Search results
Results From The WOW.Com Content Network
Systematically observing the sunrise, people discovered that it occurs between two extreme locations at the horizon and eventually noted the midpoint between the two. Later it was realized that this happens on a day when the duration of the day and the night are practically equal and the word "equinox" comes from Latin aequus, meaning "equal", and nox, meaning "night".
A contemporary German popular astronomical book also noticed that light-year is an odd name. [25] In 1868 an English journal labelled the light-year as a unit used by the Germans. [26] Eddington called the light-year an inconvenient and irrelevant unit, which had sometimes crept from popular use into technical investigations. [27]
Dawn begins with the first sight of lightness in the morning, and continues until the Sun breaks the horizon. The morning twilight is divided in three phases, which are determined by the angular distance of the centre of the Sun (degrees below the horizon) in the morning. These are astronomical, nautical and civil twilight.
Multiple other interstellar clouds exist in the region within 300 light-years of the Sun, known as the Local Bubble. [262] The latter feature is an hourglass-shaped cavity or superbubble in the interstellar medium roughly 300 light-years across. The bubble is suffused with high-temperature plasma, suggesting that it may be the product of ...
The first images from space were taken on the sub-orbital V-2 rocket flight launched by the US on October 24, 1946. Satellite image of Fortaleza.. Satellite images (also Earth observation imagery, spaceborne photography, or simply satellite photo) are images of Earth collected by imaging satellites operated by governments and businesses around the world.
This is the first time that these galaxies have been imaged in such detail, and the first time scientists were able to confirm that they produced enough radiation to end the light-less tyranny of ...
The Milky Way is a barred spiral galaxy with a D 25 isophotal diameter estimated at 26.8 ± 1.1 kiloparsecs (87,400 ± 3,600 light-years), [10] but only about 1,000 light-years thick at the spiral arms (more at the bulge).
In more recent developments, geography has become a distinct academic discipline. 'Geography' derives from the Greek γεωγραφία – geographia, [1] literally "Earth-writing", that is, description or writing about the Earth. The first person to use the word geography was Eratosthenes (276–194 BC).