Category: Astronomy

The Universe has a Redshift and its Increasing

Super fact 79 : Distant galaxies appear redder (redshifted) because of the universe’s expansion. The farther away the galaxy, the redder it is. This cosmological redshift is also increasing because the Universe’s expansion is accelerating. Our Universe is getting more and more red every day.

Esther’s writing prompt: January 14 : Red

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Many people are aware that the Universe is expanding but may not know that this results in a measurable redshift. The faster a galaxy is moving away from us the redder it appears. This is called the cosmological redshift. Measuring these redshifts was how we discovered that our Universe is expanding.

Cosmological redshift vector illustration. Stretched and original space wavelength with earth and distant galaxy. Doppler effect astronomical phenomenon distance example. | The Universe has a Redshift and its Increasing
As the Universe expands and galaxies are moving away from each other the light will be stretched. Stretched light with longer wavelengths are more red. The phenomenon is called redshift. Shutterstock Asset id: 1180828402 by VectorMine.

At the end of the 1990’s it was also discovered that the Universe’s expansion was accelerating. This discovery came from measuring the redshifts (and apparent dimness) of distant Type Ia supernovae. I should add that measuring the increase in the cosmological redshift directly is difficult. However, it is expected to be possible when the Extremely Large Telescope (ELT) starts gathering data in 2027. I can add that there are also other types of evidence showing that the Universe’s expansion is accelerating.

Another surprising aspect is, if the Big Bang was like an explosion, gravity would pull back the galaxies making the expansion slow down and perhaps eventually even reverse. However, the opposite is happening. A common explanation is that a repulsive force, a sort of anti-gravity, referred to as dark energy, is responsible for this acceleration.

I call this a super fact because this is an observed phenomenon, it is important knowledge for how we view the world, and it is surprising. Many people have heard bits and pieces of this but do not have the fuller picture.

The Doppler Effect

The cosmological redshift is an example of the so called doppler effect. The doppler effect is the change in the frequency or wavelength of a wave in relation to an observer if the origin of the wave and the observer are moving compared to each other. If an object is moving towards you, let say an ambulance, the frequency of its sound will be higher (wavelength shorter).

After it passes you and moves away from the frequency will be lower (wavelength longer). In other words, the sound changes when the ambulance passes you. The same is true for other kinds of waves, including waves on the water, and light. If a light is travelling towards you at a high speed, it will look bluer. If a light is travelling away from you at a high speed it will look redder. The latter is what is called a redshift, cosmological redshift in our case.

The object is indicated by a red dot, and a red arrow indicates the direction of motion.
Change of wavelength caused by motion of the source. When an object moves toward you the wavelengths get shorter and the frequency higher. When an object moves away from you the wavelengths get longer and the frequency lower. Original: Tkarcher Vector:  Tatoute, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/&gt;, via Wikimedia Commons
An animation illustrating how the Doppler effect causes a car engine or siren to sound higher in pitch when it is approaching than when it is receding. The red circles represent sound waves.
The Doppler effect causes a car engine or siren to sound higher in pitch when it is approaching than when it is receding. The red circles represent sound waves. Charly Whisky 18:20, 27 January 2007, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/&gt;, via Wikimedia Commons

Below is a three minute video explaining the doppler effect and redshift.

I can add that the constancy of the speed of light in vacuum changes the exact size of the doppler effect. The doppler effect remains as is for the most part but the formulas for the classical doppler effect, which you would use for sound, and the relativistic doppler effect, which you would use for light in space, are different. It is just to pick the right formula.

Doppler Effect Formula on a green chalkboard. Education. Science. Formula. Vector illustration. | The Universe has a Redshift and its Increasing
The classical formula for the doppler effect. There is a medium (air) but you don’t need to consider the constancy of the speed of light in vacuum. You use it for sound and water waves. Shutterstock Asset id: 2365938267 by Sasha701.
Relativistic Doppler Effect Formula on a black chalkboard. Education. Science. Formula. Vector illustration.
The relativistic formula for the doppler effect considers the constancy of the speed of light in vacuum but there is no medium to worry about. You use this formula for the doppler effect of light in space. Shutterstock Asset id: 2416786951 by Sasha701.

