- 3147 - EQUINOX - spring returns ? The March and September equinoxes occur when both the Northern and Southern Hemispheres equally face the sun and all parts of the world have the sun above the horizon for exactly 12 hours, and below the horizon for exactly 12 hours. Equal days and equal nights are the equinox.
- ----------------------- 3147 - EQUINOX - spring returns?
- Spring will officially arrived on Saturday morning, March 20, 2021 with the occurrence of the “vernal equinox“.
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- The vernal equinox occurs when the sun is positioned directly over the Earth's equator at 09:37 Universal Time; 5:37 a.m. Eastern Daylight Time or 2:37 a.m. Pacific Daylight Time.
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- At that particular moment, the sun will appear to shine directly overhead from a point 5 miles south of Meru, in Kenya; a city of approximately 241,000 residents.
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- Until the occurrence of the “summer solstice” on June 20, the sun will appear to migrate northward and the length of daylight in the Northern Hemisphere will continue to increase.
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- As the altitude of the midday sun gets progressively higher, the arc that it takes across the sky will also increase. On the date of the equinox, the sun will rise due east and will set due west.
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- During the coming days and weeks, as the sun's direct rays are concentrated more and more on the Northern Hemisphere, its rising and setting positions will become increasingly oriented more to the north of due east and north of due west.
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- The 2020 vernal equinox was the earliest spring in 124 years
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- Use your clenched fist held at arm's length to measure roughly 10 degrees in width. On the first day of summer, as seen from mid-northern latitudes, the sun will be rising not due east, but 33 degrees, or a bit more than "three fists", to the north of due east. And a bit more than 15 hours later, it will be setting not due west, but 33 degrees to the north of due west.
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- Our seasons take place because as our planet revolves around the sun, its axis is tilted at a 23.5-degree angle. This tilt causes different latitudes on Earth to receive varying amounts of heat and light from the sun throughout the course of the year.
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- For the Northern Hemisphere, the June solstice marks the start of the summer season and occurs when the direct rays of the sun shine down on that part of the globe 23.5 degrees north of the equator, the “Tropic of Cancer“.
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- The December solstice marks the beginning of winter, when the direct rays of the sun are shining down on that part of the globe 23.5 degrees south of the equator, the “Tropic of Capricorn“.
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- The March and September equinoxes occur when both the Northern and Southern Hemispheres equally face the sun and all parts of the world have the sun above the horizon for exactly 12 hours, and below the horizon for exactly 12 hours. Equal days and equal nights are the equinox.
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- Well … that's not exactly true. A complication revolving around the vernal equinox concerns the length of day versus night. Since grammar school we all have been taught that on the first days of spring and autumn, that day and night are equal to exactly 12 hours all over the world.
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- Yet, if you check the calculations made by the U.S. Naval Observatory or the sunrise/sunset tables in any reputable almanac, you will find that this is not so. In fact, on the days of the spring and fall equinox the length of time that the sun is above the horizon is actually longer than the time it spends out of sight below the horizon by several minutes.
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- The difference in the number of hours separating sunrise and sunset on the day of equinox are not equal at all.
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- Check out New York City. As the table below shows, days and nights are equal not on the equinox, but actually, a few days earlier, on Saint Patrick's Day , March 17:
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- Date Sunrise Sunset Length of Day
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- March 17 6:05 a.m. 6:05 p.m. 12 hrs. 00 min.
- March 18 6:03 a.m. 6:06 p.m. 12 hrs. 03 min.
- March 19 6:02 a.m. 6:07 p.m. 12 hrs. 05 min.
- March 20 6:00 a.m. 6:08 p.m. 12 hrs. 08 min.
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- One factor is that the moments of sunrise and sunset are considered when the top of the sun, and not its center, is on the horizon. This alone would make the time of sunrise and sunset a little more than 12 hours apart on these days. The sun's apparent diameter is roughly equal to half a degree.
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- The main reason that this happens can be attributed to our atmosphere that acts like a lens and refracts (bends) its light above the edge of the horizon. In their calculations of sunrise and sunset times, the U.S. Naval Observatory routinely uses 34 minutes of arc for the angle of refraction and 16 minutes of arc for the semi diameter of the Sun's disc. The geometric center of the sun is actually 0.83º below a flat and unobstructed horizon at the moment of sunrise.
