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The Sky at Night Phần 7

Đường kính đầy đủ là 95 năm ánh sáng, và gần trung tâm các ngôi sao quá gần nhau mà va chạm đôi khi phải xảy ra. Trong tháng 5 năm 1861, một nova bùng lên trong cluster và một thời gian ngắn outshone tất cả các thành viên cluster khác kết hợp, nó được đưa ra một chỉ - T-Scorpii - nhưng chưa bao giờ xuất hiện trở lại. Nghe Đọc ngữ âm Xếp hạng bản dịch | 98 24 Scorpion in the Sky and contains several hundred thousand stars. The full diameter is 95 light-years and near the centre the individual stars are so close together that collisions must sometimes occur. In May 1861 a nova flared up in the cluster and briefly outshone all the other cluster members combined it was given a designation - T-Scorpii - but has never reappeared. It was probably an ordinary nova a one-off but M80 is worth monitoring. Adjoining Scorpius are the beautiful clouds of the star Rho Ophiuchi and the whole region is exceptionally rich. So when the sky is clear go and seek out the Scorpion with its red leader its chain of bright stars and its wonderful star fields. There is no other constellation quite like it. Chapter 25 The August Perseids Perseids 2006 Credit Pete Lawrence The Perseids provide the most reliable of all the annual meteor showers. Conditions in 2007 were expected to be good so we planned a meteor watch at my observatory. It turned out to be a distinct success. Meteors can be seen on almost any clear night and there can be few people who have not been impressed with shooting stars flashing across the sky and vanishing in a second or two. Yet not everybody knows what they are and only during the past couple of centuries have we been able to learn much about them. They are phenomena of the upper atmosphere and each streak indicates the last moments of a tiny object generally no larger than a grain of sand dashing into the upper air from outer P Moore The Sky at Night DOI 10.1007 978-1-4419-6409-0_25 Springer Science Business Media LLC 2010 99 100 25 The August Perseids space and burning away by friction against the atmospheric particles. It enters the air at a speed of anything up to 45 miles per second and is destroyed by the time it has penetrated to about 40 miles above sea level ending its journey in the form of ultrafine dust. Meteors are cometary debris. A comet has a nucleus made up of ice and solid particles its mass is .