Our Solar System

I periodically collect postings about similar subject matter into compound postings. I am planning some more upcoming consolidations.

This compound posting is about insights and observations of the Solar System that I have never seen before. There are some links throughout to other compound postings. This posting is not the same thing as another posting, "The Configuration Of The Solar System Made Really Simple", which is about the origin of the Solar System, although it does have references and links to it.

TABLE OF CONTENTS

1) THE AVERAGE DISTANCE OF A PLANET FROM THE SUN

2) THE GAPS IN SATURN'S RINGS

3) THE SOLSTICE GAP

4) THE WONDERFUL WORLD OF LAGRANGIAN POINTS

5) WHY THERE ARE METEOR SHOWERS

6) THE WANNABE STAR OF THE SOLAR SYSTEM

7) LIGHT FROM PLANETS AND STARS

8) CONCLUDING THE SEARCH FOR THE NINTH PLANET

OUR SOLAR SYSTEM

1) THE AVERAGE DISTANCE OF A PLANET FROM THE SUN

Here is something relatively simple that I cannot see has ever been pointed out.

We know that planets revolve around the sun in ellipses, rather than circles. While a circle has one focal point, it's center, an ellipse has two, with the sun at one of the focal points. This means that the distance between the planet and the sun varies. The point in the orbit at which the planet is closest to the sun is called perihelion, and the furthest point is aphelion.

The planet moves in it's orbit fastest when it is closer to the sun, and more slowly when it is further away. One of Kepler's Laws of Planetary Motion describes it mathematically as "A line between the planet and the sun will sweep over equal areas of space in equal periods of time".

In school we learn the distances of the planets from the sun. At perihelion the earth is 91 million miles from the sun and at aphelion 95 million miles. So the distance that we learn of the earth from the sun is the average distance of 93 million miles.

Except that this is not really correct.

Sorry but when I was 15 years old neighboring Canada converted to the Metric System, and at that point I learned the Metric System as well. But the things I learned before that, including the distances of the planets from the sun, I remember in miles. You do not need a conversion of units to understand this.

It is true that the average distance of the earth's orbit from the sun is 93 million miles. But that cannot really be considered as a satisfactory answer. The earth moves fastest through it's orbit when it is closest to the sun and slowest when it is furthest from the sun. This means that the earth spends more time further from the sun and less time closer.

We can say that the average distance of the earth's orbit from the sun is 93 million miles but that is not true if we measured the distance from the earth to the sun at regular intervals over the course of the year and took an average, simply because the earth spends more time further than the average than closer.

If we measured the distance from the earth to the sun every day over the course of the year, and took an average, we would get a figure higher than the 93 million miles. This is because, while the earth rotates at a constant rate it doesn't revolve around the sun at a constant rate. It spends more time further from the sun because it is moving through it's orbit more slowly than when it is closer to the sun.

Suppose that we wanted to measure the average depth of an area of water. If we simply measured the greatest depth and the shallowest depth, and averaged the two, it would in no way give a satisfactory answer. But that is what we do when we say that the average distance from the sun is 93 million miles. To get a satisfactory answer it would be necessary to take depth measurements at regular intervals and then average them together. A greater number of measurements would give greater accuracy.

My reasoning is that, to find the true day-by-day average distance between the earth and the sun we have to use squares. This shouldn't come as a surprise because it is the Inverse Square Law that describes space so well.

We take the distance at perihelion and the distance at aphelion and square both of them. Then we average them and our answer is the square root of the average.

That gives us an answer of just over 94 million miles as the average distance between the earth and the sun if distance measurements are taken at regular intervals throughout the year, such as every day.

This is yet another reason why I am such an admirer of the Inverse Square Law, and of how useful it is. This posting has been added to the compound posting, "A Celebration Of The Inverse Square Law". If you are interested in science and have time to read here is a link to it:

www.markmeeksideas.blogspot.com/2015/08/a-celebration-of-inverse-square-law.html?m=0

2) THE GAPS IN SATURN'S RINGS

There was a lot of recent attention to the conjunction of Jupiter and Saturn in the sky. The two planets were not really close together, it was just a line-of-sight effect as seen from earth. Saturn is about as far from Jupiter as Jupiter is from earth.

Saturn is the planet that is known for it's spectacular ring system. All of the outer planets actually have rings around them, but those of Jupiter, Uranus and, Neptune are faint. Saturn's rings are not visible from earth with the unaided eye, but are easily visible in a small telescope.

The current Wikipedia article on "Saturn's Rings" give the reason for the gaps in Saturn's rings, other than "gravitational resonance" with Saturn's moon's, as "unexplained".

https://en.wikipedia.org/wiki/Rings_of_Saturn#/media/File:Saturn_and_its_3_moons.jpg

The gaps in Saturn's rings are actually simple to explain if we use the concept of "The Effective Center Of Gravity", June 2009, on the Physics And Astronomy blog.

Without thinking further we might presume that the "center of mass" and the "center of gravity" of a planet are the same. But they aren't.

The "center of mass" of a planet is constant. It is the point from where the planet's concentration of mass is equal in all directions. We should expect that the center of mass of the planet will be just about exactly the same as it's geometric center.

But the "center of gravity" of the planet is relative, and not constant. According to the Inverse Square Law, the force of gravity is inversely proportional to the square of the distance. In other words, an object at three times the distance will exert 1 / 9 of the gravitational force.

The reason that the center of gravity is relative is that, if we are at a finite distance from a planet, the close half of the planet will have a greater gravitational effect on us than the far half of the planet. This means that the center of gravity would be closer to us than the center of mass. It is only if the planet were infinitesimal in scale, or if we were an infinite distance from the planet, that the center of gravity would be the same as the center of mass.

