fall back into the Sun.
As the tetherball moves around the pole, it has to have a certain speed to stay away from the pole. If the speed decreases, the ball moves closer to the pole. As the speed increases, the tetherball moves further away from the pole. And if you increase the speed past a certain point, the tetherball will break free from the pole. This is how we launch rockets into space. We have to go a certain speed to break free from the Earth's gravitational force. |
Because of the Earth's distance from the Sun, it experiences less gravitational force than planets closer to the sun (remember that the gravitational force decreases with increased distance between the objects), so it requires a lower speed than the closer planets do to remain in orbit. The closer planets stay in orbit around the Sun because they are moving at a faster speed. Being closer to the Sun, they are more gravitationally attracted to it and must move at a faster speed than more distant planets to keep from falling into the sun.
So, the Earth doesn't crash into the Sun because it is in motion at the right speed for the distance it is from the sun. What if the Sun suddenly disappeared and it no longer exerted gravitational force on Earth? Then Earth would simply move outward in a straight line, much as if the tetherball rope suddenly snapped. |
Ceres - the dwarf planet
The image of Ceres on the right shows 2 very interesting and mysterious bright spots reflecting sunlight. Scientists still haven't figured out what is causing this highly reflective spot. There is also a 4 mile high, pyramid-shaped mountain (seen below) that has the scientists puzzling. You can see that one side is also very reflective. The video above discusses these interesting phenomenon.
Comparing the sizes of the dwarf planets
On the right you can see a comparison of the size of the moon, Pluto and Ceres to Texas.
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Pluto isn't the only dwarf planet in our solar system. While Pluto is out past Neptune near the outlying Kuiper belt, Ceres is a dwarf planet that resides in the asteroid belt between Jupiter and Mars. NASA sent the DAWN spacecraft in 2006 to orbit and photograph Ceres. Ceres is the largest object in the asteroid belt and about the same size as Texas (see below). It is a mere 257 million miles from Earth (compared to the 93 million miles Earth is from the sun, and to Pluto, which is 2.7-4.7 billion miles away, depending on where we are in our orbits around the sun). It took 9 years for the Dawn spacecraft to arrive!
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Planet 9?
On the right is the predicted orbit of the newly predicted Planet 9 in relation to the orbits of the dwarf planets Sedna, VP113 and Pluto. It is thought to have about 10 times the mass of the Earth. There is evidence of Planet 9 out past the Kuiper belt, however, it has yet to be seen.
Below is a video that shows the relative distances of the planets from the sun - including Planet 9. There is a small ad towards the end, but then he shows you how far Planet 9 is. |