- 2981 - SUN - sunsets are beautiful, why? With the larger distance of atmosphere to cover, the blue light mostly bounces back out into space. But the red, orange and yellow light have longer wavelengths. This means they can scatter for longer and travel through more of the atmosphere to reach us.
----------------------------------- 2981 - SUN - sunsets are beautiful, why??
- What creates the beautiful colors of sunsets and sunrises. Why does this happen, when most of the time the sky is blue?
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-It is all because of the fact that light has color. Believe it or not, the light you see is a combination of all the colors in the world.
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- Then why do we only see some colors in the sky at certain times, and not all of them?
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- We first need to know how day turns into night.
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- Our planet, Earth, moves in space with seven other planets nearby. They all spin in circles on the spot, but also move in much larger circles around the Sun. When the Sun is setting this means our side of the planet is turning away from the Sun. During sunrise, we are turning towards it.
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- Night time happens when we are no longer facing the Sun at all. Daytime happens when we have twirled to face the Sun directly so its sunbeams travel directly to us.
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- Beams of light from the Sun come in different sizes. All light does from microwaves to gamma rays. Scientists measure these sizes using “wavelength”. A wave length is one complete of a single wave. “Frequency” of waves is the number of these cycles each second.
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- Each different wavelength of light has its own unique color.
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- We know why the sky is bright during the day and dark at night. And we know sunbeams come in different sizes, or “wavelengths”.
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- The colors we see during sunset and sunrise happens because of the blanket of air wrapped around Earth, the atmosphere. Earth’s atmosphere is made up of many very tiny objects called molecules.
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- Each molecule is much, much smaller than a grain of sand. When the Sun’s beams reach Earth, they meet the molecules in Earth’s atmosphere. The molecules then begin bouncing the light waves back and forth between themselves. This is called light “scattering”.
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- The longer a wavelength of light is, the longer it can keep scattering between the molecules in our Earth’s atmosphere.
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- Blue light has a shorter wavelength than red or pink light. This means it can only bounce between the molecules for a shorter distance.
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- When directly facing the Sun (daytime), there’s less atmosphere for the light to pass through. Blue light can easily come out the other side giving us a blue sky.
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- We already know Earth spins in its place. During sunset we are circling away from the Sun and no longer facing it directly. This means sunlight has to travel through a thicker slice of the atmosphere to reach us. This happens during sunrise too, when we are moving towards the Sun.
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- With this larger distance of atmosphere to cover, the blue light mostly bounces back out into space. But the red, orange and yellow light have longer wavelengths. This means they can scatter for longer and travel through more of the atmosphere to reach us.
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- And this is why we have beautiful bright sunsets and sunrises. To learn more see Review 2613 - SUNSPOTS - The Sun is supposed to follow 11-year cycles of minimum and maximum activity that should trace set patterns pretty much like clockwork, give or take weaker and stronger sunspot patterns, flares, and periods of coronal mass ejections. What’s going on?
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- Now you know why the sunrises and sunsets have colors . Let’s explore why the sun has spots.
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- Humans have observed sunspots which are dark blotches that arise from strong magnetic activity for more than 1,000 years, and tracked them in detail since the invention of the telescope, for the past 400.
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- Even with the modern-day host of spacecraft studying the Sun, taking the time to draw sunspots remains the chief way they're counted. Surveying sunspots is the most basic of ways we study how solar activity rises and falls over time, and it's the basis of how we track the solar cycle.
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- Sunspots correspond with the Sun's natural 11-year cycle, in which the Sun shifts from relatively calm to stormy. At its most active, called solar maximum, the Sun is freckled with sunspots and its magnetic poles reverse. On Earth, that would be like if the North and South Poles flip-flopped every decade. During solar minimum, sunspots are few and far between. Often, the Sun is as blank and featureless.
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- Understanding the Sun's behavior is an important part of life in our solar system. The Sun's powerful outbursts can disturb the satellites and communications signals traveling around Earth, or one day, Artemis astronauts exploring distant worlds.
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- NASA scientists study the solar cycle so we can better predict solar activity. As of 2020, the Sun has begun to shake off the sleep of minimum, which occurred in December 2019. Solar Cycle 25 is underway, and scientists are eager for another chance to put their understanding of solar cycle signs to the test.
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-Around the world, observers conduct daily sunspot censuses. They draw the Sun at the same time each day, using the same tools for consistency. Together, their observations make up the international sunspot number, a complex task.
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- Some 80 stations around the world contribute their data. Exactly how many stations are included in each day's count depends on a number of factors like weather ,clouds and high winds obscure view of the Sun.
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- Despite the interference of daily life, these manual surveys are still the most reliable, long-term record of sunspots we have. Long-term studies are the backbone of solar cycle science. With extensive historical records, scientists can trace the arc of decades-long patterns in the Sun's behavior.
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- When it comes to counting sunspots, it's not so much about the accuracy or resolution of the observations as the consistency of the data itself. Even while their city was shut down due to the coronavirus pandemic, an observer from the Royal Observatory team made their way each day to the telescope tower, to keep the record intact.
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- Sunspots arise from clusters of intense magnetic energy. Buoyed by their magnetic force, they rise through churning solar material like a grain of rice in a boiling pot. Sunspots appear darker because they're cooler than their surroundings; the magnetic knot at their core keeps energy from radiating out past the Sun's surface.
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- When enough magnetic energy builds over the sunspot, a powerful eruption can burst free, like an exploding soda bottle, spewing light and solar matter.
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- If they happen to be facing Earth, these solar storms can disrupt satellites, astronauts, and communications signals like radio or GPS. Earth's upper atmosphere might expand in response, slowing satellites in orbit eroding satellites' lifetimes.
