Rare Earth

Earth from Space (nasa.gov)

Welcome to Earth, third rock from the Sun. In this segment on Knowledge of the Spheres, we will continue our quest through the cosmos by taking a look at our very unique observational platform. Our planet is rare, it is distinct from other bodies in our solar system. Through this differentiation, we are able to look outside the atmosphere and observe the universe. In this post, it is my goal to astronomically and geologically surmise what forces give rise to our very privileged and unique position.

When we think about our planet, the first thing that comes to mind is life. Yes, complex intelligent life is very uncommon in the Universe. There are many factors that contribute to this such as the atmosphere, oceans, size, distance and size of our local star, protection contributed by Jupiter’s mass and distance, size and distance of our moon and location within our galactic home.

All of these factors we will explore. While all of these factors are very important, there is one crucial mechanism that paved the way for our existence in the Universe. It is the combination of all of these factors that gave rise to our very unique and privlidged observational platform. So, without further ado, I present Earth, third rock from the sun.

As we look at our planet from the perspective of another planetary body, we notice several things. Earth is a terrestrial planet, meaning it has a solid surface. It is rather small compared to other planetary bodies, especially the gas and ice giants (Jupiter, Saturn, Uranus, and Neptune). It resides within the inner solar system accompanied by other terrestrial (rocky) planets (Mercury, Venus, and Mars).

All of these factors allow us to look outside our atmosphere and observe the celestial realms in Earth inhabits. Cosmically speaking, Earth is a planetary gem-a rocky planet where liquid water exists by the oceanful. Positioned in a benign region of our galaxy where both comet and asteroid bombardment are tolerable. A moon possessing the right amount of solar mass, just large enough to stabilize axial tilt and create tides, but not so large that gravity pulls our planet apart. Without these seemingly mundane factors, life would not exist.

To fully understand the uniqueness of our observational platform, we need to surmise how these random factors integrate into the cohesive whole we call Earth. We will begin with the atmosphere.

Earth’s Atmosphere:

Earth’s atmosphere is pivotal in permitting life. The atmosphere is a mix of nitrogen (78%), oxygen (21%), and other gases (1%) that encompass the planet. This envelope of gases is held in place around the planet by Earth’s gravity. High above the planet, the atmosphere becomes thinner until it reaches space.

Credit: NASA/Goddard-Earth’s Atmospheric Layers | NASA

The atmosphere is divided into five layers:

Troposphere
The troposphere starts at the Earth’s surface and extends 5 to 9 miles. This part of the atmosphere is the densest. All of our weather happens in this region.

Stratosphere
The stratosphere starts just above the troposphere and extends to 31 miles high. Most commercial airlines cruise within this layer of the atmosphere. The air is thin and cold, reducing air resistance. The ozone layer, which absorbs and scatters solar ultraviolet radiation also resides in this layer.

Mesosphere
The mesosphere starts just above the stratosphere and extends to roughly 53 miles high. Meteors burn up in this layer

Thermosphere
The thermosphere starts just above the mesosphere and extends to 372 miles above the surface. Auroras occur in this layer. It is also the layer where satellites orbit the Earth.

Ionosphere
The ionosphere is an abundant layer of electrons and ionized atoms and molecules. Stretching from about 30 miles to the edge of space at about 600 miles, overlapping into the mesosphere and thermosphere. This region is what makes radio communications possible.

Exosphere
This is the upper limit of our atmosphere. It extends from the top of the thermosphere up to 6,200 mi.

The atmosphere is an important factor in allowing Earth to be a habitable planetary body. The atmosphere is crucial in blocking some of the most dangerousaspectst of the light spectrum produced by the Sun. Ionized atoms in the atmosphere burn up meteors and other space debris, protecting the Earth from impacts.

Acting as a warm blanket on a cold night, the atmosphere traps heat keeping the planet warm. This envelope of warm air acts as a safeguard keeping water present on our planet in a liquid state. Without this warming effect, our planet would suffer the same fate as Mars. Contrary to popular belief, Mars has abundant water on the planet, enough to cover the entire planet at depths of 30 feet. However, due to the lack of an atmosphere, Mars is extremely cold thus, all water present on the planet is frozen.

Finally, our planet can retain the atmosphere essential for life thanks in part due to the perfect size of our moon. If the Earth were smaller, such as the size of the moon, the gravity needed to retain an atmosphere would be too weak. The moon does possess an atmosphere, but it is tenuous, and not sufficient to retain heat or protect against impacts. For this reason, our moon is heavily cratered and not habitable without specialized equipment. Thanks to our atmosphere, Earth can regulate heat from the sun and sustain human, aquatic and animal life.