If we were in a spacecraft, orbiting a planet at a finite distance from the planet, the planet's center of mass would remain constant but the center of gravity would be continuously changing. The center of gravity of the planet would follow our orbit, within the planet, and always closer to us than the center of mass.

It is very unlikely that a planet will be of uniform density throughout. Almost certainly the innermost parts of the planet will be the most dense. The earth, for example, consists of a heavy iron core, above which is the mantle which consists of dense rock but not as dense as the core. Above the mantle is the less-dense crust.

The closer the spacecraft, or observation point, is to the planet, the closer the effective center of gravity is to the surface of the planet, meaning the furthest from the center of the planet. This is simply because the closer we are to the planet the greater the gravitational effect of the close half of the planet, relative to the far half.

Now, back to Saturn's rings. The rings are made mostly of particles of ice. The particles of ice closest to the planet have their real center of gravity in the least-dense outermost part of the planet. But those particles of ice in orbit at a somewhat higher altitude have their real center of gravity in the denser layer beneath that.

The effect of this is as if the particle at the higher altitude is in orbit around a more dense planet. An orbit around a more dense planet would mean that an object in orbit, at the same altitude around the heavier planet, would have a higher orbital energy. 

In orbit around the same planet, a higher altitude means a higher orbital energy. The orbital energy is governed by the same Inverse Square Law that governs gravity. If there is an object in orbit, and we give it 3x the orbital energy, it would then orbit at 9x the altitude, but would move at only 1 / 3 the speed.

So if one of the particles of ice composing Saturn's rings is in orbit, with it's effective center of gravity in a less-dense outer part of the planet, and a particle in a little bit higher orbit has it's effective center of gravity lower than that, in a more-dense inner part of the planet, the higher particle will have to have more orbital energy, than that which would be proportional to altitude, if the planet were of uniform density.

Since orbital energy is proportional to altitude, with a higher orbit having a higher orbital energy, this means that the particle in higher orbit, with it's real center of gravity in the lower and denser part of the planet, will have to gain more altitude to reflect it's higher orbital energy because it is, in effect, in orbit around a more-dense planet.

This is why there are gaps in Saturn's rings. The gaps are a reflection of the layers of material composing the planet, with the denser layers deeper inside the planet making necessary a higher orbital energy for the particles of ice with their effective centers of gravity within those denser layers. Since a higher orbital energy means a higher orbital altitude, this creates the gaps in the rings that reflect the layers of different density within the planet.

3) THE SOLSTICE GAP

Here is something that I have never seen explained.

The solstice is when either the northern or southern hemisphere is tilted at it's maximum angle away from the sun, while the opposite hemisphere is tilted at the maximum hemisphere toward the sun. But the two hemispheres are not equal. The vast majority of the world's land is in the northern hemisphere, and this means that the northern hemisphere must be heavier than the southern hemisphere.

Like the other planets, the earth's orbit is elliptical. That means that it is closest to the sun on one side of it's orbit, and furthest from the sun on the opposite side. In seeking the maximum mechanical balance, this means that the heavier northern hemisphere should point away from the sun, which would give it winter, when the earth is at it's closest to the sun.

This is indeed what happens and the earth is at it's closest to the sun during the northern hemisphere winter.

But here is what I have never seen explained. The solstice and the point of closest or furthest distance from the sun do not match up exactly, as it would seem that they should. There is a gap of about two weeks. The northern hemisphere winter solstice is around December 21, but the point of closest approach to the sun is on January 4. Why would this be?

My explanation is that the rotation of the earth is constant throughout the year, a day is always 24 hours. But the earth moves faster through it's orbit when it is closer to the sun. That means that, while it is always half a year between the solstices, there are fewer days during the half of the earth's orbit when it is closer to the sun than in the half of the orbit when it is furthest from the sun.

Why does this show up as the two week gap? Let's stop and think. We know that the distance at which the earth is closest to the sun is about 4% less than the distance at which it is furthest from the sun. What do you notice about two weeks? There are 52 weeks in a year and the two weeks are about 4% of a year.

I have never seen this explained before.

Let's refer to this approximately two week difference between the solstices and the corresponding apogee or perigee as "The Solstice Gap.

4) THE WONDERFUL WORLD OF LAGRANGIAN POINTS

The James Webb Space Telescope is named for the administrator of NASA during the Apollo Missions that landed astronauts on the moon. This telescope is the successor to the Hubble Space Telescope, which has been a fantastic success that has far exceeded all expectations.

I consider these space telescopes as the culmination of the Space Age and really more important than actually putting astronauts on the moon. The main long-term benefit of the moon landings was the many technology spin-offs, from super-strong glass to powdered orange juice. The landings didn't teach us that much about the moon that wasn't already known. 

The Cold War was a vital part of the Apollo Missions. The space probes that have been sent to photograph the planets are probably more important with regard to our Solar System but the space telescopes are more important to our learning about the universe overall. 

The great advantage of putting a telescope in space is simply that it is above the earth's atmosphere. The best place to put a telescope on earth is on a mountain in a desert, so that it is above at least some of the earth's atmosphere and water vapor. But nothing is as good as having the telescope above the atmosphere altogether.

Aside from the James Webb Space Telescope being much more powerful than the Hubble Telescope the main difference between the two will be their location in space. The Hubble Telescope is in orbit around earth, at an altitude of about 500 km. 

