Related topics: nasa

Dawn reveals recent changes in Ceres' surface

Observations of Ceres have detected recent variations in its surface, revealing that the only dwarf planet in the inner solar system is a dynamic body that continues to evolve and change.

Ceres' temporary atmosphere linked to solar activity

Scientists have long thought that Ceres may have a very weak, transient atmosphere, but mysteries lingered about its origin and why it's not always present. Now, researchers suggest that this temporary atmosphere appears ...

Where is the ice on Ceres?

At first glance, Ceres, the largest body in the main asteroid belt, may not look icy. Images from NASA's Dawn spacecraft have revealed a dark, heavily cratered world whose brightest area is made of highly reflective salts—not ...

Ceres: The tiny world where volcanoes erupt ice

Ahuna Mons is a volcano that rises 13,000 feet high and spreads 11 miles wide at its base. This would be impressive for a volcano on Earth. But Ahuna Mons stands on Ceres, a dwarf planet less than 600 miles wide that orbits ...

Dawn spacecraft begins approach to dwarf planet Ceres

(Phys.org)—NASA's Dawn spacecraft has entered an approach phase in which it will continue to close in on Ceres, a Texas-sized dwarf planet never before visited by a spacecraft. Dawn launched in 2007 and is scheduled to ...

Telescope spies water plumes on dwarf planet Ceres

(Phys.org) —Scientists using the Herschel space observatory have made the first definitive detection of water vapor on the largest and roundest object in the asteroid belt, Ceres.

New type of 'space weathering' observed on asteroid Vesta

The surface of the giant asteroid Vesta is weathering in a way that appears to be completely different from any other asteroid yet visited, according to new data recorded by NASA's Dawn spacecraft. This new type of space ...

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Dawn

Dawn is the time that marks the beginning of the twilight before sunrise. It is recognized by the presence of weak sunlight, while the sun itself is still below the horizon. Dawn should not be confused with sunrise, which is the moment when the leading edge of the sun itself appears above the horizon.

The duration of the twilight period between dawn and sunrise varies greatly depending on the observer's latitude, from a few minutes in equatorial regions to many hours in polar regions. Dawn may easily be determined by observing a thread. When the color of a thread can be determined, changing from black to the thread's distinctive color, the 'crack of dawn' has occurred. This same measure of ambient light can be used to determine, conversely, the instant of dusk.

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