The Moon:

Earth’s moon, with its dark basaltic mare, clearly visible in great detail.
Credit: Lick Observatory/ESA/Hubble –
Hubble Shoots the Moon | NASA
Apollo 16 launched on April 16, 1972 and landed on the moon on April 20. The mission was commanded by John Young; Thomas K. Mattingly II was the command module pilot and Charles M. Duke, Jr. served as the lunar module pilot. – Image Credit: NASAEarthrise | NASA

Our Moon is a wonder of astronomy and cosmology. Above is the famous picture taken by the Apollo 16 crew that orbited the moon on April 20, 1972. I love this picture because it shows just how large our moon is and how close it orbits our planet. This is not just amazing; it is fundamental to our existence on Earth.

Earth-Moon System:

Earth and Moon caputred by MESSENGER satillie orbiting Mercury 114 million miles from Earth. – Image Credit: NASA image provided by the MESSENGER science team, NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington. Caption by Mike Carlowicz.

The Earth-Moon relationship that our planet possesses is indeed rare. Let’s take a closer look at our moon and see why it is so rare.

Without the moon, there would be no moonbeams, no month, no lunacy, no Apollo program, less poetry, and a world where every night is dark and gloomy. Although there are dozens of moons in the solar system, the familiar ghostly white moon that illuminates our night sky is highly unusual and its presence has played an important role in life on Earth.

What is most fascinating is the likelihood that an Earth-sized planet should have a moon in the first place. The fact that our planet has a moon and then a moon as large as ours is indeed one in a billion. Due to the gravitational pull of our planet, our moon should be much smaller than our celestial companion.

Of the many moons that orbit within the regions of our solar system, nearly all of them orbit the large gas and ice giants. Most of the warm, Earth-like planets that orbit close to the Sun are nearly devoid of moons. The only other terrestrial planet that has moons is Mars, orbited by Phobos and Deimos.

These moons are small and irregularly shaped. Although a spectacular sight to see two moons in the blue Martian sunset, these moons do not aid Mars as our moon aids Earth. Some of the solar system’s moons are huge. Jupiter’s Ganymede is nearly as large as Mars. Saturn’s Titan is so large that it has an atmosphere, although much denser than Earth’s and much colder.

Our moon is a freak of cosmology because of its large size in comparison to the parent planet. Our moon is nearly a third the size of Earth and is in some ways more of a twin rather than a subordinate. The only other case and point are Pluto and its companion Charon. I will discuss Pluto and the Kuiper Belt Objects in a later post.

Image Credit: Full Moon above the Earth’s horizon | NASA

The Moon’s Role in Life on Earth:

The moon plays two pivotal roles in affecting life on earth, tides, and stabilizing Earth’s rotational axis. Both these effects are due to the combined gravitational effects of the Sun and Moon. The pull of these two bodies produces bulges in the ocean, toward and away from the Sun and Moon. The alternating effects of these two celestial bodies cause the ocean to bulge respectively to the near and far sides of our planet.

As Earth spins under the bulges, the sea rises and falls, moving the water of the oceans. This motion oxidizes the oceans, allowing life to flourish under the waves. When the moon is in line with the Sun every 2 weeks (full moon and new moon), the tidal ranges are at a maximum (high tide). When the Sun and Moon are 90 degrees apart in Earth’s sky (quarter moon overhead at sunrise and sunset), the tidal change is minimized (low tide). Through these motions, the moon provides a way to keep the oceans from becoming stagnate and harboring harmful bacteria. As waves ebb and flow, the ocean renews itself, allowing oxygen to permeate, breathing life into the ocean.

Secondly, the moon affects the angular tilt of the axis relative to the plane of Earth’s orbit, commonly referred to as Obliquity. This means that the moon causes seasonal changes. Without the moon, the tilt and angle of our planet would wander in response to the gravitational pulls from the Sun and Jupiter. The monthly motion of our moon prevents any tendencies for the tilt of the axis to change.

If the Moon were smaller or more distant, or if Jupiter were large or closer, or if Earth were closer or farther from the Sun; the moon’s stabilizing influence would be less effective. Without a large moon, Earth’s rotational axis might vary by as much as 90 degrees. Mercury provides an example of what can happen to a planet whose rotational axis is nearly perfectly perpendicular to the plane of its orbit.

