Also called: visible horizon, apparent horizon the apparent line that divides the earth and the sky.

Horizon. Science specifies dawn as a particular moment defined by the solar elevation angle, which is the position of the Sun in relation to the horizon.

The area corresponding to the farthest distance which can be seen in a given direction. The higher the observer, the lower and more distant is his visible horizon.

The particle horizon is the sphere centered on us that has a radius equal to the distance that light can travel in 13.8 Gyr (the age of the Universe). Astronomy. All Free. (In astronomy it is defined as the intersection on the celestial sphere of a plane perpendicular to a plumb line.) Synonyms: skyline, view, vista, field or range of vision More Synonyms of horizon. As with dusk, astronomers differentiate between 3 different stages of dawn, each marking the beginning of 1 of the 3 phases of morning twilight: To one 5 feet (1.5 m) above

the line or circle that forms the apparent boundary between earth and sky. Scientific Definition.

the small circle of the celestial sphere whose plane is tangent to the earth at the position of a given … This region is typically considered the “black hole”. 2 (Astronomy) a level reflecting surface, such as one of mercury, that measures the altitude of a celestial body as half the angle between the body and its reflection B horizon n the layer of a soil profile immediately below the A horizon, containing deposits of leached material

In the planetarium, a meridian line with a scale in degrees can be projected on the dome. Event Horizon & Schwarzschild Radius.

The ‘event horizon’ is the boundary defining the region of space around a black hole from which nothing (not even light) can escape.In other words, the escape velocity for an object within the event horizon exceeds the speed of light.The name arises since it is impossible to observe any event taking place inside it – it is a horizon beyond which we cannot see.

noun. That is, light that was emitted when the Universe was born at a point on that horizon, reaches us today. 2. countable noun. And when there's a lot of haze or your target is close to the horizon, atmospheric extinction is a major problem. An imaginary line in the sky, it is the half-circle that runs from the horizon in the south up through the zenith and back down to the horizon in the north.

astronomy.

The essential guide to astronomy Even when the air is perfectly clear, a significant fraction of starlight is lost in the atmosphere. The horizontal branch (HB) is a stage of stellar evolution that immediately follows the red giantbranch in stars whose masses are similar to the Sun's. …

1. singular noun. Horizon, in astronomy, boundary where the sky seems to meet the ground or sea. In the distance, the dot of a boat appeared on the horizon. horizon definition in English dictionary, horizon meaning, synonyms, see also 'A horizon',on the horizon',artificial horizon',celestial horizon'.

The event horizon of a black hole marks the dark region in space where the escape velocity is higher than the speed of light.

horizon - WordReference English dictionary, questions, discussion and forums. noun. Enrich your vocabulary with the English Definition dictionary Nothing can escape it, both photons and matter is inevitably pulled into the singularity. The horizon is the line in the far distance where the sky seems to meet the land or the sea. Also called: sensible horizon the circular intersection with the celestial sphere of the …