The James Webb Telescope, in contrast, is positioned much further out in space, about a million miles or 1.6 million km away. The James Webb Telescope is in orbit around the sun, rather than the earth, but is in a very special place, called a Lagrangian Point, that will keep it in the same position relative to the earth.

Being in orbit around the sun, instead of the earth, makes it possible to keep one side of the James Webb Telescope at the required very low temperatures. There will generally be a much better view from where the James Webb Telescope will be located, because the far side will always face away from the sun. 

The great disadvantage of where the James Webb Telescope will be located, as opposed to the Hubble, is that, since it is so much further away, repair missions will not be possible if something goes wrong. In the early days of the Hubble Telescope several such missions were necessary. On the James Webb Telescope everything has got to work right the first time.

There is nothing really complicated about Lagrangian Points. When one astronomical object is in orbit around another, such as the earth around the sun or the moon around the earth, five Lagrangian Points are produced. These points are labeled L1 to L5 and are the points where there is some kind of gravitational balance between the two astronomical objects.

Because the smaller astronomical object will be in orbit around the larger one their Lagrangian Points will be continuously moving. The following link is so that you can see the Lagrangian Points of the earth moving around the sun:

https://en.m.wikipedia.org/wiki/Lagrange_point#/media/File%3ALagrange_points_simple.svg

Only at the first two Lagrangian Points is the gravity of the earth and the sun actually equal. If we move toward the sun we reach a point where the gravity of the two are equally balanced, that is L1. If we move in the opposite direction, away from the sun, we reach another point where the gravity of the two is equally balanced, that is L2.

Gravity operates by the Inverse Square Law, an object at three times the distance will exert only one-ninth of the gravitational force. Gravitational force is proportional to mass. The sun is so much more massive than the earth that the gravity of the two balances at about 1% of the distance to the sun.

What is so interesting about L1 and L2 is that an object in either of these positions will orbit the sun at the same rate as the earth, even though it is closer to or further from the sun than the earth. The James Webb Telescope is positioned at L2.

L3 is the point on the earth's orbit around the sun that is diametrically opposite to where the earth is now located. If we draw an equilateral triangle, with the sun at one of the points and the other two points on the earth's orbit and the present position of the earth in the middle of the side opposite the sun, the two points other than the sun are L4 and L5.

L4 and L5 are both on the earth's orbit around the sun. L4 is 60 degrees ahead of the earth, as it moves around the sun, and L5 is 60 degrees behind it.

Unlike L1 and L2, the gravity of the earth and sun is not equal at L3, L4 and, L5. What is so important about all of the Lagrangian Points is that they are "preferred" positions in space. Objects, whether asteroids or satellites or clouds of dust, "prefer" to be located at Lagrangian Points than elsewhere in space. Objects sometimes orbit around one of the points, even though there is nothing at the point.

Jupiter has large collections of asteroids at it's L4 and L5. These asteroids are known as the Trojans. One group is ahead of Jupiter in it's orbit around the sun, and the other group is behind it. Any Lagrangian Point is designated by the two astronomical bodies and it's number, such as Jupiter-sun L4. We wouldn't just state "Jupiter L4" because Jupiter's moons also create Lagrangian Points in their orbits around the planet. Both astronomical objects that create the Lagrangian Points have to be specified.

Another thing that is so interesting, and useful, about Lagrangian Points is that objects in space can move from one Lagrangian Point to another with much less energy than would usually be required. There is a network, called the Interplanetary Transport Network, along which objects can move with a lot less energy than would usually be required.

Since there are more than two astronomical objects in the universe Lagrangian Points must be more complex than this. At the same time that the earth has Lagrangian Points in it's orbit around the sun, the moon has Lagrangian Points in it's orbit around the earth. We have looked at what we could call "primary" Lagrangian Points, but there must also be "secondary" points which share one of the two astronomical objects. Also, Venus is almost as massive as the earth and there are times when it is closer to the earth's L4 and L5 than the earth is.

These rules of Lagrangian Points only apply when one astronomical object is in orbit around another and one object is many times as massive as the other. The rules may not apply, for example, to a double or multiple star system where the stars were closer to each other in relative mass.

You have probably heard of a "geostationary orbit" but it has nothing to do with Lagrangian Points. The higher a satellite is placed in orbit the more slowly it revolves around the earth. At the same time the earth is rotating. This means that there must be a certain altitude where a satellite will orbit at exactly the same speed at which the earth is rotating. This means it will stay in the same spot in the sky overhead. This makes it very useful for communication satellites and is called a "geostationary orbit". The altitude of a geostationary orbit is 22,300 miles. But a geostationary orbit has nothing to do with Lagrangian Points.

The so-called "Interplanetary Transport Network", there is a Wikipedia article about it, of a route through space that requires much less energy than usual because it makes use of Lagrangian Points. An object will require less energy than usual to move between Lagrangian Points. This reflects on my concept that what exactly a straight line is, defined as the shortest distance between two points, may be open to definition.

Another thing that is interesting is that some believe black holes to act as "doorways" or "tunnels" in space. Black holes have tremendous gravity. If the gravity of ordinary astronomical objects like the sun and planets provide a lower energy route through space by Lagrangian Points, then what might we expect the far more massive black holes to provide?

Somewhere out there is a network of easier routes around the galaxy that we could call the "Black Hole Highway".

5) WHY THERE ARE METEOR SHOWERS

While driving at night I saw a bright shooting star and it got me thinking.

There are regular meteor showers throughout the year. As the earth moves through it's orbit around the sun it passes through clouds of dust. Particles burning up by friction with the atmosphere is what produces the "shooting stars".

