Dynamic Space

PLANETS? Planet , broadly, any relatively large natural body that revolves in an orbit  around the Sun  or around some other star  and that is not radiating energy  from internal nuclear fusion  reactions. In addition to the above description, some scientists impose additional constraints regarding characteristics such as size (e.g., the object should be more than about 1,000 km [600 miles] across, or a little larger than the largest known  asteroid ,  Ceres ), shape (it should be large enough to have been squeezed by its own  gravity  into a sphere—i.e., roughly 700 km [435 miles] across, depending on its density), or mass (it must have a mass insufficient for its core to have experienced even temporary nuclear fusion). As the term is applied to bodies in Earth’s solar system, the  International Astronomical Union   (IAU), which is charged by the scientific  community  with classifying astronomical objects, lists eight planets orbiting the Sun; in order of increasing distance, they ar

Who is the free source of Vitamin D?  Answer:   Sun Star The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy mainly as visible light and infrared radiation. It is by far the most important source of energy for life on Earth. Surface temperature:  5,778 K Distance to Earth:  149.6 million km Mass:  1.989 × 10^30 kg Age:  4.603 billion years Radius:  696,340 km Moons:  3122 Florence ,  130 Elektra Layers The layers of the Sun are divided into two larger groups, the outer and the inner layers. The outer layers are the  Corona , the Transition Region, the  Chromosphere , and the  Photosphere , while the inner layers are the  Core , the  Radiative Zone , and the  Convection Zone . Core The  Sun's core  is the central region where nuclear reactions consume hydrogen to form helium. These reactions release the energy that ultimately leaves the surface as vis

  ON THIS PAGE 10 Things to Know About Our Solar System Our Solar System Why Is It Called The "Solar" System? There are many planetary systems like ours in the universe, with planets orbiting a host star. Our planetary system is named the "solar" system because our Sun is named Sol, after the Latin word for Sun, "solis," and anything related to the Sun we call "solar." Our planetary system is located in an outer spiral arm of the Milky Way galaxy. The Latest   NASA's Juno Reveals Dark Origins of One of Jupiter's Grand Light Shows Our solar system consists of our star, the Sun, and everything bound to it by gravity — the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, dwarf planets such as Pluto, dozens of moons and millions of asteroids, comets and meteoroids. Beyond our own solar system, we have discovered thousands of planetary systems orbiting other stars in the Milky Way. Go farther.  Explore Our Solar System