Mercury: Image Credit – Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington – First Image Ever Obtained from Mercury Orbit | NASA

Mercury is the closest planet to the Sun. Most of its surface is hellishly hot. However, radar images from Earth show that the poles of the planet are covered in ice. Despite Mercury’s proximity to the Sun, viewed from the poles, the Sun is always on the horizon. In contrast to Mercury’s lack of axial tilt, the planet Uranus has a 90-degree tilt; one pole has exposed the sunlight for half a year, while the other experiences cryogenic darkness for a year.

The situation on Earth is very peculiar. Most terrestrial planets in our solar system have experienced large-scale and chaotic behaviors due to the obliquity of axial tilt. The presence of the Moon has a stabilizing effect on Earth, allowing life to thrive. Without this effect, Earth could very easily be another Mercury or Uranus. We owe our present climate stability to an exceptional celestial companion, the Moon.

Our Moon is not only rare but a freak of cosmology. The moon is one of the primary reasons that life on Earth exists.

I will take a break here. I’m sure that many of you are getting tired of reading or have other important things to attend to. I will be back soon to conclude our discussion on why our observational platform is rare. I will discuss the impact of Jupiter, the Milky Way, and my reflection of why Earth is so rare.

If you have any astronomy-related questions, feel free to post in the comments or drop me a line at kuntryklucker@gmail.com

I am a published author, multi-disciplinary writer, and blog contributor. If you liked this blog, please visit some of my other sites.

Coffee and Coelophysis – A blog about Dinosaurs!

The Kuntry Klucker – Adventures in keeping backyard chickens.

Chicken Math University – Adventures in Homeschooling.

As always, thanks for reading.

Clear Skies,

Noelle

The Celestial Sphere

Before we leave for our trip into the realms of the cosmic spheres, it’s a good idea to get our bearings and understand our observational platform, the Earth.

To fully understand the academics of Astronomy and Astrophysics, one has to conceptualize ideas in the 3rd and 4th dimensions. To make this subject matter easier to explain, Astronomers often utilize visual aids to help others understand this science dealing in the abstract. One of those tools is the Celestial Sphere.

I was first introduced to the Celestial Sphere in college, and the utilization of this very simple visual aid helped me understand the night sky as seen from Earth. Although this particular visual aid is conceptualized as the outdated Platonic Geocentric model (Earth Centered), rather than the accepted Copernicus Heliocentric model (Sun Centered), it still has practical applications.

The Celestial Sphere aids in the understanding of the constellations and motions of the planets as we see them fixed in the night sky. While the stars and planets look as though they are rigid, they are very much in motion. The Celestial Sphere helps us to understand these varying motions and what they mean for our observational proposes.

Image Credit: Noelle K. Moser

For example, have you ever noticed that the Sun and Planets follow a particular path across the sky? Maybe you have not stopped to think about it, but the Sun and Planets follow a very precise path through the sky called the Ecliptic. The Ecliptic is an imaginary line that is represented on the Celestial Sphere.

Image Credit: Noelle K. Moser

In the image above, I have outlined the Ecliptic in red. The Ecliptic traverses at a shallow angle across Earth’s sky, concerning the Celestial Equator.

The Celestial Equator is an extension of Earth’s equator onto the Celestial Spheres. I have outlined the Celestial Equator in blue in the image above. This line is important because it represents the 0h to 24h mark or latitude on the Celestial Sphere. Instead of using latitude in degrees as we do on Earth, astronomers use “hours” or Right Ascension on the Celestial Sphere to represent these coordinates.

Image Credit: Noelle K. Moser

Another very important coordinate system on the Celestial Sphere is that of Declination. Declination on the Celestial Sphere runs from North to South, just like longitude on the Earth. I have marked examples of Declination on the Celestial Sphere in green. This line is used to express how many degrees above or below the Celestial Equator an astronomical object is positioned.

Declination is expressed in 0 to 90 degrees and -0 to -90 degrees. The positive degrees being above the Celestial Equator or in the Northern Celestial Hemisphere, negative being below the Celestial Equator or in the Southern Celestial Hemisphere.

Running from the North Celestial Pole (NCP) to the South Celestial Pole (SCP) through the 0h mark on the Celestial Equator is another imaginary line called the Celestial Prime Meridian.

The Celestial Prime Meridian allows an observer to express their Zenith position relative to the NCP and SCP. Allow me to express this complex idea in a picture. See the diagram below.

Image Credit: Noelle K. Moser

The Earth is our observational platform. While all observers view the night sky from the same platform, each observer has a different position.

The coordinates on the Celestial Sphere help us to express these different positions in scientific terms. This allows us to facilitate a cohesive understanding of astronomical objects relative to another observer’s position.

