Mars IV 火星 IV (27/8/2003)
火星，你今日看左未？六萬年最接近地球的日子來了，哈勃太空望遠鏡也一起參加今次的盛會，圖中的是其中一張拍回來的火星，明天再貼另一張。因為是六萬年一次的盛事，所以英文解說很長，介紹了很多火星的特徵，有意請看下面。

Caption:: NASA's Hubble Space Telescope snapped this portrait of Mars within minutes of the planet's closest approach to Earth in nearly 60,000 years. This image was made from a series of exposures taken between 5:35 a.m. and 6:20 a.m. EDT Aug. 27 with Hubble's Wide Field and Planetary Camera 2. In this picture, the red planet is 34,647,420 miles (55,757,930 km) from Earth.

This sharp, natural-color view of Mars reveals several prominent Martian features, including the largest volcano in the solar system, Olympus Mons; a system of canyons called Valles Marineris; an immense dark marking called Solis Lacus; and the southern polar ice cap.

Olympus Mons [the oval-shaped feature just above center] is the size of Arizona and three times higher than Mount Everest. The dormant volcano resides in a region called the Tharsis Bulge, which is about the size of the U.S. and home to several extinct volcanoes. The three Tharsis Montes volcanoes are lined up just below Olympus Mons. Faint clouds are hovering over Arsia Mons, the southernmost of these volcanoes.

The long, dark scar, below and to the right of the Tharsis Bulge, is Valles Marineris, a 2,480-mile (4,000-km) system of canyons. Just below Valles Marineris is Solis Lacus, also known as the "Eye of Mars." The dark features to the left of Solis Lacus are the southern highlands, called Terra Sirenum, a region riddled with impact craters. The diameters of these craters range from 31 to 124 miles (50 to 200 km).

The image was taken during the middle of summer in the Southern Hemisphere. During this season the Sun shines continuously on the southern polar ice cap, causing the cap to shrink in size [bottom of image]. The orange streaks are indications of dust activity over the polar cap. The cap is made of carbon dioxide ice and water ice, but only carbon dioxide ice is seen in this image. The water ice is buried beneath the carbon dioxide ice. It will only be revealed when the cap recedes even more over the next two months. By contrast, the Northern Hemisphere is in the midst of winter. A wave of clouds covers the northern polar ice cap and the surrounding region [top of image].

This view of Mars reveals a striking contrast between the Northern and Southern hemispheres. The Northern Hemisphere is home to volcanoes that may have been active about 1 billion years ago. These volcanoes resurfaced the north's landscape, perhaps filling in many impact craters. The Southern Hemisphere is pockmarked with ancient impact craters, which appear dark because many are filled with coarser sand-sized particles.

Mars and Earth make a "close encounter" about every 26 months. These periodic encounters are due to the differences in the two planets' orbits. Earth goes around the Sun twice as fast as Mars, lapping the red planet about every two years. Both planets have elliptical orbits, so their close encounters are not always at the same distance. In its close encounter with Earth in 2001, for example, Mars was about 9 million miles farther away. Because Mars was much closer during this year's rendezvous, the planet will appeared 23 percent larger in the sky. Mars will not be this close again until 2287.

This photograph is a color composite generated from observations taken with blue, green, and red filters. A total of 11 filters, spanning a wide wavelength range—-from blue to near infrared—-were used during the observations. The shorter wavelengths show clouds and other atmospheric changes. The longer wavelengths, including the near infrared, reveal Martian surface features.

Credit:: NASA, J. Bell (Cornell U.) and M. Wolff (SSI)

Milky Way II 銀河 II (26/8/2003)
我們的銀河很長，所以也分為很多段，現在圖中的是銀河的北段。你認得出圖中的星座嗎？(有天鵝座、仙后座等)，不認也得也不要緊，你看到銀河就已經足夠了。另外，在銀河上還可以看到些紅色的星雲呢。

Caption:: Many of the stars in our home Milky Way Galaxy appear together as a dim band on the sky that passes nearly over the Earth's north and south poles. Pictured above is the part of our Galaxy that passes closest over the north pole. The diffuse white Galaxy glow is created by billions of stars, while red patches are large emission nebulas, usually marking areas where bright stars have recently formed. In the north, all of the lights visible at night and all lights that created this image were emitted within the past few thousand years from within the Milky Way Galaxy -- except one. On the upper right is a small faint patch designated M31, the Andromeda Galaxy. M31 is a spiral galaxy similar to our Milky Way but so distant it emits the oldest light distinguishable by the unaided eye -- light that takes over two million years to reach us.

Credit:: Jerry Lodriguss

SIRTF Launch 太空紅外線望遠鏡升空 (25/8/2003)
經過多次的押後，美國第四台，也是系列中最後一台的大型太空望遠鏡 － 太空紅外線望遠鏡，成功發射升空了，時間是香港時間13:35:39。之前也介紹過它，這是一台專間負責觀測紅外線波段的太空天文望遠鏡，宇宙中有大部份的東西都躲藏在不透光的塵埃後面，而紅外線卻可以穿過這些塵埃的阻檔，所以這台太空紅外線望遠鏡可以大派用場。圖中的是發射的Delta二型火箭。

Caption:: After a couple of delays, the forth and the last Great Observatory - Space Infrared Telescope Facility (SIRTF) launch successfully at 13:35:39 HKT. SIRTF, previously introduced, is aim at the infrared window observation. As our universe got a lot of dust and hide many matter, we need to use the power of infrared wavelength, to see the stuff behind the dust. The picture featured here is the Delta II rocket which launched SIRTF.

Credit:: NASA

Hurricane 颱風 (24/8/2003)
碰上今天打風，所以貼上一張颱風的相來。要這麼的影一張颱風相，一定要到太空去，太空穿梭機上的太空人就成為了這一類相的攝影師了。圖中的颱風是於85年時影的，所以你都可能見過這張相甚至這張相已經成為一張經典的颱風相了，原因是它的形狀很清析，而且風眼的位置很明顯，但原來大部份的颱風都不是那麼的正常的，有機會再給大家看。

Caption:: Astronauts aboard Space Shuttle Discovery shot this view of Hurricane Elena from their vantage point in space September 2, 1985, the same day the storm hit the Mississippi Gulf Coast.

Credit:: NASA

Olympus Mons 奧林匹斯山 (23/8/2003)
這是一張火星全球化的地圖，火星被拉平了，這樣可以更清楚看到火星各種不同的地形。南北兩面白色的是火星的極冠，另外你也可以很容易找到一些火山，它們很明顯的突了出來，還有在中間位置的峽谷－水手谷，都非常明顯。經常都提及奧林匹斯山，究竟這是一個怎樣的山呢？答案是它是火星，不，全太陽系上最高的山。它要地球的珠穆朗瑪峰還要高出三倍。不單只是高，奧林匹斯山的底部也有整個夏威夷群島那麼大，真是一座異常宏偉的山，或者正確點說，是火山才對，只不過你看不到它有任何的火山活動而己。這山的高度，可以穿透火星的大氣，獨自站立在火星的大氣上，從側面角度看火星，更可以看到火星表面突起了一起東西，正就是這全太陽系最高的火山。

Caption:: Color mosaic of Olympus Mons volcano on Marsfrom the Viking 1 Orbiter. The mosaic was created using images fromorbit 735 taken 22 June 1978. Olympus Mons is about 600 km in diameter and thesummit caldera is 24 km above the surrounding plains. The complexaureole terrain is visible at the top of the frame. North is up.

Credit:: NASA / JPL