[单项选择]

The explosion of a star is an awesome event. The most violent of these cataclysms, which produce supernovae, probably destroys a star completely. Within our galaxy of roughly 100 billion stars the last supernova was observed in 1604. Much smaller explosions, however, occur quite frequently, giving rise to what astronomers call novae and dwarf novae. On the order of 25 novae occur in our galaxy every year, but only two or three are near enough to be observed. About 100 dwarf novae are known altogether. If the exploding star is in a nearby part of the galaxy, it may create a "new star" that was not previously visible to the naked eye. The last new star of this sort that could be observed clearly from the Northern Hemisphere appeared in 1946. In these smaller explosions the star loses only a minute fraction of its mass and survives to explode again. Astro A. occurs about 25 times a year B. last occurred in 1946 C. results in a new star D. last was seen in 1604 查看答案 更多"The explosion of a star is an aweso"的相关试题: [单项选择] The explosion of a star is an awesome event. The most violent of these cataclysms, which produce supernovae, probably destroys a star completely. Within our galaxy of roughly 100 billion stars the last supernova was observed in 1604. Much smaller explosions, however, occur quite frequently, giving rise to what astronomers call novae and dwarf novae. On the order of 25 novae occur in our galaxy every year, but only two or three are near enough to be observed. About 100 dwarf novae are known altogether. If the exploding star is in a nearby part of the galaxy, it may create a "new star" that was not previously visible to the naked eye. The last new star of this sort that could be observed clearly from the Northern Hemisphere appeared in 1946. In these smaller explosions the star loses only a minute fraction of its mass and survives to explode again. Astro A. Cataclysmic Variables B. Miracles in the Skies C. Exploding Stars D. New Stars 查看答案 [填空题]explosion 查看答案 [单项选择]Where did the explosion take place A. At a subway station. B. In a crowded street. C. In a market. D. In a tourism center. 查看答案 [单项选择]With the population explosion, scientists will have to（）new methods of increasing the world’s food supply. A. come up with B. carry out C. lead to D. stick to 查看答案 [判断题] The explosion took place in the northwestern Baghdad, killing at least 7 people. 查看答案 [填空题]An explosion had thrown radioman Harley Olson out of bed. He worked wildly, trying to (36) an SOS. But the power was gone. Harley ran on deck. The crew was (37) into lifeboats. There was no room for him. He had no choice but to jump into the black water and start to swim. Suddenly, in the darkness, his fingers hit something hard. It was a life raft. Climbing (38) , Harley called out again and again. But no one answered. Soon his first feeling of (39) . left him. In one way he was lucky. The raft had enough food and water for 15 men for several weeks. At daybreak, Harley saw some little boxes (40) by. He fished one out of the sea. Chewing gum. Quickly, he (41) in 20 small cartons. In the aftemoon, Harley (42) another raft he tied it to his own. Later, a third raft bobbed up. And then a mattress floated by him in the wreckage. Harley could hardly believe his eyes. Here was the start of a bed room. He tugged 查看答案 [简答题]Like the population explosion, the scientific and technological revolution began to pick up speed slowly during the eighteenth century. And this ongoing revolution has also suddenly accelerated exponentially. For example, it is now an axiom in many fields of science that more new and important discoveries have taken place in the last ten years than in the entire previous history of science. While no single discovery has had the kind of effect on our relationship to the earth that nuclear weapons have had on our relationship to warfare, it is nevertheless true that taken together, they have completely transformed our cumulative ability to exploit the earth for sustenance—making the consequences of unrestrained exploitation every bit as unthinkable as the consequences of unrestrained nuclear war. 查看答案 我来回答: 提交 最新试题 ●    [单选题]动车组在兰州西站出入兰州西动车所按（ ）办理 ●    [多选题]可以作为测定纳税能力大小的指标有( )。 ●    2011年全国农民工总量达到25278万人，比上年增加1055万人。其中，外出农民工15863万人， ●    [多选题]持通勤乘车证可以乘坐（ ）。 ●    未经化学处理的海鸟粪(每包毛重10kg) ●    关于调解书及其效力，下列说法正确的是( )。 网站地图 我要搜题网  版权所有  ©2023  湘ICP备18016427号   购买搜题卡查看答案 [会员特权] 开通VIP， 查看 全部题目答案 [会员特权] 享免全部广告特权 推荐91天 ¥36.8 ￥80元 31天 ¥20.8 ￥40元 365天 ¥88.8 ￥188元 请选择支付方式 微信支付 支付宝支付 点击支付即表示同意并接受了《购买须知》 立即支付 系统将自动为您注册账号 已有账号登录 找回账号密码 请使用微信扫码支付 订单号： 请不要关闭本页面，支付完成后请点击【支付完成】按钮 支付完成 取消支付 恭喜您，购买搜题卡成功 系统为您生成的账号密码如下： 账号 密码 重要提示：请拍照或截图保存账号密码！ 我要搜题网官网：https://www.woyaosouti.com 我已记住账号密码