Now let’s move on to another important application that comes with understanding the Celestial Sphere. Astronomical explanations behind the Summer/Winter Solstice and the Vernal/Autumnal Equinox. All of these imaginary positions can be found on the Celestial Sphere. Once again, allow me to explain this with a diagram.

Image Credit: Noelle K. Moser

The Vernal Equinox (First day of Spring), is defined as the point on the Celestial sphere where the Sun traveling along the Ecliptic intersects the Celestial Prime Meridian at the 0h or 0-degree point on the Celestial Equator.

Likewise, the Autumnal Equinox (First day of Fall), is defined as the point of the Celestial Sphere where the Sun traveling along the Ecliptic intersects the Celestial Prime Meridian at the 12h or 180-degree point on the Celestial Equator.

The Summer Solstice (The first day of Summer) is when the Sun reaches the highest point in the sky along the Ecliptic. The Winter Solstice (First Day of Winter) is the opposite of the summer solstice when the Sun reaches the lowest position in the sky along the Ecliptic. All of these motions along imaginary lines can be easily understood through the aid of the Celestial Sphere. Now let’s see how this model can help us understand the stars.

The Constellations:

When we look up at the stars at night, we see points of light. These points of light belong to a larger group of stars we refer to as the Constellations.

Each of the constellations has boundaries. The Celestial Sphere marks these boundary lines helping us to understand where each of the boundary lines is drawn. This is of uttermost importance when locating celestial objects. Knowing where to look, and in what part of the sky, is essential to understand the locations of various points of interest in the night sky.

Image Credit: Noelle K. Moser

Let’s take a constellation that everyone knows very well because it lies on the Celestial Equator, Orion. I have outlined Orion’s constellational boundary in yellow and highlighted some of the brightest stars forming his figure. One of the most spectacular stellar nebulas lies within the boundary of Orion, M42 (circled in purple). If an observer wants to know where they can find this celestial gem, they will know that it lies within the boundary of Orion.

Image Credit

Above is an image taken by the Hubble Space Telescope of the Orion Nebula. This region in Orion is a huge stellar nursery where new stars are evolving. I will do a post that focuses on the astrophysics of this incredible stellar nursery at a later date. But for now, Orion is a reference point in understanding constellational boundaries on the Celestial Sphere.

The Celestial Sphere helps us to understand and make sense of the points of light that we see from Earth. The Celestial Sphere surrounds the Earth like a blanket on which all the stars that we see reside. This model however is incorrect in assuming that the stars are at all the same distance from Earth. The stars that make up the constellations are all at varying distances, we just see them as homogeneously correlated due to our observational platform and vantage point. That aside, the Celestial Sphere is correct in showing how the patterns of these points of light are associated with each other, forming the constellations.

Now that we have a better understanding of Earth’s Sky as we see it from our observational platform, we are nearing the assent into the realm of the cosmic spheres. But before we go, I want to make one last stop. To understand the knowledge of the spheres, we need to first understand our sphere, the Earth.

Next time, we will take a closer look at our planet from an astronomical perspective. I will dig deep and uncover the secret and unlikely reason that the Earth sustains life. By understanding our astronomical history we can then understand the history of the other cosmic spheres around us. We are but a tiny part of the cosmos, understanding our place allows us to gain the ability to begin to grasp the Knowledge of the Spheres.

Image Credit: Noelle K. Moser

Thank you for coming along with me as we traverse the cosmos and discover the Knowledge of the Spheres.

I am a published author, multi-disciplinary writer, and blog contributor. If you liked this blog, please visit some of my other sites.

Coffee and Coelophysis – A blog about Dinosaurs!

The Kuntry Klucker – Adventures in keeping backyard chickens.

Chicken Math University – Adventures in Homeschooling

Clear skies,

Noelle

Image Credit: Noelle K. Moser

Standing in the Shadow of the Moon.

As we embark on our journey through the cosmos, let’s start with a place that we all know well. Planet Earth. From our incredible vantage point, we can observe the universe around us and even experience the effects that neighboring celestial bodies have on our lives. Allow me to take you back to several years ago when our planet witnessed a remarkable celestial event. Although this event occurs yearly as observed from our planet, this time the event was personal. As an active astronomer would do, I got out all my tech equipment and recorded this incredible celestial wonder from my backyard.

In August 2017, a Total Solar Eclipse overtook the United States. I was fortunate as my property lay directly in the path of totality. Observing a total solar eclipse from my backyard was a thrill of a lifetime. While many had to journey to be in the shadow of the moon, I had to do nothing more than step out my back door.

