Search results
Results from the WOW.Com Content Network
The widely accepted modern variant of the nebular theory is the solar nebular disk model (SNDM) or solar nebular model. [1] It offered explanations for a variety of properties of the Solar System, including the nearly circular and coplanar orbits of the planets, and their motion in the same direction as the Sun's rotation.
Reflection nebulae themselves do not emit significant amounts of visible light, but are near stars and reflect light from them. [25] Similar nebulae not illuminated by stars do not exhibit visible radiation, but may be detected as opaque clouds blocking light from luminous objects behind them; they are called dark nebulae .
Box Nebula NGC 6445: 1786 4.5 11.2 Sagittarius: Eye of Sauron Nebula M 1-42: 10 14 Sagittarius
The following articles contain lists of nebulae: List of dark nebulae; List of diffuse nebulae; List of planetary nebulae; List of protoplanetary nebulae;
A typical planetary nebula is roughly one light year across, and consists of extremely rarefied gas, with a density generally from 100 to 10,000 particles per cm 3. [40] (The Earth's atmosphere, by comparison, contains 2.5 × 10 19 particles per cm 3.) Young planetary nebulae have the highest densities, sometimes as high as 10 6 particles per ...
If the universe is flat, there must be an additional component making up 73% (in addition to the 23% dark matter and 4% baryons) of the energy density of the universe. This is called dark energy. In order not to interfere with Big Bang nucleosynthesis and the cosmic microwave background, it must not cluster in haloes like baryons and dark matter.
Dark energy does not exist, some scientists have claimed – which could help get rid of one of the universe’s biggest mysteries. For a century, scientists have thought that the universe was ...
The Hubble law implies that the universe is expanding. [11] A decade before, the American astronomer Vesto Slipher had provided the first evidence that the light from many of these nebulae was strongly red-shifted, indicative of high recession velocities. [12] [13]