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- Deep inside the Sun, electrified gases flow in currents that generate the Sun's magnetic field, which fuels its mighty outbursts. During solar minimum, the Sun's magnetic field is relaxed. At the height of the solar cycle, it's a tangled mess of magnetic field lines.
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- Since 1989, the Solar Cycle Prediction Panel has met each decade to make their prediction for the next solar cycle. The prediction includes the sunspot number at maximum and the cycle's expected start and peak. The effort requires assessing many different models and navigating many personalities.
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- Since minimum is defined by the lowest number of sunspots in a solar cycle, scientists have to see the numbers steadily rise before determining when they were at the bottom.
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- To complicate things, solar cycles often overlap. As one cycle transitions to the next, both old and new sunspots emerge on the Sun at once. Sunspots often appear in groups, which are like magnets, each with a positive and negative end.
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- As the Sun's magnetic field slowly flips, so does the polarity of sunspot groups. Where one cycle's sunspots drift across the Sun with their positive end in the lead, the next cycle's spots walk negative foot first. On top of that, sunspots in the Sun's two hemispheres also have opposite orientations.
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- Each sunspot's unique magnetic signature makes it possible to determine which cycle produced it, the old one or the new. When the Sun stirs from solar minimum, besides counting the sunspots, scientists want to make sure all the spots rising to the surface are actually new.
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- It can be six to eight months past minimum before we can say minimum has actually occurred. Not until September 2020 did scientists confirm the Sun reached solar minimum in December 2019.
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- Besides sunspots, other indicators can signal when the Sun is reaching its low. If the Sun's magnetic field were a jigsaw puzzle, one piece is still missing: the magnetic field at the poles. Although scientists can't measure the polar magnetic field as accurately as other parts of the Sun, estimates provide clues.
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- In previous cycles, scientists have noticed the strength of the polar magnetic field during solar minimum hints at the intensity of the next maximum. When the poles are weak, the next maximum is weak, and vice versa.
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- The past few cycles, the strength of the magnetic field at the Sun's poles has steadily declined; so too has the sunspot number. Now, the poles are roughly as strong as they were at the same point in the last cycle, Cycle 24.
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- Another indicator of solar cycle progress comes from outside the solar system. Cosmic rays are high-energy particle fragments, the rubble from exploded stars in distant galaxies. During solar maximum, the Sun's strong magnetic field envelops our solar system in a magnetic cocoon that is difficult for cosmic rays to infiltrate.
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- In off-peak years, the number of cosmic rays in the solar system climbs as more and more make it past the quiet Sun. By tracking cosmic rays both in space and on the ground, scientists can measure of the solar cycle.
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- One area of solar study, called “helioseismology“, involves scientists collecting soundwaves from inside the Sun, as a way of probing the elusive dynamo. During solar minimum, they don't have to worry about soundwaves bouncing off the sunspots and active regions characteristic of solar maximum. When sunspots disappear from view, scientists have a chance to fine tune their models .
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- Solar Cycle 25 has begun. How will the coming upswing in space weather impact our lives and technology on Earth, as well as astronauts in space. As we emerge from solar minimum and approach Cycle 25's maximum, solar activity never stops; it changes form as the pendulum swings.
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- Space weather predictions are also critical for supporting Artemis program spacecraft and astronauts. Surveying this space environment is the first step to understanding and mitigating astronaut exposure to space radiation.
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- The first two science investigations to be conducted from the “Gateway” will study space weather and monitor the radiation environment in lunar orbit. Scientists are working on predictive models so they can one day forecast space weather much like meteorologists forecast weather on Earth.
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- With solar minimum behind us, scientists expect the Sun's activity to ramp up toward the next predicted maximum in July 2025. Cycle 25 is anticipated to be as strong as the last solar cycle, which was a below-average cycle, but not without risk.
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- The Sun's impact on our daily lives is real and is there.
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-------------------------------- Other Reviews available:
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- 2652 - PARKER SOLAR PROBE - new discoveries about our sun? - A mission to “touch” the Sun. NASA launched the probe in August 2018, and it has already made a few laps around the Sun. It has brought new insights into the Sun's outer atmosphere, as well as uncovered surprising facts about the solar wind and the Sun's magnetic fields.
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- 2618 - SUN - learning closer than ever? The Solar Orbiter spacecraft, a collaboration between the European Space Agency and NASA, launched February 9, 2020. On January 29, NASA's Parker Solar Probe made its closest swing pass the sun to date, a record it will continue to break until 2025. We have been studying the sun for a thousand years. Learning is closer that ever!
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- 2613 - SUNSPOTS - The Sun is supposed to follow 11-year cycles of minimum and maximum activity that should trace set patterns pretty much like clockwork, give or take weaker and stronger sunspot patterns, flares, and periods of coronal mass ejections. That is what I learned in High School. So, what’s going on?
- 2599 - SUN - End of Humanity? The Sun is 4.6 billion years old. What happens to the Sun when it runs out of hydrogen for fusion energy? It will live another 5 billion years then its hydrogen will have mostly burned off and the core of the Sun will be solid helium. It will continue burning but it will be twice as hot. Humanity will need to have found another home.
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- 2598 - SUN - from our latest satellites? A new spacecraft is journeying to the Sun to snap the first pictures of the Sun's north and south poles. Now, we'll be able to look down on the Sun from above. The Sun plays a central role in shaping space around us. Its massive magnetic field stretches far beyond Pluto, paving a superhighway for charged solar particles known as the solar wind.
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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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January 15, 2021 SUN - sunsets are beautiful, why?? 2981
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--------------------- --- Friday, January 15, 2021 ---------------------------
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