New Horizons imagery reveals small, frozen lake on Pluto

NASA's New Horizons spacecraft spied several features on Pluto that offer evidence of a time millions or billions of years ago when – thanks to much higher pressure in Pluto's atmosphere and warmer conditions on the surface ...

Researcher shows that black holes do not exist

Black holes have long captured the public imagination and been the subject of popular culture, from Star Trek to Hollywood. They are the ultimate unknown – the blackest and most dense objects in the universe that do not ...

Five-dimensional black hole could 'break' general relativity

Researchers have shown how a bizarrely shaped black hole could cause Einstein's general theory of relativity, a foundation of modern physics, to break down. However, such an object could only exist in a universe with five ...

Research team discovers path to razor-sharp black hole images

Last April, the Event Horizon Telescope (EHT) sparked international excitement when it unveiled the first image of a black hole. Today, a team of researchers have published new calculations that predict a striking and intricate ...

Astronomers deliver first photo of black hole

Astronomers on Wednesday unveiled the first photo of a black hole, one of the star-devouring monsters scattered throughout the Universe and obscured by impenetrable shields of gravity.

What are white holes?

Black holes are created when stars die catastrophically in a supernova. So what in the universe is a white hole?

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Horizon

The horizon (or skyline) is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting intersection of earth and sky is called the visible horizon. When looking at a sea from a shore, the part of the sea closest to the horizon is called the offing. The word horizon derives from the Greek "ὁρίζων κύκλος" (horizōn kyklos), "separating circle", from the verb "ὁρίζω" (horizō), "to divide, to separate", and that from "ὅρος" (oros), "boundary, landmark".

This text uses material from Wikipedia, licensed under CC BY-SA