Measuring redshift

A common misconception is that astronomers take pictures of distant galaxies and somehow measure the “redness” of them, but that is not the case. When you take a spectrum of a heated element (such as hydrogen or helium in stars) it creates characteristic dark lines in the spectrum — like a fingerprint. Everything on the periodic table has its own characteristic fingerprint of lines at characteristic frequencies. In addition to measuring the cosmological redshift it makes it possible to identify the elements in a star and their proportions. See the picture below.

The top shows a colorful spectrum from blue to red with absorption lines in black. The bottom portion of the picture shows the same thing expect the black absorption lines have moved a bit to the right.
Visualization of redshifted absorption lines are redshifted due to velocity away from observer. Top lines are for an object at rest and in the bottom picture the object is moving away. Maxmath12, CC0, via Wikimedia Commons. This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.

Expanding Universe Hazy IPA

Expanding Universe is a Hazy IPA, or a so called New England style IPA from First State Brewing, ABV 6.5%, IBU 25 (IBU = International Bitter Units). The fact that it is an IPA (India Pale Ale) means that it is Ale and therefore not a Lager. The fact that it is an IPA means that it is hop-forward and has an intense flavor and aroma. The fact that it is a Hazy / New England style IPA means that it is more fruity than bitter and looks cloudy, hazy, like juice. The flavor of Expanding Universe is mango, pineapple, and grapefruit. It has a low bitterness, it is fruity, juicy, and it is great if you like New England IPAs.

The picture shows a glass with yellow to light orange hazy liquid. There are green plants in the background.
Expanding Universe ABV 6.5%, IBU 25.

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Neutron Stars Trillions of Times Denser than the Sun

Super fact 78 : A neutron star is vastly denser than the Sun, typically hundreds of trillions of times denser. In addition, the gravity on a neutron star is a few billion times stronger than on the Sun’s surface. Therefore, a cubic meter of neutron star material weighs roughly septillion times (1,000,000,000,000,000,000,000,000 times) more than a cubic meter of Sun’s average density material placed on the sun’s surface.

A neutron star is the core of a collapsed supergiant star. It is the remnant of a supernova explosion of a massive star. The original star typically has a mass of 10 to 25 solar masses and the core remnant a mass between 1.4 to 2 times the mass of the sun but confined into a sphere with a diameter of on average 12 miles. That is quite small for so much mass and will result in a material so compressed that it is hundreds of trillions of times denser than our sun. A tablespoonful of a neutron star would have the same mass as Mount Everest.

The neutron star is so compressed that it has the density of an atomic nucleus. The extreme pressure causes the electrons and protons in normal matter to combine into neutrons. If the core remnant would be a bit more than 2.2 times the mass of the sun it would turn into a black hole. In that sense a neutron star is the last stop before a collapsing giant star becomes a black hole.

Four pictures: 1: massive star with an inner core. 2: Inner core implodes under gravity. 3: Gravity smashes electrons and protons together, forming neutrons, and releasing a shower of neutrinos. Outer layers slosh violently from standing accretion shock instability. 4: Outer layers implode and collapse onto the inner core at 25% of the speed of light. | Neutron Stars Trillions of Times Denser than the Sun
Simplified representation of the formation of neutron stars. BedrockPerson, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0&gt;, via Wikimedia Commons

Let’s do the calculation. Let’s say the density of a neutron star is 200 trillion times that of the Sun, and the gravity is 5 billion times stronger (100 billion to 200 billion times stronger than Earth’s gravity). That results in the matter on a neutron star weighing a septillion time (1,000,000,000,000,000,000,000,000 times) more than the same volume of matter of the average density of the sun on the sun’s surface. I should say I asked ChatGPT to make this calculation using its own numbers, and it got roughly the same answer.

I can add that the average density of the sun is 1.4 grams per cubic centimeter which is less than that the average density of the earth, which is 5.5 grams per cubic centimeter. On the other hand, the gravity on the Sun’s surface is about 28 times stronger than on Earth, so if you make these comparisons with Earth instead of the sun the numbers get seven times worse, or seven septillion (7,000,000,000,000,000,000,000,000). I can add that even though neutron stars are extreme they are not rare. NASA estimates that there are a billion of them in our Milky Way Galaxy.

I consider this a super fact because it is true, and it is somewhat important to be aware of the extremes of the Universe. It tells us about who we are and our place in the Universe. A septillion times more weight, for the same volume and densities hundreds of trillions of times larger than the Sun or the Earth are surprising and shocking numbers.