The dust was mostly left behind by comets. These comets are composed mostly of ice and collect dust in space as they move along in their orbits around the sun. The orbits of comets around the sun tend to be extremely eccentric, coming from far out in space and spending only a brief time near the sun before going far back out into space for long periods of time. There are comets with orbital periods of thousands of years.

When the comet gets close to the sun the outermost ice gets vaporized by the heat. This is what produces the visible "tail" of the comet, as the vapor reflects sunlight. It also leaves a trail of dust in space in the part of the comet's orbit that was close to the sun. It is this trail of dust that the earth passes through every year to create the predictable shower of "shooting stars".

The comets have orbits around the sun in geometric planes that are not the same at all as the earth's. This is why different meteor showers that occur every year seem to come at us from different directions in the sky. Each meteor shower has it's own direction.

Meteor showers, which occur on the same date every year as the earth passes through the cloud of dust during it's orbit around the sun, are thus named for the constellations in the sky that they seem to radiate from. Some of the meteor showers are the Perseids, Geminids, and, Leonids.

What I want to discuss today is what exactly is happening to the particles of dust and other debris that the earth is passing through in space to cause these meteor showers.

The first thing that is obvious is that the particles of dust cannot be in orbit around the sun. For the particles to enter the earth's atmosphere would mean that the particles are the same distance from the sun as earth. This would then mean that the earth and the particles would never run into each other since everything in the Solar System orbits the sun in the same direction, and objects at the same distance from the sun will orbit at the same rate. In a similar way Jupiter has two groups of asteroids that share it's orbit at Lagrangian Points L4 and L5, known as the Greeks and the Trojans, but which never meet Jupiter.

Neither is it possible that the particles of dust that are shed by the comet when it is near the sun continue with the momentum of the comet in the orbit of the comet. Comets have very eccentric orbits with long orbital periods. A comet comes close to the sun, where it's outer layers are vaporized into the familiar "tail" and it sheds the dust that it has collected in it's journey through space, for only a relatively brief time during it's long orbit. If the particles of dust continued with the momentum in the orbit of the comet they would be there for the earth to pass through them for one, or just maybe two, years. But the earth has been passing through the same cometary clouds of dust that have been producing the same predictable meteor showers that have been recorded for hundreds, or even thousands, of years.

The only possible conclusion is that the clouds of dust that the earth passes through during it's orbit around the sun are stationary in space and do not orbit the sun. I don't see how it could be any other way.

This requires some special explanation. These dust particles are made of matter, which has mass, and gravity acts on mass. So why aren't these clouds of dust that the earth passes through in it's orbit in orbit themselves around the sun? The vast clouds of dust and gas in our galaxy orbit the center of the galaxy along with all of the stars.

The answer, that I had never seen explained anywhere, is that orbits, as well as escape velocities, require compression. We saw this in the compound posting, "Orbital And Escape Velocities And Impacts From Space" Sections 1 and 3, November 2014.

The simplest and lightest atom is hydrogen, with only one proton and one electron in it's nucleus. The original atoms in the universe were about 75% hydrogen and 25% helium, with traces of the next two heavier elements. An atom of helium is formed from four atoms of hydrogen being crunched together and there was enough energy left over from the Big Bang to crunch some of the hydrogen atoms into helium.

As we know lighter atoms, starting with hydrogen, are crunched together in the centers of stars into heavier elements. Electrons in the orbitals of atoms are negatively-charged so that they repel each other, and do not merge if pressed together. But if enough mass comes together by it's mutual gravity to overcome this electron repulsion a star is born as the tremendous gravity crunches lighter atoms together into heavier ones. 

The new heavier atom contains less overall energy than the lighter atoms that were crunched together to form it. The excess energy is released as radiation and this is why stars shine. This ordinary fusion process only goes as far as iron, atoms heavier than iron are only formed during the great release of energy during a supernova.

Now imagine a vast cloud of hydrogen atoms in space. This is the beginning of a star that will, in the center of the star, start crunching hydrogen atoms into helium, and later that into successively heavier atoms. My hypothesis is that such a cloud of hydrogen, the lightest of all atoms, cannot have anything in orbit around it. If an object were at the edge of the cloud, and moving away from it, the "escape velocity" of the cloud would be essentially zero. It is only when the cloud has been compressed, such as by nuclear fusion fusing the hydrogen atoms into heavier ones, that the former cloud of hydrogen can have an escape velocity and objects in orbit around it.

Before proceeding further let's have a look at two examples of how the information in orbits cannot be lost. The orbits of the planets around the sun form ellipses, rather than circles, even though a circle would be the lowest information state. But yet this requires some explanation because the rings of Saturn, which are composed of particles, form a perfect circle. The Asteroid Belt also forms a circle, and not an ellipse. This must mean that the orbits of individual asteroids around the sun are circles because, if they were ellipses but the belt as a whole was circular, asteroids would be colliding and we see no evidence of that.

The reason that the orbits of planets must be ellipses is that the planets formed from agglomerations of debris like the asteroids. Some of the debris, pulled together by it's mutual gravity, had been closer to the sun and some had been further from the sun. The way that the information of the orbits of the former closer and further components of the planets is conserved is for the planet to orbit the sun in an ellipse, with a point when it is closest and a point when it is furthest from the sun.

The second example of how the information in orbits cannot just be lost concerns the extremely eccentric orbits of comets. We know that the sun was preceded by a large star that exploded in a supernova. Some of the debris fell back together by it's mutual gravity to form the sun and planets. My theory is that at least one, but probably three, nova preceded the supernova. As stellar fusion proceeds to successively heavier atoms more energy is released per time and this upsets the equilibrium of the star. A nova is the blasting away of the outer layers of the star, in an effort to regain equilibrium. If that doesn't restore equilibrium then the star explodes from the center in a supernova.

