When, when moving around the Earth, the Moon falls into the cone of the earth’s shadow, which is cast by the globe illuminated by the Sun, a total lunar eclipse occurs. If only a part of the Moon plunges into the shadow of the Earth, then a partial eclipse occurs. A total lunar eclipse can last about 1.5 to 2 hours. It can be observed from all over the night hemisphere of the Earth, where the moon is above the horizon at the time of the eclipse. Therefore, in any area, full lunar eclipses can be observed much more often than solar ones.
During a total lunar eclipse of the moon, the lunar disk remains visible, but it usually acquires a dark red hue. This phenomenon is explained by the refraction of sunlight in the earth’s atmosphere. Passing through the earth’s atmosphere, the sun’s rays are scattered and refracted. Moreover, mainly short-wave radiation is Continue reading
White dwarfs are one of the most fascinating topics in the history of astronomy: celestial bodies were discovered for the first time, possessing properties that are very far from those with which we deal in terrestrial conditions. And, in all likelihood, the resolution of the riddle of white dwarfs laid the foundation for studies of the mysterious nature of matter hidden somewhere in different corners of the Universe.
There are many white dwarfs in the universe. At one time, they were considered rare, but a careful study of the photographic plates obtained at Mount Palomar Observatory (USA) showed that their number exceeds 1500. It was possible to estimate the spatial density of white dwarfs: it turns out that in a sphere with a radius of 30 light-years there Continue reading
Scientists strongly believe that black holes really exist. Albert Einstein’s general theory of relativity predicted the existence of such objects back in 1917, and over the past decades, astronomers have found plenty of evidence of their presence in many areas of outer space.
More than 5 objects are known, which probably include black holes. However, there is only indirect evidence, but there is no conclusive evidence. The most likely candidate for black holes is the X-ray source Cygnus X-1, discovered in the early 1970s in X-binary systems. The mass of the source in this system, which can be estimated from the observed speed of the optical star in its orbit and Kepler’s laws, exceeds the limiting mass for a neutron star. The Chandra X-ray Observatory found in several galaxies with a high rate Continue reading