For 400 years people have tracked sunspots, the dark patches that appear for weeks at a time on the sun's surface. They have observed but been unable to explain why the number of spots peaks every 11 years.
Plasma Physics
Sep 19, 2019
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West Virginia University researchers have helped discover the most massive neutron star to date, a breakthrough uncovered through the Green Bank Telescope in Pocahontas County.
Astronomy
Sep 16, 2019
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A newly discovered comet has excited the astronomical community this week because it appears to have originated from outside the solar system. The object—designated C/2019 Q4 (Borisov) - was discovered on Aug. 30, 2019, ...
Space Exploration
Sep 13, 2019
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801
Experimenting at 4.1 million degrees Fahrenheit, physicists at Sandia National Laboratories' Z machine have found that an astronomical model—used for 40 years to predict the sun's behavior as well as the life and death ...
Plasma Physics
Sep 10, 2019
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188
A team of researchers with members from China, Germany, the U.K. and the U.S. has found a way to entangle photons generated millions of miles apart. In their paper published in the journal Physical Review Letters, the researchers ...
Since NASA's Parker Solar Probe launched on Aug. 12, 2018, Earth has made a single trip around the sun—while the daring solar explorer is well into its third orbit around our star. With two close passes by the sun already ...
Space Exploration
Aug 13, 2019
1
17
This image shows a snippet of the Sun up close, revealing a golden surface marked by a number of dark, blotchy sunspots, curving filaments, and lighter patches known as 'plages' – brighter regions often found near sunspots. ...
Space Exploration
Aug 05, 2019
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The sun's solar wind affects nearly everything in the solar system. It can disrupt the function of Earth's satellites and creates the lights of the auroras.
Space Exploration
Jul 29, 2019
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An international team of astronomers has witnessed a rare dynamic event foreshadowing the death of a red giant star for the first time – a discovery that reinforces predictions about our Sun's ultimate demise.
Astronomy
Jul 25, 2019
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261
A newly discovered series of genes related to feed efficiency could pave the way to making cattle farming cheaper and more sustainable, according to a new study by University of Alberta researchers.
Plants & Animals
Jul 17, 2019
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The Sun is the star at the center of the Solar System. The Earth and other matter (including other planets, asteroids, meteoroids, comets, and dust) orbit the Sun, which by itself accounts for about 99.86% of the Solar System's mass. The mean distance of the Sun from the Earth is approximately 149.6 million kilometers (93.0 million miles), and its light travels this distance in 8 minutes and 19 seconds. This distance varies throughout the year from a minimum of 147.1 million kilometers (91.4 million miles) on the perihelion (around 3 January), to a maximum of 152.1 million kilometers (94.5 million miles) on the aphelion (around 4 July). Energy from the Sun, in the form of sunlight, supports almost all life on Earth via photosynthesis, and drives the Earth's climate and weather. The Sun consists of hydrogen (about 74% of its mass, or 92% of its volume), helium (about 24% of mass, 7% of volume), and trace quantities of other elements, including iron, nickel, oxygen, silicon, sulfur, magnesium, carbon, neon, calcium, and chromium.
The Sun has a spectral class of G2V. G2 means that it has a surface temperature of approximately 5,780 K (5,510 °C) giving it a white color, which often appears as yellow when seen from the surface of the Earth because of atmospheric scattering. It is this scattering of light at the blue end of the spectrum that gives the surrounding sky its color. The Sun's spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines. The V (Roman five) in the spectral class indicates that the Sun, like most stars, is a main sequence star. This means that it generates its energy by nuclear fusion of hydrogen nuclei into helium. There are more than 100 million G2 class stars in our galaxy. Once regarded as a small and relatively insignificant star, the Sun is now known to be brighter than 85% of the stars in the galaxy, most of which are red dwarfs.
The Sun's hot corona continuously expands in space creating the solar wind, a hypersonic stream of charged particles that extends to the heliopause at roughly 100 AU. The bubble in the interstellar medium formed by the solar wind, the heliosphere, is the largest continuous structure in the Solar System.
The Sun is currently traveling through the Local Interstellar Cloud in the low-density Local Bubble zone of diffuse high-temperature gas, in the inner rim of the Orion Arm of the Milky Way Galaxy, between the larger Perseus and Sagittarius arms of the galaxy. Of the 50 nearest stellar systems within 17 light-years (1.6×1014 km) from the Earth, the Sun ranks 4th in mass as a fourth magnitude star (M = +4.83)., although slightly different values for the magnitude have been published, for example 4.85 and 4.81. The Sun orbits the center of the Milky Way galaxy at a distance of approximately 24,000–26,000 light years from the galactic center, moving generally in the direction of Cygnus and completing one revolution in about 225–250 million years (one Galactic year). Its orbital speed was thought to be 220 ± 20, km/s but a new estimate gives 251 km/s. Since our galaxy is moving with respect to the cosmic microwave background radiation (CMB) in the direction of Hydra with a speed of 550 km/s, the sun's resultant velocity with respect to the CMB is about 370 km/s in the direction of Crater or Leo.
This text uses material from Wikipedia, licensed under CC BY-SA
