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  2. Horizon - Wikipedia

    en.wikipedia.org/wiki/Horizon

    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 ...

  3. Cosmological horizon - Wikipedia

    en.wikipedia.org/wiki/Cosmological_horizon

    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 ...

  4. Observable universe - Wikipedia

    en.wikipedia.org/wiki/Observable_universe

    The observable universe is a spherical region of the universe consisting of all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion.

  5. Celestial navigation - Wikipedia

    en.wikipedia.org/wiki/Celestial_navigation

    Celestial navigation by taking sights of the Sun and the horizon whilst on the surface of the Earth is commonly used, providing various methods of determining position, one of which is the popular and simple method called "noon sight navigation"—being a single observation of the exact altitude of the Sun and the exact time of that altitude ...

  6. Rare comet may be visible to the naked eye. Here's ... - AOL

    www.aol.com/rare-comet-may-visible-naked...

    The comet will become the largest visible object in our solar system (after the moon, obviously). On Saturday, the comet was about 6 degrees above the west-southwest horizon about 45 minutes after ...

  7. Long distance observations - Wikipedia

    en.wikipedia.org/wiki/Long_distance_observations

    The yearly changes in the twilight azimuth determine the contrast enhancement between a certain part of our horizon and the sky that is still illuminated by the Sun. Considering the northern hemisphere after sunset, the wintertime will be supportive for objects visible at the south-western and western horizon, whereas, around the summer ...

  8. Moonrise and moonset - Wikipedia

    en.wikipedia.org/wiki/Moonrise_and_moonset

    The Moon appears to be more yellowish near the horizon. This is for the same reason the Sun and/or sky appears to be orangey-red at sunrise/sunset. When the Moon appears near the horizon, the light coming from it has to pass through more layers of atmosphere. This scatters the blue away, and leaves yellow, orange, and red. [10]

  9. Circumpolar star - Wikipedia

    en.wikipedia.org/wiki/Circumpolar_star

    Circumpolar star trails in a long-exposure photo of several hours. The stars near the celestial pole leave shorter trails with the long exposure. A circumpolar star is a star that, as viewed from a given latitude on Earth, never sets below the horizon due to its apparent proximity to one of the celestial poles.