04 May 2011
NASA recently announced that its Dawn spacecraft has started to approach asteroid Vesta, for an orbital encounter with Vesta on 16 July. (An asteroid is a small rocky object in orbit around the Sun.) Vesta (530 km across) is small by planetary standards, but it is one of the largest known asteroids. It orbits the Sun between Mars and Jupiter, in a zone populated by millions of asteroids, termed the asteroid belt. Astronomers regard Vesta a protoplanet, a cosmic object that almost formed into a planet.
01 May 2011
NASA recently published a beautiful image, showing sunset, as observed from Earth orbit. The image was taken by an astronaut, onboard the International Space Station (ISS), orbiting about 350 km above Earth’s surface. The ISS, Earth’s largest artificial satellite, is 109 m across, and weighs over 400,000 kg. It serves as an orbital manned observatory, from which astronauts can monitor our dynamic planet, and explore the entire cosmos.
28 April 2011
NASA’s Hubble Space Telescope (HST) was launched into space on 24 April 1990. It is a sophisticated observatory, exploring the universe from an Earth orbit. It has acquired hundreds of thousands of images of numerous celestial objects, and yielded startling discoveries that revolutionized modern astronomy.
24 April 2011
NASA recently published a wonderful image of Enceladus, Saturn’s icy, geologically-active moon. The image was acquired by the Saturn-orbiting Cassini spacecraft. Enceladus (504 km across), shining in the crescent phase, is characterized by a rare type of volcanic activity, known as ice volcanoes, or cryovolcanoes. Ice volcanoes spew icy material and very cold vapors, rather than lavas! In the image, plumes of water ice emanate from fissures located in Enceladus’ south polar region.
20 April 2011
NASA recently published a wonderful satellite image of Wadi Rum, a splendid valley, located in southwestern Jordan, near Aqaba. Wadi Rum, declared a protected area in 1998, is the largest valley in Jordan, and features bizarre landscape. Mountains of granite and sandstone rise next to valleys filled with red sand. Some of the mountains reach a height of about 1,700 meters above sea level, and many have very steep slopes. Intriguingly, Wadi Rum is also known as the “Valley of the Moon,” and it has served as the film set for a movie about the planet Mars.
17 April 2011
NASA recently published a stunning image of Mimas, a small bizarre moon of Saturn, the ringed giant planet. The image was acquired by the Saturn-orbiting Cassini spacecraft. Saturn’s graceful rings are visible in the background as dark diagonal lines, due to the orientation of Cassini. Curiously, the shape of Mimas (396 km across) is not round, but, remarkably, its right limb is partly flat! This is due to the presence of a huge deep impact crater, known as the Herschel Crater, which was visible edge-on, when the image was obtained.
04 April 2011
On 17 March 2011, NASA’s Terra satellite obtained an exquisite image of the eastern Mediterranean Sea, showing snow, covering Lebanon’s two magnificent mountain ranges, respectively known as Lebanon Mountains (Jebel Liban) and Anti-Lebanon Mountains (Jabal ash Sharqi). (Jebel or jabal mean “mountain” in Arabic.)
31 March 2011
On 26 March 2011, a massive dust storm lashed the Arabian Peninsula. It stretched more than 500 km across the peninsula, covering parts of Saudi Arabia, Yemen, Oman, and the United Arab Emirates.
29 March 2011
NASA recently published an exquisite image of a beautiful nearby galaxy, known technically as NGC 2841. The image was obtained from Earth orbit, by the Hubble Space Telescope (HST). It is a close-up of the central region of the spiral galaxy, located 46 million light years away.
25 March 2011
NASA recently published an amazing image of a small icy moon of Saturn, known as Helene. The image was acquired by the Saturn-orbiting Cassini spacecraft, on 31 January 2011, when Cassini flew by Helene (33 km across), at a distance of approximately 31,000 km.