Comets formed from molecules of light atoms that were blasted into space by a nova. These comets were in orbit around the former star before it exploded. After the previous star exploded in the supernova some of the debris fell back together to form the sun and Solar System. But the sun was much less massive than the previous star had been, and therefore had less orbital energy. The information in the orbits of the comets could not, however, just be lost. So what happened is that the orbits of the comets greatly contracted, but with the highest point of the orbit still intact, because the energy of an orbit is defined by the distance from the central body. This is why the comets of the Solar System tend to have very eccentric orbits.

Now let's get back to our cloud of hydrogen in space, that is the beginning of a star. As fusion takes place in the center, by the inward force of gravity overcoming the electron repulsion between atoms, the now-star shrinks in size. This is because the new heavier atoms are smaller, more compact, than the larger atoms that were crunched together to form them. Not only that but the successively-heavier atoms actually get more compact as we move to the right across a row of the Periodic Table, at least until we reach the next row when another electron shell is added.

The ordinary fusion process goes as far as iron. To illustrate how much compression takes place during fusion a hydrogen atom, in terms of diameter, is almost as large as an iron atom, but the iron atom is 56 times as massive.

So what happens as our original cloud of hydrogen becomes a star and it's atoms are fused into successively-heavier and much more compact elements is that the information of the original edge of the hydrogen cloud must be maintained. As in the examples above it cannot just be lost.

The way that the information of the original edge of the hydrogen cloud is retained is by orbits. An object can now orbit the star, and it has an escape velocity, whereas that was not the case when it was a cloud of hydrogen. This is what I mean when I state that orbits as well as escape velocities require compression.

But if a cloud of hydrogen in space is compressed into a star an object can orbit the star far beyond the original boundary of the hydrogen cloud. This is because the atoms of the object have undergone compression too. Not directly but all heavy atoms outside of stars were once part of a star that exploded, including every atom in your body. The compression factor of the object in orbit is multiplied by that of the star.

So now let's go back to the stationary clouds of dust in space, left by comets, that the earth passes through in it's orbit around the sun. The question is why the particles of dust don't orbit the sun so that the earth passes through them in it's orbit every year.

The dust is not entirely stationary. It is stationary with regard to the sun but the sun itself is in orbit around the center of the galaxy, bringing the Solar System with it. Dust consists of heavier atoms and the atoms in the dust underwent compression, fusion, into these heavier atoms. This compression brought an orbit but it was the same orbit as the star that produced them, the star that preceded the sun before exploding in the supernova. The comets orbit the sun because they were in orbit around the previous star before it exploded.

Unlike this dust the planets and asteroids do orbit the sun, and their atoms were formed in the previous star in the same way as the atoms in the dust. But remember that compression is necessary for orbits and, in terms of information, the orbit is the "ghost" of the collection of matter prior to compression. The planets and asteroids have coalesced from matter and debris in space, and this is why they orbit the sun. The particles of dust haven't undergone any such coalescing, they are the same as when ejected from the previous star, so they continue in orbit around the center of the galaxy, along with the sun, but do not take on the additional orbit around the sun. 

This shows that orbits, and with it orbital and escape velocities, require compression, whether the compression is lighter atoms being crunched into heavier atoms in a star or dust and debris in space coalescing into a planet or moon.

Again this confirms what we saw in the compound posting, "Orbital And Escape Velocities And Impacts From Space", Sections 1 and 3, November 2014.

6) THE WANNABE STAR OF THE SOLAR SYSTEM

Jupiter is by far the largest planet of our Solar System. It has more than twice the mass of all the other planets combined. In fact, Jupiter is built much like a star. It has plenty of hydrogen, for the initial stage of fusion like the sun is in now, and is of about the same density as the sun.

The reason that Jupiter isn't a star is that, despite it's great mass relative to the planets, it doesn't have enough mass to ignite as a star. A star forms when enough matter comes together in space by it's mutual gravity to overcome the electron repulsion between atoms that keeps atoms from merging into each other.

The like charges of the outer electrons in each atom, both negatively-charged, mutually repel to keep the atoms separate. Smaller atoms, starting with hydrogen, are crunched together into larger atoms in the center of the star. The new heavier atoms have less overall energy than the smaller atoms that were crunched together to form them. The excess energy is released as radiation and that is why stars shine.

But why would such a massive planet form, that was built very much like a star, but with not enough mass to be a star? That brings us to some interesting questions.

Let's start with how our Solar System formed. We know that a very large star exploded in a supernova, which happens to only the largest stars. Some of the matter that was scattered across space by the explosion fell back together by gravity to form the sun and the planets. Such explosive stars happen because as the star ages and fuses atoms of successively heavier elements together, this increases the energy per time that is released.

Since a star is an equilibrium between the inward mutual gravity of it's mass and the outward force of the energy released by fusion in the star's core, this upsets the equilibrium in favor of the outward energy. 

The star may try to regain the equilibrium by blasting off some of it's outer layers with the outward energy from the fusion. This would reduce the gravitational pressure on the star's core and slow the rate of fusion. This only happens in the largest stars, where the tremendous mutual gravity of the mass prevents the star from simply swelling to regain equilibrium. A smaller star, like the sun, will swell into a "red giant" when it reaches this stage, instead of blasting off outer layers.

If the removal of the outer layers of the star does not restore equilibrium, as successively-heavier elements are fused at it's core so that more energy per time continues to be released, the entire star may explode from the center, scattering it's matter across space. 

