зрак

The angular dimension of the cone of light from reflectorized lamps (such as R and PAR types) encompassing the central part of the beam out to the angle where the intensity is 50% ...

метеорит

Astronomy; Planetary science

A natural solid object (metallic or stony/silicate) larger than 10 µm (microns) that has traveled through space, by natural means from the celestial body on which it formed, and ...

хелиум

Astronomy; Planetary science

An element with atomic number 2; symbol: He. It is the second most common element in the Sun and outer planets, but rare on the rocky planets.

кратер

Astronomy; Planetary science

A hole or depression. Most are roughly circular or oval in outline. On Earth most natural craters are of volcanic origin. On the Moon most are of impact origin.

магматски океан

Astronomy; Planetary science

Term used to describe the layer of magma, hundreds of kilometers thick; thought to have covered the Moon 4. 5 billion years ago. The timing, duration, cooling rates, convection, ...

негравитациони сили

Astronomy; Planetary science

Forces that alter the path of a comet, which are not caused by gravitational interaction with the Sun and planets. Typically this refers to uneven outgassing from vents on the ...