Search results
Results from the WOW.Com Content Network
View of the ocean with two ships: one in the foreground and one to the left of it on the horizon. Historically, the distance to the visible horizon has long been vital to survival and successful navigation, especially at sea, because it determined an observer's maximum range of vision and thus of communication, with all the obvious consequences for safety and the transmission of information ...
In astronomy, coordinate systems are used for specifying positions of celestial objects (satellites, planets, stars, galaxies, etc.) relative to a given reference frame, based on physical reference points available to a situated observer (e.g. the true horizon and north to an observer on Earth's surface). [1]
The particle horizon, also called the cosmological horizon, the comoving horizon, or the cosmic light horizon, is the maximum distance from which light from particles could have traveled to the observer in the age of the universe. It represents the boundary between the observable and the unobservable regions of the universe, so its distance at ...
In standard cosmology, comoving distance and proper distance (or physical distance) are two closely related distance measures used by cosmologists to define distances between objects. Comoving distance factors out the expansion of the universe , giving a distance that does not change in time except due to local factors, such as the motion of a ...
The pseudorange (from pseudo-and range) is the pseudo distance between a satellite and a navigation satellite receiver ... more if satellites are all near the horizon ...
where F g is the gravitational force acting between two objects, M E is the mass of the Earth, 5.9736 × 10 24 kg, m s is the mass of the satellite, r is the distance between the centers of their masses, and G is the gravitational constant, (6.674 28 ± 0.000 67) × 10 −11 m 3 kg −1 s −2.
The Sun is said to be at the nadir at a location when it is at the zenith at the location's antipode and is 90° below the horizon. Nadir also refers to the downward-facing viewing geometry of an orbiting satellite, [2] such as is employed during remote sensing of the atmosphere, as well as when an astronaut faces the Earth while performing a ...
A typical example of long-distance observation. The Tatra Mountains as seen from the Łysa Góra, in southeast Poland, at a distance of about 200 km (120 mi).. Long-distance observation is any visual observation, for sightseeing or photography, that targets all the objects, visible from the extremal distance with the possibility to see them closely.