I refer to the blasting away of outer layers of the star as a nova, and the explosion of the star from the center as a supernova. Such a supernova resulted in our Solar System as some of the matter from the previous star fell back together by gravity to form the sun and planets. Iron is so plentiful in the inner Solar System because the ordinary fusion process only goes as far as iron.

I am certain that the previous star, which exploded in a supernova to form the present sun and planets, underwent at least one nova, a blasting away of it's outer layers, before exploding as a supernova. I actually believe that it most likely underwent three nova.

The outer layers of the previous star would naturally contain light atoms. The energy released by the nova welded atoms together into light molecules, such as water, salt, diatomic hydrogen and oxygen, methane and, ammonia. This "welding together" of light atoms by the energy released in the nova is in the same principle as elements heavier than iron being formed from smaller atoms being crunched together only during the tremendous release of energy during a supernova.

The first nova of the previous star, with the highest starting point relative to successive nova, resulted in the distant comets of the Oort Cloud. The second nova resulted in the nearer comets of the Kuiper Belt. The third nova resulted in the molecular gases, particularly methane and ammonia, that compose much of the outer planets of our Solar System.

Finally the star exploded from the center in a supernova, much of the material fell back together by gravity to form the sun and the heavy rocky and metallic material in the planets. We know that the sun is such a second-generation star because it contains heavy elements that are beyond it's current stage in the fusion process.

The vast majority of stars exist in pairs or groups. What looks to us like a single star may actually be a system of multiple stars. We know that Solar Systems, many of which exist around other stars, are formed only from a supernova. An interesting question, which I have never seen before, is whether more than one star can form from a supernova, the explosion of one star.

It seems to me that we tend to presume the way our Solar System came together from a supernova must be pretty much the way other Solar Systems came together also. But what if our previous star had exploded as a supernova without any nova preceding it? There would be no water, which came to earth by comet, or salt which I believe must have come with it because salt on earth is always either in water or where water has been. 

The two atoms of diatomic hydrogen and oxygen in the atmosphere were also put together with energy released during a nova. When we use hydrogen as fuel the two atoms are split so that it releases this energy. So the energy released by a nova joins atoms together into molecules, but the much greater energy released by a supernova crunches atoms together into entirely new, larger, atoms.

It would also mean that the supernova would have been more powerful. If the supernova had been more powerful more light material, particularly hydrogen, would have been thrown further outward. 

That brings us back to the giant planet Jupiter. It is built so much like a star but doesn't have enough mass to ignite as a star. Maybe Jupiter was meant to be a star but the fact that there were nova in the previous star weakened the supernova in which the star finally exploded. 

If not for these nova, if there had only been a supernova, Jupiter might well have gained enough mass to ignite as a star and our sun would be part of a dual star system. The earth would still be there, although there would be no water. This means that more than one star can indeed form from the same supernova.

Conditions in other Solar Systems depend on how the supernova that formed the system played out. I think we tend to presume that it must have been pretty much like our system, but that may not be the case.

7) LIGHT FROM PLANETS AND STARS

Here is something in science that should definitely get more attention. 

There are two ways to tell the difference between planets and stars when looking up at the night sky. The first is that the planets move against the fixed background of the stars, as the planets move in their orbits around the sun. The word "planet" actually means "wanderer".

But the second way involves light. Stars seem to "twinkle" while planets shine with a steady light. There is no twinkling of the planets.

The question is why? There are answers online. Because the star is so much more distant it's light beam is much narrower and so is bent more than the planet's, causing it to twinkle, or something like that. 

I am writing this because I do not agree with the answer online.

Physics and astronomy are related, because the universe operates by the laws of physics. But the two subjects are usually studied separately. While the question of why stars twinkle but planets don't is an astronomical question the answer lies in physics, in the nature of light.

Light consists of electromagnetic waves that can be modeled as a sine wave. It operates much like a water wave except that the light wave is two-dimensional. A sine wave means that one wave cycle starts at zero, continues to a peak, drops back to zero, continues to a corresponding peak in the negative direction, and finally returns to zero, before beginning the next cycle. 

The distance between corresponding points on successive wave cycles is known as the wavelength. The number of waves that pass a fixed point per second is the frequency. The stronger the wave the greater will be it's height, this is known as the amplitude.

Aside from waves in space, alternating electric current operates in the same way.

Let's briefly review how lasers work. There is actually force in electromagnetic waves. Radio waves can be received because they cause electrons to move in the radio antenna.

Light usually consists of a wide variety of different wavelengths. This dissipates the force of the waves. But if we can generate monochromatic light, just one single wavelength, the peaks and troughs of the waves will be lined up, like "marching in step", and the light can exert force.

White is a mix of all colors. Black is the absence of all colors. Gray is a mix of black and white. That is why you never see white, black or, gray lasers.

Somewhat related to the principle of the laser is polarity. The two dimensional waves of light can move forward at all different angles. This does not mean the light moving in different directions, it means the relative angle of the peaks and troughs as the waves move forward.

Suppose that someone shines a flashlight at you. Now suppose that the flashlight is the face of a clock. Some of the two-dimensional waves will be aligned at the angle of 12 o'clock to 6 o'clock. Other waves will be angled at 11 o'clock to 5 o'clock. Still others will be angled from 10 o'clock to 4 o'clock, and so on through all possible angles.

The angle of any two-dimensional wave in this manner is known as the wave's polarity. Once again, polarity does not refer to the direction the wave is moving. A good way to understand polarity is to imagine a flashlight shining at you as the face of a clock.

