Russian rocket successfully puts Iranian satellite into orbit
A Russian rocket on Thursday successfully put an Iranian satellite into orbit, a launch that underlined increasingly close cooperation between Moscow and Tehran.
A Russian rocket on Thursday successfully put an Iranian satellite into orbit, a launch that underlined increasingly close cooperation between Moscow and Tehran.
Space Exploration
Feb 29, 2024
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This image of the softly luminous spiral galaxy UGC 11105 is from the NASA/ESA Hubble Space Telescope. It lies about 110 million light-years from Earth in the constellation Hercules.
Astronomy
Feb 5, 2024
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After its successful first asteroid encounter in 2023, NASA's Lucy mission has its sights firmly set on its main targets, the never-before-explored Jupiter Trojan asteroids. In 2024, the Lucy spacecraft will transition from ...
Space Exploration
Jan 26, 2024
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Spring, summer, fall and winter—the seasons on Earth change every few months, around the same time every year. It's easy to take this cycle for granted here on Earth, but not every planet has a regular change in seasons. ...
Planetary Sciences
Jan 10, 2024
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A crippling fuel leak forced a U.S. company on Tuesday to give up on landing a spacecraft on the moon.
Space Exploration
Jan 9, 2024
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NASA's Parker Solar Probe completed its 18th close approach to the sun on Dec. 28, 2023, matching its own distance record by skimming just about 4.51 million miles (7.26 million kilometers) from the solar surface.
Space Exploration
Jan 8, 2024
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The sun emitted a strong solar flare, peaking at 4:55 p.m. EST, on Dec. 31, 2023. NASA's Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event.
Astronomy
Jan 3, 2024
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The cosmos comes alive in an all-sky time-lapse movie made from 14 years of data acquired by NASA's Fermi Gamma-ray Space Telescope. Our sun, occasionally flaring into prominence, serenely traces a path through the sky against ...
Astronomy
Dec 20, 2023
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It's a classic tale of apocalyptic fiction. The sun, our precious source of heat and light, collapses into a black hole. Or perhaps a stray black hole comes along and swallows it up. The End is Nigh! If a stellar-mass black ...
Astronomy
Dec 18, 2023
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A NASA telescope has captured the biggest solar flare in years, which temporarily knocked out radio communication on Earth.
Planetary Sciences
Dec 15, 2023
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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