A bright blue spherical neutron star on the background of the night sky.
Neutron star on a black background. Superdense remnant of a star in space. A small star with a huge mass. ShutterstockAsset id: 2369752833 by Nazarii_Neshcherenskyi

To watch a two minute video about Neutron stars, see below.

Different Types of Neutron Stars

Neutron stars are extreme stars. They are small super dense stars with extreme gravitational fields. They are in a sense like a gigantic atomic nucleus. Perhaps it is not surprising that they are extreme in other ways as well. There are pulsars, neutron stars which emit twin beams of radiation from their magnetic poles. Those poles may not be precisely aligned with the neutron star’s rotation axis, so as the neutron star spins, the beams sweep across the sky, like beams from a lighthouse. To observers on Earth, this can make it look as though the pulsar’s light is pulsing on and off.

There are magnetars, neutron stars with extremely powerful magnetic fields trillions and quadrillion times stronger than Earth’s magnetic field at the surface. If one were to get close to Earth, at the distance about the same as the moon, you would see a small new star in the sky, as cars and other metallic objects lift from the ground and the magnetic strips of credit cards and computer hard drives are erased.

There are additional classes of neutron stars such as black widow pulsars, blasting a nearby star with radiation thus killing the star, soft gamma repeaters, magnetars emitting short burst of X-rays and gamma rays in irregular repeating patterns. There are binary neutron stars (two neutron stars orbiting each other) and they sometimes merge, collide, emitting detectable gravity waves. Click on the link to see a video visualization.

A bluish neutron star surrounded by impressive looking fields. | Neutron Stars Trillions of Times Denser than the Sun
Magnetar – neutron star in deep space. For use with projects on science, research, and education. 3D illustration. Shutterstock Asset id: 1138434620 by Jurik Peter
At top there is some text stating “A neutron star is a dense core left behind after a massive star goes supernova and explodes. Though only about 10 to 20 miles (15 to 30 kilometers) wide, they can have three times the mass of our Sun, making them some of the densest objects in the universe, second only to black holes. A teaspoon of neutron star material would weigh 4 billion tons on Earth. There are several types of neutron stars.” : Below the text at the top there is a picture of a magnetar, a pulsar and a magnetar plus pulsar. The text for each picture says: Magnetar - A magnetar is a neutron star with a particularly strong magnetic field, about 1,000 times stronger than a normal neutron star. That's about a trillion times stronger than a normal neutron star. That's about a trillion times stronger than Earth's magnetic field and about 100 million times stronger than the most powerful magnets ever made by humans. Scientists have only discovered about 30 magnetars so far. Pulsar - Most of the roughly 3,000 known neutron stars are pulsars, which emit twin beams of radiation from their magnetic poles. Those poles may not be precisely aligned with the neutron star's rotation axis, so as the neutron star spins, the beams sweep across the sky, like beams from a lighthouse. To observers on Earth, this can make it look as though the pulsar's light is pulsing on and off. Magnetar + Pulsar – there are about six known neutron stars that are both pulsars and magnetars.
Courtesy NASA/JPL-Caltech, Attribution, via Wikimedia Commons

Other extreme stellar objects

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Magnetars Super Magnets in the Sky

Super fact 75 : Magnetars are a type of neutron star with extremely powerful magnetic fields ranging from 10,000,000,000,000 Gauss to 1,000,000,000,000,000 Gauss. In comparison, Earth’s magnetic field varied from about 0.25 to 0.65 Gauss at the surface. In other words, the magnetar magnetic fields are from 20 or 40 Trillion times to 2 or 4 Quadrillion times stronger than Earth’s magnetic field at the surface.

A bluish neutron star surrounded by impressive looking fields | rs Super Magnets in the Sky
Magnetar – neutron star in deep space. For use with projects on science, research, and education. 3D illustration. Shutterstock Asset id: 1138434620 by Jurik Peter

The magnetic fields of magnetars are trillions of times stronger than the sun’s magnetic field, which is 1 Gauss on a quiet sun surface and 2,000 to 4,000 Gauss in sunspots. The magnetic field of an MRI’s machine is also incredibly strong (2,000 Gauss to 100,000 Gauss). It is thousands to over a hundred thousand times stronger than Earth’s magnetic field. That’s why you should not have metals around an MRI machine. However, the magnetic field of a magnetar is still hundreds of millions to tens of billions of times stronger than the magnetic field of an MRI machine, and the magnetic field is not confined to a small machine but surrounds a neutron star and stretches far out into space.