Ordinary light is a mix of all different polarities. It is possible to filter light so that all of it's waves are of one polarity. Photographers use polarizing filters to cut down on glare. Polaroid sunglasses operate by polarizing the sunlight.

Remember that polarization in light does not mean quite the same thing as in politics. In politics is means that everyone is on one side or the other, with no moderates in between. In light it means to have all waves aligned at the same angle, such as from 7 o'clock to 1 o'clock on the face of a clock.

The reason we do not hear more about polarity is that our eyes ordinarily cannot tell whether light is polarized or not.

Now, back to the light from stars and planets. The reason that stars appear to twinkle while planets don't. 

The light from planets actually is starlight. The sun is a star and the light that we see from a planet is reflected starlight. So why does it make a difference if the light has been reflected by the surface of the planet, or it's clouds?

It doesn't matter whether the light is reflected by the solid surface of the planet or by clouds. The light we see from Mars, Mercury and, Pluto is from the planet's solid surface. The light from Venus, Jupiter, Saturn, Uranus and, Neptune is reflected from the tops of clouds.

It doesn't matter what color the planet is. Mars is red, actually colored by iron oxide or rust. When we look at Venus we are seeing the white clouds of sulfuric acid.

Here is what is happening. It involves polarization. This is my explanation. I disagree with the explanation online.

When light interacts with matter it is partially polarized. Matter consists of atoms and a rough surface. Light is typically scattered in many directions. But the light that hits the atoms at just the right angle is reflected back. This partially polarizes the light. Image a cylindrical structure. If you bounce a ball off it the ball will probably bounce to the left or right. But if the ball hits the surface just right it will bounce right back.

When the light enters the earth's atmosphere it encounters atoms. The wavelengths of light are much longer than the scale of the atoms. But the atoms in the atmosphere, which are always moving, affect some polarizations more than others.

One moment one polarization angle is blocked more, the next moment another angle. That is what causes the light from stars to seem to twinkle. The light doesn't get brighter or dimmer, it is just that the polarities are continually changing. Our eyes cannot detect whether light is polarized or not, but apparently can detect if the polarity is changing.

Our eyes detect light because the waves knock electrons out of atoms in the sensors of our eyes, creating a small electric current. Change in polarization can apparently be detected because electrons are knocked out of atoms with orbitals in one directional alignment, then in another, thus affecting the current that is produced.

With the partially polarized light from planets, because it has already interacted with matter, this does not happen. That is why planets shine with a steady light while stars twinkle.

There is another factor that I would like to add.

The vast majority of the gas that the light passes through in the atmosphere is nitrogen and oxygen. Both of these gases are in diatomic form. What that means is oxygen and nitrogen exist as molecules of two atoms, rather than as single atoms in the air.

What this means is that the molecules are longer in one direction than the perpendicular direction. Think of a diatomic molecule like a dumbbell or a pair of eyes.

The fact that the oxygen and nitrogen in the air is diatomic is why we have weather. A molecule of water, one oxygen atom with two hydrogen atoms, is lighter than the diatomic molecules in the air. This is why water can evaporate and we can have weather. If the oxygen and nitrogen in the air consisted of single atoms, water would not evaporate and we would not have weather.

Hydrogen is diatomic too and when we use it as fuel we are breaking the bond between the two molecules and releasing it's energy.

These diatomic molecules of nitrogen and oxygen cannot block light because the wavelength of light is so much longer than the scale of the atoms. But they can collectively interfere with it. But since the molecules are longer in their length than their width, they interfere with one particular polarity of light more than others.

The molecules in the air are always moving. This means that overall, by random chance, some polarities are more blocked one moment, and other polarities the next moment. The visible polarities of light from stars is thus always changing.

This is what causes stars to "twinkle".

The light from planets, in contrast being already at least partially polarized, does not undergo this process. This is why stars appear to shine with a steady light.

8) CONCLUDING THE SEARCH FOR THE NINTH PLANET

There have been articles in the news about how there must be a massive planet in our Solar System that has yet to be discovered. It would be the ninth planet. The reason for this conclusion is the eccentricity of the orbits of objects in the outer Solar System, such as Pluto and Sedna that are not considered as planets.

By eccentricity I mean the difference between the apogee and perigee of their orbits, the points in the orbits when they are furthest from and closest to the sun. An orbit that was a perfect circle would have an eccentricity of zero.

All planets in the Solar System have elliptical orbits, meaning with some eccentricity. No planet has an orbit that is perfectly circular. But the inner planets, those closest to the sun from Mercury to Mars, have orbits with much less eccentricity, much closer to being circular, than those further out.

My reasoning for why planets inevitably have elliptical orbits is that the planets were formed by collections of debris, that drew together by gravity. The debris came from the large star that preceded the sun, before exploding in a supernova. Some of the debris from that exploding star fell back together by gravity to form the sun and planets. 

This is the way planets are formed and we know that the sun is such a second-generation star because it already contains heavier elements that are beyond it's current stage in the fusion process. The previous star must have been much larger than the sun because only the largest stars can explode as a supernova.

But then why are the icy outermost members of the Solar System, such as Pluto and Sedna, in orbits that are so much more eccentric than the rocky and metallic inner planets? The proponents of a yet-unseen ninth planet claim that there is a massive planet further out that is exerting gravitational pull on these planets, thus distorting their orbits.

This is what led to the discovery of first Neptune, and then Pluto. The orbit of Uranus didn't seem quite right, and the conclusion was that there must be a gravitational influence on it coming from further out. But Pluto is a mere speck, compared to the other two, and could not have much of a gravitational effect on them.