If anyone followed the link from my blog on keeping chickens, The Kuntry Klucker, you are well aware that I have backyard chickens. In addition to taking pictures with my telescope, I chronicled the reaction of my flock to the waning daylight during the eclipse. Below are stills taken from a time-lapse video that I recorded of the girl’s reaction to the sky darkening at mid-day.

The girls were indeed a bit confused by the sky darkening in the middle of the day. As the sky began to darken, the flock made their way to the coop in an effort to begin roosting. No further did they make it into their pen before the moon traversed the sun, daylight resuming once more.

The reaction to the evening setting in on their busy afternoon of hunting and pecking was not only educational but entertaining. The flock was confused as daylight waned only to resume several minutes later. The wild birds also observed the same roosting behavior, settling into roosting in anticipation of approaching nightfall.

In addition to observing the behavior of my girls, I captured other interesting aspects of the total solar eclipse that day.

DSCF5938.JPG

I observed the eclipse on my hammock as my telescope and computer recorded other aspects of the eclipse. Here crescent-shaped shadows can be seen between the leaves of the shade tree above me. As the shadow of the moon advanced over the disk of the sun, the crescent shapes on my hammock likewise decreased in size. This allowed me to safely view the progression of the eclipse while my tech equipment recorded the actual events.

Below are chronological order stills of the eclipse I recorded with the aid of a solar filter.

As the moon’s shadow crept further and further in front of the Sun, I noticed several things.

First, as these two celestial spheres appeared to intersect, radiating heat felt from the Sun was greatly diminished. A 90+ degree day cooled down to a pleasant 80-degree day.

Secondly, neighborhood floodlights began to turn on as did the landscape solar lights around my coops. I can only describe the light from the sun at this point as a virtual Mist World.

It was a surreal feeling as I witnessed one of nature’s most dynamic shows. This event was one for the record books, I still am stunned by the photos.

As I gazed upon the total eclipse, I marveled at the perfect size/distance relationship between these two celestial bodies. I was overwhelmed with wonder and amazement as I stood in my backyard and gazed up at the shadow of the Moon.

Our little part of the universe is indeed an amazing place. Even as amazing as this event was, it is only the beginning of our discovery into deep and further parts of the universe in which our Solar System is only one tiny part.

I have a lot of fun and educational posts in store for this blog. But before we journey to far from home, we need to understand the platform on which we observe the universe around us.

Next time, I will introduce you to the celestial sphere, and use this aid to help you understand our unique vantage point. Understanding this model will help us on our cosmic adventure as we uncover the knowledge of the spheres.

Clear Skies,

Noelle

The Beginning…

Image Credit: Noelle K. Moser

Well, as they say, the best place to start is at the beginning. For me, that requires coffee in my constellation mug and a passion. I’ll start by introducing myself and what I hope to achieve through Knowledge of the Spheres.

My name is Noelle, I am an avid lover of coffee, lava lamps, astronomy, and science, if you called me a space geek you would be right, basically I am a geek of many trades. Science and Astronomy however are my forte and subject areas for which I choose to focus my geekdom.

Since the dawn of humanity when our hominid ancestors first left the arboreal habitat in Africa, took to bipedalism, became intelligently aware, and set our evolutionary course into motion, we looked to the stars and have been captivated ever since. Our Hominid and Human ancestors looked to the night sky with the same sense of awe and wonder as we still do today. Many people want to understand what they are looking at but find it hard to completely comprehend. The night sky is where the secrets of the stars reside. I want to expose these secrets and put the night sky into the hands of those who want to understand their place within the cosmos. This is my goal and my passion, the night sky has a story to tell, all we have to do is learn how to listen to the cosmic song of the spheres.

With “Knowledge of the Spheres” I plan to work my way through all the constellations, yes, all 88 of them, both northern and southern hemispheres. Within each constellational border are hidden celestial gems, things like galaxies, nebula, and star clusters. We will also work our way through the Solar System, bringing into light the secrets of our celestial address.

I want to bring all of these wonders into view for my readers. As we embark on our tour of the celestial spheres, we will meet other galaxies, some near to us and other far away. We will encounter other star systems and discover what it is like within a star cluster. We will also witness the glorious deaths of stars as we observe the most spectacular things in nature, supernova explosions. We will explore the remnants of these stellar catastrophes as we investigate the rips in space-time they leave known as Black Holes.

Most of all, I want to present the wonders of the night sky in a way that is both educational and entertaining. The stars have a life, they have an evolution, and they have a story to tell, all we need to do is listen. Join me as we journey to the cosmos and discover the Knowledge of the Spheres.

Clear Skies,

Noelle

Me and Jupiter