ebook
Le saviez vous ?
Lisez votre e-book sur ordinateur, tablette et mobile grâce aux applications :
Coups de cœur Cultura
Tous les passeurs de culture peuvent partager leurs découvertes !
Tu as aimé ce produit ? Partage dès maintenant ton coup de coeur :
A concise history of Venus from the earliest pre-telescopic observations, to the often fraught efforts of 18th century astronomers to observe transits, to the robotic probes of the Space Age. This 12,000 word eBook short read describes how our views of Venus have changed over the last two centuries - from a tropical or possibly ocean world to a hellish place with surface temperatures higher than the melting point of lead. Despite these hostile conditions, the possibility of life cannot be ruled out.
Venus is can be seen in daytime and is bright enough to cast shadows. Only the Moon exceeds its night time brightness, but Galileo's suggestion that it also exhibited phases landed him in trouble with the Inquisition. Nevertheless, the phases can be seen by keen-sighted naked-eye observers, and were probably known to the ancient Babylonians.
The thick clouds that permanently shroud Venus masked a peculiarity that remained hidden until the first crude radar mapping was attempted in the 1960s. Venus spins backwards, unlike any other planet in the Solar System. Furthermore, the rotation period of Venus is longer than its orbital period: the Venusian 'day' is longer than its 'year'. Another peculiarity is that Venus is by far the largest Solar System body to lack a moon. Mercury is also moonless, but it barely the size of a large moon itself. By contrast, Venus is comparable in size to Earth.