If you placed a magnetar halfway to the moon from Earth (a magnetar is around 12 miles in diameter), it would erase all the credit cards on Earth (see video below). If you get close to a Magnetar (1000 kilometers) cars and other metal would float up in the air and the atoms in yourbody would stretch into rods making organic chemistry impossible and kill you. If you placed a steel beam on the surface of a magnetar the magnetic field would pulverize it and destroy the atoms.

In 2004 a magnetar named SGR 1806-20 located 50,000 light years from our solar system (700 million times farther than the planet Jupiter) had a starquake disturbing the magnetic field and sending out a gamma burst that disrupted radio communication on Earth. I consider the existence of magnetars a super fact because the existence of these super magnetic monsters is shocking and not well known amongst the public, and yet their existence has been confirmed.

The picture shows a bright magnetar surrounded by a bluish gamma ray burst and it is all set to a background of stars.
On 27 December 2004, a burst of gamma rays from SGR 1806−20 passed through the Solar System (artist’s conception shown). The burst was so powerful that it had effects on Earth’s atmosphere, at a range of about 50,000 light-years. U Harvard, Public domain, via Wikimedia Commons.

What Are Neutron Stars and Magnetars?

A neutron star is the gravitationally collapsed core of a massive supergiant star. The collapse causes it to become super compact and relatively small by volume. As the name implies the atoms are crushed, and protons and electrons merge into neutrons, making the neutron star mostly neutrons. The typical diameter of a neutron star ranges from 10 to 25 km (6 to 15 miles) depending on its mass. Neutron star material is extremely dense.

A normal-sized matchbox containing neutron-star material would have a weight of approximately 3 billion tons, the same weight as a 0.5-cubic-kilometer chunk of the Earth (a cube with edges of about 800 meters) from Earth’s surface, or a very large mountain. In addition, the gravity on a neutron star is immense, about 100 billion to 200 billion times stronger than Earth’s gravity.

Magnetars are neutron stars with extremely powerful magnetic fields. They have the universe’s most powerful magnetic fields (trillions of times stronger than Earth’s) that power intense X-ray/gamma-ray bursts as its field decays, often seen as highly variable pulsars. They were first theorized in 1992 to explain Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs). As of July 2021, 24 magnetars have been confirmed. According to the video below 30 magnetars have been confirmed in the Milky Way. There might be 3,000 in our Galaxy.

At top there is some text stating “A neutron star is a dense core left behind after a massive star goes supernova and explodes. Though only about 10 to 20 miles (15 to 30 kilometers) wide, they can have three times the mass of our Sun, making them some of the densest objects in the universe, second only to black holes. A teaspoon of neutron star material would weigh 4 billion tons on Earth. There are several types of neutron stars.” : Below the text at the top there is a picture of a magnetar, a pulsar and a magnetar plus pulsar. The text for each picture says: Magnetar - A magnetar is a neutron star with a particularly strong magnetic field, about 1,000 times stronger than a normal neutron star. That's about a trillion times stronger than a normal neutron star. That's about a trillion times stronger than Earth's magnetic field and about 100 million times stronger than the most powerful magnets ever made by humans. Scientists have only discovered about 30 magnetars so far. Pulsar - Most of the roughly 3,000 known neutron stars ae pulsars, which emit twin beams of radiation from their magnetic poles. Those poles may not be precisely aligned with the neutron star's rotation axis, so as the neutron star spins, the beams sweep across the sky, like beams from a lighthouse. To observers on Earth, this can make it look as though the pulsar's light is pulsing on and off. Magnetar + Pulsar – there are about six known neutron stars that are both pulsars and magnetars. | Super Magnets in the Sky
Courtesy NASA/JPL-Caltech, Attribution, via Wikimedia Commons

Magnetar YouTube Video

Other extreme stellar objects

I wish all of you Happy Holidays and Happy New Year
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The Edge of the Observable Universe is 46.5 billion Light Years Away

Super fact 67 : The Edge of the Observable Universe is 46.5 billion light years away despite the age of the Universe being 13.8 billion years. We can see 3.4 times further than light can travel in 13.8 billion years.

