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Andromeda Galaxy
TThe Andromeda Galaxy (also known as Messier 31, M31, or NGC 224; older texts often called it the Andromeda Nebula) is a spiral galaxy approximately 2.5 million light-years away in the constellation ... > more -
Extraterrestrial life
Extraterrestrial life is life that may exist and originate outside the planet Earth, the only place in the universe currently known by humans to support life. Its existence is currently purely ... > more -
Transit of Venus
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against (and hence obscuring a small portion of) the solar disk. During ... > more -
Solar eclipse
A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partially obscuring Earth's view of the Sun. This configuration can only occur during a New Moon, when the ... > more -
Space exploration
Space exploration is the physical exploration of outer space, both by human spaceflights and by robotic spacecraft. While the observation of objects in space—known as astronomy—pre-dates ... > more -
Dark matter
In astrophysics and cosmology, dark matter is hypothetical matter of unknown composition that does not emit or reflect enough electromagnetic radiation to be observed directly, but whose presence can ... > more
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