The trouble with this hypothesis of a ninth planet is, of course, that no one can find a trace of it. Some have wondered if the mystery planet might be dark, making it difficult to see, although this would put it in contrast to all of the other planets. Even if this supposed planet was too dark to be easily seen, if it were massive enough to exert such a gravitational influence then it would certainly draw many of the icy objects that are numerous in the outer reaches of the Solar System into it's orbit, and these would certainly be bright enough to be seen.

One thing that I find really interesting is that the orbital eccentricity of an object in the Solar System, a planet or planetoid or comet, depends on what it is made of. If it is composed primarily of rock and metal, as are the inner planets, it's orbit will tend to be of low eccentricity, or closer to being a circle. But if it is composed of ices, frozen water, methane or, ammonia, it's orbit will tend to be of much higher eccentricity. Comets, composed primarily of ice, have extremely eccentric orbits. Comets that collided with earth are where our water came from.

That actually leads us to an explanation of why the orbits of objects like Pluto and Sedna are so eccentric, and it doesn't require the gravitational influence of any ninth planet. 

In the compound posting on this blog, "The Configuration Of The Solar System Made Really Simple" March 2017, we saw that, before the star that preceded the sun exploded in a supernova, there must have been at least one nova. I believe that there were likely three nova before the supernova.

A star forms when enough mass is brought together by it's mutual gravity to overcome the electron repulsion that keeps atoms separate and so crunches smaller atoms together into larger ones. The new larger atom contains less overall energy than the ones that were crunched together to form it. As fusion takes place this extra energy is released as radiation, and this is why stars shine.

A star is an equilibrium between the inward pressure of gravity and the outward pressure of the energy being released by the fusion. But as the fusion process continues, fusing lighter elements into heavier ones, more energy is being released per time as successively heavier elements undergo fusion.

This upsets the star's balance between the inward and outward forces. Some stars, depending on the type of star and it's mass, swell outward to become "red giants". This is the sun's likely fate. But in larger stars the change in equilibrium is more abrupt. As the outward pressure exceeds the inward, the outer layers of the star may be blasted away. This may restore the equilibrium as the loss of mass slows the fusion process at the center of the star. If it doesn't then the entire star may explode from the center.

The blasting away of the outer layers of the star is referred to as a nova. The explosion of the star from the center is referred to as a supernova. When a supernova occurs much of the mass typically falls back together by gravity to form a second-generation star, likely with planets. That is how our Solar System formed.

Orbital energy is higher with orbits of higher altitude. The earth, in orbit around the sun, has more orbital energy than Venus. The matter that was blasted off the star that preceded the sun started at a higher altitude than the majority of the matter that was thrown outward by the supernova, simply because it started at a higher altitude.

This means that the matter initially thrown outward by the one or more nova, that occurred before the supernova, would be at a higher altitude than the matter that later fell back together, to form the sun and planets, after the supernova.

There are two differences between the matter that forms the planets and the matter that forms the objects in the outer Solar System. 

First, the matter in the outer Solar System formed from matter thrown outward by nova before the star that preceded the sun exploded. The planets, in contrast, formed from the matter that was thrown outward, but fell back together after the supernova.

Second, the matter composing the planets is mostly rocky and metallic while that composing the objects in the outer Solar System is ices of light molecules, such as water, ammonia and, methane. The reason for this is that lighter atoms were concentrated in the outer portions of the star, with heavier elements at the center, and the lighter elements were thrown outward by the supernova.

The energy released by the nova fused light atoms into the molecules of water, ammonia and, methane just as the much greater energy of a supernova fuses atoms together to form all elements that are heavier than iron. The ordinary fusion process, up until the actual supernova, only goes as far as iron. This is why iron is so abundant in the inner Solar System, it is the most common element on earth by mass.

This is the reason why elements like hydrogen and oxygen tend to be diatomic, two atoms together in molecular form. The bond contains energy and that energy came from a nova from the star that preceded the sun, before it exploded in a supernova. When we use hydrogen as fuel we are not releasing energy from the sun, as with fossil fuels, we are releasing energy from a nova from before the sun existed.

The reason that Jupiter is more massive than all of the other planets combined is that there was an overlap between the zones of where the initial light molecules were thrown outward by the nova, before the star that preceded the sun exploded, and the heavier matter that was thrown outward when that star exploded. Jupiter is in the right orbit to get the best of both worlds, it has a core of heavy rocky and metallic material, which had strong enough gravity to collect a vast amount of the lighter material.

With that background now finally we get to why the orbits of objects in the outer Solar System, for example Pluto and Sedna, have such eccentric orbits. It has nothing to do with any gravity from a massive but unseen planet. It is because of orbital energy.

The icy objects that formed from the lighter atoms thrown outward by the one or, probably more than one, nova were in orbits around the previous star, which was much more massive than the sun. That star exploded and some of the mass fell back together to form the sun. But now there had to be much less orbital energy, simply because the sun was much less massive.

Since, with orbits around a given mass, a higher orbit has higher orbital energy, this meant that the orbital energy of the icy objects in the outer Solar System, that were now in orbit around the sun, had to decrease. But the information of their orbits around the massive previous star couldn't just be lost.

What happened is that their orbits "shrank", keeping the highest point but drastically decreasing the area that their orbits covered. Their perigees, the lowest points of their orbits, moved much closer to the sun. That is why these icy outer objects, which include comets, have such eccentric orbits and we do not need the gravity of an unseen planet to explain that.

Here is a link to the compound posting, "The Configuration Of The Solar System Made Really Simple":

http://markmeeksideas.blogspot.com/2017/03/the-configuration-of-solar-system-made.html?m=0