Esther’s writing prompt: October 29 : Edge

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That sounds impossible at first. The age of the universe is 13.8 billion years. How can we see something that is farther away than 13.8 billion light-years if that’s how long the light had to travel. The reason it works is that space itself has been expanding the entire time that the light has been traveling toward us. The light we see today from the most distant regions of the universe was emitted 13.8 billion years ago, but the space between us and the origin of that light has stretched enormously. You can say that the light hitched a ride on the expanding space.

The pictures show an expanding Universe starting with quantum fluctuations followed by inflation, then an afterglow light pattern 375,000 after the Big Bang and then the so-called dark ages, the creation of stars and galaxies. | The Edge of the Observable Universe is 46.5 billion Light Years Away
An overview of the last 13.8 billion years. This file is in the public domain in the United States because it was solely created by NASA. From Wikimedia commons.

As mentioned, the edge of the observable universe is now about 46.5 billion light-years away in every direction, which means that the observable universe is about 93 billion light-years across (46.5 billion light years times 2) vastly larger than what you’d expect if you just multiplied the age of the universe by the speed of light. Beyond that observable edge there may be much more—possibly an infinite Universe, but it is forever hidden from us because light hasn’t had time to reach us yet and will never reach us.

The speed of light in vacuum is a universal constant and nothing can travel faster then the speed of light. However, space itself can expand faster than the speed of light if measured across large enough distances. The distance between two points in space can expand faster than the speed of light if that distance is large enough. This is possible because there is nothing material that is traveling faster than light. It is just the space of the Universe itself expanding because of dark energy.

Space is expanding right where you are standing too. Can you feel space expanding around you? Well, probably not but it is. I consider this a super fact because it is an important aspect of our view of the universe, it is surprising to those who did not know it before, and it is true.

Galaxies are Moving Beyond the Observable Universe

In the future the far away galaxies will continue to move away from us faster and faster, and beyond a certain distance their light will no longer ever reach us again. Therefore, more and more galaxies will disappear from our view. They won’t vanish physically; they’ll just slip beyond our observable horizon. In about 100 billion years, observers in the Milky Way (or what is left of it) may only see the Local Group of galaxies (Milky Way, Andromeda, etc.). Everything else will have faded out of visibility.

Our Local Group of galaxies consists of 80 galaxies compared to the estimated two trillion galaxies in the current observable universe. That means that the observable universe at that point will have 25 billion times fewer galaxies than now, or in other words only 0.000000004% of the galaxies in the observable universe will remain observable.

3D rendered Digital Illustration of a cluster of galaxies. | The Edge of the Observable Universe is 46.5 billion Light Years Away
Large-scale structure of Multiple Galaxies in Deep Universe. When will all these galaxies forever disappear beyond the edge of the observable universe. Asset id: 389006449 by vchal

The Cosmological Event Horizon Another Edge of the Universe

Beyond roughly 16 billion light-years, galaxies recede faster than light due to the expansion of space. Again, that’s allowed in relativity because it’s space expanding, not them moving through space faster than light. Eventually, most of them will cross a boundary called the cosmic event horizon. Once they do, their light will never be able to reach us, not even given infinite time. We can still see these galaxies because of the light they emitted in the past, but the light they emit now will never reach us.

The cosmological event horizon, not to be confused with the event horizon for a black hole, is 16 billion light years away. That is another limit, or edge of the universe. Below is a 10 minute video explaining both the horizon / edge of the observable universe and the cosmological event horizon for those who are interested.

Black Holes Edges of the Universe

A black hole with a large bright accretion disk.
3D illustration of giant Black hole in deep space. High quality digital space art in 5K – realistic visualization. Stock Illustration ID: 2476711459 by Vadim Sadovski.

A black hole is a region of spacetime where gravity is so strong that nothing, including light, can escape it. The boundary of no escape is called the event horizon. If you pass the event horizon you cannot come back out no matter how much energy you use. Nothing can escape, no matter, no radiation, not light, or other electromagnetic radiation, and no information. Nothing at all can escape. The curvature of time and space itself forbids it.