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- When you watch the sun either coming up above the horizon at sunrise or going down below the horizon at sunset, you are actually looking at an illusion, the sun is not really there, but actually is below the horizon.
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- We actually end up seeing the sun for a few minutes before its disk actually rises and for a few minutes after it has actually set. Thanks to atmospheric refraction, the length of daylight on any given day is increased by approximately six or seven minutes. I thought you needed to know that.
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- 2981 - SUN - sunsets are beautiful, why??
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- 2592 - SUN - This review discusses how the stars and the Sun formed the elements in the Periodic Table. You will learn how elements are identified in the stars. Discoveries are made in the stars that are later reproduced in the laboratories on Earth. Discoveries of the abundance of elements in the Sun tell astronomers about the evolution of the Universe.
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- 2489 - SUN - facts you won’t believe? - The Sun is HOT but not so HOT. In fact, your body heat is hotter than the Sun. What? You’re kidding? Right? What you will learn from this review is that the Sun is not so hot but it is so big.
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- 2544 - SUN - and stars at our galactic center? The Milky Way's early life was the fastest growth period for nuclear disk at the center of our galaxy. During our galaxy's first 5 billion years, over 80% of the galaxy's stars were born, but then it dipped into a "quiescent" state, where star formation dropped away. A huge increase in activity occurred just 1 billion years ago, when approximately 5% of the center's stellar mass suddenly burst to life.
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- 2542 - SUN - our closest star.? It is an average star compared with the population of stars in our Universe. We can learn a lot about stars by studying our Sun, which is only 93,000,000 miles away. Sun light takes just 8.3 minutes to reach us from the surface of the Sun.
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- 2540 - SUN POWER - How much reaches your backyard? The fusion energy that heats my yard comes from 0.000000000115 pounds of hydrogen mass converted to energy every second. One hydrogen atom, a proton, has a mass of 1.67*10^-27 kilograms. My yard uses 31,000,000,000,000,000 hydrogen atoms every second in order to grow grass and a vegetable garden.
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- 2525 - SUN - new discoveries with the solar probe. The Parker Solar Probe launched in August 2018 and made its first solar flyby in November. Over its seven-year mission, the probe will buzz by the sun 24 times, swinging lower on each pass until it finally comes within four million miles of the sun’s surface.
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- 2488 - SUN - facts you won’t believe? - The Sun is HOT but not so HOT. In fact, your body heat is hotter than the Sun. What? You’re kidding? Right? What you will learn from this review is that the Sun is not so hot but it is so big.
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- 2169 - The Universe is 13.8 billion years old. Our sun is 5 billion years old. Our sun must be a second or third generation star. It is composed of the residue of 2 or 3 earlier supernovae explosions from earlier stars that died spreading their elements all over the cosmos. The more we learn about our sun the more we will know about the other stars in the Universe.
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- 2168 - SUN - Parker Solar Probe. The mission's objectives include tracing the flow of energy that heats and accelerates the sun's corona and solar wind, determining the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind and explore mechanisms that accelerate and transport energetic particles.
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- 2165 - Why is the Sun so hot? The Sun’s surface is about 10,000 degrees Fahrenheit. But, surrounding the Sun is an atmosphere of gas known as the corona. This envelope of superheated gas is called a plasma and it measures more than 3,000,000 degrees. Astronomers are still trying to figure out how the outer layer of this star is so much hotter than what lies beneath it.
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- 1834 - That Lucky ol’ Sun got nothing to do? This review tells how the Sun gets its energy and how it compares with other stars in the Universe. And, how long will the Sun live?
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- 1720 - How do we know the age of the Sun? How do we know the age of the Sun? How fast is it “ burning” hydrogen? What does how fast it spinning have to do with this?
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- 1674 - What causes a star to evolve into a Red Giant star , like our Sun will do in another 5 billion years.
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- 1455 - Our Sun was born with a family of stars? Astronomers are trying to find them.
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- 1220 - Does the Sun contain the Periodic Table?
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- 533 - Why our Sun will become a variable star? A White Dwarf star.
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- 383 - Could our Sun be a variable star?
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- May 3, 2021 EQUINOX - spring returns? 3147
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--------------------- --- Tuesday, May 4, 2021 ---------------------------
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