I should add that right at the event horizon, there is so called Hawking radiation, but without complicating things it is not the same thing as escaping a black hole. You can guess from physical laws what might be inside, but you can never observe and report what is inside to planet Earth. In a sense, the event horizon of a black hole is another edge of the Universe. You can read about different types of black holes here. You can read more about black holes here, or here.

Below is an animation created by NASA that depicts what an observer falling into a black hole would see.

Black hole devouring a planet. The planet is on the right. It is being consumed.
Black hole devouring a planet. Black Hole Stock Photo ID: 2024419973 by Elena11
A black hole with an orange accretion disk is approached by futuristic starship. | The Edge of the Observable Universe is 46.5 billion Light Years Away
Realistic spaceship approaching a black hole. This content was generated by an Artificial Intelligence (AI) system. Stock AI-generated image ID: 2448481683 AI-generated image Contributor Shutterstock AI Generator.
A depiction of a black hole surrounded by a space-time geometric grid that is bending due to gravity.
AI-generated image Description : This image depicts what a black hole is doing to space around it. Gravity bends space time depicted as a grid. Stock AI-generated image ID: 2457551367 by AI-generated image Contributor Shutterstock.AI
Fuzzy orange blur surrounding a black speck.
The photo of the supermassive black hole at the center of the galaxy M87 taken by the event horizon telescope in 2017. CC BY 4.0, Event Horizon Telescope, uploader cropped and converted TIF to JPG, CC BY 4.0 <https://creativecommons.org/licenses/by/4.0&gt;, via Wikimedia Commons.
The quasar is ejecting an enormous energy beam. In the background are stars possibly being absorbed by the quasar. | The Edge of the Observable Universe is 46.5 billion Light Years Away
Quasar in deep space (a huge black hole emitting an energy beam). Elements of this image furnished by NASA. Asset id: 1758938918. by NASA images.
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A Total Solar Eclipse the Ultimate Moon Shade

Esther’s writing prompt: October 8 : Shade

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On April 8, 2024, a narrow sliver of the United States, including Dallas, where we live, experienced a total solar eclipse whilst most of the United States experienced a partial solar eclipse. We also had a three hour long partial solar eclipse and the total solar eclipse lasted four minutes. To explain, first there was a one and a half hour partial solar eclipse, then the total solar eclipse lasting four minutes, and then a one and a half hour long partial solar eclipse again. A partial solar eclipse is interesting, but a total solar eclipse is something else entirely. A total solar eclipse is the ultimate moon shade and an unforgettable lifetime experience.

We were all sitting outside in our backyard having a little party, drinking beer and eating snacks, as the partial solar eclipse began. During the partial solar eclipse, it was still daylight, and you could not look at the sun unless you had ISO certified solar eclipse glasses, which we did. When you put on the solar eclipse glasses you could see that the sun looked like a crescent. This was not possible to see without the solar eclipse glasses, and you certainly should not look at the sun during a partial solar eclipse.

Suddenly, it got dark, not entirely dark, but more like as if it was well into twilight. The sun turned into a black circle surrounded by a faint wispy light. That was the sun’s corona, which normally is invisible due to the sun’s powerful light. The sun’s transformation only took a few seconds. The darkness fell extremely fast as if someone turned off the lights. Now you could look straight at the sun without the ISO certified solar eclipse glasses. Looking straight at the sun during a total eclipse is perfectly safe since all you see is a black circle in the sky. What you see is the black moon. The sun is hidden behind the moon. However, you need to be ready to put on your glasses, or turn your head, when it is time for the sun to come back.

As the sun suddenly vanished, the birds and the insects became quiet. The stars came out. Venus appeared above our heads, not far from the sun. It shone brightly in a location where you normally never see Venus. Venus typically appears above the western horizon after sunset (the evening star) or above the eastern horizon before sunrise (the morning star), not right above you. It was quiet, dark, the sky was beautiful and filled with stars, and there was a black circle in the sky surrounded by the magical faintly shining corona.

I knew what was coming next as the four minutes came to a close, so I put my ISO certified solar eclipse glasses back on. At first, I saw nothing. Then I saw something that looked like a big star that was quickly expanding like a super nova and turning into a thin bright thin crescent. The lights came on, the stars and Venus disappeared, the birds and insects began making noise again. Daylight and the whole world returned in just a few seconds. Now we had another one and a half hour of a partial solar eclipse to enjoy (using our solar eclipse glasses).

Map of north America showing the path of the total solar eclipse on April 8, 2024. Several cities in the path of totality are marked | A Total Solar Eclipse the Ultimate Moon Shade
Path of totality (total solar eclipse). I am allowed to use this image as long as I link back to the National Eclipse. Click on the image to visit the National Eclipse.

What is a Total Solar Eclipse?

Solar eclipse occurs when the Moon passes between the Sun and Earth, blocking the Sun’s light and casting a shadow on Earth’s surface. This is illustrated in the picture below. As you can see there’s a weaker but larger shadow covering a portion of earth. This corresponds to the moon not blocking all of the sun, which results in a bright sun crescent. The darker smaller region/circle on earth corresponds to the moon blocking all of the sun resulting in near total darkness. This is the region on earth that has a total solar eclipse.

The illustration shows the sun on the left, then the moon blocking the sun’s light for earth, which is located on the right.
Solar Eclipse with Sun Moon and Earth Orbit. Shutterstock Asset id: 2292547031 by Nandalal Sarkar
Blue planet earth with a small moving dot for totality and a big blue shadow showing the extent of partial solar eclipse | A Total Solar Eclipse the Ultimate Moon Shade
Gif animation illustrating totality and extent of partial solar eclipse. Official work for NASA.
The photo shows a dark blue sky and a black circle surrounded by a wispy light. That is the sun’s corona.
Solar Eclipse. The moon moving in front of the sun. The wispy light is the sun’s corona. It is typically invisible due to the sun’s strong light. It is fine to look at the sun’s corona with the naked eye. It is not very bright, more like the moon’s light. I can add that this photo corresponds the closest to what we saw with our naked eyes. Asset id: 2441654015 by GagliardiPhotography
Solar Eclipse photo | Black circle surrounded by a wispy white fog like light. That’s the sun’s corona | A Total Solar Eclipse the Ultimate Moon Shade
Solar Eclipse photo taken with a photo filter solar Stock Photo ID: 2344355767 by aeonWAVE
The photo shows total solar eclipse, the sun totally covered by the moon. It is very small in the photo. There is a star-like object, that’s Venus, a cloud and airplane contrail.
Total solar eclipse photo that my daughter took with her iPhone. The sun, I mean the moon, looks small in the picture, but they were the normal size. Can you find Venus?
Photo of my 10 solar eclipse glasses | A Total Solar Eclipse the Ultimate Moon Shade
My solar eclipse glasses that I bought on Amazon.

Partial Solar Eclipse

As I said, most of the country had a partial solar eclipse and we had a partial solar eclipse as well as a total solar eclipse. During a partial solar eclipse, it does not get dark, no stars come out (the sun is too bright), the birds don’t stop singing, and you cannot see the partial solar eclipse with the naked eye. You need ISO certified solar eclipse glasses. However, there are other cool effects such as the shadows of the trees turn into thousands of little crescents.

The photo shows a shiny crescent on black background.
Partial eclipse photo taken with my old Samsung Galaxy phone and a photo filter.
The moon is passing in front of the sun causing a partial solar eclipse.
Illustration / enhanced photo of partial solar eclipse. Shutterstock Asset id: 2237042889 by Kolonko

Annular Solar Eclipse

Lastly there are also annular solar eclipses. That is almost a total solar eclipse, but the moon is not covering all of the sun’s disc resulting in circle of the sun being visible. It is similar to a partial solar eclipse in the sense that it is still daylight, the stars won’t come out, etc. I can add that even though the light is dimmed a bit during an annular solar eclipse it does not get dark as during a total solar eclipse. The picture below is a bit misleading in that sense (probably a photo filter).

A ring of fire around a black circle with a silhouette of a dromedary camel | A Total Solar Eclipse the Ultimate Moon Shade
Annular solar eclipse in desert. Liwa desert, Abu Dhabi, United Arab Emirates. Shutterstock Asset id: 1598991664 by Kertu

Miscellaneous Solar Eclipse Photos taken with Cell Phones

These eight pictures above were taken with cell phones by my daughter Rachel, and friends Denise Mosier-Wanken, and Margaret Weiss Bloebaum.

If you want to read more about this experience you can click here or here.

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